While waiting for the first ESA student CubeSat to be deployed from the International Space Station at the beginning of October, the three Fly Your Satellite! CubeSats candidate for rocket launch are completing their environmental test campaign.
During the past few months, the student satellites had to pass a number of tests in order to make sure they would be able to perform properly in the harsh conditions encountered during launch and in orbit. This test campaign represented Phase 2 of the Fly Your Satellite! educational programme.
The satellites were tested before, between, and after being exposed to extreme environmental conditions, such as vibrations and temperature cycles in a thermal/vacuum chamber. These tests are necessary to demonstrate that the CubeSats are capable of working in these harsh environments and are not visibly damaged by them.
The three CubeSats that underwent the 'Fly Your Satellite!' environmental test campaign are presented
OUFTI-1, developed by students from the University of Lige, Belgium, successfully underwent the Thermal Vacuum Thermal Cycling test in 2014 (see article here). However, during the vibration test campaign that took place in November of that year, an anomaly was observed (see article here), and required the interruption of the vibration tests. A Non-Conformance Report was generated, corrective actions were identified by the students in consultation with ESA specialists and were successfully implemented. The vibration test campaign was repeated in March 2015 at ESA's Space Research and Technology Centre (ESTEC) to see if the corrective actions implemented had resolved the problem. Additional vibration tests were carried out in April 2015 at V2I, a company close to the University of Lige, and no new anomalies were detected. The OUFTI-1 environmental test campaign was finally completed successfully.
The AAUSAT4 CubeSat, developed by students from the Danish University of Aalborg, underwent a Thermal Vacuum - Thermal Cycling test campaign, and also did a first partial vibration test campaign in the last quarter of 2014. New vibration tests on AAUSAT4 were performed in April 2015 at Hytek, a company in Aalborg that closely collaborates with the students from the University. During the test campaign a malfunction was observed, related corrective actions were identified by the CubeSat team and the ESA specialists and were subsequently implemented by the students. The malfunction detected during the vibration tests demonstrated once more the essential value of performing accurate testing on the ground, as this enabled the team to resolve the malfunction before launch, thus avoiding that a similar anomaly could occur during the actual mission.
The Est@r-II CubeSat, developed by students from the Polytechnic University of Turin, performed its first Vibration Test Campaign in April2015 at ESTEC. An anomaly was observed on one of its subsystems, leading to the interruption of the test campaign in order to investigate the issue. In close agreement with ESA, corrective actions were implemented, and the CubeSat did a vibration test again in May 2015. Soon after, the CubeSat team performed two weeks of Thermal Vacuum Thermal Cycling test campaigns, during which the satellite underwent four cycles of alternating hot and cold temperatures in vacuum conditions. At various predefined intervals, functional tests were performed according to a pre-defined test plan in order to assess the satellite's ability of working during its mission to space.
Preparing for Phase 3 Selection
The CubeSat teams are currently finalising their test reports as well as a set of additional documents to be delivered as part of the Phase 2 data package. Together with ESA specialists, some students are also working on the finalisation of non-conformance reports in order to document the root causes of anomalies and malfunctions that came up during tests, and to describe the corrective actions implemented. After the delivery of the data packages, which also include the demonstration of compliance to frequency registration and space debris mitigation requirements, ESA will select the teams that will participate in 'Ticket to Orbit!', Phase 3 of the 'Fly Your Satellite!' programme. Phase 3 will include the preparatory actions for launch, the integration of the CubeSats in their orbital deployer, the delivery to the launch site, and the installation on the launch vehicle.
When this phase is completed, the programme will enter its fourth and final phase called 'CubeSats in Space', where teams will finally see their satellite launched into orbit, and will perform the satellite operations needed to accomplish their space mission.
"Now that the 'Fly Your Satellite! CubeSat environmental test campaign' is over we can say that the three university teams personally experienced the key importance of performing an accurate verification of their satellites on the ground so as to significantly increase the chances of mission success," says Piero Galeone, Head of the Tertiary Education Unit at ESA. "Several anomalies and malfunctions were detected, and a few of them could have been fatal if they had occurred during the actual mission. Instead, their detection on the ground allowed the student teams to investigate the root causes and identify and implement corrective actions. Now we can predict that those same malfunctions will not occur during the real mission".
Note: All Thermal Vacuum Thermal Cycling, and most of the vibration tests executed during Phase 2 of 'Fly Your Satellite!', were executed at the ESTEC Mechanical Systems Laboratory.
Background: Fly Your Satellite!
Fly Your Satellite! was introduced by ESA's Education Office in January 2013. Its main purpose is to assist university students in the design, development and testing of their CubeSats through the transfer of technical competence and experience from ESA specialists.
The initiative gives students the opportunity to get acquainted with good practice standards in space engineering, and support is offered in the verification of their spacecraft, thus helping to improve the chances of mission success.
Fly Your Satellite! follows the successful programme that in 2012 launched the first CubeSats supported by ESA: seven student-built CubeSats that were launched onboard the first flight of ESA's new Vega launcher. It also builds on the experience that ESA's Education Office developed in CubeSats environmental tests when they supported the thermal vacuum - thermal cycling test campaign of the HumSAT-D CubeSat from University of Vigo .