Category: Updates

IPFS-tiny: attempting to take IPFS to Space

The Libre Space Foundation (LSF) has been working on developing IPFS-tiny. A project aimed to bring the InterPlanetary File System (IPFS) to…other planets and Space.

The development of IPFS-tiny is funded by Protocol Labs.

IPFS-tiny is built in C++, and it is operating and file system agnostic. It is designed to work well on embedded systems and resource-limited devices, such as satellites and spacecraft.

IPFS in a nutshell

IPFS is “designed to preserve and grow humanity’s knowledge by making the web upgradeable, resilient, and more open.” This is a vision that we at LSF can identify with, especially when it comes to enhancing knowledge and supporting openness for the interests of all humanity.

The way IPFS goes about achieving that is by using a distributed architecture.

Contrary to traditional file systems that store data in a centralised location, the IPFS distributed network stores and accesses data peer-to-peer. The data is stored across multiple nodes in the network, and this allows for faster and more efficient access to files. As well as increased security and resiliency. Even though some nodes in the network may be unavailable, the data can still be accessed.

This approach bears many benefits. Because files live across the network, this enables the downloading of a file from multiple locations, and thus, it enhances decentralisation. Especially since these files are not managed by one organisation alone. This way, IPFS can be used in decentralised web applications, content distribution, and data archiving. It allows the versioning and caching of data, as well as the creation of permanent web links, and it can potentially transform how we think about and access data online.

IPFS: A closer look

IPFS and Content Addressing

Content addressing plays an integral part in IPFS. This is because files are not identified by their location but by what they comprise. In other words, they are identified by their content. The files added to IPFS are split into smaller chunks, cryptographically hashed, and given a unique fingerprint called a content identifier or CID. This CID acts as a permanent record of the file, as the specific file exists at that exact point in time.

When the time comes for other nodes to lookup for that file, they ask their peer nodes which one is storing the content referenced by the file’s CID. When they view or download the file, they cache a copy of it. This way, they become another provider of the content until their cache is cleared. When the original file is modified, its cryptographic hash becomes different, and it gets a new CID. This means that any file stored on IPFS can neither get tampered with nor censored. Any potential changes made to a file do not overwrite the original content. What is more, common chunks across files are reusable and, thus, help cut down on storage costs.

Thus, each CID request results in the correct file being delivered securely and efficiently and protecting against any malicious actors attempting to manipulate the system. The safety of this approach is facilitated by IPLD.

What is IPLD?

IPLD originally began as a part of IPFS, but over time, it has matured and developed to become a project on its own.  InterPlanetary Linked Data (IPLD) addresses content through hashes as a unified information space where the data is presented as a graph that can verify itself. The graphs are known as Merkle DAGs or Merkle Directed Acyclic Graphs (DAGs).

In Merkle DAGs, the data structure is illustrated as trees bearing nodes where each node has an Identifier. The nodes are self-descriptive, and every other sub-section of the file can describe itself as well. This provides a multitude of significant information, such as the type of file they are, the type of information they store, and their size too. Every time a tiny bit of information is changed, the graph realises that, and it updates itself with a new, precise self-description. Leading, thus, to compatibility backwards as well as forwards as the graphs are self-verifiable. In other words, the same rules and same graph construction will always have the same CID.

IPLD plays an integral part in IPFS. Its role expands, though and becomes even more significant when IPFS-tiny gets into the picture too.


IPFS and IPFS-tiny: Distinguishing between the two

As we have mentioned, IPFS-tiny is a project developed by LSF attempting to bring IPFS to space and other planets. In essence, IPFS-tiny is a smaller version of IPFS, designed to work well on devices with limited resources.

These devices, including micro and nanosatellites, can have limitations in their processing capabilities, as they often rely on microcontroller units (MCUs) for their main processing needs. They also face storage restrictions with flash storage that may result in wear-off issues. All these challenges restrict the use of IPFS with micro and nanosatellites. And this is why the need for IPFS-tiny has arisen.

This clearly points out that IPFS-tiny is different from IPFS. To connect IPFS-tiny to the main IPFS network, a bridge is required to allow for data to be shared between the two. This is where IPLD is helpful, making it possible for IPFS and IPFS-tiny to interact and work together safely and efficiently.

IPFS-tiny and Space!

By utilising the interoperability of IPLD, we can use IPFS-tiny to bring IPFS (and its benefits) to space. This can be achieved by using SatNOGS, a project run and maintained by LSF. SatNOGS is the largest open-source network of satellite ground stations, with more than 400 stations spread in 54 countries across the globe. Let us take a closer look at some scenarios on how this network can be utilised.

Scenario 1: The SatNOGS Network of ground stations can serve as a bridge, allowing satellites to transmit information blocks using IPFS-tiny. However, if one ground station attempts to alter the data, it will be unsuccessful. As the IPLD ensures that even small changes result in a unique file, it is difficult for malicious actors to manipulate the system.

Scenario 2: The network of ground stations could be further enhanced by incorporating additional satellites, creating a cross-satellite system where information could be shared and made readily available. This expands on Scenario 1 by including additional satellite participants in the network, increasing the overall accessibility and distribution of data.

Scenario 3: Another option would be to expand the network of satellites even further by incorporating IPFS into the setup. This would turn the satellites into dedicated storage units for the IPFS network, making it a true InterPlanetary File System with a space-based layer.

Potential Use cases

Micro and nanosatellites generating much data are increasingly used in missions for various applications. A stable operational state of the space segment must be guaranteed for the missions to be able to complete their goals successfully. Since these micro and nanosatellites operate in Low Earth Orbit (LEO), their communication window with the ground stations is highly limited. In this case, using IPFS could significantly benefit these LEO operations by enabling them to exchange data with IPFS-enabled ground stations as the satellites pass over them. As channel resources are essential, IPFS could significantly assist towards that by uploading or downloading only what is necessary or only those parts of a file that have changed.

This approach helps overcome challenges and reliably transmit information, and share and access data easily and efficiently. Turning the network into a Delay Tolerant Network that is designed in such a way as to operate effectively under extreme conditions, large distances, and challenging circumstances. As is often the case with space communications.

IPFS-tiny: Key implementation features

Let us now take a closer look at some of the key implementation features of IPFS-tiny:

  • Nanopb for Protobuf support. Nanopb encodes and decodes messages following the format of Protobuf, Google’s Protocol Buffers. This format comes with minimal requirements for RAM and code space as well as statically allocated memory, and it is, thus, suitable for use in microcontrollers.
  • ETLCPP/ETL. The ETL is an embedded template library that improves the features of the Standard Template Library (STL). The latter is not suitable for limited resource requirements. This is why in IPFS-tiny, STL-like C++ containers are used, with a static memory model that is a great fit for lower-resource embedded applications. Allowing, thus, for improved performance in limited-resource devices.
  • libcppunit-dev for testing and the CMake build system, which is open-source and versatile enough to support different open-source platforms for software development.

All the key implementation features are designed to be compatible with microcontrollers and ensure efficient, reliable, and accurate performance.

IPFS-tiny supported features

IPFS-tiny supports various features, including Multiformats, CID v0 and v1 support, IPLD dag-pb, and an expandable IPLD implementation. This has the ability to easily implement new coding schemes and support basic IPFS operations such as add(), del(), and get().

Next Steps

IPFS-tiny is a project that is under development, and finalising the implementation of the project is the goal. Once it is completed, it will be tested in orbit.  It could fly in space onboard a future QUBIK mission, with SIDLOC and on the SatNOGS-COMMS. Another part of this implementation would have to be to connect IPFS-tiny to IPFS with a bridge through the SatNOGS Network and consider the CCSDS File Delivery Protocol as part of this implementation.

Are we InterPlanetary yet?

The way IPFS is designed supports a vision for data sharing that overcomes boundaries and limitations, enabling a safer and more resilient internet. IPFS-tiny is a more simplified version of IPFS developed to fit the requirements of actual InterPlanetary data sharing. Adapted to the challenging conditions of satellite communications and space, IPFS-tiny is a tool under development that, when completed, will take IPFS to space, making it truly InterPlanetary. Stay tuned…

Libre Space Foundation participates in the REWIRE Research and Innovation Action on compositional security verification and assurance.

Libre Space Foundation participates in the REWIRE Research and Innovation Action, which officially started on October 1st, 2022. The project is funded by the European Commission under Horizon Europe Programme (Grant Agreement No. 101070627) and spans the period of October 2022 – September 2025.

REWIRE envisions a holistic framework for continuous security assessment of open-source and open-specification hardware and software for IoT devices. As well as the development of cybersecurity certification in accordance with the requirements and guidelines of the recent EU Cybersecurity Act. In particular, REWIRE proposes a scalable and multifunctional cybersecurity platform that will ensure security throughout the life of IoT devices. This will be achieved with continuous security auditing, trust computing and theorem proofs for defining a hardware-based microarchitecture for enhanced protection targeting open-hardware/software vulnerabilities.

REWIRE has invested in three carefully selected pilots (Automotive, Smart Cities, Smart Satellites), which can address the ambitious objectives of the project, i.e., a customizable TEE based on RISC-V and micro benchmarking for quick and automated assessment of h/w vulnerability. Thus, REWIRE aims to safeguard the entire workflow of secure processing; from the Deployment and Operation of a software-based System of Systems to their patch management when new exploits have been identified during run-time, by providing new trust management mechanisms towards the auditability and certification of SW/HW open-source specifications.

Libre Space Foundation (LSF) undertakes the demonstration and evaluation of the Smart Satellites Use Case of the REWIRE action. Specifically, Libre Space Foundation will work on specifying the requirements, design, set up and deployment of an indicative “flat-sat” engineering model of a complete satellite. This flat-sat model will be featuring a RISC-V-based Onboard Processor, a Commercial-Off-The-Shelf (COTS) Onboard Data Handling Unit, and an LSF, in-house developed COMMS Subsystem and Ground Segment simulator.

