Nikoletta Triantafyllopoulou, Author at Libre Space Foundation
2 - 3 minutes
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 SatNOGSby Corey Shields | Libre Space Foundation
“MetaSat: An Open Metadata Toolkit for SmallSat Missions” by Daina Bouquin | Harvard-Smithsonian Center for Astrophysics
“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!
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.
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 element.io), 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), Element.io 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.
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 communications 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 the Firefly Aerospace’s DREAM payloads program on its inaugural Firefly Alpha launch.
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.
While the hardware was undergoing all the testing, the software was polished and tested too, aiming at enabling a series of fascinating communications 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 communications experiments. These are primarily scheduled to take place during the Launch and Early Orbit Phase (LEOP) of the operations and the 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 and several communications experiments that need to be conducted in search of possible solutions.
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 space-track.org 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 they 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.
Create a reusable, open-source PocketQube Platform.
At LSF, we have been focusing our attention to 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 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 afore-mentioned objectives to the fullest. These will be investigated in-depth through a series of communications experiments regarding Identification and Tracking of Satellites.
This part of the experiments focuses on radio beacons and Telemetry transmissions, and they include:
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 preamble not an ideal solution to allow unambiguous identification.
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 experiments that LSF will be running as this experiment 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).
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.
Differences in beacon cadence can also help distinguish between satellites, through 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 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 experiment, the RILDOS proposed protocol was chosen, transmitting a beacon with low transmission power. The basic idea which 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 experiment LSF will attempt exploring possible techniques that can be applied on 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 experiments that are scheduled to be conducted in QUBIK-1 and QUBIK-2.
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.
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.
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 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 to be 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.
Both procedures took place at the LSF Headquarters, at hackerspace.gr, in the centre of Athens, Greece and were carefully orchestrated and successfully carried out while being streamed live on the LSF YouTube Channel.
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 communications 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 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.
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.
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.
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 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.
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.
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.
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.
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.
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!
Libre Space Foundation is an organization dedicated to creating open-source, space technologies. Often we come across a project that wishes to join us, or we are approached by exciting initiatives to assist them in their endeavors. However, joining LSF as a project is a process that must meet specific criteria and particular requirements. In this article, we wish to clarify a project’s eligibility to join LSF while at the same time, we elaborate on the pillars of the Libre Space Manifesto and the philosophy governing Libre Space Foundation. This article is not about the management, the organization or the development process alone. It is about the principles fueling our approach. It is about how and why we do things differently.
Joining the Libre Space Foundation
For us, the Manifesto is found at the core of our operations and processes. Thus, all projects and all project decisions must adhere to the Libre Space Manifesto. The projects must abide by the Manifesto principles starting with the primary principle that Space should be open and available to all humanity. All the projects that join us are devoted to Space being available to all and open for everyone to explore. All projects we onboard work towards creating opportunities for learning, exploring innovative ideas and bringing Space closer to the public (such as LSTN offering public library communities the chance to build and engage with space technology).
For the principles of the Libre Space Manifesto to materialize, there are four pillars to which all our practices adhere.
Open-source, copyleft license.
Based on the Libre Space Manifesto, the projects joining LSF must have an open-source, copyleft license for anything developed and released within the project. For those not familiar with the term, a copyleft licensing scheme is a process that allows people to freely distribute copies of a certain work or even modified versions of it. Provided that the same rights will be preserved in derivative works created later down the line.
It should be noted that we strive to use open-source tools and applications, and it is imperative for the projects onboarded to adhere to the open-source methodology at every step of the workflow. In practice, we develop and use open-source tools and software, we modify them, explore their potential, and then we give back to the open-source community by distributing our work under an open-source, copyleft license.
The significance of this approach is that new types of software, features, projects and initiatives are created under an open-source license which enables their use by everyone who needs them. This approach delivers free solutions and tools and it guarantees that new ideas can continue to explore new potentials, fuel solutions and features for other individuals to enjoy.
Open Data (available to everyone in the community or to anyone who is interested).
According to the Libre Space Manifesto, all findings, all data should be available to everyone. Open data has always been in the core of our operations. The SatNOGS network, our global network of satellite ground stations, is a collaborative, world-wide community which receives satellite data. The observations made are stored online in the SatNOGS Database and are available for everyone to see and use. SatNOGS Database is a machine-readable data resource. The Open data approach we have at LSF has helped many projects, teams, universities to study Space and satellites in much detail. It has facilitated and helped other projects too. Polaris, par example, uses telemetry data that is received by the SatNOGS network of satellite ground stations.
Following Open Development processes.
At LSF, true to our beliefs, we use open development processes for our projects. We use Gitlab for organizing, managing, developing our projects and for the teams and team members to communicate efficiently. Since our collaborators, contributors and team members come from all over the world, Open Development processes are the best way to include everyone in the development process. This way we achieve a natural flow of conversations and contributions as the team members work towards accomplishing a common goal (or towards working on completing a project).
Every contribution, every idea and every discussion benefits not only an individual but the whole team, the whole project and often the contributions made are beneficial for other projects too. This, of course, is one of the advantages of open-source and open development.
Sequentially, under an open development process, documentation of the code is open for the public to view and detailed to allow for a better understanding of how a project works. New members can be introduced to the complexities of a project faster, and a greater audience of collaborators can contribute more easily. Code is tested in a collaborative way focusing on high-quality but often achieving fast progress, too. The team members can review the code, offering feedback, flagging problems early on, suggesting solutions and resolving issues. Quite often, this discursive approach to a project and the exchanging of ideas leads to the emergence of new and innovative projects and useful tools.
