April 26, 1990

Astronauts deploy space telescope

Launch encounters trouble

By MARK CARREAU

After a trouble-plagued day that took them to the brink of a spacewalk, NASA's Discovery astronauts on Wednesday successfully deployed the Hubble Space Telescope.

The $1.55 billion space telescope drifted free of the shuttle's grasp at 2:38 p.m. CDT.

The maneuver came as Discovery soared over the Pacific Ocean northwest of the Galapagos Islands with the observatory secured to the end of Discovery's outstretched robot arm.

"Thanks for the great work you've done. It's special working with you," said veteran shuttle astronaut Story Musgrave, who was stationed in Mission Control to converse with the Discovery crew.

"Galileo is real proud of you," added Musgrave, a reference to the 17th century Italian physicist. Astronomers compare the significance of Tuesday's launch of the 12 1/2-ton observatory to Galileo Galilei's early studies of the universe with a crude telescope.

"It was our pleasure, too," responded Discovery commander Loren Shriver.

The deployment came about only after ground controllers overcame a problem in unfurling the telescope's solar panels, needed to supply power.

Moments after deployment, the Hubble's control system and solar panels started to function. Shriver and shuttle pilot Charles Bolden then steered Discovery to a position 45 miles behind the telescope, where it will trail until ground controllers have finished testing the Hubble's operation.

The door which covers the opening of the telescope is slated to flip up by midday Friday, flooding the Hubble's observing mirror with starlight for the first time.

Next week, during early focusing trials, the space agency plans to make public a test image of a star field in the Southern Hemisphere called NGC 3532.

However, scientists and engineers at the Space Telescope Science Institute at Johns Hopkins University in Baltimore and a 24-hour control facility at NASA's nearby Goddard Space Flight Center, expect to spend eight months testing the Hubble's performance before it begins its celestial observations.

NGC 3532, (the initials stand for New General Catalog of 1888), is a fairly bright cluster of about 150 stars. The cluster is in the southern sky, below the horizon for viewers in Houston.

Wednesday's deployment activities started smoothly, as astronaut Steve Hawley commanded Discovery's robot arm to grasp the telescope, which was secured in the shuttle's payload bay.

Carefully, Hawley lifted the Hubble from its resting place, inching it out with such caution that plans for a 1:15 p.m. deployment fell about 30 minutes behind schedule.

That was not of great concern, however, because the Hubble's batteries were able to furnish sufficient electricity for the telescope's scientific instruments and communications needs until 3:30 p.m.

That was contingent, however, upon the telescope's two winglike solar panels unfurling on schedule.

Supplied to the Hubble program by the European Space Agency, the panels were designed to take over for the batteries by converting sunlight into electrical power.

Positioned on opposite sides of the telescope, the 10-foot-wide, 40-foot-long panels were rolled up like window shades and bundled in packages, or booms, that folded against the observatory at liftoff.

When ground controllers experienced some difficulty pivoting and locking the booms into place, Discovery astronauts Bruce McCandless and Kathy Sullivan began some of the elaborate preparations to undertake a spacewalk in the event more serious schedule problems developed.

With the booms in place, the telescope's left side "window shade" solar panels unfurled in response to remote commands. The right side "window shade" stalled, however, because of a control device intended to protect the unfurling fabric from undue stress.

It took three attempts and a command radioed from the ground to override the control device and coax the second solar panel to unwind fully.

By that time, McCandless and Sullivan, both veterans of previous spacewalks, were dressed and waiting in Discovery's airlock, prepared to venture outside and manually crank out the panel.

"They were probably 30 minutes away from being out in the payload bay with tools in hand and ready to work," said NASA lead flight director Bill Reeves.

The shuttle program's most recent spacewalk occurred during a December 1985 flight, and the next is not planned until this November.

Sullivan expressed slight disappointment at the lost opportunity.

"Close, but no cigar," said the first American woman to walk in space. "Better for the Hubble it went the way it did.' The shuttle is scheduled to land at 8:49 a.m. Sunday at Edwards Air Force Base in Calif.


HUBBLE

An archive of news items chronicles the telescope's history.