For more information and updates, you can connect with the project at the dedicated LinkedIn Page or on Twitter.

…And we are back in Space!

On the 1st of October 2022 and at 07:01 UTC, Libre Space Foundation’s QUBIK mission made it to space! Launched onboard Firefly Aerospace’s Alpha Flight 2, #ToTheBlack.

With this mission, Libre Space Foundation (LSF) returned to Space!

..and this is the story of the QUBIK mission. Picking up the thread of the narration from the very beginning, from assembling the satellites to them making it to space successfully.

This is the timeline of the events that narrate:

the transformation of arranged pieces

into flying PocketQubes


the assembling of scattered metal parts

into a ride in space

This is the story of how we went from scraps and pieces to space. ( in less than a year)

The QUBIK Mission: A Timeline 

  • In early October 2021, the LSF teams embarked on building the new set of QUBIK satellites, part of the QUBIK series of PocketQubes created by the Organisation. On October 13th, the solar panel boards for the new QUBIK satellites were under assembly. The teams were working at, at the LSF lab, in downtown Athens, Greece.

  • 19 October 2021: Production was ramping up, and the freshly-baked COMMS subsystems were ready to be used for the mission.

In November 2021, a number of streaming sessions were hosted on the LSF YouTube channel, broadcasting live the final steps of the satellites’ assembling process.

  • 10 November 2021, The Final Assembly of the QUBIK PocketQubes was streaming live:
  • 11 November 2021 was the time of the bake-out process:

As the year was drawing to an end, so did the process of finalising the building of the QUBIK Mission.

  • 20 December 2021: PICOBUS Reloaded, satellites’ integration.
    In late December, the integration of the satellites into the PICOBUS deployer was also streamed live from the LSF channel on YouTube. During the 3-hour live integration, five satellites were integrated into the PICOBUS deployer. The satellites were AMSAT-EA’s satellites GENESIS-G and GENESIS-J, FOSSA Systems’ FOSSASAT-1B and LSF’s QUBIK-3 and QUBIK-4.
PICOBUS PocketQube deployer

  • At the end of 2021, the PICOBUS was ready to be shipped to the US in a similar container.

With the shipping of the container to the US, the process of building the QUBIK mission was completed successfully. In the months leading to the launch, the teams were working on things regarding the mission. From collaborating with the Firefly team to optimising the reception and transmission of the satellite signals to vamping up the SatNOGS network of satellite ground stations.

To The Black

And so we fast forward to September 2022. The #ToTheBlack mission of Firefly Aerospace’s Alpha Flight 2 was originally scheduled to fly to space on September 11 2022. After being scrubbed twice in that month, the team at Firefly secured a new date for the beginning of October. And October it was!

  • On October 1st 2022, at 12:01 AM PDT-07:01 UTC, Firefly Aerospace’s Alpha Flight 2 experienced a nominal countdown and lift-off. Libre Space Foundation’s QUBIK mission was onboard.

The launch was streamed live from the Vandenberg Space Force Base in California, USA, and hosted on YouTube by Tim Dodd and the Everyday Astronaut.

Making it to space: Deployment and operations

The satellites integrated inside PICOBUS were set to be deployed at T+01:01:57. Shortly after, QUBIK-3 and QUBIK-4 were making their way through space. Just 30 seconds after the antenna deployment

QUBIK antenna deployment at the lab

, the QUBIK PocketQubes began transmitting their signal that was received using the SatNOGS network. The first signals were received by station “2623 – vk2pet ” in Western Australia.

Waterfall of the first QUBIK signal received

A few minutes later, more signals were received from the SatNOGS network, and these are the waterfalls illustrating the first decoded data of the received signals.

These decoded data came from two different stations. QUBIK-3 was received by station 2550 – USU GAS, the ground station of the Utah State University, and QUBIK-4 by station 2461 – N1ESK-Loudon.

As the data kept rolling in, the dashboard was created. It illustrated the data received by the network.

The two satellites were making their way through space for two days, and their re-entry marked the end of the mission. You can find more details about it here.

The scope of the mission

Comprised of a set of PocketQubes and a PocketQube deployer, the QUBIK mission was built using open-source hardware and software. This constitutes PICOBUS, the first-ever open-source PocketQube deployer. The two PocketQubes, QUBIK-3 and QUBIK-4 were to be short-lived and were tasked to perform a series of experiments to explore further the possibilities of satellite identification and tracking. This would be possible by using amateur radio frequencies and extensively testing a number of hypotheses. A list of the amateur-radio experiments and an extended description of the scope of the mission can be found here. The findings of these experiments were also to be used to enhance the knowledge and contribute towards the development of SIDLOC. This is another project under active development that LSF has been working on, and its goal is to explore the creation of a proposed standard for the Identification and Localization of satellites and spacecraft alike.

The Libre Space Manifesto

…outer space accessible to everyone

With every LSF’s QUBIK satellite that has flown to space, the Libre Space Manifesto has travelled with it. The Libre Space Manifesto is a set of Principles about Space that inspires and guides all LSF operations.

You can read the full version of the Manifesto here or find its Principles etched on the ballasts of the QUBIK series of satellites.

Similarly-etched ballasts travelled to space inside QUBIK-3 and QUBIK-4.

Want to join a special Treasure Hunt in space?

Back in October 2021, when we were assembling the QUBIK PocketQubes, there were about 8 Bytes of FREE space left in our telemetry beacon. And what did we do? We decided to orchestrate a Treasure Hunt with our satellites. Inside their telemetry, we have placed a clue for you to find and join the hunt in space.
If you find the clue hidden in the QUBIK mission, get in touch with us!

And do stay tuned for our next missions to locate the clues missing from the space hunt puzzle!


For us at Libre Space Foundation, the QUBIK mission was our return to space. And though short-lived, it still signifies a huge milestone for us to take great pride in. We made it to space for the second time, and we could not have done this without the opportunity offered to us by Firefly Aerospace, for which we are deeply grateful. We are also grateful to the entire LSF and SatNOGS community, paid and non-paid members and contributors who have toiled with us and dedicated their valuable time, expertise and effort to the mission.
Thank you, everyone, for working hard with devotion to help make …outer space accessible to everyone!


Image by Firefly Aerospace.

Cronos: A hybrid-fueled sounding rocket designed and manufactured by a University-student team

At Libre Space Foundation (LSF), we support open-source projects that enhance scientific research and promote knowledge. For the past two years, and true to our values, members of the LSF team have been overseeing the development of Cronos. A hybrid-fueled sounding rocket that is an inspiring and promising project engineered by a talented university-student team.

Project Cronos: A Closer Look

The team

Cronos is a hybrid-fueled sounding rocket. It is a student-researched and developed (SRAD) project designed and manufactured by White Noise and Libre Space Foundation (LSF). White Noise is an open-source aerospace engineering team comprised solely of university students. The team collaborates closely with Libre Space Foundation to develop the sounding rocket in an open and participatory manner. 

Engineered at, at LSF’s headquarters in Athens, Greece, the Cronos project is built to enhance knowledge. By enabling University students to hone their hard skills ( in development, electronics, avionics and mechanics) as well as their soft skills (in creating solid collaborations, communication strategies and organising the processes in a professional way).

The team initially embarked on building the project to participate in international student competitions, but these were postponed due to the pandemic. Cronos, thus, became a lesson in itself. An educational endeavour. The highly-focused and hard-working team devoted itself to exploring its capabilities and familiarising itself with the processes of following open development and open-source methodologies.

The sounding rocket

Cronos is designed to lift 4kg of deployable payload mass, housed right below the airframe’s nose cone. Its paraffin wax and nitrous oxide hybrid propulsion system can produce an estimated 3000 N of thrust for approximately 3s. The sounding rocket is estimated to reach Mach 0.88 and an apogee of 3km AGL. Note that it is designed to be safely recovered after the launch and to achieve this when at apogee, two parachutes will be ejected by utilising CO2 cartridges. These will contribute to the safe recovery of the rocket in its entirety, thus, making Cronos a sounding rocket that is 100% reusable.

The story so far 

Reaching the First Significant Milestone: A successful Cold Flow Test

After two long years of continuous tinkering, the time was ripe for the White Noise team to run the first Cold Flow Test of the Cronos’s rocket engine at the end of March 2022. In aerospace engineering, Cold Flow Testing is a significant step in the manufacturing process of a rocket; it is the testing of the rocket’s engine without firing it. This test is performed to validate the integrity of the engine’s injector, the part that atomises the oxidizer and feeds it to the combustion chamber. 

The Cold Flow Test: Important lessons learned

The White Noise team of University students organised, ran and brought to completion successfully the first Cold Flow Test of Cronos’s engine. With it, Cronos became the first hybrid-fueled sounding rocket to have achieved that in Greece and thus, the White Noise team reached a new, noteworthy Milestone. Following the steps of the process with great care and precision, taking all the necessary safety measures and showing outstanding professionalism in organising and carrying out the Testing from start to finish.

Want to join the team and get involved with the project?

Cronos is an aspiring project bringing together University students from different disciplines. As part of the Libre Space Foundation, the project is backed by a diverse, international community, welcoming people from different continents, cultures and backgrounds. As with all the LSF projects, Cronos too is developed in a collaborative, open-source way and is fostered by an inclusive community. If you want to keep track of all the updates on the project, take part in the conversations and meet the team, you can follow the dedicated Cronos Rocketry element/matrix channel. You are welcome to join the channel, introduce yourself and contribute to the discussions there. You can also have a look at the Cronos Rocketry repository on Gitlab.

What’s next?

With the first Cold Flow Testing successfully coming to completion, the team is working towards the Static Test, which is the next significant milestone to reach. 

At the same time, all the different groups within the White Noise team are working on their sub-projects about Cronos. They have been focusing on testing and debugging the latest addition of PCBs.

PCBs are considered to be among the most complicated parts of a rocket. This is because they are responsible for handling data from a wide variety of sensors and deciding upon the progress of the launch sequence.

