The miniaturization of scientific instruments for space probes means that the exploration of Mars can be carried out for much less money than originally envisioned, according to a top expert for the Jet Propulsion Laboratory.
But James Cutts, program manager of JPL's Office of Advanced Science Instruments and Space Technology, Pasadena, Calif., warned against shrinking payloads so much that their instruments become "rudimentary" and fail to keep the interest of scientists or the public.Cutts spoke Tuesday at the annual Conference on Small Satellites, which will continue through Thursday at Utah State University.
JPL designs and controls many of the country's most advanced spacecraft for NASA. It is a division of the California Institute of Technology, and Cutts and other JPL experts are Cal Tech employees working to assist NASA.
About 15 years ago, NASA thought of sending an automated Mars rover to the red planet. The vehicle would weigh about 2,000 pounds - so heavy that the expense of landing it on Mars would be enormous.
Later, planners realized such an expensive mission was impossible. So a tiny rover was developed that weighed about 30 pounds.
Then two years ago, JPL began building a 15-pound vehicle to explore the surface of Mars. This "microrover" would be lofted as part of the Pathfinder program, which is being developed through partnerships among NASA, industry and the universities.
The Mars studies are called Mars Environmental Survey (MESUR) and have been scheduled for launch in 1996.
According to the American Institute of Aeronautics and Astronautics, MESUR Pathfinder development is required to cost no more than $150 million, not counting $25 million for the Mars microrover.
The prototype looks something like a toy car with six wheels, but at the cost of millions of dollars, it's no toy. It will carry a spectrometer and a stereo camera (two lenses), and radio information to a lander.
The lander, in turn, will relay data to Earth.
The small vehicle, called Microrover Flight Experiment, will be able to "traverse a region around the lander of around 100 meters," Cutts said.
He showed a photograph of the brains of the camera and spectrometer; it looked something like a computer's chip board. That part of the assembly weighs only about 18 ounces.
Another experiment JPL is designing for a Mars mission is a miniature seismometer. A typical seismograph station could weigh about 22 pounds, but JPL has been working on a much smaller one.
"The seismometer does surprisingly well," he said. In a trial of the device, it recorded a small earthquake - only magnitude 4 - that struck 70 or 80 miles from the instruments.
He projected a graph of the recording by the micro-seismometer and one made with ordinary instruments during the same quake. They were strikingly similar.
After praising the ability of scientists to shrink instruments, he added that he had "a few words of caution. . . . We need to be very careful about reducing the size of instruments we put on our planetary spacecraft to the point where the missions become unattractive."