In June 1990, a few months after Hubble had been deployed into orbit, scientists discovered a spherical aberration in Hubble’s primary mirror. Aiming at correcting the optics of its flawed mirror shape and at installing new instruments as part of a maintenance plan, the first Servicing Mission (STS-61) to the Hubble Space Telescope was launched in December 1993. Among the seven-member crew was European astronaut Claude Nicollier.
The installation of a new device - the COSTAR (the Corrective Optics Space Telescope Axial Replacement - corrected the flatness problem of the mirror’s outer edge (2 microns too flat), which had been up until then responsible for the fuzzy images taken with Hubble. This abnormality was resulting in the light of the observed objects being scattered by forming a fuzzy halo around them.
COSTAR consisted on five pairs of corrective mirrors that were placed in front of the Faint Object Camera, the Faint Object Spectrograph and the Goddard High Resolution Spectrograph. This new tool successfully restored Hubble’s blurry vision.
Another major renewal was the replacement of the older Wide Field Planetary Camera (WFPC) with the Wide Field Planetary Camera 2 (WFPC2), which significantly improved Hubble’s ultraviolet performance due to the WFPC2’s incorporating advanced detectors and a built-in corrective optics system.
Additionally, astronauts installed and replaced other instruments:
- Solar Arrays
- Solar Array Drive Electronics (SADE)
- Coprocessors for the flight computer
- Two rate Sensor Units
- Two Gyroscopes Electronic Control Units
- GHRS Redundancy Kit
Links
Images of mission
NASA’s description of STS-61
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Astronauts are replacing the ESA built solar arrays during the First Servicing Mission.
The 280 kg Wide Field Planetary Camera is easily lifted by the astronauts in the weightless environment of space. |