The team has also been working on manufacturing the carbon fibre and fibreglass composite parts of the rocket’s outer body tubes and fins; as well as testing and continuously verifying the proper functionality of the rocket’s CO2 recovery system. They have also been upgrading their communications and reach-out strategy and finding ways to network with other teams and promote knowledge. All the working groups have been collaborating closely, running all the processes successfully to create Cronos, turning it into an aspiring educational initiative. The team has been aiming at making the sounding rocket the test platform for exploring future possibilities of building more advanced rockets capable of reaching higher altitudes-designed and manufactured in a collaborative and participatory way.

In their words the White Noise team..

….aspires to encourage the next generation of space exploration through experience and engagement in Science, Technology, Engineering, and Mathematics (STEM).

The Cronos, hybrid-fueled sounding rocket is powered by a hardworking team of University students dedicated to following open-source methodologies, collecting data and sharing the knowledge acquired with the world. They have worked through the difficulties and have successfully overcome the pandemic obstacles, reaching the first Cold Flow Test. We cannot wait to see what the future holds for them and the Cronos sounding rocket.  

Join us for the Software Defined Radio makerspace results webinar in 6-8 September

SDRmakerspace is a European Space Agency activity implemented by Libre Space Foundation in collaboration with the Institute of Reconfigurable & Embedded Digital Systems (REDS) of the Haute Ecole d’Ingénierie et de Gestion du Canton de Vaud – HEIG-VD in Switzerland.  The activity is part of the ARTES programme of the European Space Agency that supports innovation in satellite communications.

SDRmakerspace brings together makers, open-source hackers, radio amateurs, and researchers providing funding, resources and a passionate community tackling together challenges in using Software Defined Radio for space communications. By doing so, it is opening up development to a wide variety of people, organizations, and companies.

We will present the final results of the subactivities undertook within SDRmakerspace in three 2-hour slots (for which you are requested to register separately) in the afternoon at 15:00 CEST (13:00 UTC) on Mon 6, Tue 7 and Wed 8 September 2021.

The event is organized by the European Space Agency, and will be contacted using the Webex platform, it is open to all interested individuals provided they register through Eventbrite in the provided links below.

Monday 6 Sep will be focused on the evaluation of various SDR boards and FPGA tools chains. High-rate direct sampling by SDR’s and SDR on Android will also be presented.

Tuesday 7 Sep will be dedicated to building blocks that have been implemented as open-source developments for GNURadio, such as gr-leo, gr-ccsds, gr-soapy etc.

Wednesday 8 Sep is mainly about the combination of SDR and AI/ML to do signal detection and classification. In addition, an SDR test-bed and spectrum monitoring will be presented.

Building paper models of the Qubik twin satellite mission, as we get ready for launch

Firefly Aerospace a few days ago announced the successful static fire test of the Firefly Alpha launch vehicle on its launchpad, preparing for its inaugural flight. On the final stage of this rocket, Firefly Aerospace engineers have integrated PicoBus, Libre Space Foundation’s open-source hardware PocketQube class satellite deployer, hosting several satellites including Qubik 1 and Qubik 2.

The Qubik twins as soon as they will be deployed in orbit will perform radio amateur experiments investigating various modulation schemes for performance and orbit determination.

As we get ready for this launch, Zach’s PaperSat Designs has created a paper model of the Qubik satellite.

Don’t hesitate to build your own. You will just need a couple of sheets of 65lb card stock paper (160gr/m2 might also work for you), glue, a colored printer and download the following PDF files for the paper model and instructions.

We recommend checking out all of Zach’s PaperSat Designs models, including UPSat, the previous open-source satellite mission Libre Space Foundation re-designed, integrated and delivered (PDFs of the model and instructions).

GSoC Project: Producing Rich Analysis Reports for Polaris-Ayush Bansal

In the past two weeks, we focused on the projects that Libre Space Foundation has been mentoring in this year’s GSoC programme. Thus, we have already presented the project about Improving the transmission capabilities of gr-satnogs by Michalis Raptakis and Expanding events detection in Poliastro by Yash Gondhalekar. Today, we will focus on Rich Analysis Reports for Polaris by Ayush Bansal.

Polaris ML: An Introduction

Polaris ML is an open-source, python-based, machine-learning tool aimed at helping satellite operators detect spacecraft behaviour. It is a solution developed to facilitate space diagnostics. This is achieved by helping spacecraft operators investigate anomalies. Polaris ML explores and analyses satellite telemetry data and delivers helpful graph visualisations. These visualisations are machine-learning models illustrating the dependencies of the telemetry parameters.

*The project is under active development, and the team will be implementing more changes in the future.

Polaris ML and GSoC

For Polaris, this is the third year that the project participates in the Google Summer of Code. This programme has benefitted Polaris ML massively, as it has brought the project in liaison with excellent students that have helped it evolve greatly. Talented, past participants of the GSoC programme are now integral members of the team developing Polaris ML. This year, the project has welcomed Ayush Bansal, an Electronics and Communications Engineer student at the Indian Institute of Technology, Roorkee in Rajasthan, India.

Rich Analysis Reports for Polaris

During his GSoC internship, Ayush has been working on developing two new module commands. These are polaris behave and polaris report.

  • polaris behave. This module uses a pre-built autoencoder model from the BETSI library to detect anomalies in satellite telemetry data. The results found will be delivered in an easy-to-read, exploitable format.
  • polaris report. The second module that Ayush has been working on aims to use the results from polaris behave and portray them in an interactive way in a web browser for the users to comprehend, interpret, and read more easily. The visual module will use the results of the anomaly detector and other raw data to produce a graph. A local, browser-based webserver will be created to serve interactive graphs. The graphs will be presenting the different anomalies, their points of occurrence in frames and the different parameters.

Check out this detailed demo and see for yourself the work that Ayush has created. You can also check this article to find out more details about the Web Reports.

As Ayush describes the GSoC experience with Polaris..” We planned stuff, fixed bugs. [D]id some sword fights over topics and Merge Requests and Issue Filing became [a] regular thing for me.

I learnt [the] importance of how to code properly, give proper names to different functions, explain the aims of the code more clearly and a lot more.”.

You can have a closer look at the Merge Requests that Ayush has worked on here.

What is next?

As Polaris ML is a project under active development, a series of interesting updates are coming up. In the next months, the team will be working on many improvements optimising the tool even further. As far as web reports are concerned, supporting multiple satellites by URL separation, improving the responsiveness of the reports themselves, using Graph Comparison to collect all the information responsible for an anomaly are some of the features that the team will be working on.

A PDF generator is to be developed, too. It will be customisable to the user’s needs as they will be able to choose which parameters will be included in the PDF. For instance, they will be able to customise the time period and the number of anomalies detected. Ayush will also be developing a feature that will allow the users to combine all the graphs in a bundle and deliver them in a zip file for further use of the results found. Lastly, a command-line option will be explored to be able to trigger the reports easily.

Polaris logo

Want to join the community?

If Polaris ML sounds fascinating to you and you want to join the team, you can reach them at the dedicated Polaris matrix/element channel. You are welcome to sign up and contribute to the project and the discussions taking place there. The Polaris team is made up of talented individuals from around the world, and the community is open to everyone interested in space, machine learning, and open-source technology. As Ayush describes it in his article..”I didn’t know much about space telemetry and satellites, so I learned a lot from the community

..Despite these people’s various engagements, they were responsive, which helped me get my doubts cleared as soon as possible.

It was a great summer working on this project….[this was] More than an Internship. “

*You can follow Ayush’s personal blog and read about his journey as a Web developer here.

GSoC Project: Expanding events detection in Poliastro-Yash Gondhalekar

Supporting knowledge and scientific research are among our main goals at Libre Space Foundation. This is why we have been participating in the Google Summer of Code for the third year in a row, mentoring three amazing projects. The first project is about Improving the transmission capabilities of gr-satnogs developed by Michalis Raptakis. We presented this project in more detail last week. This week, we are delving into Poliastro.

Poliastro and GSoC

In 2021 Poliastro is participating in the Google Summer of Code programme via Libre Space Foundation. Yash Gondhalekar, a Computer Science student at the Birla Institute of Technology and Science in Pilani, India, is spending the summer working on the project. Tinkering with the code to achieve a streamlined execution of algorithms, adding event detection capabilities and improving the tool.

Poliastro: An Introduction

Poliastro is a pure Python library that provides an API tackling issues of astrodynamics and orbital mechanics. Its goal is to benefit users by providing valuable scientific information. This information will contribute towards creating more effective space strategies, improved orbital designs and more efficient maintenance policies.

The software for this tool is under constant improvement and development. Thus updates are to be released regularly.

Poliastro: A closer look

Events detection is a challenging process. Upon embarking on the GSoC experience, the Poliastro team began focusing on the eclipse detector, which appeared to be a more challenging task to tackle. After brainstorming over the most suitable method to handle this, the team decided to opt for SciPy’s event support.

Though SciPy did offer a solution to approach the issues, the team “.. still needed to come up with a time-varying and continuous “shadow” function without having to solve analytical equations manually .”

For this to be achieved, an equation had to be formulated.

After a series of geometric manipulation tests, an equation was created comprised of classical orbital elements. But the team did not stop working on the solution. As Yash points out, ” We were still questioning the performance and complexity of the method since by enacting it, we could lose the accuracy of entry and exit times of the event. In any case, the other (methods) didn’t seem to work just yet, so we decided to go with this approach since it looked feasible.”

At the same time, the team also worked on the altitude and latitude crossing detectors. However, soon enough, they realised that there are far more intricacies in the longitude detector. This required more thinking and more exploration to find the right approach and method to deal with the issue. ” All the events are supposed to work for any attractor, thus aligning with one of (the )Poliastro’s aims of having capabilities not restricted to (the )Earth.”

