Innovative project to return small capsule from space using

20 September 2007 by DELTA-UTEC SPACE

After 11 years of dedication a unique European satellite will be carried into space by a Soyuz rocket from the Baikonur Cosmodrome September 14th.

For Delta-Utec Space in Holland the launch is the culmination of over a decade of lobby and development effort. And even though Delta-Utec is only a small company, the result is to become the longest structure ever in space. Rather than using a rocket engine, the emptiness of space is exploited by using a massive slingshot, a 30 kilometer tether, to

accurately deliver a small capsule from space to the Earth. The capsule itself, Fotino, is 40 cm in diameter and weighs only 6 kg. It is planned to land on the steppes of Kazakhstan on September 25th.

The concept of using a tether to deliver packages from space to Earth, "SpaceMail", was brought forward in 1995 by Dutch astronaut W. J. Ockels. Using a tether for this purpose would reduce system complexity, storage risks and fuel cost. Leiden-based R&D company Delta-Utec has since worked on maturing the technology for a demonstration flight. In 1996 Delta-Utec built its first tethered satellite, YES (Young Engineers'' Satellite), as part of the European Space Agency''s (ESA) TEAMSAT, launched on Ariane 502 in 1997. Its sequel on the launch pad is simply called YES2. Tethers have flown several times successfully in space, but 30 kilometers would be an absolute record. The tether can be seen from some spots on the Earth with the bare eye and will seem to the observer to be even larger than the Moon. Mission success could give an important push to the use of space tethers, now still only an image from science fiction. There are many potential applications such as artificial gravity in spacecraft using a rotating tethered system (such that astronauts on the way to Mars can walk rather than float), propellantless propulsion using the interaction of the Earth''s magnetic field and a metal tether suspended from a spacecraft or coordinated science measurements by tethering multiple satellites together. The YES2 tether is employed in yet another way: as a spaceslingshot, using the principle of "momentum transfer" to change orbit in space without using fuel. It is made from Dyneema and despite its length weighs only 5 kg. This light and strong material is used today for sports with extreme demands, such as kite-surfing, and for bullet-proof vests. Delta-Utec has brought forward all these technologies over the past decade with a broad research program

and is with that one of the world''s leading experts in the field.

As for the re-entry aspect of the mission, little is still understood about the dynamics of gases under the extreme temperatures that occur as a capsule rushes into the atmosphere from space. Michiel Kruijff, the company''s CTO and YES2 Lead Engineer, explains. "The capsule, called Fotino, is lighter than any other capsule before - therefore there are not yet reliable models that can calculate the heat it will be subjected to. We have interpolated between existing models, tested the result in a plasma chamber and trust the capsule will survive. On-board are many sensors that may shed light on this matter to support design of future capsules."

YES2 was born five years ago, in 2002, as one of the ESA experiments on the Russian microgravity platform Foton, supported and largely funded by ESA''s Education and HME Departments.

During the course of YES2 development, the innovative tether deployment system and re-entry capsuleheatshield were qualified. Apart from the technology carried, the project is unique because it is fully designed and qualified by students. It is the first time that such an ambitious project has been developed by students to meet the Space Agency''s high quality standards.

"We started the project with a tour around Europe to meet 350 students in person, and brainstorm with them about the project," says Kruijff. "YES2 could make a difference because we had a very personal relationship with the students and universities and cared for their interests. The students paid back with their astonishing effort. It has been 5 years of late nights and short weekends."

 

After a preliminary design phase in which 25 universities participated, 4 YES2 "Centers of Expertise" focussed on the detailed design and tests (in Krefeld, Patras, Samara and Reggio Emilia). The satellite was eventually constructed and qualified by a group of 25 interns brought together in ESA''s technology center, ESTEC. Academic support came also from beyond Europe''s borders: universities from Australia, USA, Canada and Japan contributed significantly.

Kruijff says: "Many companies and experts we encountered are afraid to give students truly

responsible tasks. But they tend to forget that geniuses like Werner von Braun and Albert Einstein made their most ground-breaking achievements before the age of 30. Dare to give young people responsibility and some of them will turn out to be great innovators, developers and eventually, leaders. In YES2, students and universities novel to space were given the possibility to proof themselves." Apart from succeeding in building a complex satellite, the young people and universities of YES2 brought many valuable innovations to the often conservative space industry by introducing and qualifying non-space technologies, such as textile technology for the tether test facility, modern insulation materials for the heatshield and modern IT for the satellite''s software and ground support.

Working with students also presents its challenges. Students often need several months to get

accustomed and often are required by their curriculum to leave before they can finish their

task. "Information transfer between the generations and providing consistency throughout the project has been one of my key duties," says Kruijff. In addition, throughout the course of the project, the project was descoped or expanded several times and also the launch long remained uncertain, thus renewing again and again the challenge and need for high spirits.

Finally, also in the quest for technological solutions, the project went through challenging periods despite the motivation and the contributions of the newborn student stars. ESA experts and aerospace companies -like Bradford Engineering, Emxys, Activespace and TNO- as well as space experts acting on a personal basis helpfully jumped in to get the project back on track. Kruijff:

"Students can get very far, but maybe not all the way to the finish line without involved professionals behind them."

Erik J van der Heide, Delta-Utec CEO and YES2 project administrator concludes: "Based on the YES2 lessons learned, if we appreciate and combine both the strengths of the students and that of the industry I would say innovation can be done tomorrow for half the price that is common practice today. This means that not only students learn but innovation is done that otherwise would not be affordable. Everyone benefits."

 

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