HOUSTON The busiest person on Discoverys mission to rescue the Hubble Space Telescope probably wont be the spacewalkers, but the operator of the shuttles robot arm.
Jean-François Clervoy will have his work cut out for him when he uses Discoverys Remote Manipulator System, or robot arm, to capture the telescope, work daily with spacewalkers on their repair efforts, and then release the telescope when the work is completed.
For arm operators, working with the Hubble is the Superbowl of space operations.
"You get to use all operators' skills -- tracking and capture and move a human on the end of the arm," said veteran RMS operator Steven Hawley. "Its really part of what we expect guys to train to do. Its kinda fun, and the pinnacle for RMS missions."
Hawley, who is also an astronomer, should know.
In 1990, he operated Discoverys arm to release the Hubble Space Telescope and returned in 1997 on the second repair mission to the telescope. Claude Nicollier operated the arm during the 1993 repair mission and returns on this flight as a spacewalker.
Before the astronauts can begin their work though, the arm operator works with the shuttle commander to position the orbiter and robot arm to capture the telescope.
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| Jean-Franois Clervoy will use Discovery's Remote Manipulator System, or robot arm, to capture the telescope and then work daily with spacewalkers on their repair efforts before finally releasing the telescope. |
Veteran RMS operator Steven Hawley notes that training involves preparation for various scenarios, including one where the Hubble is in a difficult position for a grapple. |
Hawley said the arm operator trains for various scenarios including one where the Hubble is in a difficult position for a grapple, as well as for malfunctions of the robotic arm.
After grappling the telescope, the arm operator places it inside a rotating cradle located in the orbiters cargo bay in preparation for the space walks.
While the two teams of spacewalkers work on alternating days, the arm operator works every spacewalk, which can amount to seven or eight hours of work and concentration each day.
"The most demanding thing is to always be attentive all the time -- every second."
In dealing with the close confines of the Hubbles interior and delicate outer areas, such as antennas and solar arrays, it can be a matter of inches rather than feet.
The arm operator keeps his eyes focused on the spacewalking activities. One of the astronauts is poised on a foot restraint at the end of the arm, while the other uses tethers or foot restraints attached to the telescope.
"The most demanding thing is to always be attentive all the time -- every second," Hawley said, "and not taking your eyes off the crewmember, anticipating what he does next and see where he is in respect to telescope surfaces."
The operator controls the Canadian-built 50-foot arm with two hand controls while its computer calculates how to move the joints. Its a job that requires training and some dexterity.
"At some level you have a knack for that and eye-hand coordination to integrate what you see out the window," Hawley said. "Its really a lot of practice to get comfortable with how it performs and to some extent instinctive."
Arm operators train in Johnson Space Centers virtual reality lab, shuttle simulators and in the Neutral Buoyancy Laboratory.
Once the repairs are completed, the operator grapples the telescope again and lifts it out of the orbiters cargo bay.
Hawley said if everything is operating properly, the release of the Hubble is the simplest of the arm operators jobs
"Its the easiest task of all as long as you dont think about it being a $2 billion telescope and the most exquisite scientific instrument ever built," he said.
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