By leveraging some of the in-built functionalities of solve-ivp, users can stop the integration when an event is detected or control the direction of triggering an event. With the development of validation cases for the Orekit software, the team enhanced the possibility of further implementation; the tool was optimised even more by adding tests, fixing bugs and improving computation.

You can read how the team went about approaching all the issues arising in Yash’s detailed article.

Want to join the team?

As is the case with all the project communities at Libre Space Foundation, the Poliastro team is an open and inclusive community welcoming members from all over the world. In his first article about the GSoC experience with Poliastro, Yash states, “Needless to say, this is a place where I would get to interact with an engaging community and learn several things”.

If this sounds like an interesting project to you and you want to be part of this team, you can join the dedicated Poliastro channel on element/matrix and contribute to the discussions there.

The next steps

Yash and the team are working hard on further optimising Poliastro, and in the weeks to come, more event detectors will be included!

*You can follow the updates of the Poliastro project here.

Polaris: Applying Machine Learning to Satellite Operations

At Libre Space Foundation, we are dedicated to developing and supporting open-source space technology and projects that promote knowledge and improve space operations. Polaris is a project developed with the support of Libre Space Foundation (LSF). It brings together developers, engineers and university students from around the world. A diverse group of people with a shared interest in space and open-source technology. They are the ones working hard on designing, developing and optimising Polaris: a Python-based, Μachine-Learning (ML) tool, developed in an open-source, collaborative way, aimed at applying machine learning to satellite telemetry.

Polaris ML for SpaceOps

The challenge: Satellite operators, during a mission, have to tackle a daunting yet critical task; to monitor and keep track of numerous telemetry parameters to maintain a clear idea of the behaviour of their satellite. They need to comprehend how these parameters interfere with each other and estimate their impact accurately.

The Solution: This is where Polaris ML gets into the picture. It is a command-line based, machine-learning tool providing a satellite-telemetry analysis that can be of great help to satellite operators. The data collected are turned into comprehensive graph visualisations, using machine-learning models to understand and predict a satellite’s behaviour. Other data sources are also converted into valuable information available to spacecraft operators.

Note: Before examining Polaris ML in more detail, allow us to describe briefly how satellite operators handle these issues at the moment. Though satellites are built to be more self-aware nowadays, operators are still required to jump in and evaluate the situation by setting manual limits. This is called the Out-Of-Limit (OOL) technique which analyses and evaluates the behaviour of a satellite by collecting data and raising out-of-limit alarms about the state of a satellite. Consequently, a ‘soft out-of-limit’ alarm indicates a dangerous trend, while a ‘hard out-of-limit’ alarm is indicative of a failure occurring.  At this point, let us clarify that Polaris ML does not seek to replace operators or the techniques already applied. Instead, what Polaris ML is after is to be able to provide assistance and amplify the process. Polaris ML is after becoming a reliable, efficient and complementary solution for Space Operators.

A closer look

Before analysing the project, let us point out that this is a tool under active development, thus, the interface is very likely to change. Allow us now to delve into the different components of Polaris ML.

Polaris ML makes use of the XGBoost algorithm to analyse the relationship and the inter-dependencies between telemetry parameters. The XGBoost library allows for eXtreme gradient boosting. This is an approach enabling new, updated, and better-informed models to be created by predicting the errors of the previous models. Then, both models are added together to deliver a final prediction. Using this approach, Polaris ML predicts every telemetry parameter in a satellite. It then provides a graph illustrating the interdependence between the parameters, depicting the degree to which one parameter affects the other. The importance of telemetry parameters and how these are linked is presented as a web-based, 3D-interface graph. 3d-force-graph is the component used for the graph output.

Polaris ML is made up of these distinct parts:

  • polaris fetch: As the name reveals, this part fetches the data from various sources. Including telemetry data from the SatNOGS Network and Space Weather from SWPC (NOAA).
  • polaris learn: This part consists of a machine-learning (XGBoost)-based module that analyses the relationship of all the “fetched” data and returns a JSON graph file as the output.
  • polaris viz: A 3d graph-based visualisation module providing an intuitive graph representation of the data.
  • polaris convert: A tool used to convert graph outputs from “polaris learn” and “polaris viz” into other formats. For now, it only supports the .gexf formats, which is a language utilised for describing complex networks structures, as well as the associated data and their dynamics.


Vinvelivaanilai is a Python module that fetches space weather data from servers of SWPC/NOAA. It then stores the data in text files or on the InfluxDB. It also includes functions enabling TLE and OMM parsing (any GP data) and propagating the orbit of a satellite to locate both its position and its velocity at any given time.

Vinvelivaanilai is the word for space weather in Tamil.


The word BETSI stands for “Behaviour Extraction for Time-Series Investigation”, and it aims to implement a state-of-the-art model to detect anomalies automatically without any manual intervention. The model for creating the concise representation is called autoencoder, and it utilises deep-learning techniques to detect any anomalies found within the telemetry data.

But what exactly is an anomaly? 

Anomalies are all events that fall outside the spectrum of the nominal behaviour of a system, generating massive shifts in the values of one or more parameters. Anomalies can have a catastrophic impact on the satellite, especially since their spectrum is quite broad, as it may range from a simple change in orientation to a massive explosion. (One can only imagine the impact).

Polaris ML in a nutshell

Polaris is an open-source, python-based solution developed to facilitate space diagnostics and help spacecraft operators investigate anomalies. It aims to support and enhance satellite operators to improve their processes by enabling them to detect spacecraft behaviour and helping them drive their investigations when anomalies occur.

Valuable Resources on how to get started and join

As we plan to take this project to a broader scale and see it developing further and expanding, we have created a list of resources that can help you familiarise yourself with Polaris ML. To start with, these are the Polaris repositories on GitLab. Then, you can check the detailed documentation that is available online as it walks users through the Polaris ML project. There are also several exciting talks and presentations by some of the members of the Project.

Want to join the community? Find out how you can get in touch with the team

Polaris ML is backed up by a diverse, international team, welcoming people from different continents, cultures and backgrounds. The project is developed in a collaborative, open-source way and is fostered by an inclusive community. If you want to join, you can contact the team at the dedicated Polaris ML element/matrix channel: You are welcome to join the channel, introduce yourself and contribute to the discussions there.

Polaris ML and GSoC

The Polaris ML team welcomes students from all over the world, and it is a popular project sought after by students applying for the Google Summer of Code program. Polaris ML participates in the programme for the third year in a row. The entire team has had great experiences with GSoC, and the project itself has expanded due to the support and contribution of the GSoC students. Adithya Venkateswaran, who has created the Vinvelivaanilai library, has been a star student of GSoC and is an integral member of the Polaris team.

What next?

Polaris ML is an aspiring project with great potential; it aims to optimise space diagnostics, reduce operation workload and enhance autonomous spacecraft operations. With the help of machine learning, Polaris ML aims at becoming a reliable, scalable solution for Space Operations. The project is still developing, optimised to deliver even better intuitive graph models, creating valuable and dynamic anomaly reports. Polaris ML is after opportunities to implement and test this solution in future satellite operations. We have already worked with BOBCAT-1  and the QUBIK pair of satellites. Still, as we wish to improve further and expand, collaborations with satellite operators for upcoming missions are welcome. Especially since we want to test further and optimise the solution itself and its key components.

Help us translate the LSTN Handbook and bring space technology to more public libraries around the world

The Library Space Technology Network (LSTN) is a project brought to life by Wolbach Library in collaboration with Libre Space Foundation. LSTN is a pilot program aimed at offering public library communities the opportunity to engage with Space Technology. Though the project is ambitious, language poses substantial limitations for communities to join. And this is where we need your help!

The LSTN project: a more detailed look

The goal of LSTN is to broaden participation in space-based science and engineering, through novel educational opportunities and hands-on learning experiences with open satellite technology in public libraries. It achieves that by giving communities a SatNOGS ground station and educational resources to support their use. At the moment, there are 5 public libraries around the world participating in this initiative: Public Library “B.P. Hasdeu”, in Chișinău, Moldova, Public Library of Santiago, Chile, Cambridge Public Library in Cambridge, MA, USA, John G. Wolbach Library in Cambridge, MA, USA and Marathon Public Library in Marathon, TX, USA.

LSTN is a project with great significance and potential; capable of expanding and including more libraries worldwide. LSTN can grant people access to a set of shared resources that can open doors, provide novel learning experiences, and inspire lifelong learning. Especially, in communities where opportunities to connect with space-based science are limited.

The LSTN Handbook

For libraries to be able to install a SatNOGS ground station, there are several valuable resources available, including a Handbook. The latter provides a detailed walkthrough and guidelines for the entire process in English. And this is where your help is required to get this project to the next stage! As language can be an insurmountable barrier, the LSTN Handbook needs to be translated into more languages to help spread knowledge and space technology to more communities worldwide. For this, we would like your help in translating it into Spanish and Romanian. These two languages are of a high priority now, however, you can add more languages and help us with those translations too!

The Handbook Translation is powered by Weblate, and a tutorial has been created to make the process easier for you. In addition, there is a Weblate Glossary to help you understand the terms Weblate uses. For any questions you might have you can use the LSF community forum, the dedicated MetaSat element/matrix channel, or email the team at

Update: The Progress so far

In the last couple of months, the project has attracted the attention of many volunteers that dedicated their time and effort to translating the Handbook into more languages. New languages have been added and progress is made slowly yet steadily. At the moment, the Handbook is being translated into 14 languages and 30.2% of the translations are completed. This is why your contribution is still very much needed to make this project accessible to more communities and make space available to the public. 


At LSF, we are devoted to promoting knowledge and finding ways to introduce and include more individuals, teams and communities in space technology development and exploration. We are excited to be working with the Wolbach Library on LSTN to include and engage more communities. However, we need your help to break linguistic barriers and make the LSTN Handbook accessible to many languages. So if you are a space enthusiast, a supporter of knowledge, and want to contribute to take this project globally, you are welcome to begin working on a translation. Do not hesitate to share this article with someone who might find it useful or is willing to help!

