confirmed Compton had broken apart and impacted the Pacific Ocean in its intended landing site. NASA designated a stretch of the Pacific Ocean -- about 2,500 miles (4,025 kilometers) southeast of Hawaii -- as the impact area. The location was picked to virtually eliminate the risk of human casualty.
Taking a tumble
So low was the spacecraft's last orbit, just 93 miles (150 kilometers) above Earth, that it began to heat as it skimmed through the uppermost fringes of Earth's atmosphere.
As Compton started its fall to Earth, ground controllers could see heat building up on the satellite's solar panels and an antenna. A packed room of over 30 engineers, navigation experts and spacecraft controllers anxiously looked at their monitors, watching for tell-tale signs of the satellite's death throes.
"This is a painful time for the scientists who have used Compton for nine years...as it plunges into the atmosphere and flies apart," said Neil Gehrels, project scientist for the observatory at Goddard.
Since Compton began its operation in orbit, over 700 scientists have used the satellite and its instruments to survey the surrounding universe, Gehrels said.
Hitting the wall
Slicing through increasingly thick layers of the atmosphere, Compton's demise grew near. "We're about to hit the wall," announced one controller. "We've lost lock," he said.
"The spacecraft is now tumbling, and the solar arrays are heating up," Gehrels said.
Video animation of Compton Observatory fiery reentry.
Turning into a fireball, Compton then began to break up between 50 to 43 miles (80 to 70 kilometers) altitude above Earth.
The spacecraft's solar panels and antennas were thought to pop off during the uncontrolled tumble, with the spacecraft actually melting as it plowed its way through the atmosphere.
"We started to see it loose attitude control. We saw it start to heat up a little bit. Then we lost communication. We didn't see anything in terms of breakup. That happens too late compared to loss of communication," Tom Quinn, Goddard's lead engineer for Compton's reentry, told SPACE.com.
Compton's conductor
Quinn said that preparations for Compton's fall from grace began in mid December 1999, picking up in intensity in early February.
The failure of one of the satellite's three gyroscopes in December 1999 led to the space agency's decision to shut down the $670 million satellite and terminate its time in orbit.
"This is the first time that we've done this. There were very few surprises," Quinn said. "It was like conducting," he said, underscoring the team-building necessary to bring Compton down to Earth in a controlled manner.
Since it was dropped off in orbit by Space Shuttle Atlantis in 1991, Compton had completed 51,658 orbits of Earth.
"This is an end of an era...a discovery era for gamma-ray astronomy," said Gehrels. "I admit that I shed a tear while the controllers in the other room were happy with the splashdown," he said.
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