Young Engineers' Satellite 2

The reconstructed deployment of the YES2 tether, i.e., the trajectory of the Fotino capsule in relationship to the Foton spacecraft. Orbital motion is to the left. The Earth is down. Mount Everest is shown several times for scale. The Fotino was released at the vertical, 32 km below Foton, about 240 km above the surface of the Earth, and made a re-entry towards Kazakhstan.

The Young Engineers' Satellite 2 (YES2) was a 36 kg student-built tether satellite that was part of ESA's Foton-M3 microgravity mission. The launch of the Russian Foton-M3 occurred on September 14, 2007, at 13:00 (CEST) by a Soyuz-U launcher lifting off from the Baikonur Cosmodrome in Kazakhstan.[1] Foton-M3 returned successfully to Earth on 26 September 2007, landing in Kazakhstan at 7:58 GMT.[2] The YES2 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 deployment took place Sept. 25, 2007. The mission objective was to deploy a 30 km long and 0.5 mm thin tether (made of Dyneema) in two controlled stages, in order to release a small, spherical, lightweight reentry capsule called Fotino into a predetermined trajectory to a landing area in Kazakhstan.[3] The scientific objectives of the mission were achieved. The YES2 featured the first multi-stage tether deployment. It could be reconstructed within about 20 m accuracy for the first stage (3400 m) and 100–150 m for the 31.7 km deployment as a whole. The first stage was deployed accurately (about 10–20 m error), the second stage overdeployed by 1.7 km. Fotino released as planned during a swing of the tethered system through the vertical (as seen from Foton). The tether properties, deployment dynamics and tether deployer system performance could be evaluated. The tether deployer performed nominally. However, due to an electrical fault, the on-board computer failed to register the final length correctly and only a partial deployment was initially reported based on telemetry available in real-time. Initial deployment friction was found to exceed the nominal range, revealed by post-mission testing to be most likely due to a thermomechanical settling of the tether spool.[4] Some weeks after mission completion, analysis of the full data set confirmed that the tether deployed to its full length of 31.7 km.[5][6] No signal was ever received from the "Fotino" re-entry capsule after separation, and it was lost.[4] YES2 established a new world record as the longest artificial structure in space and was later included in the Guinness Book of Records Edition 2009.[7]

  1. ^ "Lift-off for Foton microgravity mission". ESA.
  2. ^ "Foton-M3 experiments return to Earth". Retrieved 2007-09-26.
  3. ^ Katharine Sanderson (2007-09-26). "Dropping a line from space". Nature. 449 (7161): 387. Bibcode:2007Natur.449..387S. doi:10.1038/449387a. PMID 17898730.
  4. ^ a b ESA YES page
  5. ^ Michiel Kruijff; Erik J. van der Heide; Wubbo J. Ockels (November–December 2009). "Data Analysis of a Tethered SpaceMail Experiment". Journal of Spacecraft and Rockets. 46 (6): 1272–1287. doi:10.2514/1.41878. Retrieved 9 April 2023.
  6. ^ Michiel Kruijff, "Tethers in Space, a propellantless propulsion in-orbit demonstration", ISBN 978-90-8891-282-5([1])
  7. ^ "YES2 team claims a space tether world record". 2007-11-08. Retrieved 2008-07-10.