Google Summer of Code 2021: Announcing the three projects that will participate in the program with Libre Space Foundation

For the third year in a row, Libre Space Foundation is selected as a mentoring organisation for the Google Summer of Code program. The application period has now closed and the results are in!
The three projects that will be participating in this iteration of the Google Summer of Code via Libre Space Foundation are the following. Let us check them out:

Expanding events detection in Poliastro

Poliastro is an open-source, python library for interactive astrodynamics and orbital mechanics. This project will work on expanding the event-detection capabilities of Poliastro. It plans on achieving that by adding several event-detection algorithms and methods to it. These detectors will allow Poliastro to calculate eclipses, collisions, line-of-sight, sunlight exposure, altitude thresholds, longitude/latitude crossing, visibility of orbiting objects from a location on earth, and sunrise/sunset and moonrise/moonset times also from a location on earth.

Rich analysis reports for Polaris

Polaris is an open-source tool that applies machine learning to satellite telemetry. This year’s project will create a visual module for Polaris. This will use the results of its anomaly detector to generate web-based interactive graphs, visualising anomalies and their points of occurrence. At the same time, it will allow pdf generation and command-line tools for these.

Improving the transmission capabilities of gr-satnogs

Gr-satnogs is the GNU-Radio, Out-of-tree module used by the SatNOGS open-source satellite ground-station network. The scope of this project is to expand the current transmission capabilities of gr-satnogs. This has already been tested on UPSat while in orbit and on Qubik 1 and Qubik-2 in the lab. To achieve that the project aims to improve the gr-satnogs transmission framing API and add new encoders to the already existing AX.25 and IEEE 802.15.4 such as the Nanocom AX.100, various AMSAT-related encoders and more.

Google Summer of Code is an annual program offering university students the opportunity to work on open-source projects during their summer break while earning a stipend! Libre Space Foundation is devoted to working on open-source space technologies and you can find out more about our Principles regarding open-source and space in our Manifesto.

This year’s Google Summer of Code application received 6991 applications submitted by 4975 students from 103 countries. These applications were reviewed by 199 mentoring organizations. Eventually, 1292 students from 69 countries were selected.

We are thrilled to be part of this grand initiative. But we are also excited and looking forward to working with our students over the next few months. Congratulations to everyone and welcome aboard!

2021 CubeSat Developers Workshop: Interesting talks and workshops

The 2021 CubeSat Developers Workshop is happening in a few days and is organised by Cal Poly, San Luis Obispo, CA, USA. It will be a virtual conference taking place from the 27th to the 29th of April. The CubeSat Developers Workshop (#CubeSatDW) “Working Together” will feature amazing talks and useful workshops. You can find the full schedule of the event here.

To start with, the event this year features a mix of pre-recorded and live sessions and the registration is free for both. For the Keynote Addresses and the Live Q&A Panels, a passcode will be forwarded to you via email, after the registration. By using that passcode, you will be able to join the live discussions. On April 27th, the pre-recorded presentations from the Live Q&A panellists will be released. This will allow for the registrants to view the presentations and prepare the questions before the live Q&A panels. During the event, there will be time available for the attendees to network.

Libre Space Foundation’s strong presence at the 2021 CubeSat Developers Workshop

At Libre Space Foundation we are thrilled to join this year’s CubeSat Developers Workshop with a number of fascinating and significant presentations from many of our projects. No day of the event will pass without a presentation from a Libre Space Foundation project. With Day #1 featuring two projects of ours. Let us take a more detailed look at the Libre Space Foundation presentations and our speakers:
On Tuesday the 27th of April, Day #1 of the event there are two LSF-related presentations:

  • “I hunt satellites”: crowdsourced satellite telemetry collection with SatNOGS
    by Corey Shields | Libre Space Foundation
  • MetaSat: An Open Metadata Toolkit for SmallSat Missions”
    by Daina Bouquin | Harvard-Smithsonian Center for Astrophysics

On Wednesday the 28th of April, Day #2 of the Event:

  • Polaris: open-source deep learning for telemetry behavior and anomaly detection”
    by Red Boumghar | Libre Space Foundation

And on Thursday the 29th of April, Day #3 of the Event:

  • “SatNOGS – COMMS: Turnkey Nanosatellite Communications”
    by Manolis Surligas | Libre Space Foundation

We are very excited and looking forward to enjoying all the presentations featuring at the event.
Save the dates and join us at the 2021 CubeSat Developers Workshop virtual conference.

See you online!

Call for students: Join us in building open-source space technologies through Google Summer of Code 2021

Google announced today that Libre Space Foundation is among the mentoring organizations of Google’s Summer of Code 2021.

This selection provides opportunities for students that would like to work on open-source space technologies during their summer break and start participating in the Libre Space community.

If you are an eligible student and interested in working with open-source space technologies this summer, don’t hesitate to study the student guide thoroughly, and check our detailed instructions, with suggested ideas, or introduce your ideas for consideration.

To get a taste (and inspiration) of the work of last year’s mentees check the reports of their contributions to Deep Learning and Space Weather for satellite data and a python library to detect RF collisions in SatNOGS.

Overview, talks and takeaways of the 4th iteration of the Open Source CubeSat Workshop

The Open Source CubeSat Workshop 2020!

The Open Source CubeSat Workshop is a yearly event that brings together enthusiasts from the fields of space technology, engineering, CubeSats, mission control and analysis, and of course, Open Source. The event has been around for four years and has been gaining continuous success and building rapport among Space and Open Source Technology supporters. In an attempt to maintain stability in a rather unpredictable year when a pandemic has been sweeping the globe, the event was decided to take place online. We found no better way to guarantee the safety of attendees and speakers alike, than participating in an online event from the comfort and safety of our home. And that brought on the Open Source CubeSat Workshop 2020 – online edition; with a strong focus on sharing ideas and promoting collaboration; even when confined at home on different meridians of the planet.

The Event

On the 12th and 13th of December, the Open Source CubeSat Workshop 2020 kicked off online! The event was streamed live on the Libre Space Foundation YouTube Channel and it brought together people from different continents, backgrounds and disciplines. At the same time conversations and insightful discussions were taking place on the YouTube Chat and on dedicated matrix channels (via, where information provided by speakers (tips/source code/awesome list) was also shared. A community buzzing of ideas for cooperation that you can join any time of the year and explore collaboration potentials.

The event featured two Rooms where presentations took place in parallel; fascinating lightning talks and detailed tutorials. Overall there were 20 presentations, 12 lightning talks and 5 tutorials and here is the playlist with all the videos from the event.

The Open Source CubeSat Workshop 2020 was a fun and informative event where knowledge and great ideas were shared openly. Fascinating discussions and Q&As provided insightful approaches and there were some interesting conclusions.

Key take away

OSCW is a great occasion, every year, to realize the immense impact of the open-source projects that compose the space industry, by playing an important role in enabling access to key technologies for creating and supporting space missions. Every year we see gaps being filled like the DOCKS software suite, managed by Observatoire de Paris (CCERES), offering a complete set of tools for space mission profiling. Thanks to the feedback provided by the community, the project has been restructured, to feature an easier interface and understanding of its different tools. SatNOGS project, the Satellite Network of Ground Stations, is realized by volunteers across the globe and it continues to expand. Coverage expansion, the well-scaling infrastructure and its evolution were presented while the project maintains user-friendly interfaces for flight control teams to store, access and view their spacecraft telemetry. SatNOGS puts the finger on key challenges (satellite detection, identification and tracking, easy deployment of SDR-based ground stations, and ground infrastructure). OpenSatCom was also presented at the event. This is an activity of the European Space Agency managed by the Libre Space Foundation; the latter has recently produced a resourceful report about Open Source, development methodology models for satellite communications.
The workshop also featured a lot of tutorials and information about the things you need to know if you are into creating your own smallsat mission or managing an existing one. It included everything from open-source embedded software and implementation of ECSS standards to the latest update on how to propagate an orbit and why you have to say goodbye to TLEs; as well as how to use machine learning to analyze your operations data.
There were plenty of other key projects presented like MetaSat or the standardization of PC/104 connectors with the Librecube initiative that you can retrieve from the contributions list.

OSCW is also the siege of numerous shared ideas as all interventions do trigger one’s imagination. Lightning talks provide great inspiration. They are the perfect example of how you can quickly get a team of contributors for a project like a ground station in a backpack. Or they can inspire the birth of an idea which was not even on the initial list and it was formed on the spot. By raising the interest of the attendees during a talk, you get to inspire people who wish to contribute to your project. It is because of this that often you can find somebody saying “I’ve got something I can share with you and we can make it”; such as the air-bearing testing equipment for testing your ADCS (during the astonishing liquid metal-based pico reaction “wheels”).


Though this year the event was different, as it went fully online, it was indeed a successful one! As it did manage to gather an online community of enthusiasts who are dedicated to Open Source, Technology and Space. It managed to overcome boundaries and a pandemic and to allow individuals from around the globe to unite under their shared interest. For this, we would like to thank everyone! The attendees for forming a friendly community of great diversity and knowledge, the speakers and presenters for creating great interactions and sharing insights, the contributors for enabling a smooth experience and the OSCW committee for putting everything together and overseeing the event. We would also like to thank the teams behind Indico (our conference management tool), The Big Blue Button (amazingly smooth video conferencing, with multi-user whiteboarding and break sessions), and Matrix for powering the conversations, links & file-sharing of this year’s iteration of The Open Source CubeSat Workshop 2020!

Until we meet again, next year and hopefully in person, feel free to enjoy the recordings of this year’s event and go through the presentations and talks. They are a great source of knowledge and you can shuffle through them and acquire great insight.

In the meantime, stay safe and connected!

The QUBIK Mission: Ready for orbit

Libre Space Foundation (LSF) is devoted to designing and building open-source space technologies. We always support and promote space exploration, scientific research and knowledge. For the past year, we have been working hard on the QUBIK mission to create a platform on which a series of amateur radio experiments will be conducted, upon the mission’s launch.

