NASA reaching for the heavens, and beyond

From sampling comet dust to probing for life on one of the moons of Jupiter, the vision of space exploration for the early 21st century is an ambitious one
By Paul Hoversten

       The final frontier is about to become a busy place.
       Once the domain of a few intrepid explorers, human and robotic, the solar system and points beyond will be bursting with activity in coming years. NASA is charting a new course of exploration of the early 21st century that includes a search for signs of life within our solar system and for Earth-like planets outside it.
       In just a few years, an armada of little robot spacecraft will be swooping through space like curious tourists. The ships will be snatching dust from the tail of a comet, probing the icy slush of Jupiter's moon Europa and firing space "bullets" at Martian moons so they can bring the debris to Earth.
       Far beyond Earth, new space telescopes with 10 times the power of the Hubble will be seeking out other planets where life might have been or may still be. But NASA will have to be content with just looking. It would take decades or even hundreds of years for today`s spacecraft to even get close to the neighborhood of such faraway galaxies.
       Closer in, astronauts will be settling into the $40 billion International Space Station for six months or more starting in 2002. What they learn may help set the stage for a manned mission to Mars in the next century. Construction is due to start next year.
       "You're going to see the next 10 years far more exciting than the last 10," says Charles Elachi, head of space and Earth science programs at NASA's Jet Propulsion laboratory in Pasadena, Calif. "This is just the beginning of the appetizer. Now we'll have the main course coming."
       That main course is coming with less money. The space agency's budget has been shrinking during the past few years. It's about $13.5 billion for 1998, down $1 billion from its peak in 1993.
       Here's what's on NASA's drawing boards:
1997: Mars Global Surveyor, launched last year, arrives at the Red Planet Sept. 11 for a two-year mapping mission. From its orbit 234 miles up, the Global Surveyor should be able to spot both the Pathfinder lander, which touched down July 4, and its rover, Sojourner. Eight other spacecraft, some with surface rovers, are being built to visit Mars, leading to a mission to return a soil sample from the planet in 2005.
1998: A revolutionary spacecraft called Deep Space 1 will be launched in July to fly by Mars, an asteroid and a comet in a two-year test of new technologies. The probe will be the first to use electrically charged particles from the sun to move through space instead of liquid-fueled rocket engines. Its success could revolutionize space travel.
1999: Deep Space 2, being launched to Mars in January will carry a basketball-size shell that will fall to the Martian surface and shatter. Then a lipstick-size "microprobe" will drill 6 feet into the soil to see whether Mars has water beneath its surface.
1999: The Near Earth Asteroid Rendezvous, launched in 1996, arrives in February at the rocky asteroid Eros about 240 million miles from Earth. NEAR will orbit the 25-mile-long Eros for a year to study the composition of one of the largest asteroids that crosses Earth's orbit. After that, the probe will attempt to land on Eros.
1999: Also in February, Stardust will take off for the comet Wild 2 to catch some dust from its tail and return it to Earth.
       Snatching the dust is no easy feat. Stardust will use a sort of giant catcher's mitt made of aerogel--an amazing light-weight insulation that is 99% air--to capture the particles.
       Stardust will rendezvous with Wild 2 about 240 million miles from Earth and will get as close as 93 miles to the comet. Once the dust is captured, the spacecraft will head for Earth and release a capsule containing the dust into Earth's atmosphere, where it will parachute to the ground.
       If all goes well, scientists should have the comet dust in their hands in 2006. Because comets are thought to have sprinkled organic chemicals--building blocks for life--throughout the solar system, scientists hope to learn more about how the early solar system formed.
       Others missions on the drawing board are awaiting final approval this fall. NASA probably will pick one:
2002: Aladdin would gather samples of the Martian moons Phobos ("fear") and Deimos ("terror") by firing four small bullet-type penetrators into them and collecting the dust during slow flybys. Aladdin then would return the dust to Earth for study.
2002: Contour would map the cores and analyze the dust of three comets.
2002: Genesis would collect a sample of the sun's "wind," or charged particles ejected from the star's surface, and return it to Earth. The spacecraft would collect the dust in a capsule that would be dropped to Earth when the probe swung past.
       Genesis wouldn't get too close to the sun, where surface temperatures reach 10,000 degrees. It will be just 930,000 miles from Earth, or 92 million miles from the sun.
2002: Messenger would orbit the planet Mercury, taking measurements of the surface and studying the chemistry of the planet closest to the sun.
2002: Venus Environmental Satellite would study the atmosphere and climate of Earth's neighbor.
       In 2000, NASA will pick one of these deep-space missions:
2003: The Europa Lander would fly to Jupiter's icy moon and send a spacecraft down to melt its way through the crust. When it reached what scientists think might be water, it would release a tiny submarine to seek out possible life.
2003: The Pluto-Kuiper Express would give NASA its first look at the most distant planet in the solar system. Pluto is so far away that it would take at least 12 years to get there using today's technology.
       While some or all of these spacecraft are cruising the soar system, NASA plans to launch at least three successors to the Hubble Space Telescope:
2003: The Space Interferometry Mission would map nearby stars to see whether they wobble along their paths under the gravitational influence of planetary companions. The laser-controlled telescope would be able to chart the positions of stars with a precision comparable to that of a person in New York watching a fly in Los Angeles flap its wings.
2007: The Next Generation Space Telescope would look for new galaxies. The telescope would have a unique 25-foot collapsible mirror that could be unfolded in space.
After 2010: NASA hopes to launch the Planet Finder, a set of telescopes, each 5 feet across, strung along a 240-foot-long truss. This combination of telescopes, akin to having a football-field-size mirror in space, would allow astronomers to analyze planets as far as 100 light years away. The Planet Finder would look for atmospheric gases such as carbon dioxide, water vapor and ozone that could indicate the presence of life.