A day before the Foton-M3 spacecraft returned to Earth, a small re-entry capsule, named Fotino, was to be released from the end of a 30 km tether, the longest such structure ever to be deployed in space. However, no signal was ever received from Fotino and its fate has been uncertain ever since.
First indications, based on real-time data processed by the YES2 flight computer and released by Russian mission controllers, suggested that the tether only unwound about 8.5 km before Fotino was cut free, but engineers wanted to know the full story of Fotino’s final hours. Now, after weeks of careful analysis, the YES2 team has informed the ESA Mission Review Board of its findings.
“All of the data we now have available point to the fact that the tether unwound fully before the Fotino capsule was released,” said Roger Walker, YES2 project manager for ESA’s Education Office. “This means that the most challenging part of the mission was completed and that YES2 smashed the world record for the longest man-made object flown in space.”
“This outcome can be regarded as a triumph for the students who contributed many hours of hard work to bring YES2 to fruition.”
The team of engineers from ESA’s technical centre, ESTEC, and prime contractor Delta-Utec has been piecing together the events of 25 September using evidence from a number of direct and indirect sources. Some of the most important clues have been provided by the YES2 data stored in the TeleSupport Unit, which recorded all of the data from the ESA experiments on Foton-M3. This data included raw unprocessed data about the rate at which the tether was unwinding.
“By looking at the data from the tether deployment speed sensors, we are able to determine how much of the tether was unwound and how quickly it deployed,” said Michiel Kruijff, lead system engineer for Delta-Utec. “We can tell that the deployment was accelerating in the later stages, rather than slowing down as we first believed. We have also found that the tether deployed to a minimum of 29.5 km, or more likely to its full length of 31.7 km, at high speed.”
Other indirect evidence comes from the orbital behaviour of the Foton-M3 spacecraft. Data from the U.S. Space Surveillance Network, which was tracking Foton-M3, show that the spacecraft moved about 1300 metres higher in its orbit when the Fotino capsule was cut free from its tether, as expected for a 30 km tether. However, the tracking data offer no evidence that Fotino remained in orbit around the Earth, leading the YES2 team to conclude that it re-entered the atmosphere immediately after its release.
“It seems that the braking and control mechanism did not work as expected in the later stages of deployment due to an intermittent fault in the flight computer’s real-time processing of the deployment sensor data,” said Marco Stelzer, the mission analyst in the ESA YES2 team. “This leaves us with two possible scenarios. The tether may have unwound so quickly that it broke free from the reel with the capsule still attached, or the tether jerked to a halt at the end of its deployment, allowing the capsule to be released close to its nominal position.”
Further clues will become available in the coming weeks after the YES2 team receives the complete acceleration and orientation dataset from the DIMAC (Direct Measurement micro-Accelerometer) experiment that flew on board Foton-M3. Additional information about the orbit of Foton is also expected from GPS data acquired by a student experiment from Samara State Aerospace University, one of four University Centres of Expertise that contributed significantly to the project.
“Unfortunately, we received no data from Fotino, so at the present time we have no way of knowing the fate of small capsule,” said Roger Walker. “It may have burnt up on re-entry, it may have crash-landed, it may have touched down in difficult terrain somewhere in Turkmenistan, Kazakhstan or Siberia, or its radio beacon did not transmit. However, this is the first time that a tether has de-orbited a re-entry capsule, therefore we are very satisfied that the most novel and challenging parts of the SpaceMail concept have been demonstrated.”
YES2 was one of the ESA-provided payloads on board the Foton-M3 microgravity mission. The Foton spacecraft and the piggybacking YES2 payload were launched by a Soyuz rocket from Baikonur, Kazakhstan, on 14 September. The YES2 experiment was installed on top of the battery pack of the Foton-M3 capsule.
The 6 kg Fotino capsule was attached to the end of a 0.5 mm thick, 31.7 km long tether. Once the tether unwound and deployment stopped smoothly at 30km, the Fotino capsule was to be automatically released by a pyrotechnic device and sent on a return path to Earth’s surface through the atmosphere and landing safely by parachute in a pre-determined location. The objective was to demonstrate the ‘SpaceMail’ concept of delivering parcels back to Earth from an orbiting spacecraft using only a tether.
Almost 500 students from most ESA Member States and Associated States, together with the United States, Russia, Japan and Australia, worked on YES2. Although these were mainly involved in the preliminary design phase, some 60 students participated in the latter stages of developing and building hardware and software.
Future education satellite projects already under development by the ESA Education Office include the European Student Earth Orbiter (ESEO), to be launched in 2010, and the European Student Moon Orbiter (ESMO), currently planned for 2011.
Roger Walker | alfa
German Research Foundation supports new theoretical physics project at Jacobs University Bremen
18.12.2018 | Jacobs University Bremen gGmbH
New Foldable Drone Flies through Narrow Holes in Rescue Missions
12.12.2018 | Universität Zürich
Researchers from the University of Basel have reported a new method that allows the physical state of just a few atoms or molecules within a network to be controlled. It is based on the spontaneous self-organization of molecules into extensive networks with pores about one nanometer in size. In the journal ‘small’, the physicists reported on their investigations, which could be of particular importance for the development of new storage devices.
Around the world, researchers are attempting to shrink data storage devices to achieve as large a storage capacity in as small a space as possible. In almost...
The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.
Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...
What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...
A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.
The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...
A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.
Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...
12.12.2018 | Event News
10.12.2018 | Event News
06.12.2018 | Event News
18.12.2018 | Materials Sciences
18.12.2018 | Physics and Astronomy
18.12.2018 | Physics and Astronomy