Ιn a nutshell

For the QUBIK project, Libre Space Foundation has designed and developed two open-source PocketQube Satellites, QUBIK-1 and QUBIK-2. As part of the QUBIK mission, LSF has also designed and built PICOBUS; the first, open-source PocketQube deployer. The QUBIK PocketQubes along with AMSAT-EA’s GENESIS-L and GENESIS-N and Fossa Systems’ FOSSASAT-1 and FOSSAT-2 were integrated into the deployer and are part of Firefly Aerospace’s DREAM payloads program on its inaugural Firefly Alpha launch.

The QUBIK-1 & QUBIK-2 PocketQubes
The PICOBUS deployer

The Story so far

Over the past year, the PicoBus, as well as QUBIK-1 and QUBIK-2, underwent all the necessary standard testing and verification campaigns.

For example, by the first months of 2020, PICOBUS had undergone the thermal vacuum test and the vibration test. From there, it was time for assembling the PocketQubes and the deployer, and then the bake-out was in order. Shortly after, the Acceptance campaign took place for PICOBUS, and so did the Protoflight Campaign for QUBIK-1 and QUBIK-2. You can read more about the extensive testing and the processes that took place earlier in the year here.

Qualification model of the PICOBUS deployer just out of the Thermal-Vacuum chamber

While the hardware was undergoing all the testing, the software was polished and tested, too, aiming at enabling a series of fascinating amateur radio experiments.

The Experiments

The two PocketQubes, QUBIK-1 and QUBIK-2 are designed to have a short life span of 3-4 weeks. Though this period of time is relatively short, it is enough for LSF to run a series of amateur radio experiments. These are primarily scheduled to take place during the Launch, and Early Orbit Phase (LEOP) of the operations and the amateur radio experiments revolve around satellite identification and tracking. LEOP is a critical phase for satellites and spacecraft operations; since the sooner a team identifies and picks up communication with the satellite, the better it is for the entire operation. Identifying and tracking a satellite early on, almost upon deployment, helps the team to proceed fast and tackle possible problems arising. It is the significance of early identification and tracking and the impact this has on saving missions and operations that prompted LSF to decide to focus the scheduled experiments on that specific Phase of operations. By forming a series of assumptions about Satellite identification and tracking, LSF has set the objectives for experiments that need to be conducted in search of possible solutions.

QUBIK-1 & QUBIK-2 inside the Clean Box before final testing and integration

Thus, QUBIK-1 and QUBIK-2 will set out to help explore the following objectives:

  • To unambiguously identify satellites as soon as possible after deployment

As we mentioned above, early satellite identification and tracking are of primary importance as they allow the operations team to act fast and address possible issues early on. Be it communications or altitude-related issues, they should be dealt with swiftly, especially since failure to do so promptly might render an operation unsuccessful. QUBIK-1 and QUBIK-2 are designed to enable easy RF Identification during the LEO Phase.

  • Generate or update existing orbital elements based on Doppler curve tracking of satellite transmissions

The process of identification and tracking becomes even more complicated. As is often the case, nanosatellites and microsatellites are deployed in numbers, many together, from the same launch vehicle and flying in the same orbit. Distinguishing between them and tracking is a daunting task, puzzling the teams as the operators of these satellites often rely only on external tracking alone. They rely on the only available public resource providing orbital elements, and that is the Combined Space Operations Center (CSpOC) (through their dissemination website.) Nevertheless, things get even more perplexed for operators as, in addition to crowded deployments, the small radar cross-section makes identification via CSpOC quite a challenge. Both of these parameters are the cause of significant delays in the publishing of the initial orbital elements. It can take up to a few weeks to identify a satellite accurately, and sometimes it might not be identified at all.

For dealing with the issues of misidentification and no-identification at all, for the QUBIK PocketQubes, passive Doppler tracking will be utilised. This will be facilitated through SatNOGS (the global network of satellite ground stations) in order to independently determine orbital elements during the Launch and Early Orbit Phase.

  • Extensively explore objectives 1 and 2 and do so in a way that adheres to the Principles of the Libre Space Manifesto.

All LSF’s operations and projects are led forward by the Principles of the Libre Space Manifesto, which constitutes the operational framework of all LSF processes. This means that the objectives mentioned above will be explored accordingly; in a scalable and open-source way, with the data collected being distributed openly for everyone to have access.

QUBIK PocketQubes
  • Create a reusable, open-source PocketQube Platform.

At LSF, we have been focusing our attention on the PocketQube format, and for this, we have worked hard to build a reusable, open-source ProcketQube Platform with a complete stack of open-source technologies developed for it. This is because we see potential in the PocketQube format as it is versatile enough and low-cost, able to facilitate a wide variety of amateur radio experiments, payloads and to have a wide range of technology developed around it.

QUBIK-1 and QUBIK-2 will be used for testing, aiming at exploring the aforementioned objectives to the fullest. These will be investigated in-depth through a series of amateur radio experiments regarding the Identification and Tracking of Satellites.

The final antenna deployment test for one of the QUBIK PocketQubes

Identification Experiments

This part of the amateur radio experiments focuses on radio beacons and Telemetry transmissions, and they include:

Beacon preamble/postamble

Digital modulation schemes may use a preamble or a postamble in order to provide narrow-band transmissions, which can help facilitate tracking from RF spectra. Distinguishing between satellites can be achieved by estimating the differences in preamble/postamble length. However, since preambles in most framing schemes are often the same, this constitutes a preamble not an ideal solution to allow unambiguous identification.

Beacon decoding

By demodulating and then decoding the signals captured, this approach allows for identification via a call sign or address within the packets. It requires full demodulation and decoding data chain. The assumptions required about SNR, RX sensitivity and RF collisions on narrow, non-spread-spectrum modulations will only compromise demodulation and decoding.

Note that this is one of the amateur radio experiments that LSF will be running as this does not require any changes to be made in the existing workflow. Thus, it will be introduced in QUBIK as a control case (since the team already utilizes it).

Beacon length

Identifying a satellite by estimating the differences in beacon length. In crowded deployments, as is the case of QUBIK-1 and QUBIK-2, this is not a scalable option.

Beacon cadence

Differences in beacon cadence can also help distinguish between satellites by estimating how often a beacon is transmitted. Though this approach helps prevent beacons and satellites from overlapping, it can not be applied in crowded operations.

Barker codes

Barker codes can be utilised to provide monotonic identification right from the RF level by performing only cross-correlation at the raw signal. Barker codes require only bit-level changes, and they can be used to facilitate lower SNR identification and decoding, identifying a spacecraft right from the PHY. However, for this approach to work, it would require ground stations to have multiple decoders operating in parallel. As the number of the decoders would have to be possibly equal to the number of different code sequences, this approach is not scalable for us to pursue.

Spread spectrum low power beacon

For this amateur radio experiment, the RILDOS proposed protocol was chosen, transmitting a beacon with low transmission power. The basic idea that we will explore is to use the spread sequences of the RILDOS protocol and retrieve a message from a satellite even in a negative SNR environment. What is more, with this amateur radio experiment LSF will attempt to explore possible techniques that can be applied to an SDR-based ground station estimating the frequency drift between the spacecraft and the ground station. The techniques applied will be estimated and evaluated on the grounds of their accuracy and whether the RILDOS protocol can be used for both identification and tracking.

Keep in mind that even though RILDOS requires 2 Mbps, in this experiment and due to hardware restrictions, RILDOS will be tested in lower bandwidth. In this case, the basic features of the protocol will remain intact while the performance in terms of BER is expected to be affected and possibly degraded.

This too, will be one of the amateur radio experiments that are scheduled to be conducted in QUBIK-1 and QUBIK-2.

One of the QUBIK PocketQubes while charging

Tracking Experiments

The tracking of the QUBIK PocketQubes through their Doppler curves must be achieved by measuring transmitter frequency as a function of time. This can be determined directly either from waterfalls, the artifacts provided by the observations made by the SatNOGS Network or by demodulating transmissions. Tracking waterfalls does work well for lower signal strengths, but when it comes to digital modulation schemes, it gets harder to obtain the transmitter frequency. This becomes difficult when transmissions of satellites overlap.


Waterfalls can facilitate satellite tracking for any modulation scheme with narrow-band features. CW would provide the highest accuracy at the expense of low bit rates.

Beacon preamble/postamble

By using a preamble or a postamble, digital modulation schemes can provide narrow-band features in the waterfalls. Examples of this approach are the BPSK transmissions of Funcube satellites or the FSK transmissions like those of UWE-4 or Firebird-4.

Residual carrier

The residual carrier is a strong carrier found on top of the modulation spectrum mask as it runs for the entire frame duration. Usually, the residual carrier is utilised to drive the PLL that tracks any frequency drift that can be retrieved either from the RF level or visually.

Since the RF IC of QUBIK (AX5043) does not support an optional residual carrier, LSF will opt for an alternative yet innovative approach. By using QPSK with special precoding, it can be forced to use only two of the QPSK symbols. This produces a DC-biased BPSK, which eventually will have a carrier at the center of the spectrum mask. What makes this approach possible is the absence of a DC block filter on AX5043.

If you want to have a look at the amateur radio experiments in more detail, you can read the documentation.

The latest Updates: Final QUBIK-1 and QUBIK-2 Testing and PICOBUS Integration

The QUBIK team has been developing and testing the software throughout the summer, updating and implementing features; following strict procedures so that the QUBIK project is ready for the final testing and integration. The last weekend of October 2020, was an exciting one, for us at Libre Space Foundation because not only did the final testing of the PocketQubes take place but also because of the integration of the PocketQubes in the PicoBus deployer.

QUBIK PocketQube Integrated into the PICOBUS deployer
GENESIS (AMSAT-EA) integration into the PICOBUS deployer

Both procedures took place at the LSF Headquarters, at, in the centre of Athens, Greece and were carefully orchestrated and successfully carried out while being streamed live on the LSF YouTube Channel.

