Launching Science Science Opportunities Provided by NASA's Constellation System (2009) / Chapter Skim
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4 Human and Robotic Servicing of Future Space Science Missions
4 Human and Robotic Servicing of Future Space Science Missions
Pages 83-96
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From page 83... ...
and at the time of the writing of this report was preparing for a fifth and final servicing mission to the Hubble Space Telescope, the concept of regular servicing of spacecraft has not been a part of NASA's future planning for numerous reasons. Both the Constellation System and new robotic capabilities can change that situation.
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From page 84... ...
The Skylab experience successfully demonstrated that humans could conduct complex, challenging, and unplanned repairs to spacecraft in low Earth orbit. From relatively early in its development, the space shuttle was designed to be capable of rendezvous with and capture of orbiting spacecraft, and the possibility of using shuttle crews to repair and upgrade spacecraft evolved out of these plans.
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From page 85... ...
Before the space shuttle even began flying, NASA recognized that in addition to tools and techniques for servicing spacecraft, it would be easier to service spacecraft if they were designed for such servicing. This meant not only a grapple fixture, but also requirements that instruments and important systems be easily accessed by astronauts in their bulky spacesuits.
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From page 86... ...
However, the SMM had been fitted with a shuttle "grapple feature" in anticipation of unforeseen malfunctions, and this enabled a shuttle to use its robotic arm to capture the satellite for repair. On April 6, 1984, a servicing mission by space shuttle Challenger successfully repaired it.
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From page 87... ...
The Palapa, LEASAT, and SMM repair missions all demonstrated the ability of astronauts to adapt to unforeseen challenges, and SMM demonstrated the value of designing a spacecraft for modularity and repair. Both of these attributes were employed extensively for the best-known examples of spacecraft repair and upgrade -- the four completed Hubble Space Telescope servicing missions (plus one planned)
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From page 88... ...
Mission planners have credited the follow ing factors for the success of Hubble servicing: a focus on "EVA friendliness" in the telescope design, and the extensive preplanning involved in the servicing missions themselves. Servicing Hubble requires the space shuttle's robotic arm to grapple Hubble and to place it on and latch it to a special carrier platform that can rotate and pivot the telescope in the shuttle payload bay.
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From page 89... ...
Under congressional pressure, NASA sponsored a National Research Council (NRC) study on whether a robotic or a human servicing mission would accomplish the goals of a servicing mission most successfully.1 After thorough deliberation, the committee concluded that the state of robotic technology was not advanced enough to complete the mission and successfully overcome unanticipated risks that are bound to occur on any given mission.
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From page 90... ...
The final Hubble servicing mission, scheduled for October 2008, is to be performed by the crew of space shuttle Atlantis (STS-125)
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From page 91... ...
SUCCESSFUL ROBOTIC SERVICING MISSIONS Orbital Express, a mission managed by the Defense Advanced Research Projects Agency, was launched on March 8, 2007, with the goal of demonstrating the technical feasibility of autonomous, on-orbit satellite servicing. The spacecraft's two vehicles were the Autonomous Space Transfer and Robotic Orbiter (ASTRO)
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From page 92... ...
FUTURE SERVICING CAPABILITIES The successes of Orbital Express and ESA's ATV demonstrate how far technology has progressed and hint at a future when the robotic servicing of space science missions will not only be possible but also a practical and cost-effective solution to servicing spacecraft in orbit. If NASA investigates the value of on-orbit servicing using autonomous robotics, more advanced concepts can be tested and implemented.
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From page 93... ...
develop repair procedures and, in some cases, specialized tools that were used successfully to repair or replace failed or aging components. FUTURE HUMAN AND ROBOTIC SERVICING OPTIONS The Orion spacecraft, although capable of traveling beyond low Earth orbit, has a number of limitations with respect to acting as a servicing mission.
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From page 94... ...
Large spacecraft deployed at distant locations may have to be moved nearer to Earth for servicing, and human servicing missions will require the development of major new pieces of equipment, such as airlocks, which are not currently planned by NASA. The recent development of robotic servicing options opens up additional exciting possibilities for future spacecraft servicing.
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From page 95... ...
Additionally, while NASA's space science budget has been stable in recent years, cost overruns and setbacks (e.g., the Columbia accident and its return to flight costs and effect on the shuttle launch schedule) have caused budgets for the various divisions in the Science Mission Directorate to become even more restrictive.
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From page 96... ...
Human servicing missions have already enabled fantastic advances in space science through the Solar Maximum Mission and the Hubble Space Telescope. In the future, these advances can only improve as technology and science continue to progress at increasing rates.
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