Compton supporters seek reprieve for condemned observatory

The observatory was launched in 1991

May 25, 2000
Web posted at: 12:02 PM EDT (1602 GMT)

From Correspondent Miles O'Brien

(CNN) -- NASA plans to bring down the Compton Gamma Ray Observatory in less than two weeks, but some scientists want to stop the satellite from becoming the largest spacecraft ever brought down in a deliberate, controlled crash.

A final rocket thrust would aim it into a remote area of the Pacific Ocean, reducing the risk that the 17-ton observatory might crash into a populated area.

Concern over failing gyroscopes onboard the aging observatory prompted the NASA decision. Yet some astronomers contend it could make important observations in the future, and consider the concerns over safety extreme.

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"I think it has a lot of good years left. It is a real tragedy to bring it down at this point," said physicist Jim Ryan. Part of the Compton project for years, Ryan now spends nearly all of his time fighting to save the observatory.

The $600 million observatory went into orbit nine years ago aboard the space shuttle Atlantis. It quickly transformed astrophysics, changing the way scientists thought about quasars, black holes and supernovas.

"In essence we really revolutionized the field," Ryan said.

But the aging satellite has shown signs of wear in recent years. One of its three gyroscopes failed in December. It needs two working gyroscopes for a safe descent, according to NASA. Worried about another failure, space agency managers decided to send the orbiter into the South Pacific on June 4.

"To me this is a rather simple decision. It all comes down to what is the safest thing for innocent people on Earth," said Ed Weiler, NASA associate administrator.

A gyroscope-guided entry would mean a one in 29 million chance that a piece of the falling satellite hurt someone, according to NASA. Without the gyroscopes, the risk increases to one in 4 million.

But former NASA astronaut Jay Apt, who helped deploy Compton, thinks the odds are acceptable. He wonders if the space agency has overreacted in the wake of the embarrassing loss last year of the Mars Climate Orbiter and Mars Polar Lander.

"If you look back at NASA's history, that's often been the case. There has been an accident and people have gone back to an ultra safe mode for quite a bit of time," Apt said.

Ryan also expressed disappointment with the agency.

"That is not the NASA that put a man on the moon. Instead of 'Can do,' it is shrug your shoulders and, 'C'est la vie.'"

The timing is unfortunate for scientists who study gamma rays. The sun is about to reach the peak of its 11-year solar cycle, boosting solar activity and bombarding the planets with gamma rays.

Compton supporters have asked for a temporary stay of execution so alternatives can be studied. NASA has not budged.

"It is not a rocket science decision. It is almost a philosophical decision or a moral decision," Weiler said.

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