After three weeks of in-orbit checkout, following its deployment from
Space Shuttle Columbia on March 9, the Hubble Space Telescope has been
declared healthy and fit by engineers and scientists at NASA’s Goddard
Space Flight Center in Greenbelt, Md., and the Space Telescope Science
Institute in Baltimore.

Initial checkout of the spacecraft and instruments has largely been
completed. However, the calibration process for the instruments will
continue for another two months. The new rigid solar arrays, coupled with
the new Power Control Unit, are working perfectly, generating 27 percent
more electrical power than the old arrays. This increase in power roughly
doubles the power available to the scientific instruments. The new
reaction wheel is operating normally.

The powerful new Advanced Camera for Surveys (ACS) is now undergoing its
final optical alignment and focus checks. The image quality of individual
stars observed in a standard calibration field is excellent. The Advanced
Camera’s light-sensing detectors are also working very well. It is
anticipated that the first Early Release Observations of astronomical
targets taken with the Advanced Camera for Surveys will be available
around the first week in May.

The new, high-tech mechanical cooler inserted by the Astronauts during
SM3B has been working continuously and properly since March 18. The
cooler’s intended purpose is to attempt to resuscitate the dormant
Near-Infrared Camera and Multi-Object Spectrometer (NICMOS), which
depleted its expendable solid nitrogen coolant in January 1999. Although
this new “refrigerator”, dubbed the NICMOS Cooling System (NCS), has been
reliably generating the amount of cooling power expected, Hubble engineers
report that the NICMOS instrument is cooling down more slowly than
originally expected. Because it will take longer to reach the proper
operating temperature, below approximately 80 degrees Kelvin, the initial
checkout and scientific observations with NICMOS will be delayed for
several weeks.

Routine science observations have now resumed with the Space Telescope
Imaging Spectrograph and the Wide Field and Planetary Camera 2, the two
instruments that were operating on Hubble prior to Servicing Mission 3B.
On another note, a gyro (Gyro 3) that had not been performing as well as
it should prior to the mission resumed perfect operation after it was
turned off and re-started while Hubble was in Columbia’s payload bay.

The Space Shuttle Columbia journeyed to the Hubble Space Telescope for the
fourth servicing mission on March 1, 2002. During a series of five
spacewalks, Astronauts installed new hardware and upgraded older systems,
leaving the telescope better than ever. After a successful mission
spanning 11 days in orbit, the shuttle landed safely on March 12 at
Kennedy Space Center, Fla.