Open development processes is a common practice for us; an approach taking place on all channels of communication: on Gitlab, on the LSF Riot Channels and our Community Forums too. Consequently, this takes us to the next significant pillar of the Libre Space Manifesto.
Open Governance (with transparency and direct communication) for all projects.
As mentioned above, we try to use tools in our projects which are open-source. We use Matrix/Riot for all communications concerning the projects. We have a buzzing, collaborative and constructive community where individuals contribute. They share their worries, their problems, their achievements and their ideas. As project discussions and interactions are held in public, they become accessible to everyone, and everyone can join. This, in fact, has a catalytic impact on the way the community manages itself while working as a whole. The projects govern themselves, delegating responsibilities and asking for assistance or advice always having the project’s best interest at heart. Though different projects have different maturity levels and thus different governance paradigms, yet they too follow the general open governance principles. These include unrestricted participation, open and clear communications and decision making processes, and accountability for project roles.
Being part of the Libre Space Foundation
Once a project is given the green light to join LSF, then it receives the support and the tools necessary for project development, operations, legal guidance and even marketing, branding and communications. LSF guides the project through to success and completion. If your project meets all the necessary requirements and provided it adheres to the Libre Space Manifesto principles, LSF will give you all the assistance, guidance and tools to see it through.
If the way we do things sounds fascinating to you and you wish to join us, feel free to check out the Libre Space Manifesto! Don’t hesitate to show your support by signing up and sharing it with your friends and network!
For the second year in a row, Libre Space Foundation was selected as a mentor organisation for the Google Summer of Code initiative. The application period has closed and the results are in, and so it is with great excitement that we announce the two projects we will be mentoring over the next few months.
The first project titled “Deep learning for Cubesat Behavior Segmentation with Collection of Contextual Information” will be working on the Polaris codebase. The project aims at supporting spacecraft operators by predicting the behaviour of their satellites and linking it to various data sources. There is a data challenge in collecting and sometimes in converting into time series. This data collection phase will allow for better information when understanding and estimating the behaviour of a spacecraft. External sources of data, namely, orbit propagation, solar and magnetic events, and various elements of space weather, will be some of the external sources providing the data needed. The machine learning approach employed for Polaris will transform these data sources into learning features so that a spacecraft’s behaviour is not only predicted but also explained by the “machine”. Deep learning means that the project is exploring the usage of different neural network architectures of several layers. The project is undertaken in close collaboration with the amazing team of the Polaris project.
The second project that Libre Space Foundation will be mentoring is a “Python Module for RF Collisions”. This project’s goal is to tackle an issue that troubles satellite observers quite frequently. With the number of deployed satellites in constant increase, it is often that satellites transmit with the same or near frequencies. This overlapping of frequencies interferes with the results of the observations and affects their accuracy. Thus, the project we will be mentoring aims at dealing with this exact issue. By building a Python module that will allow the ground station operators to specify the time and the location this interference occurs. This project is closely related and linked to SatNOGS and it will be used by the SatNOGS network as an internal or an external tool to let the observers know which other satellites are expected to be found in the results of their observations.
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 period has been indeed a groundbreaking one as the initiative received 8,902 applications submitted by 6,626 students from 121 countries. These applications were reviewed by 199 mentoring organizations. Eventually, 1,199 students from 66 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!
Libre Space Foundation is devoted to the vision of open-source technologies in space, and for this, we often join forces with researchers, individuals, and teams who share this vision with us. One exciting project we have taken up is the QUBIK Project.
A few words about the Project
Our love for space has brought us in collaboration with Firefly Aerospace and the DREAM payloads program. This is a global competition to host academic and educational payloads as rideshare participants on the inaugural flight of the Firefly Alpha launch vehicle. For this project, we have been working together with FOSSA Systems and AMSAT EA. We have developed two PocketQube satellites, QUBIK-1 and QUBIK-2, and PICOBUS, a PocketQube deployer.
The satellites are expected to have a short lifespan of up to 3 weeks of orbit. Regardless of how short-lived they will be, though, they are built to perform a range of communications experiments. While those experiments will be taking place, the SatNOGS network of ground stations will be receiving signals from these satellites. By exploiting Doppler Variations, the network of ground stations will perform orbit determination and satellite identification as early as possible. This will utilize the benefits and the capabilities of the SatNOGS network to the fullest and demonstrate the Space Situational Awareness aspect of it.
How the Project has been progressing for the last few months
On the 12th of December 2019, the thermal vacuum test for the PICOBUS took place at Instituto Nacional de Técnica Aeroespacial, and on the 16th of the same month, the vibration test was conducted at the NanoSat Lab of the Polytechnic University of Catalunya. A few months later, on the 8th of February 2020, our team working at Hackerspace.gr completed the assembly of the PICOBUS and QUBIK-1 and QUBIK-2. The next day marked the bake out day for the project at the Institute of Electronic Structure and Laser. Lastly, on the 12th of February 2020, at the NanoSat Lab, the vibration acceptance campaign took place for PICOBUS, and so did the Protoflight campaign for QUBIK-1 and QUBIK-2. At this point in the process, the software is being developed so that the project will be able to facilitate all the experiments that need to be carried out.
QUBIK-1, QUBIK-2, and the PICOBUS deployer form an exciting project for which we have worked hard, and we have collaborated with inspiring teams. As the development draws to completion we are excited to see what this project will achieve.