Frontiers of Engineering Reports on Leading-Edge Engineering from the 2004 NAE Symposium on Frontiers of Engineering (2005) / Chapter Skim
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The Challenges of Landing on Mars--Tommaso P. Rivellini
The Challenges of Landing on Mars--Tommaso P. Rivellini
Pages 23-32
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From page 23... ...
The National Aeronautics and Space Administration (NASA) is currently developing a third-generation landing system in an effort to reduce cost, mass, and risk while 23
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From page 24... ...
Either the lander becomes top heavy and incapable of landing on sloped terrain or a significant amount of structural reinforcement must be carried along for the remote chance that the lander will directly strike a rock. The decreased stability because of the high center of mass is exacerbated if a mission carries a large FIGURE 1 First-generation landing system used on the Viking lander, which landed on Mars in 1976.
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From page 25... ...
To prevent the guidance and control system from inadvertently destabilizing the lander during touchdown, contact sensors have been used to shut down the propulsion system at the moment of first contact. On sloped terrain, this causes the lander to free fall the remaining distance, which can significantly increase the total kinetic energy present at touchdown and, in turn, decrease landing stability and increase mission risk.
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From page 26... ...
For vehicles designed to explore a larger fraction of the Martian surface and, therefore, land in more diverse terrain, combinations of slopes and rocks could conceivably obstruct or render useless the two primary egress paths. AIR-BAG LANDING SYSTEMS The second-generation landing system was developed for the Mars Pathfinder mission and subsequently improved upon for the Mars Exploration Rover (MER)
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From page 27... ...
Although the air-bag landing system has addressed some of the challenges and limitations of legged landers, it has also introduced some challenges of its own. Horizontal velocity control using solid rockets and air-bag testing were significant challenges for both the Mars Pathfinder and MER missions.
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From page 28... ...
As a result, their operation is uninterrupted during the entire landing sequence. One important result of this feature is that the velocity control of the whole system is improved, and, therefore, the rover touches down at lower velocity.
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From page 29... ...
29 and vertically m/s 0.75 are velocities touchdown Nominal events. and phases main three the showing sequence landing Sky-crane 5 horizontally.
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From page 30... ...
The SLS takes advantage of the fact that the rover's mobility system is inherently designed to interact with rough, sloping natural terrain. Rovers are designed to have high ground clearance, high static stability, reinforced belly pans, and passive terrain adaptability/conformability.
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From page 31... ...
ACKNOWLEDGMENT The research described in this paper was carried out at the Jet Propulsion Laboratory of the California Institute of Technology under a contract with the National Aeronautics and Space Administration. REFERENCE Pohlen, J., B
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