ESA To Hear Proposal To Finance Life-Extending Space Tug

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A European industrial team is expected to present a proposal this summer to the European Space Agency (ESA) to co-finance development of a space tug to provide life-extending fuel to telecommunications spacecraft in orbit.

After three years of development work partially funded through ESA’s Artes telecommunications research program, Dutch Space and its ConeXpress Orbital Life Extension partners would appear to be facing a make-or-break year in 2006.

Leiden, Netherlands-based Dutch Space — which in December was acquired by EADS Space Transportation — and its partners are seeking about 80 million euros ($97 million) in funds from ESA. The industrial team and ConeXpress marketing manager Orbital Recovery Ltd. of Britain would be responsible for finding a matching amount.

Dutch Space officials said that with about 160 million euros, they will be able to complete the design, production and launch of the first ConeXpress module, which could be launched aboard a European Ariane 5 rocket in 2009.

SingTel Optus of Australia is one of several satellite-fleet operators that have shown an interest in the system, but no operator has yet committed to providing ConeXpress’ first target satellite.

Dutch Space and some ESA officials believe ConeXpress will succeed where other satellite in-orbit servicing projects have not.

“Satellite life-extension system designs in the past have been overly complex and expensive,” Gianfranco Visentin, head of automation and robotics at ESA’s Estec center here, said April 5. “ConeXpress captures a satellite, clasps down and that’s it — 10 years of life is added. We have managed to convince satellite users to look at this.”

The ConeXpress hardware is based on the existing Ariane 5 payload adaptor. After Ariane 5’s main telecommunications satellite payloads are released into orbit, the ConeXpress vehicle is separated, its solar arrays extended and its electric-propulsion system switched on.

Using electric propulsion provides weight and volume savings but also means it would take the ConeXpress module several months to climb from geostationary-transfer orbit to geostationary orbit, where it would attach itself to the target satellite via the larger vehicle’s motor nozzle.

ConeXpress would provide up to 10-12 years of additional life to an aging spacecraft by keeping it in its proper orbit. When a satellite’s onboard fuel is exhausted, its orbit begins to drift, ultimately rendering it useless even if its transponders remain operable. Alternatively, the ConeXpress vehicle could provide a few years’ additional service before placing the target satellite into a graveyard orbit 300 kilometers above the geostationary arc, and then returning to geostationary orbit to salvage another aging spacecraft.

The preliminary design review for ConeXpress was completed in March. Dutch Space has been working on the system with the German Aerospace Center, DLR; Kayser-Threde of Germany; Sener of Spain; the Swedish Space Corp.; and Contraves of Switzerland.

Geert Mennenga, Dutch Space’s director of strategy, said ConeXpress is in line with the company’s focus on space robotics. Dutch Space does about 60 million euros in annual revenues, and its other two business lines are satellite solar arrays and Ariane 5 components including the payload adaptor.

“We think we have answered a lot of the early questions about safety and insurance, and our new owners have backed us in the ConeXpress work,” Mennenga said here April 5 during an ESA presentation of the Dutch Space-built European Robotic Arm, ERA.

The 630-kilogram, 11.3-meter-long ERA is a largely autonomous, seven-jointed system designed to move astronauts and hardware weighing up to 8,000 kilograms from point to point on the outside of the international space station.

The ESA-funded system, which has cost the agency some 200 million euros, is expected to be shipped to Moscow in August and be attached to the outside of Russia’s Multipurpose Laboratory Module. It is slated for launch in 2007.

Philippe Schoonejans, ERA project manager at ESA, said the arm is capable of memorizing the station’s design to avoid banging into the complex’s various modules and support structures. The basic mission is automatic, with minimal astronaut intervention needed. “This is very much a robot,” he said.

ERA’s seven joints are assembled so that the shoulder end can become the hand, and vice versa, permitting the arm to maneuver itself from place to place on the station. Its electrical system is programmed to prevent one side from letting go before the other side is attached.

ERA’s development has mirrored the complexity of the station’s overall assembly. It was originally designed to launch aboard a Russian Proton vehicle. When the Russian module designed to carry it was canceled, ERA was redesigned, at considerable cost, for launch aboard the U.S. space shuttle.

When the station’s assembly was rearranged following the loss of the Columbia shuttle in 2003 , ERA was reworked to be put back onto the Russian rocket. Wrapped around the Russian module, ERA just barely fits under the Proton vehicle’s fairing, but only if its handles are removed. Station astronauts will reattach the handles once ERA is at the station.

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