Disco ball satellite launched by shuttle falls back to Earth

Posted: April 26, 2002

A small student-built satellite designed to be tracked by schoolchildren around the globe re-entered Earth's atmosphere Friday morning, ending the mission after just over four months in space.

Estimates say the fiery plunge back to Earth occurred within a few minutes of 1100 GMT Friday morning (7:00 a.m. EDT), most likely near the British Isles.

The Starshine 2 satellite was deployed from space shuttle Endeavour during its mission to the international space station last December.

Officials originally expected the craft to survive in orbit for up to eight months, but space weather had other plans. Increased solar activity in early 2002 caused the thin atmosphere at such altitudes to expand, therefore increasing aerodynamic friction on Starshine 2 and other satellites in low orbits.

This drag slowly lowers the orbits of all satellites in near-Earth orbits. Because Starshine 2 had no propulsion system to boost its orbit like many other spacecraft, it was forced down early.

Even with the premature return to Earth, Starshine officials say they are happy with the mission. "I'm thrilled," said Gil Moore, Starshine project director. "This is exactly what Starshine 2 is supposed to do."

A major goal of the Starshine project is to improve orbital decay predictions for all satellites, and Moore explained that the timing of the Starshine 2 mission could not have been any better. The chance to study the affect of solar activity on the shortened life of Starshine 2 aided scientists that are trying to more accurately predict the altitude decline that precedes re-entry for a number of spacecraft.

Starshine 2 was fitted with over 900 mirrors that were polished and prepared by thousands of students from across the globe. The mirrors that dot the exterior of the sphere made the 86-pound satellite look similar to a disco ball.

Sunlight reflected off the mirrors could be seen from the ground during times around sunrise or sunset, letting observers spot and track the tiny craft as it flew around 200 miles overhead.

However, a problem arose with a cold gas thruster system on Starshine 2 that was intended to keep the satellite rapidly spinning to allow for better ground sightings. This malfunction caused the spin rate of the spacecraft to significantly diminish, making naked eye observations from the ground difficult.

Although called Starshine 2, this satellite was actually the third to be launched. Starshine 3 was launched in September 2001 aboard an Athena rocket from Kodiak Island, Alaska. This craft's spin rate has also decreased quite a bit since its launch.

Starshine officials say they are preparing another pair of spacecraft for launch aboard shuttle mission STS-114 in early 2003.

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The student-built Starshine-2 satellite was deployed from space shuttle Endeavour's payload bay as the ship flew 240 miles over the South Pacific.
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This view of the Starshine-2 satellite deployment was recorded by a hand-held camcorder inside shuttle Endeavour's crew cabin.
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