Young Engineers' Satellite 2
The Young Engineers' Satellite 2 (YES2) is a 36 kg student-built tether satellite that is part of ESA's Foton-M3 microgravity mission. The launch of the Russian Foton-M3 occurred on September 142007 at 13:00 (CEST) by a Soyuz-U launcher. The project was carried out by Delta-Utec SRC and supervised by the ESA Education Office and was nearly entirely designed and build by students and young engineers.
The YES2 mission took place 2007-09-25. During the mission an attempt was made to deploy a 30km long and 0.5mm thin tether in order to release a mini-satellite and re-entry vehicle called Fotino. The telemetry downloaded during the mission showed that, after a quite nominal deployment, the tether started deploying slower than planned and stopped when it reached 8.5 km. Fotino was then released. The small, spherical, lightweight re-entry capsule, intended to demonstrate the SpaceMail concept, has not yet been successfully recovered. However, it is hoped that a transmitter on the capsule will allow mission controllers to locate its landing site[1].
The YES2 project
Most of the work done in this ambitious project (like design, manufacturing and integration) was done by students and young engineers. In total some 450 students participated.
Soon after the beginning of the project 5 so called Centres of Expertise were created. These were universities which were responsible for parts of the satellite or subsystems. The centres were: university of Samara, Russia (mission analysis, GPS); university of Modena and Reggio Emilia, Italy (re-entry capsule); Hochschule Niederrhein in Krefeld, Germany (tether); university of Patras, Greece (mechanical and thermal) and university of Kent, Great Britain. The most workload was carried out by prime contractor Delta-Utec SRC from the Netherlands, they also coordinated the students' participation.
Towards the end of the project, in the manufacturing and integration phase, the work concentrated on the Delta-Utec office in Leiden and ESA's ESTEC in Noordwijk, where the satellite was build and tested.
Part of the test-campaign:
- electromagnetic compatibility testing in the EMC-test-chamber "Maxwell"
- simulation of space environment in a thermal vacuum chamber
- vibration test on a shaker table
- functional tests of all components and sub-systems
The satellite was handed over to ESA at the beginning of May 2007 and was shipped to Samara (Russia) soon after, where YES2 was mated to Foton-M3 for the first time for test purposes. Afterwards YES2 and Foton were separated again and brought to Baikonur (Kazakhstan) by train where the whole satellite was completely integrated and mated with the launcher, a Sojuz-U rocket. Foton-M3 and YES2 finally launched on the 14th of September 2007 at 13:00 (CEST) from Gagarin launch-pad at Baikonur Cosmodrome.
Design of the satellite
There are three main components of the experiment:
- FLOYD – the YES2 deployment mechanism located on the Foton spacecraft;
- MASS – the Mechanical Acquisition and Support System;
- FOTINO – a small spherical capsule, with a diameter of 40 cm and a mass of 5.5 kg.
YES2 mission design
During the flight, FLOYD will eject the other two components. There will then be controlled deployment of a 30 km long tether. Orbital dynamics will cause the Fotino capsule to be positioned in front of the mother spacecraft. By bringing the deployment to a halt, a pendulum-like swing will be induced. When the capsule and tether are swinging through the local vertical, the tether will be cut. Since the capsule will then be going too slowly to stay in orbit, it will begin to re-enter the atmosphere from an altitude of about 250 km, protected by a heat shield made of novel materials. Once it reaches an altitude of 5 km, a parachute will deploy to ensure a soft landing on the steppes of Kazakhstan.
Links
References
- NATURE|Vol 449|27 September 2007, p387.
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