ESA Science & Technology - INFO 26-1998: European astronaut selected for the 3rd HST servicing mission

The STS-104 crew will rendezvous with the orbiting Hubble Space Telescope, which is the size of a city bus, capture it using the Shuttle's Canadian robot arm and secure it in Columbia's payload bay. Then, working in teams of two, the four astronauts will leave the Shuttle's pressurised cabin and venture into the payload bay, performing a variety of tasks that will improve the productivity and reliability of the telescope. The four astronauts will perform a series of six "extravehicular" activities in the open space environment. Such activities are commonly called spacewalks, but this term does little justice to the considerable physical and mental efforts that astronauts need to make in doing the very demanding work involved.

The Shuttle commander and pilot for this flight have not yet been appointed, but the four designated mission specialists begin training for the STS-104 mission immediately. "The ambitious nature of this mission, with its six spacewalks, made it important for the payload crew to begin training as early as possible," said David C. Leestma, NASA Director of Flight Crew Operations at the Johnson Space Center in Houston, to which Claude Nicollier is on resident assignment from ESA's European Astronaut Centre in Cologne, Germany, the home base of the European astronaut corps.

The Hubble Space Telescope was launched into orbit in April 1990. It is one of the most capable optical telescopes available to astronomers today, producing images and spectral observations at the forefront of astronomy. The European Space Agency contributed a 15 share to the development of Hubble. One of the five scientific instruments on board, the Faint Object Camera, was built by a European industrial consortium made up of British Aerospace, Dornier and Matra under a contract with the European Space Agency. The solar arrays which provide Hubble with electrical power were manufactured by British Aerospace and Dornier.

In its eight years of operation, the telescope has not only observed relatively near celestial objects, like the planets in our solar system, but also looked thousands of millions of light years into space, taking images of the most distant galaxies ever seen. "The observations and spectral measurements taken with Hubble have improved our understanding of the origin and age of the universe. In some cases, the Hubble Space Telescope has already changed our thinking about the evolution of planetary systems, stars and galaxies," points out Roger Bonnet, ESA's Director of Science.

Astronomers throughout the world are using the telescope. European astronomers have a significant share in the scientific utilisation of Hubble. The Space Telescope Science Institute in Baltimore, USA, coordinates and schedules the various observations. Europe's centre for coordinating observations from Hubble, the Space Telescope European Coordination Facility, is located at the Headquarters of the European Southern Observatory (ESO) at Garching, near Munich, Germany.

The Hubble Space Telescope is the first spacecraft ever built that has been designed for extensive in-orbit maintenance and refurbishment by astronauts. Unlike other satellites launched on unmanned rockets, Hubble is accessible by astronauts in orbit. It has numerous grapple fixtures and handholds for ease of access and the safety of astronauts. Hence the telescope's planned 15-year continuous operating time, despite the harsh environmental conditions, and the ability to upgrade it with more powerful instruments as technology progresses. At regular intervals of 3 to 4 years, the US Space Shuttle visits the telescope in orbit to replace components which have failed or reached the nominal end of their operational lifetime and to replace and upgrade instruments with newer, better ones. STS-104 will be the third Hubble servicing mission, after STS-61 in December 1993 and STS-82 in February 1997.

To increase Hubble's scientific capability, Nicollier and his fellow crew members from NASA will remove the European-built Faint Object Camera, which has been working without any problem since the launch in 1990, and replace it with a new-generation instrument, called the Advanced Camera for Survey. With its three electronic cameras and complement of filters, this camera is expected to improve the telescope's sensitivity tenfold.

Other primary tasks to be accomplished during STS-104 mission include replacement of the existing solar arrays with rigid, high-efficiency arrays for which ESA will deliver the mechanisms, manufactured by Daimler-Benz Aerospace/Dornier. In common with optical instruments, solar arrays gradually decline in performance when exposed to the space environment. Further tasks are the replacement of a mechanical tape recorder with a new-generation solid-state recorder and the replacement of Fine Guidance Sensor no. 2, one of three such devices that help to point the telescope at a celestial target with an accuracy of 0.007 arc seconds. This is equivalent to keeping the telescope pointed at a candle in Amsterdam from Vevey, Switzerland, about 700 km away, where Nicollier was born.

The crew will also install a cooling system to improve the thermal protection of some of the telescope's systems, a new-technology cryogenic cooler for the Near Infrared Camera and Mutli-Object Spectrometer instrument and six improvement kits which will enhance Hubble's battery charge capability. In addition, they will repair and replace much of the multi-layer exterior thermal insulation on the sun-facing side of the telescope. On the second Hubble servicing mission, STS-82 in February 1997, the crew noticed peeling on several areas of the insulation and applied four patches to the worst affected areas.

Both Smith and Nicollier have previous in-flight experience with Hubble: Smith performed three extravehicular sorties during the STS-82 mission to Hubble and Nicollier operated the Shuttle's Canadian robot arm during the first servicing mission on the STS-61 mission in 1993. Foale has conducted extravehicular activities from both the Space Shuttle and the Russian Mir space station. Grunsfeld has two previous spaceflights to his credit.

For Nicollier, who was selected by ESA in 1978 in the first group of European astronauts, it will be the fourth flight into space, more than any other European astronaut to date. Prior to taking part in the first Hubble servicing mission in December 1993, he was a mission specialist on the August 1992 STS-46 mission during which Eureca - the European retrievable experiment platform - was deployed and the first Tethered Satellite System test flight conducted. In February 1996 he participated in STS-75, which carried the US Microgravity Payload experiments and the second flight test of the Tethered Satellite System.

Nicollier, who is delighted and honoured to be reassigned to a Hubble servicing mission, points out: "obviously, it makes sense to take advantage of our previous training and mission-specific experience to increase the likelihood of success, but it will nevertheless be a complex and demanding flight. 'Routine' is a word that has no place in astronaut's vocabulary."

With three previous space missions, Nicollier is thoroughly experienced in the operation of the Shuttle's robotic arm and the procedures associated with meeting, capturing and redeploying free-flying platforms from the US Space Shuttle. Regular contacts with European development engineers ensure that Nicollier's experience from the Shuttle missions will also flow into the development of European elements for the International Space Station, most notably the Automated Transfer Vehicle and the European Robotic Arm.

"Together with the selection of Pedro Duque for the STS-95 mission in October this year, and others we confidently expect in the future, the selection of Claude Nicollier, who is one of ESA's most experienced astronauts, is a clear signal of the high esteem in which NASA holds high professional skills and human qualities of Claude and the other European astronauts.

This is a sound basis for fruitful cooperation of mutual benefit on the International Space Station, where astronauts from the USA, Russia, Europe, Japan and Canada will work together closely as a single integrated crew. It is also very useful to the development work on the European-built Station elements," comments Jörg Feustel-Büechl, who, as ESA Director of Manned Spaceflight and Microgravity, is responsible not only for the European astronaut corps but for the European participation in the International Space Station as well.

Feustel-Büechl also points out that: "The Hubble servicingmission shows that men and women can significantly augment the efficiency and lifetime of complex systems in space. Humans have two essential 'built-in tools' which make them superior to any robot: their brain and their hands. No robot offers a comparable combination of high intelligence, adaptability to unexpected situations, mobility, dexterity and tactility. Robotic systems can perform pre-defined routine tasks and even support astronauts in their work, as the Shuttle's robotic arm shows, but they soon reach their inherent limitations when it comes to evaluating results and deciding what to do next. That is one of the key reasons why we are building and operating a manned space station."