NASA's Hubble Space Telescope orbits Earth after being released from space shuttle Discovery on December 25. Photo: NASA

NASA's Hubble Space Telescope will resume routine science operations Monday evening, the first time it will have been used for science since being repaired during a Space Shuttle mission in December.

Two sets of Early Release Observations have been scheduled for this week. The first set will take place tonight, the second will extend over a 3-day period beginning on Tuesday evening. Observers will use the Wide Field Planetary Camera 2 (WFPC2) to peer into two targets, a cluster of galaxies and a planetary nebula. Scientists will need approximately two weeks to process the data and transform it into pictures ready for release. Limited prime science observations with the Space Telescope Imaging Spectrograph (STIS) will begin on January 13, and full science operations with STIS will resume on January 17.

While Guest Observer science has been scheduled at close to normal levels, Servicing Mission Orbital Verification calibrations will continue for several more weeks. Of particular interest will be the activities for commissioning the newly installed Fine Guidance Sensor 2 for guiding and verifying its long-term stability. To date, the spacecraft and all instruments are operating nominally.

HST has been unable to perform science since the failure of a fourth gyro on November 13. All six gyroscopes were successfully replaced during Servicing Mission 3A which began with the launch of Shuttle Discovery on December 19. In addition to the replacement of the six gyroscopes, a new advanced computer, voltage improvement kit, fine guidance sensor, transmitter and a solid state recorder were installed.