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Anatomy Of A Satellite Delay
NASA artist of Hubble Space Telescope orbiting Earth
NASA started work on the now-famous Hubble Space Telescope back in 1977. At that time, the space agency wanted to launch the telescope to Earth orbit in 1985. Unfortunately, that date slipped to Fall 1986 when launch was postponed by the January 1986 explosion of space shuttle Challenger.
During the delay, NASA changed Hubble's software, upgraded the safe mode, and inserted new solar arrays and higher-power nickel-hydrogen batteries.
HST was to have cost $435 million, but delays ballooned that to $1.5 billion. It was years behind schedule in a California warehouse generating storage bills of $8 million a month.
The Challenger disaster set shuttle flights back three years. NASA knew it had to fly the huge telescope to space in a shuttle, but the space agency had trouble scheduling a launch. There was a shortage of booster fuel and Pentagon demands for early shuttle rides after flights resumed pushed the flight date into a time when the Sun would be blossoming with sunspots.
An eleven-year peak in the Sunspot Cycle was approaching. Those exploding gases on our star heat Earth's upper atmosphere, expanding it deeper into space and causing extra drag on satellites. That threatened to pull the 12-ton, 43-ft. Hubble Space Telescope down to a low orbit from which it might fall to Earth like a meteor.
The sunspots gave NASA an exasperating choice -- launch Hubble so high in the atmosphere a shuttle might not be able to reach it again for repair or else launch it so low shuttles would have to fly up every six months to boost it higher at $300 million per nudge. The space agency decided to delay the launch to prevent such frequent service flights.
Hubble finally was shipped to a cleanroom at Kennedy Space Center, Florida, in October 1989, in a special container meant for large military spy satellites aboard an Air Force C-5A cargo jet from Sunnyvale, California. The satellite was set up in NASA's large Vertical Processing Facility hangar where it was prepared for 15 years in space.
Hubble's wide-field planetary camera, itself as big as a baby grand piano, was not shipped to Florida. One of two computers to control the instrument had broken, so the camera had to be repaired at NASA's Jet Propulsion Laboratory at Pasadena. The camera was shipped to Florida in December.
At last, after the many delays, Hubble was loaded aboard shuttle Discovery and on April 24, 1990, ferried to an orbit 380 miles above Earth. That was 70 miles higher than any previous shuttle had flown.
Hubble began its solo voyage in space when astronauts used the shuttle's fifty-ft. mechanical arm to lift the satellite out of the cargo bay and drop it overboard into its own orbit. Hubble's solar arrays and dish antenna were extended. Two astronauts almost had to spacewalk when a solar panel didn't unfold until the third try. Their work done, the astronauts flew the empty Discovery home April 29.
Postscript:
Since its launch in 1990, NASA space shuttles have flown to HST twice for updates, repairs and refueling -- in 1993 and 1997. A third maintenance visit will be in Dec. 1999 or Jan. 2000.
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