Integration of PICOBUS PocketQube Deployer with satellites QUBIK-1 and QUBIK-2 (Libre Space Foundation), GENESIS-N and GENESIS-L (AMSAT-EA), FOSSASAT-1b and FOSSASAT-2 (FOSSA Systems)

What’s next?

The PicoBus Deployer with the six integrated PocketQubes will be shipped to the US.

Firefly’s Aerospace Alpha launch is expected to happen as early as Dec. 22, with room in the schedule to launch as late as Jan. 31.


For us, at Libre Space Foundation, the QUBIK is an aspiring project of which we are immensely proud. It is a self-funded initiative to create an ideal environment for testing and conducting amateur radio experiments. All the technology stacks used and the tools created are open-source. The solutions to be found (if any) will further enhance and enable a wide variety of amateur radio experiments, payloads, technology development and missions.

All these are governed by and conform to the Libre Space Manifesto, and its Principles found etched on the QUBIK PocketQubes.

September 2022, Update:

PocketQubes QUBIK-1 and QUBIK-2, along with the PICOBUS deployer, were onboard the Alpha Flight when that was launched on September 2nd 2021. That flight was controlled terminated two minutes into the launch.

QUBIK Mission Reloaded: heading back to space

LSF’s team of engineers began working on building a new set of twin PocketQubes, QUBIK-3 and QUBIK-4, and a new PICOBUS deployer, as Firefly Aerospace kindly provided Libre Space Foundation with another launching opportunity. To this opportunity, the QUBIK Mission is joined by AMSAT-EA’s satellites GENESIS-G/ASTROLAND-1 and GENESIS-J/ ASTROLAND-2, and FOSSA Systems FOSSASAT-1B. The integration of the satellites into the deployer took place in December 2021 at, and it was streamed live.

The QUBIK Mission reloaded is scheduled to fly in orbit onboard Firefly Aerospace’s Flight 2 #ToTheBlack from the Vandenberg Space Force base in California, USA. The launch is scheduled for the 11th of September 2022.

October 2022, Update:

The mission was launched successfully on October 1, 2022 and you can read all about it here.

Libre Space Foundation joins the International Astronautical Federation

We are proud to announce that Libre Space Foundation has been accepted as a member of the International Astronautical Federation! We are excited to be part of such a great community with which we share a love for Space, Space exploration and research.

International Astronautical Federation and Libre Space Foundation

IAF aims at “Connecting @ll Space People” bringing together organisations, universities, space agencies, research institutions and individuals with a profound interest in space. It has managed to successfully build a community, A space-faring world cooperating for the benefit of humanity. It does so through establishing collaborations and partnerships, by creating events and educating the public so that scientific knowledge and information are shared and spread for everyone to acquire. Libre Space Foundation works hard towards bringing space exploration closer to the public, enabling research and supporting education through all of its projects. We believe that Space is humanity’s future and that space should be accessible to all. This is why we support openness in space tech development and data distribution so that knowledge about Space technology and information about space exploration can fuel a better future for all. We both perceive Space as a great opportunity for growth and development but only when it is used to promote peace, knowledge and scientific research. When it is open to everyone to learn and explore freely. We firmly believe that the only way to explore Space to its fullest potential and to benefit humanity is through partnerships and collaborations with shared ideals and dreams. This is why we are very excited to have joined IAF.

A few words about the International Astronautical Federation (IAF)

IAF was founded in 1951 and it is the world’s leading space advocacy body. It counts over 397 members in 69 countries worldwide. Among its members, there are leading space agencies, Universities, companies, research institutions and even museums.

IAF encourages the development of astronautics for peaceful purposes and supports the spreading of knowledge and information about space. It is also the organiser of many thematic events promoting scientific research and knowledge, and it is the organiser of the International Astronautical Congress (IAC) – a significant annual event about space. 2021, marks IAF’s 70th Anniversary. You can read more about IAF’s long history of supporting space and knowledge by reading its History Page.

IAF’s Missions

The International Astronautical Federation has always supported Space, Space exploration and making technical and scientific knowledge available to those interested. Its vision is powerful and its missions are noteworthy and not limited to one field.

  • Promoting Cooperation. By organising events and committees it brings experts from all over the world together to collaborate on research and to deal with the issues the industry faces.
  • Advancing International Development. Through collaboration between nations, companies, institutions from all over the world.
  • Sharing Knowledge. The information collected and the knowledge acquired is shared using many well-established channels.
  • Recognizing Achievements. Not only does it keep an eye on the developments regarding space but it also presents awards to the individuals and groups which help move the global space community forward. Each year the IAF awards are amongst the most prestigious awards to be given.
  • Preparing the Workforce of Tomorrow. With a range of activities dedicated to nurturing new talent, IAF focuses on knowledge and how to help students and young professionals to grow, learn and evolve.
  • Raising Awareness. With the help of its members and its global community, the IAF publications spread around the globe enabling the public to get a closer look at the information about space.

The International Astronautical Federation is a non-profit organisation devoted to spreading knowledge about space and supporting the development of astronautics for the betterment of humanity. With a long history of collaborations and achievements towards making “A space-faring world cooperating for the benefit of humanity,” it works hard to enhance powerful collaborations and build the conditions for a future where space and scientific knowledge prevail.

A few words about Libre Space Foundation

Libre Space Foundation is a non-profit organisation focusing on the development of open-source space technologies. Its mission is to support, promote and enable innovative ideas, projects and initiatives that promote space technology, space exploration and enhance knowledge. All the projects the Foundation runs and its operations are governed by the Principles of the Manifesto. This is why all the projects are open-source, designed and developed under open-source methodologies, operating in transparency and are accessible to everyone. LSF shares its vision of Space being accessible to all humanity not only with a number of organisations, university teams and research institutions but with its global and diverse community of contributors who put their expertise and continuous effort into developing open-source projects and tools. LSF has a wide range of projects under its wings ranging from Machine Learning for satellites (Polaris), satellite missions (UPSAT, QUBIK) to upstream space projects like deployers (PICOBUS) and of course, developing and operating the world’s biggest open-source network of satellite ground stations worldwide (SatNOGS). Libre Space Foundation is proud to be the first-ever member based in Greece to be joining IAF.

Libre Space Foundation joins RISC-V International as a Community Member.

At Libre Space Foundation, we are always thrilled when we join forces with organizations and initiatives promoting the open-source development methodologies.
For this, we could not be more excited to announce our membership to RISC-V International.

A few words about RISC-V

What RISC-V is

RISC-V is an open-standard, instruction set architecture (ISA).

For those not very familiar with the term, an instruction set is the set of basic instructions a processor understands. The instruction set is part of the processor’s architecture. ISAs fall under two categories: the Reduced (RISC) and the Complex (CISC).

The RISC-V instruction set is designed to facilitate a wide range of uses and, it comes under an open-source licensing scheme making it available for everyone to use.

How it started

For a CPU design to be created, many experts from different specialities are required to contribute, making the cost of such a creative high. Some commercial vendors of ISAs charge royalties. But RISC-V follows an entirely different approach.

The project was initially begun at the University of California, Berkley in 2010 and it was the result of the collaborative work and effort of many non-affiliate-with-the-University volunteers. They contributed their time, effort and know-how in creating an open-source instruction set that would be useable for practical computers.

The mindset

The aim was to come up with a non-proprietary, academically useable ISA whose usage would not require any fees and it would be versatile enough as to be integrated with any hardware or software. Instead of focusing on creating complex microarchitecture, the contributors of RISC-V focused on its usability and its successful design. The more functionality it acquired, the more popular it became. Over the years, the number of contributing entities which have been creating and releasing RISC-V hardware or operating systems supporting RISC-V has increased tremendously.

RISC-V supports small, fast and low-power implementations responding to the real needs of the users. This way, an array of designs has been built to fit as many uses as possible. By working with a good, open-source instruction set, you can focus less on software support and more on design; less on worrying about software, more on focusing on implementation. Its open intellectual property enables the modification, improvement, reusability and publication of updated, adjusted and robust designs.

Libre Space Foundation

At Libre Space Foundation, we believe that the future of humanity is Space but only experienced and explored following open-source approaches; in development, data distribution and governance too. These are principles which we apply to all our projects, both hardware and software. Though this might seem hard to implement, the truth is that it is not. Because if you take a closer look at all of our projects, you will see that they are guided by the same principles of openness and accessibility. All the tools and solutions we build are modular and reusable so as to serve as level-field, highly-reliable solutions. The hardware design, schematic design, Printed Circuit Board (PCB), firmware we create, everything is non-proprietary. Because what we aim for is creating tools which are:

  • versatile enough to respond to the users’ needs
  • powerful enough to fuel versatility
  • reliable enough to function well in extreme conditions and
  • reproducible to such an extent that gives the user the opportunity and the freedom to build what

they have in mind regardless of the types of tools they decide to use. Thus, they might as well use the tools we provide them, but they can just as easily opt for any other set of tools available. It does not matter, and their choice does not affect their creation because, from our part, the solutions provided are easily integrated. This way, functionality, modification and reusability are not obstructed nor affected in any way, as they do not rely on any proprietary solutions.

RISC-V International and Libre Space Foundation: where the two converge

For us at Libre Space Foundation, becoming a Member of RISC-V International is a great honor as we see eye-to-eye with it. This is a partnership towards making open-source even more powerful and enhancing the efforts to familiarize wider audiences with it.

Libre Space Foundation functions and operates within a niche industry, and this is particularly challenging at times. We do believe that the challenges arising can be dealt with effectively when open-sourced methodologies are applied. These should be implemented widely not only when it comes to creating Space Technologies but also on ISA too. End-to-end, open-source methods to enable modifications enhancing functionality, to bring in new users and expand the pool of active contributors.

