ESA Science & Technology - INFO 20-1997: ESA is now a major player in global space science

1 - Results from current missions

• Results from the star-fixing satellite Hipparcos, released this summer to the world's astronomers, give the positions and motions of 118,000 stars a hundred times more accurately than ever before.
• Every day the Infrared Space Observatory, ISO, examines 45 cosmic objects on average at many different wavelengths never observable before, giving fresh insights into cosmic history and chemistry.
• Invaluable new knowledge of the Sun comes from SOHO, the Solar and Heliospheric Observatory, which is the first spacecraft able to observe the Sun's deep interior as well as its stormy surface and atmosphere.

2 - Besides these missions making present headlines, several other spacecraft are helping to fulfil ESA's scientific objectives.

• The launch in October 1997 of ESA's probe Huygens, aboard the Cassini spacecraft bound for Saturn, foreshadows a breakthrough in planetary science in 2004. That is when Huygens will carry its scientific instruments into the unique and puzzling atmosphere of Saturn's moon Titan.
• Ulysses, also built in Europe, is exploring hitherto unknown regions of space, after making the first-ever visit to the Sun's polar regions in 1994-95. It will return to the Sun in 2000-2001, to observe the effects of the climax of solar activity due at that time.
• The Cluster 2 mission, announced in April 1997 and to be launched in 2000, will explore the Earth's space environment far more throughly than ever before. ESA's decision to replace the four Cluster satellites lost in a launch accident in 1996 ensures that Europe will continue as the leader in solar-terrestrial research in space.
• An example of the three unique 58-mirror X-ray telescopes for the XMM mission was unveiled for the press in May 1997. When it goes into orbit in 1999 XMM will make, in seconds, observations of cosmic objects that took hours with previous X-ray astronomy missions.
• The Hubble Space Telescope, in which ESA is a partner, continues to deliver the sharpest pictures of the cosmos after its February 1997 refurbishment. Europe's astronomers make outstanding use of their right to make observations with Hubble, guaranteed by ESA's participation.

ESA's table d'hôte for Space Scientists

To provide world-class opportunities in space for Europe's scientific community is one of ESA's primary duties. The successes summarized here are not a matter of luck, but of decades of sustained planning and effort. Although ESA's science budget is small as compared with NASA's equivalent programme, and is even being squeezed, yet every one of ESA's missions is first in its class.

3 - The scientists of ESA's member states draw up the table d'hôte, with a balanced menu of research opportunities in Solar System exploration and in astronomy. ESA coordinates the technological and scientific efforts across Europe needed to accomplish the missions, after many years of preparation and sometimes adversity. One of ESA's strengths is that it sticks to its promises, and maintains a balance with several small missions, remaining alert to new tasks for short-term projects. Besides the spacecraft mentioned earlier, ESA is actively working on:

• Rosetta: as the successor to the very successful comet mission Giotto, which intercepted Halley's Comet in 1986 and Comet Grigg-Skjellerup in 1992, Rosetta will confirm ESA's role as the world leader in comet science. To be launched in 2003, Rosetta will rendezvous with Comet Wirtanen, and fly in close orbit around it as it makes its closest approach to the Sun ten years later.
• INTEGRAL: adapted from the XMM spacecraft to save money, INTEGRALl will go into orbit in 2001 and renew ESA's role in gamma-ray astronomy, pioneered in its COS-B mission some twenty years ago. Gamma-rays reveal the most violent events in the Universe, including the gamma-ray bursts that are exciting astronomers greatly at present.
• FIRST and Planck Surveyor: FIRST is a long-standing major project to extend the scope of infrared space astronomy to wavelengths longer than ISO's. Planck Surveyor was recently selected as a medium-scale project, to chart the cosmic microwave background carefully enough to trace the origin of the galaxies. ESA is now examining the option of combining these two missions in a single spacecraft, for launching in 2005.

Prominent among other enticing possibilities is Mars Express, a high-level, low-cost mission that could set off for the Red Planet in 2003. It would give Europe an important stake in the exploration of Mars, by remote sensing from an orbiter and by experiments in landers. The latter can exploit ESA's experience in preparing for the Huygens mission to Titan. Some of the Mars experiments should be readily adaptable from instruments prepared for other missions.

4 - ESA is also considering SMART missions, using small satellites to test key technologies. Solar-electric propulsion, long seen as a much-needed advance in spacecraft engines, could take a small spacecraft to the Moon and then onwards to an asteroid. A second candidate for a SMART mission would develop drag free technologies for testing Einstein's theory of gravity. Other possibilities under review include participation in a replacement for the Hubble Space Telescope, and opportunities for science associated with the International Space Station. In addition, three major projects have been selected by Europe's space scientists as long-term goals.

A spacecraft to orbit the hot planet Mercury, barely explored till now, will shed new light on the history of the Solar System. An astronomical interferometric mission using two or more telescopes in combination will observe the stars and galaxies more accurately by visible or infrared light. And a novel kind of astronomy is promised by an ambitious gravitational-wave mission to detect radiation predicted by Einstein's theory of gravity, which supposedly stretches and squeezes space itself.

In short, ESA is delivering superb space science and, if future funding allows, has exciting ideas for the new millennium.