Slipping across the vacuum void of interplanetary space, U.S. spacecraft have made up-close-and-personal treks to all the known planets except Pluto. The names of a few of these far-flung robot explorers are likely to sound familiar: Mariner, Viking, Voyager, Magellan, and Galileo. Each spacecraft has helped unravel the secrets of the solar system, adding to our zeal for exploration and fostering a sense of wonder about the surrounding universe.
Nestled within the San Gabriel Mountains near Pasadena, California, the Jet Propulsion Laboratory (JPL) is the leader of NASA's Space Science Enterprise. Managed for NASA by the California Institute of Technology, JPL is the space agency's Center of Excellence in deep space systems.
JPL also manages the worldwide Deep Space Network, radio dish complexes situated in the Mojave Desert near Goldstone; near Madrid, Spain; and near Canberra, Australia. This network communicates with spacecraft and conducts scientific investigations.
Looking back to 1973, the laboratory was undertaking several major flight projects, in addition to preparing for two major missions to come. Mariner 9 became the first spacecraft to orbit another planet--Mars. Studies of the data acquired by the Mariner continued throughout 1973, offering new discoveries about the Mars atmosphere, topography, and gravity field.
Yet another Mariner was leaving its launch pad on November 3, 1973. It would later become NASA's first dual-planet mission, flying by Venus February 5, 1974, then onward to make a succession of Mercury flybys in 1974 and 1975. This spacecraft, Mariner 10, was the first to use "gravity-assist"--a method that is akin to celestial square-dancing, using the gravity of one planet to slingshot a spacecraft onward to another. The innovative technique has been applied to many space craft missions over the years, with more being planned.
Today, the Jet Propulsion Laboratory's agenda is a far-reaching one compared to its early, pioneering work.
JPL has long been a reservoir of the best scientific minds and engineering muscle to conceive and execute robotic exploration of the Moon and planets. Ranger and Surveyor missions to the Moon prepared the way for Apollo astronauts to explore that barren and crater-pocked globe. Mariner spacecraft reached Mercury, Venus and Mars, unlocking the mysteries of those distant worlds. Each successful mission was a trailblazer.
In the mid-1970s, strange shadows fell across the face of Mars. Two Viking robot landers touched down on the reddish Martian sands in July and September 1976. As two Viking Orbiters circled the red planet, the Viking Lander duo carried out an extensive reconnaissance of Mars, including a search for evidence of Martian life. The elaborate Viking program involved several NASA centers, with JPL building the Viking Orbiters, conducting mission communications, and eventually assuming responsibility for mission management.
Launched in 1977, JPL's twin spacecraft Voyager 1 and Voyager 2 chalked up interplanetary mileage by flying past Jupiter and Saturn. Voyager 2 then went on to encounter the Planet Uranus in 1986 and Neptune in 1989. These Voyagers are just that, both voyaging out toward interstellar space, still communicating scientific findings, perhaps until the second decade of the 21st century.
|The Cassini spacecraft is placed on a trailer at NASA's Jet Propulsion Laboratory for transport to test facilities.|
Ulysses is a joint NASA-European Space Agency undertaking to explore, for the first time ever, the Sun's polar regions. JPL scientists are analyzing data gathered by Ulysses in 1994 and 1995, preparing for yet another set of polar fly-overs in 2000 and 2001.
In 1996 into early 1997, images and data relayed from Galileo as it circled the massive planet were staggering in detail. Particularly exciting are stunning photos taken of Jupiter's moon, Europa. Scientists wonder whether or not this ice-covered moon might harbor primitive life. Galileo's tour-of-duty has been so spectacular, NASA is extending its data-gathering tasks into 1999.
JPL has designed and built the Cassinimission to Saturn, slated for launch in 1997. It arrives at the ringed world in 2004. Cassini carries the European Space Agency's Huygens probe, destined to land on the surface of Titan, Saturn's largest moon. This moon is an apparent locale for organic chemistry possibly like that which led to life on Earth.
Mars once again is being targeted. The planet is to be orbited starting in 1997 by the Mars Global Surveyor while the Mars Pathfinder is built for landing. After touchdown, the Pathfinder lander will dispatch Sojourner, a micro-rover.
JPL's Surveyor program for Mars involves lander and orbiter missions with each launch opportunity--about every two years--well into the 21st century. Work is underway to detail a 2005 robotic return sample mission from Mars. This string of Surveyor orbiter and landers may well answer conclusively whether or not life has been, or is even now, present on Mars.
Other JPL missions being readied include Stardust. To be rocketed spaceward in 1999, this probe heads for comet Wild-2, collecting dust and other materials tossed off from the object, then return those samples to Earth. Actually landing on a comet and hauling back to Earth cometary material is the 21st century flight of JPL's Champollion spacecraft.
The innovative New Millennium program is a high-tech initiative that promises to overhaul how space science missions are conducted. These craft are to be smaller, more compact and more versatile than the robotic explorers of the past. This breed of microspacecraft is geared to validate state-of-the-art electronics, propulsion, guidance and control, including a host of sensors and other devices. New Millennium also spearheads new industry and university partnerships with JPL.
New Millennium's Deep Space-1, being readied for launch in 1998, is to be propelled by an ion-engine, rendezvousing with both a comet and asteroid. Deep Space-2 centers on New Millennium Mars Microprobes, small penetrators that will slam into the Martian surface, dispatched from the Mars Surveyor 98 spacecraft. Developing the technology required to search for planets circling other stars is New Millennium's Deep Space-3 interferometry mission in 2000. Deep Space-4 is to test an array of Earth remote sensing technologies, also in 2000.
Another 21st century mission is Pluto Express, a two-probe encounter with the outermost planet now known and its moon, Charon, perhaps in 2010.
JPL is preparing the turn-of-the-century Space Infrared Telescope Facility (SIRTF) project. This 2001 spacecraft is being blueprinted to probe hundreds of thousands of celestial objects invisible to conventional telescopes. SIRTF would complete NASA's series of
"Great Observatories," telescopes based in space that study the universe at wavelengths ranging from visible light to x-rays and gamma rays. Part of SIRTF's work is to probe the realm of very young galaxies in the process of forming.
|Mariner 10, launched on November 3, 1973, was the first to use "gravity-assist," using the gravity of one planet to slingshot a spacecraft onward to another. The innovative technique has been applied to many spacecraft missions over the years, with more being planned.|
Although known world-wide for space exploration, JPL contributes to Earth observation missions as well. In fact, JPL is the largest provider of science instruments for NASA's Mission to Planet Earth program.
JPL's sensor technology expertise has been applied to the U.S.-French TOPEX/Poseidon, lofted in 1992 to acquire data on the oceans' role in climate change. The Spaceborne Imaging RadarC/X--band Synthetic Aperture Radar--has collected information on geological processes and air-sea interactions and is a collaborative project of NASA, the German Space Agency and the Italian Space Agency.
Japan's Advanced Earth Observing Satellite (ADEOS), orbited in August 1996, carries a NASA Scatterometer (NSCAT) to help decipher change in Earth's climate, and to help improve accuracy of weather forecasting and the nature of destructive storms. In 1997, JPL selected four industry teams to implement LightSAR, a proposed new Earth-imaging satellite. LightSAR would use advanced technologies to reduce the cost and enhance the quality of radar-based information for scientific research, commercial remote-sensing and emergency management applications.