What is more, we believe that the significant challenges that we face within the space industry can be managed successfully through the pursuit of strategic partnerships with space agencies, academic institutions and other organizations that believe in the power of openness and collaboration.

All these are part of how we see innovation, development and progress should unfold, and for this, we have joined forces with RISC-V International.

Deep Learning and Space Weather in GSoC’s 2020 Libre Space Foundation contributions

In May 2020, we announced that Libre Space Foundation would be mentoring two projects for the Google Summer of Code 2020. As the students are about to submit their final work, we would like to share with you an overview of their achievements/progress this summer. One of the GSoC proposals is to create a Python module to assist SatNOGS operators in tackling RF collisions. More details on the progress of this project and an update about it will be given to you on the SatNOGS blog within the next weeks.

Today, however, we will be focusing on the hard work Adithya Venkateswaran has put in as a valuable member of the Polaris project team. Adithya maintains a personal blog walking the readers through his work and the final post on his GSoC contribution was the inspiration for this post.

Polaris: a quick technical overview.

Before delving into Adithya’s work, allow us to provide some background information, helpful context on what Polaris is about.

Polaris is a command-line based, satellite-telemetry analysis tool using machine learning. Space operators usually have to deal with a lot of telemetry parameters from their satellites, and it is often hard to understand how they impact each other on a global picture. Polaris makes use of the XGBoost algorithm for eXtreme gradient boosting to predict every telemetry in the satellite and provide their inter-importances (like a dependency without the causality). The importance of links between telemetry parameters is represented as a graph in a web-based 3D interface. 3d-force-graph is the graph component used for the output.

Polaris output of CubeBel-1

Practically Polaris consists of four distinct parts:

  1. polaris fetch: It fetches data from various sources, such as telemetry from the SatNOGS Network and Space Weather from SWPC (NOAA).
  2. polaris learn: A machine learning (XGBoost) based module that analyses the relationship of all the data “fetched” and provides a JSON graph file as an output.
  3. polaris viz: A 3d graph-based visualisation module, which offers an intuitive graph representation of data.
  4. polaris anomaly (WIP): An autoencoder-based tool (betsi) that detects anomalies in telemetry data and warns satellite operators. In other words, deep learning for space operations.
Polaris architecture

Adithya worked on several parts of the project and added useful functionality. His main contributions to Polaris were two new modules “Vinvelivaanilai” & “Betsi”.


Vinvelivaanilai is the word for space weather in Tamil. Vinvelivaanilai is a Python module which uses File Transfer Protocol services to fetch space weather data from SWPC/NOAA’s servers and stores it locally or in InfluxDB-based docker-containers.

It also contains functions to parse TLEs and OMMs (any GP data) and propagate the orbit to find the position and velocity of the satellite at any time.
The red coloured nodes in the following graph are derived from Vinvelivaanilai.

Red coloured nodes derived from Vinvelivaanilai


Betsi is shorthand for “Behaviour Extraction for Time-Series Investigation”. It makes use of deep-learning techniques to detect anomalies in the telemetry data. The spectrum of an anomaly is broad and it ranges from a simple orientation change to a mega-scale explosion. An explosion capable enough to wipe out all of humanity according to Adithya’s post. But of course, we wouldn’t like the latter to occur.

As the Betsi development team states

If it happened, betsi detected it*.

* You can always change the sensitivity though 😛

In the following graph, the black dotted lines are the breakpoints. Keep in mind though, that at the moment, we are working on finding a better way to represent 200 parameters used for anomaly detection. If you believe you can contribute to the project with ideas, your expertise and knowledge, don’t hesitate to reach out to the team by joining their matrix/element chatroom

anomaly detection graph

Student Takeaways

As Adithya stated in his blog post, participation in the Polaris project was a more diverse learning experience than what he had expected initially. To this, we believe, that the catalytic factor was the Libre Space community and its continuous effort to share knowledge. Adithya has been an invaluable and active member of this community from the very start. And we could not be more thrilled to see him contribute and participate with such a zest and devotion.

  • Adithya learned to read, comprehend in-depth and implement research papers contributing to Betsi’s creation.
  • He learned to interface to FTP over Python and learned to create a stable API to fetch space weather data.
  • Tested several DBMS to find the best pick for space weather data which will also be future proof.
  • He familiarised himself with the Polaris API in-depth to be able to add weather data. Enabling, thus, Polaris to provide better results.
  • Learned to work on CSS and JavaScript to create a blog documenting his work and so inspiring us to write this post.
  • While also contributing to improving the web graph user experience.
  • Currently, Adithya is working on analysing a way to skip the normalisation steps (which converts data to SI units), which will allow Libre Space Foundation to support all satellites whose telemetry can be decoded. At the same time, he is collaborating closely with a satellite team to perform further tests.
  • As an active member of our community, Adithya has helped greatly guiding new users interested in Polaris to set it up.

Future work

In the future, Adithya and the rest of the Polaris team will be working on integrating Betsi into Polaris and create a way to represent Betsi’s data in a meaningful and useful manner. They will also focus on improving the experience of the visualisation module and adding more input from SatNOGS in Polaris as soon as all the afore-mentioned changes and improvements are implemented.

Community takeaways

Adithya’s final GSoC blog post carries a very moving message for his mentors.

All of this was possible because of your support. You not only helped me in my work but also helped me grow as an individual. I learnt so much more than just programming. I learnt to respect and enjoy the open-source culture, make my own decisions, put my point across and defend it. I learnt to be self-sufficient but also approach you when I need it (you were always there to guide me). If any of you are reading this, please know that you have helped me realize the potential I carry in me and I will forever be indebted to you for that!

We wholeheartedly believe that both on an individual and on a community level, our contributors deeply desire to empower their fellow community members and work hard towards achieving that. They do so with as much devotion as we have for the open-source technologies and methodologies. It is the inspiring combination of our community (and its members) and the Open methodologies we follow that empower everyone to continuously dream, contribute and innovate. We truly believe Adithya is one such valuable member of our community, and we cannot wait to see what the future holds for him and see him thrive.

Gr-leo: A GNU Radio open-source space channel simulator

In order to understand what gr-leo is and why it is considered to be a powerful, open-source simulation tool, let us first take a look at why it is necessary. Gr-leo is here to fill a gap and to ensure that the quality of communication between a satellite and the ground station is not impaired in any way.

The case

For the success of a satellite mission, there are many conditions that should be taken into consideration. Telecommunication between Earth and a satellite plays a vital role in that success. However, the quality of the telecommunication can be majorly affected by a number of parameters. These can impact and reduce the quality of transmission between Earth and a Satellite. Some of these parameters are: the relative motion of the orbiting satellite, the operating frequencies, the antenna set-up and of course the atmospheric phenomena. In order for the parameters to be predicted, the system should undergo extensive testing under realistic channel conditions and not in a lab environment as that would not be realistic enough.

The solution

Gr-leo is an open-source, simulation tool that facilitates the testing of all these parameters under realistic channel conditions. It allows for the continuous testing of a system’s development, debugging and evaluation. This way the channel conditions are simulated to be realistic enough and indicative of the failures which might affect telecommunication.

The Build-up

Gr-leo is built with the implementation of a GNU Radio module. An Out-of-the-Tree module is a GNU Radio component that no longer lives under the GNU Radio source tree. This means that one can use the basic GNU radio blocks and reconfigure them so as to extend their functionality as they deem necessary. The new blocks created are also available to the community and can be combined with the existing blocks. This is the case with gr-leo. It adheres to the programming notion of blocks as it is found on GNU Radio, but there are new blocks created to suit the project’s needs. GNU Radio provides the community with a vast range of signal processing and channel estimation blocks. However, these can not extensively cater to the needs of a space telecommunication channel. This is why in order to build gr-leo new processing blocks were configured; with each block simulating a different component found in the space channel communication.

A more detailed look into gr-leo

Gr-leo is an open-source, space channel simulator; a tool created to facilitate the simulation of the Earth-Satellite system operation and to explore the possible failures that may occur in space channel telecommunication.

At the core of gr-leo is the channel model definition. The channel model definitions link the different components making up the Earth-Space communication system with a single GNU Radio block. The blocks are synchronous. Their functionality is to pass the signal from the input port to the worker function, alongside a pointer to the output buffer for the duration of satellite observation. A channel model block accepts a list of required parameters that need to be taken into consideration during the channel simulation. Gr-leo is efficient and versatile not only because it creates the appropriate realistic conditions for testing but also because it explores a wide range of parameters in great detail.

Below is an example of a UPSAT flowgraph combining gr-leo and the UPSAT transmitter. Both are included in the gr-satnogs module.

UPSAT gr-leo flowgraph
UPSAT Transmitter

By using the gr-leo module with the GNU Radio Companion integrated blocks we succeed in:

  • Defining a satellite and describing its orbit by providing a valid TLE.
  • Defining a tracker by specifying its coordinates, the operating frequencies, the antenna type and an observation time-frame.
  • Defining the communication channel model and specifying the desired attenuation types which need to be simulated.

Once these parameters are specified, the channel model block attenuates the input signal according to the defined channel model and the orbit of the satellite described by the TLE.


Gr-leo is an open-source space channel simulator developed as a subactivity of SDR Makerspace. It is created to facilitate testing (under realistic conditions) of all those different parameters affecting the quality of transmission between a ground station and an orbiting satellite. Built on the GNU Radio’s programming blocks it adheres to the open-source principles. It extends the use and functionalities of the basic GNU blocks in order to be able to serve the needs and the purposes of a space telecommunication channel. gr-leo is open-source and the blocks created are available to be used by the GNU Radio community. Contrary to other telecommunication channel simulation projects which are proprietary and provided under expensive licenses, gr-leo is open-source, available for everyone in the GNU Radio community to use and it is a powerful and efficient simulator.

If this sounds interesting to you and you wish to find out more you can take a look at the public repo, the wiki and the documentation pages! Feel free to join our community to share your thoughts and ideas!