Future Mars Missions To Face Greater Scutiny


Sunday, December 5th 1999, 12:00 am
By: News On 6


NASA's ambitious campaign of Mars exploration could face uncertainty after the embarrassing loss of an orbiter in September and the growing likelihood that the Polar Lander may never be contacted. For a third day Sunday, the lander failed to signal Earth, although engineers believe it made a safe landing.

The space agency has been launching orbiters and landers every26 months since 1996 to explore the Red Planet's climate history, geology and water, paving the way for samples to be returned to Earth and, eventually, humans to be rocketed to Mars.

In the rush to launch probes faster and more cheaply, components and systems from one mission are often duplicated in another. It usually is a reliable way to cut down on development costs. The fear is that whatever might have caused the $165 million Mars Polar Lander to disappear could affect the Mars Surveyor 2001mission, now nearing the end of its development. Polar Lander and its 2001 cousin have similar structures, landing systems and protective heat shields. Both were designed and built by Lockheed Martin Astronautics, where the metrics mix-up that doomed the Mars Climate Orbiter originated.

"Whenever we have a problem of any type, we re-evaluate where that might be used in the future," said Sylvia Miller, a Mars program architect at NASA's Jet Propulsion Laboratory. "We look at what might be needed to be changed."

But until Mars Polar Lander is actually confirmed dead and investigators are able to determine a cause, it is impossible to know how such a loss would affect future missions, said Carl Pilcher, NASA's science director for solar system exploration.

"There's no question because of the similarity of designs ...if the lander were to be lost, surely it would have an impact on what we're doing in '01," he said. "What that impact would be is impossible to say right now."

The Sept. 23 loss of Climate Orbiter will be felt more in how future missions are run than how the spacecraft are made. Investigators were critical of JPL for failing to catch the error that caused the $125 million probe to burn up in the Martian atmosphere.

A report blamed the loss on a failure to convert navigation data from English units used by one group of technicians to the metric system used by aknowledge about the spacecraft. Poor communication between JPL and Lockheed Martin also was cited. NASA added more engineers to the Polar Lander flight team and reviewed every aspect of the mission. Another report will be issued Feb. 1 to address the issue of future missions. The 2001 mission is near the end of development in a phase of integration and testing, Miller said.

A lander is to be launched April 10 from Cape Canaveral, Fla., while an orbiter will take off March 30 from Vandenberg Air Force Base near Santa Barbara, Calif. A small rover -- an exact duplicate of the Mars Pathfinder's Sojourner -- will accompany the lander, which will carry mineralogy experiments, a robotic arm and instruments to conduct the first assessments of radiation on Mars. The orbiter will carry a gamma-ray spectrometer that will attempt to measure the abundance of frozen water immediately beneath the surface -- something Polar Lander was supposed to do locally near Mars' south pole.

Missions still under review for 2003 and 2005 would collect soil and rock samples that would be returned to Earth in 2008. One benefit of quick, inexpensive missions is that instruments lost on one probe could be duplicated and squeezed onto a future mission, Pilcher said.

"Because we have a continuing program, we have opportunities to recover the science," he said.