CHESS space mission

The EPFL Spacecraft team is launching a constellation of CubeSats to study the Earth’s exosphere.

These satellites will allow us to track the chemical composition of the Earth's atmosphere and its changes over time. The success of the mission will demonstrate that affordable and compact technology might have a significant influence on planetary research through an understanding of processes occurring in the atmosphere as well as their underlying causes. Moreover, our first launch serves as a foundation for future space missions, which will contribute to creating a fast track to space commercialization and even interplanetary research by making launches of compact devices more affordable and space-proven.

Video about our recent launch:


Humanity has been looking at the stars and dreaming of knowing what is up in the sky since the dawn of time. Ancient civilizations observed star constellations, and modern governments launch satellites far beyond the cradle of the planet they were born on; we share the same dream with the generations before us, but in this age, we can actually chase these dreams. And we do. We are not stargazers, we are space explorers.


The scientific goal of the CHESS mission is a comprehensive study of the Earth’s exosphere and ionosphere: observation of terrestrial atmospheric escape, its evolution, and variation in terms of atmospheric flux and chemical composition. The collected data will fill the gaps in the basic measurements of the upper atmospheric layers and thus enable researchers to:

  • Broaden and deepen our understanding of the processes and phenomena taking place in the exosphere;
  • Improve our knowledge of the human-induced and natural climate variation in order to find potential solutions to environmental challenges;
  • Develop and test methods and instruments for future exploration of other planets’ atmospheres;
  • Form a more accurate and detailed model of the evolution of the Earth’s atmosphere and explain its vital differences from other planetary atmospheres;
  • Assess the impact of the chemical sputtering occurring on solar panels and improve the technology to help it withstand harsh conditions;
  • Test the hypothesis of density variations in the exosphere being pre-warnings of earthquakes.

Therefore, the scientific value brought to society will positively impact both fundamental and applied research.


The project does not simply follow the well-trodden path to space, it brings scientific, technological, and industrial innovation. We aim at making innovative and reliable space technology affordable, and thus demonstrate that low-cost solutions can accomplish the goal. Finding reliable low-cost strategies is one of the major challenges of our age, when space exploration teeters on the brink of commercialization.


HOBC: The In-house onboard computer is a custom-built central component of the spacecraft developed by the EPFL Spacecraft Team. It executes commands, schedules tasks, and stores data.

Flight Software: The software running on the onboard computer is responsible for implementing the various modes of the spacecraft and ensuring smooth data exchange and communication between subsystems.

Electrical Power System: The EPS is comprised of solar panels, batteries, and power electronics. The EPS must generate electrical power to meet the power requirements of the satellite's subsystems and payloads, store excess electrical power generated by the power generation system for use when the satellite is not exposed to sunlight and distribute the electrical power to the various subsystems and payloads of the satellite in a safe and efficient manner.

UHF Telecommunication: The ultra-high frequency telecommunication module is equipped with a transceiver and an antenna that operates in the radio amateur frequency range of 435 - 438 MHz. It enables sending commands to the spacecraft and downlinking telemetry data.

X-Band Telecommunication: The X-band telecommunication module is equipped with a transceiver and antenna that operates in the radio amateur band at 10.45 - 10.50 GHz, allowing for high data rates to transmit large amounts of scientific data gathered by the instruments to the ground.

ADCS: The Attitude Determination and Control System is responsible for orienting the spacecraft and positioning it as desired. It can move the satellite in roll, pitch, and yaw.

Ground Segment: The ground station(s) enable sending commands from Earth to the spacecraft and receiving data from orbit. It consists of various antennas with transceivers in both UHF and X-band.

CubesatTOF: The CubeSat Time-of-Flight Mass Spectrometer, developed by the University of Bern's Space Research and Planetology division, is the principal scientific instrument flying on the CHESS satellites. Its purpose is to analyze the chemical composition of the exosphere.

GNSS: The Global Navigation Satellite System receiver, designed by the group of Mathematical and Physical Geodesy at ETHZ, enables the satellites to locate themselves in space and perform measurements on the atmosphere.


CHESS: The Constellation of High-Energy Swiss Satellites is the EPFL Spacecraft Team's flagship mission and a testament to their long-term vision. The mission comprises two 3U CubeSats, equipped with all of the subsystems mentioned, including the scientific instruments developed by the universities of Bern and Zurich. The satellites will be placed on slightly different orbits, with one circular and the other elliptical, enabling complementary measurements of the exosphere from different vantage points.

