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Posted by Henry Spencer on April 18, 2006, 10:52 am
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>-> Can MRO take high resolution imaging at closest approach during
>-> aerobraking?
>
>I doubt it very much. The attitude of the spacecraft has to be such
>that the heat dissipation occurs on surfaces that are designed to
>withstand it, which is unlikely to allow the camera to point at the
>ground.
Moreover, during aerobraking the attitude of a spacecraft is almost
entirely *determined* by what attitude is aerodynamically stable. The
usual attitude-control systems aren't strong enough to fight even the
fairly feeble aerodynamic forces of a typical aerobraking pass. I don't
know, offhand, what MRO's aerobraking attitude is, but a good guess would
be that it's designed to have the cameras pointing rearward then, to
minimize aerodynamic loads and heating on them.
The lack of precision attitude control (because aerodynamics overwhelm
normal attitude control) would also make it very difficult to use
"pushbroom" cameras, where spacecraft orbital motion supplies one
dimension of the raster scan. Oscillations and other irregularities would
mess up the smooth motion that the camera relies on. MRO's high-res
camera is a pushbroom system, if memory serves.
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