planetscapes WASHINGTON -- NASA is drawing up plans for the first U.S. soft landing on the moon in nearly three decades.
A robotic return to the moon toward the end of the decade is feasible, said Craig Peterson, a senior engineer at the Jet Propulsion Laboratory (JPL) in Pasadena, California. The spacecraft could grab and package lunar samples, then hurl them back to Earth. JPL is making plans for the Great Basin Lunar Sample Return Mission, replete with a lunar lander, rover and an ascent vehicle to rocket the samples Earthward.
The mission is among several that a group of international space planners is discussing as part of an effort to launch the next generation of bold, econo-class, robotic explorers.
Advances in materials, smart sensors and on-the-spot experiments are fostering an array of competitive ways to explore the solar system and beyond.
The premise of low-cost missions carrying out spectacular exploration has been buoyed by NASA's successful Discovery-class projects. The Lunar Prospector, Mars Pathfinder, Stardust and Near Earth Asteroid Rendezvous spacecraft exemplify econo-class missions of that ilk.
Econo-class explorers
Still on the drawing board, but also considered feasible early in this century are several low-cost candidate missions. These include:
- Venus Exploration of Volcanoes and Atmosphere:
A robot probe would snap the first aerial photography of the surface of
Venus. A balloon/gondola platform would drop atmospheric and camera-carrying sensors into the thick atmosphere. Cameras would be trained on ground targets, relaying up-close pictures of volcanoes and other surface features. Main Belt Asteroid Reconnaissance and Sample Return: A spacecraft would use solar-electric propulsion engines to stay 300 days at the asteroids Vesta and Ceres during a nearly 7-year mission. A smaller probe could be dropped on Vesta, to collect surface samples for return to Earth. Saturn-Ring Observer: A spacecraft would make the first close observations of Saturns mysterious rings. It would slip through a gap in the rings, hover and fly among the particles to inspect the rings' structure. The data could help scientists understand phenomena in the ring system that cannot be duplicated in laboratories on Earth. Europa Lander: A spacecraft would be sent to land on Jupiters moon Europa, which appears to have an ocean underneath its icy surface. The craft would look for evidence of living organisms or organic compounds necessary for life. Smaller probes might be dispatched from the main lander to help in the search.Planners gather
Spacecraft builders and scientists from government, academia and private companies met May 2-5 at the Fourth International Academy of Astronautics conference on low-cost planetary missions, held at The Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland.
Stamatios Krimigis, head of APL's space department, said that open competition in building and flying space missions was responsible for stirring the creative juices.
"That is the key to success. There is a plethora of concepts that offer very high science value. The more competitive, the broader the program becomes," he told SPACE.com.
APL is now controlling the lab-built Near Earth Asteroid Rendezvous spacecraft that has orbited Asteroid Eros since February.
Whether the mission is investigating Mars or other worlds, it is time to open up the solar system to competitive ideas, Krimigis said.
"There are a large number of organizations and people with ideas that have not had access to and contributed to the NASA technology pool. There is a lot of talent in the country that has not been available to NASA because the system has been closed," he said.
Ed Friedman, chief technologist for Ball Aerospace & Technologies Corp. in Boulder, Colorado, shared a similar view.
"People feel more freedom to think about inventive ways to do business. There seems to be a receptive environment for that now, particularly in the astrophysics community. The whole process of invention, of finding alternative solutions, will benefit both the commercial user and the science user," Friedman said.
Blade runners
Hopping safely about a world as strange as
Mars or Titan -- Saturn's largest moon -- is critically important. Taking to the air is one solution.George Savu of the Romanian Space Agency in Bucharest, believes that a special sort of space "helicopter" -- with vertical takeoffs and landings -- could widen the exploration of the martian environment.
The tops of the helicopter blades would be covered with solar cells. And the rotor diameter would need to be nearly 40 feet (12 meters) in order for those cells to collect enough sunlight to power the craft.
Revving up on Mars' surface, the robot helicopter would take to the air, hover at high altitude and then scoot over to another landing site.
Saturn's giant cloud-covered satellite Titan is a key target of the
Cassini/Huygens mission. Cassini/Huygens will inspect the moon between 2004 and 2008 to investigate whether conditions on Titan are suitable for life. The Huygens probe will descend to the saturnian moon's surface.The Cassini mission will surely set the stage for follow-on exploration of Titan, argues Ralph Lorenz, a research scientist at the University of Arizona's Lunar and Planetary Lab in Tucson.
A future mission will need to survey and access surface material from a number of interesting sites. Those areas are likely distant from each other, he said.
An aerial explorer of some kind is just the ticket, Lorenz said.
"Airplanes pose difficulties for surface access and either require high flight power or must have wings that are too flimsy to remain airborne. Balloons and landers are comparatively simple, but address only limited science objectives," Lorenz said. "The most promising concepts appear to be airships and helicopters."
Sail of the century
Solar-sail technology holds the great promise of opening up an era of low-cost space-exploration missions, said Manfred Leipold, an engineer at the German Aerospace Center in Cologne.
He gave a progress report on joint solar-sail efforts between Germany, the European Space Agency and NASA's Jet Propulsion Laboratory.
Solar sails are spacecraft that use the push of photons emitted by the sun for propulsion.
Ultra-thin sail materials are used with the light pressure from the sun, enabling a payload-carrying "sailcraft" to travel to the moon, Mercury or comets and asteroids.
Work is proceeding on a demonstration project of solar-sail technology, Leipold said.
Last December, the project reached a major milestone when a 4,356-square-foot (400-square-meter) prototype was unfurled in a ground test.
Next up for the sailcraft idea, Leipold said, is a possible launch aboard a modified Russian SS 18 ballistic missile. In orbit, the mechanisms to roll out the sail could be studied.
For an operational sailcraft, a French Ariane 5 booster would carry the hardware as a piggyback payload.
Once unleashed, the sail would spiral out to conduct a lunar flyby or even enter lunar orbit, he said.
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