NASA denies hiding Mars probe flaws

NASA denies hiding Mars probe flaws

United Press International - March 21, 2000 22:50

By JAMES OBERG

HOUSTON, March 21 (UPI) -- A NASA spokesman vigorously denied a United Press International article that NASA knew that the Mars Polar Orbiter was doomed prior to its December crash into Mars but kept the information from the public.

Brian Welch, director of public affairs at NASA headquarters in Washington, said "we think the story is whacko in every particular."

Two American probes to Mars were lost last year. On Sept. 23, the Mars Climate Orbiter was steered too close to the planet's atmosphere and was destroyed. On Dec. 3, the Mars Polar Lander disappeared during an attempt to land near the Martian south pole.

The loss of the first probe was explained by NASA last week as management error. Program officials without adequate experience or training did not recognize and react to a series of clues that the vehicle was off course.

The UPI story, relying on several sources close to NASA's investigation of the second accident, claimed that the second probe was lost due to a fundamental design flaw in its braking rockets. It alleged that this flaw had been recognized before the landing and that NASA experts privately realized there was no way to correct for it.

"The story's major assertions are all wrong," Welch said. He promised that an official statement would be issued by the agency.

Welch specifically denied that NASA's concerns over the Mars craft's braking engine were covered up. He cited a Nov. 10 news conference at which the concerns were disclosed.

Welch conceded that the UPI article's description of a second design flaw involving landing sensors was accurate. Preflight testing failed to notice that when the craft's landing legs opened, they could accidentally trigger a sensor which was designed to notice when the legs hit the martian surface. As a result, the sensor might have shut down the craft's braking rockets while it was still far off the ground.