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'Dent' on US Lab debris shielding
Any more information about this apparent 'dent'? When was it first 'discovered'? What was the last previous time that area was surveyed when the dent WASN'T there? Has anything like it been seen anywhere else on the exterior? Seems like the shielding is doing its job -- what might have happened if the event had occurred in a region WITHOUT shielding? Nov 4 ISS Status Report: Next week the SSRMS (Space Station Remote Manipulator System) will be used for an outside inspection of what appears to be a "dent" in the Lab module's exterior surface, specifically in the MM/OD (micrometeoroid/orbital debris) shielding surrounding the pressure shell. [The shielding, made of an aluminum alloy, is designed to absorb the initial impact of MM/OD, slowing it down while breaking it into small fragments before it hits the pressure shell. The shielding is 0.13 cm (0.05 in.) thick and is separated from the pressure shell by a 10.2-cm (4-in.) gap.] |
#2
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Seems like the shielding is doing its job -- what might have happened
if the event had occurred in a region WITHOUT shielding? An impact will make a hole rather than a dent, unless the object which impacted is in a very similar orbit (which would happen pretty much if and only if it was released from ISS itself). My first guess is that the "dent" is the result of the shielding undergoing some kind of thermal expansion/contraction. Maybe someone with more expertise would have a different first guess. |
#3
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"Jim Oberg" wrote in
: Any more information about this apparent 'dent'? When was it first 'discovered'? What was the last previous time that area was surveyed when the dent WASN'T there? Has anything like it been seen anywhere else on the exterior? Seems like the shielding is doing its job -- what might have happened if the event had occurred in a region WITHOUT shielding? If you're looking into this, it'd be interesting to find out whether NASA has any plans/capabilities to replace these panels on-orbit (I know there is the ability to install them as an upgrade on the Russian structures)? I'd think it would be a little useful to inspect damaged panels to evaluate the performance of the shielding. Secondary question: The station is oriented (generally) with the PMA/Lab end facing in the direction of "travel". Is the shielding roughly symmetric, or is it thicker on the "forward" and "spacewards" sides? I'm guessing that the probability of micrometeroid and/or debris impact on the earth-facing side is much lower than those sides, and that the probability of damage to the "rear-facing" surfaces would be somewhere between those two extremes. If I remember the details of the LDEF experiment correctly, it drifted in a gravity gradient orientation (long axis pointed towards earth) and wouldn't have provided much useful data about the isotropy of the micrometeroid distribution. The only spacecraft I can think of that have been long-duration, fixed-orientation (mostly), and human-inspectable have been ISS, Mir, Salut, and Skylab. -- Reed |
#4
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No, that was in the SM. I'm hearing this dent has been around awhile, was recently discovered during careful re-analysis of shuttle images during a 2002 visit. "Neon Knight" wrote in message Could this be related to the crunching sound they heard awhile ago? |
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