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The European Space Agency (ESA) a menu of new space missions, for 2008-2013.
By Leonard David
Senior Science Writer
posted: 05:00 pm ET
13 October 2000
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esa_future_001013 WASHINGTON -- The European Space Agency ( ESA) announced today a go-ahead on a wide-ranging menu of new space missions, to be implemented in the years 2008-2013.Five spacecraft projects -- including a mission to Mercury, sending a probe to the Sun and a search for gravity waves -- have been picked. A sixth project to spot habitable planets is on "reserve," depending on the health of future space budgets, both at ESA and NASA. The "package" of approved ESA science missions, several of which are in collaboration with NASA, are: Bepi-Colombo to explore the planet Mercury, to be launched in 2009 in collaboration with Japan GAIA, which will study the composition, formation and evolution of our Galaxy by mapping with unprecedented precision 1 billion stars and launched no later than 2012 Laser Interferometer Space Antenna (LISA) -- the first gravitational-wave space observatory, in collaboration with NASA Next Generation Space Telescope (NGST), again in collaboration with NASA Solar Orbiter, a successor of the SOHO and Ulysses missions that are now studying the Sun.Technology challenge ESA engineers will have their hands full in building the challenging roster of spacecraft. Bepi-Colombo is no exception. It will use a new solar-electric propulsion system to help it reach Mercury. 
An artist's impression of a Solar Orbiter. The spacecraft will face severe problems due to the searing heat, due not only to direct sunlight 10 times more intense than that in Earth's vicinity, but also to the infrared rays radiating from the planet's surface. The heat loads affect every aspect of Bepi-Colombo's design and construction. Special gallium arsenide solar cells -- used to power the spacecraft -- will have to cope with high light intensities as well as high temperatures. The Bepi Colombo mission was named after the late Italian scientist, Giuseppe Colombo of the University of Padua. Much of what is known about the planet Mercury is based on the NASA Mariner 10 flybys of the planet in 1974-1975. Those closeup looks at Mercury were inspired by Colombo's calculations. He suggested how to put Mariner 10 into an orbit that would bring it back repeatedly to Mercury. Colombo had researched a peculiar habit of Mercury in that it rotates three times in every two revolutions of the Sun. ~ ESA will work with NASA on another difficult-to-do project -- the LISA spacecraft mission. LISA calls for three spacecraft orbiting around the Sun. Spread out 3.1 million miles (5 million kilometers) apart, the trio of probes will comprise a gigantic triangle. Laser beams relayed between the LISA spacecraft will check their distances. Small changes in the separations of the spacecraft, occurring over seconds or hours, will tell of passing gravitational waves. Turning its back on Earth GAIA will be a 3-ton (2,700-kilogram) spacecraft suitable for launch by Europe's Ariane 5 rocket. It will go to a station 900,000 miles (1.5 million kilometers) out on the dark side of Earth, at LaGrange Point No. 2 (L2).At that point, the gravity of the Sun and Earth combine to create a place of rest relative to our planet. With its back turned to Earth, a wide "collar" outfitted with solar cells will shield GAIA from the light of Sun, Earth and Moon. GAIA will revolve slowly, scanning circles around the sky.GAIA will be geared to give precise and detailed information about the billion brightest objects in the sky. This unprecedented census, said ESA scientists, should have the same sort of impact on astronomy as brand-new overviews have had on other branches of science, such as weather satellites in meteorology or genome projects in genetics. Stellar closeups The Solar Orbiter would fly on an extended orbit that, at times during its mission, takes it to within about 19 million miles (30 million kilometers) of the Sun -- much closer than the innermost planet, Mercury. At its closest approach the spacecraft would round the Sun at roughly the same rate as the solar sphere itself rotates, so that it should seem to hover over one region. Besides giving unprecedented closeup views of the solar surface and atmosphere, the orbiter would directly sense how solar wind and energetic particles behave in the Sun's vicinity. With the passage of time, Solar Orbiter's orbit would slant at an increasing angle to the solar equator. Presence of planets One ESA project is on reserve status, the Eddington -- a mission to map stellar evolution and find habitable planets. This spacecraft could be implemented depending on the NGST and LISA schedules or provision of further resources.Eddington would take up station far from Earth and use a 3.3-foot (1-meter) telescope with a wide field of view to examine stars for oscillations and passing planets. Capable of scanning some 50,000 stars of many different kinds, Eddington would also check 700,000 stars for the presence of planets, revealed by a dip in stellar brightness when a planet passes in front of the star. Prior to detailing today's selection of future scientific missions, ESAs director of science, Roger Bonnet, said, "in spite of financial restrictions, the science program of ESA is still alive." He emphasized that ESA continues to launch the missions it promised, is harvesting a wealth of science results from its space-science missions, and is looking for avenues of international collaboration. "Space science is a constantly renewed source of knowledge," Bonnet said. "It is good that through ESA and its science community, Europe should show to its taxpayers and to the rest of the world its talents, its successes and its contribution to knowledge," he said.
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