Hubble Servicing Mission 3A

STS-103 Mission Information
Crew Positions
About the Astronauts
Payload

Hubble Fact Sheets

Hubble Space Telescope (HST) Servicing Mission 3A was launched on December 19, 1999 and the Space Shuttle Discovery landed on December 27, 1999. Its seven-member crew included two Hubble Servicing veterans.

NASA decided to split the HST Third Servicing Mission (SM3) into two parts, SM3A and SM3B, after the third of Hubble's six gyroscopes failed. The second part of the mission, SM3B, is tentatively scheduled for mid-2001.

The gyros, part of Hubble's sophisticated pointing system, help hold the telescope steady during observations. Hubble only needs three gyros to conduct science operations.

In addition to the gyros, astronauts have also replaced a guidance sensor and a transmitter, and install a new, advanced central computer, a digital data recorder, an electronics enhancement kit, battery improvement kits, and new outer layers of thermal protection. The eight-day flight included three scheduled spacewalks, each lasting six hours.

On November 13, 1999, the Hubble Space Telescope was placed into safe-hold after the failure of a fourth gyroscope. This mode had been thoroughly tested and used twice since Hubble's launch in 1990. The telescope was not at risk. This protective mode allows ground control of the telescope, but with only two gyros working, Hubble cannot be aimed with the precision necessary for scientific observations of the sky. The aperture door had been closed to protect the optics, and the spacecraft was aligned to the sun to ensure that adequate power was received by Hubble's solar panels.

Crew:

*Remote Manipulator System (robotic arm)
**European Space Agency
*** Extravehicular Activity/Spacewalkers

About the Astronauts
To prepare for these extravehicular activities (EVAs), the SM3A astronauts participated in Crew Familiarization sessions with the HST flight hardware here at Goddard. The last "Crew Fam" for SM3A took place July 6-9, 1999. From Tuesday to Friday, the astronauts trained with actual SM3A flight hardware and EVA crew aids and tools (CATs). Most of the "Crew Fam" occurred in the Clean Room at Goddard Space Flight Center, Maryland, and the crew also worked with high fidelity Hubble mock-ups in other buildings.

During these four days, the crew spent long hours rehearsing their space walks. Using space gloves, flight Space Support Equipment (SSE), and Crew Aids and Tools (CATs), the astronauts trained with and verified flight orbital replacement unit (ORU) hardware. These included the SM3A Fine Guidance Sensor, Advanced Computer, Rate Sensor Units, Voltage Improvement Kits, Solid State Recorder, S-Band Single Access Transmitter, New Outer Blanket Layer, and Forward Shell/Shield Replacement Fabric.

The crew worked with a number of trainers and simulators, such as the High Fidelity Mechanical Simulator, the Aft Shroud Door Trainer, the Forward Shell/Light Shield Simulator, and the Support Systems Module Bay Doors Simulator. They also trained and verified the flight Orbital Replacement Unit Carrier (ORUC) and its ancillary hardware.

The a stronauts replaced all six gyroscopes, a Fine Guidance Sensor, an S-Band Single Access Transmitter, and Hubble's main computer. The new main computer will be 20 times faster with six times more memory, thereby reducing flight software maintenance and significantly lowering operation costs. Astronauts had also installed battery improvement kits, a digital recorder, and new thermal protection to Hubble's exterior.

Payload Commander Steven L. Smith was in charge of this servicing work. He is a veteran of two space flights, STS-68 in 1994 and STS-82 in 1997. On STS-82, the Hubble's Second Servicing Mission, Smith performed three spacewalks.

Claude Nicollier (ESA) is another seasoned Hubble crewmember: He controlled the Shuttle's robotic arm aboard STS-61, the Hubble's First Servicing Mission in 1993. He also served aboard STS-46 in 1992 and STS-75 in 1996.

Five-time shuttle veteran Michael Foale flew aboard STS-45 in 1992, STS-56 in 1993, and the STS-63 rendezvous with MIR in 1995. STS-84 dropped him off at MIR in 1997 for a four-month stay and STS-86 returned him to Earth. Foale has spent over 160 days in space, including 10.5 hours of spacewalking.

Fellow spacewalker John Grunsfeld served on two earlier missions, the 1995 Astro Observatory mission aboard STS-67 and the fifth mission to MIR on STS-81 in 1997.

STS-103 has been Commander Curt Brown's sixth Shuttle mission, and his third as commander. He led STS-95 in 1998 (which carried several Goddard payloads including the HST Orbital Systems Test) and STS-85 in 1997, and he served as pilot aboard STS-77 in 1996, STS-66 in 1994, and STS-47 in 1992.

SM3A was Jean-Francois Clervoy's third trip to space: In 1994, he operated the robotic arm aboard STS-66 to deploy the CRISTA-SPAS atmospheric satellite, and in 1997, he visited the Russian Mir Space Station aboard STS-84.

Pilot Scott Kelly-the identical twin of astronaut Mark Kelly-was a first-time space traveler.

Back to Top