Bunny: Bunny marks the EPFL Spacecraft Team's debut in space and was developed entirely by students in just four months. It is an onboard computer that uses commercial and consumer-grade components, demonstrating their viability in the space environment. As a hosted payload on D-Orbit's ION SCV-009 spacecraft, Bunny will collect data on the behavior and reliability of its components in the first half of 2023. Lessons learned from Bunny will be used to improve the architecture of the onboard computer that will eventually fly on the CHESS satellites.

X-Band: Following the successful launch of Bunny, the next subsystem to fly to space is X-Band, targeted for Q1 2024. As no commercial options were available to meet the EPFL Spacecraft Team's needs for the desired X-band amateur frequency range at 10.45 - 10.50 GHz, the team developed tailored electronics. X-Band utilizes software-defined radio (SDR) technology and heterodyne receiver architectures to provide a flexible and agile communication system. X-Band is directly funded by the Swiss Confederation through Armasuisse via a research contract.

Twocan: Twocan is an upcoming onboard computer that will be flown alongside the X-Band module. The development and testing of Bunny revealed several limitations, particularly with regards to computational power. The primary goal of Twocan is to provide a more powerful and redundant onboard computer, replacing the unused parts of Bunny (the FPGA). This redundancy ensures that in the event of a computer failure, the other can take over, thereby increasing the reliability of the system. The redesign of the board to accommodate these changes means that only the sensors and minor parts of Bunny will be carried over to Twocan.

CanSat: The CanSat project at the EPFL Spacecraft Team was designed to provide students with first hands-on experience in developing space systems. CanSats are miniature spacecraft that simulate principal subsystems of a satellite flown on sounding rockets and recovered using parachutes. Teams develop their CanSats in a competition and collaboration with the EPFL Rocket Team.


CHESS is at the center of a growing space community connected with strong and interdependent expertise. Today, all actors of the project are heavily promoting knowledge transfer between researchers and industry, and providing advanced technology knowledge to students. Our collaboration is already strengthening the relations between Swiss space actors, and we are open to establishing further mutually beneficial partnerships with companies, research institutions, and other organizations outside of Switzerland. Even though CHESS is a Swiss space mission, the geography of our partnerships extends far beyond Swiss borders and includes sponsors from numerous countries around the world.


Studying atmosphere becomes increasingly important, because we strive to understand the composition and processes of the Earth's atmosphere better; due to climate change, monitoring the state of the atmosphere is vital; by developing methods and instruments to observe the atmosphere of our planet, we pave the way towards interplanetary travel with the objective of exploring other atmospheres.

We provide new means to solve these existing problems. CHESS is a cubesat with unprecedented characteristics. With our ground station and satellite, we provide not just a path, but a highway to space. The on-board computer was developed at record-breaking speed. It took just 4 months from a blank piece of paper to a ready-to-go OBC. The CHESS mission is not just a shot into the void that will soon fall into Lethe; the CHESS mission is a door to a myriad of opportunities, both scientific and commercial.

Since we are a non-commercial student organization, the data that we will gather will be open-source. Thus, it will be available to everyone, and anyone contributing to future research that could be based on it. Since we are not profit-driven, we cannot be swayed by any commercial motive, and our data is independent and unbiased, meaning that it is not designed to fit anyone's interests apart from the general interests of humanity. Our mission has significant educational output, for over the course of realization of the mission, dozens of students have acquired unique competencies and generated invaluable knowledge.

The generated knowledge and the acquired expertise will be used for future projects. Having succeeded in sending CHESS Satellite in 2026, we can later start sending similar cubesats with different commercial payloads. Our technology makes cubesats "smarter", and consequently, future launches could have a broader range of functions, thus more enterprises will be motivated to send their devices to space.

One of our objectives is the flight heritage of our technologies. And once they are space- proven, they can be used by companies with more trust. Businesses can benefit from the knowledge and expertise that we have obtained.


The mission is funded both by public institutions and private sponsors. The total estimated cost of the CHESS project equals to 3,4 million CHF, of which 2 million correspond to the cost of the two payloads aboard (CubeSatTOF and multi-GNSS receiver).


We are a team of dedicated students - engineers, software developers, physicists, economists, and managers - who work on the mission after classes, on weekends, at night, and sometimes even around the clock. We believe that what we are doing has enormous scientific and commercial potential, and we hope that you will believe in us.

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May 22,2023
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