Crumpled paneling on Apollo 16 lunar module Orion
This page is still under development. The crumpled paneling on Orion is an interesting image (AS16-122-19533). Without really working through the mission report, does anyone know if the launch of the LM from the lunar surface is considered the primary cause, were problems traced back to the original docking to extract the LM, and was any risk assessments performed in anticipation of Apollo 17? November 13, 2006 http://www.collectspace.com/ubb/Forum29/HTML/000678.html
No damage, just ruffled MLI
"outer layers of the mylar/foil", which is MLI. It is ruffled MLI blankets and not "damage". It was caused by the blast at liftoff.
Well -- it actually *was* unplanned damage. The exhaust blast kicked up and under the thin aluminum panels (*not* MLI foil) that covered the back of the Aft Equipment Bay. The risers which attached this thin skin to the AEB structure were torn open and the panels buckled. Note that only the bottom connectors failed; the top connectors stayed in place.
The aluminum panels on the AEB actually look a little loose in pictures taken of the rear of the LM on the surface, as well. It's possible that the riser connectors were already partially broken (possibly by descent engine exhaust funneled up from the 10-meter crater that Orion overflew just before touchdown) prior to ascent.
I found the picture I was thinking of, showing Orion on the surface and showing how the panels that buckled during ascent appear either loose or mis-adjusted, even before ascent.
Here's a picture of the AEB of LM-5 Eagle, taken from the surface. It shows somewhat less wrinkling in those panels (AS11-40-5927).
The Apollo 16 post-mission report does discuss the damage to these panels. It concludes that ascent engine plume effects caused the panels to lift up from the riser attachments at the bottom of the lower panels, and speculates (because of surface images) that those panels were loose prior to ascent. In addition, if you look at the Apollo 16 LM ascent video carefully, you can actually see these panels lift up and start flapping in the plume as it ascends from the descent stage.
Here's a close-up of Apollo 16 Orion cropped from a Hi-Res image. Also a pic of the liftoff, which sure seems pretty energetic. Found another on-orbit image showing the back from the other side. Maybe rumpled panels might not constitute a term of "damage"... but a missing piece of panel torn off could be classified as "damage" (even if it is only cosmetic and not structural). On the Hi-Res image... it almost looks like the bottom back panels extend down (overhang) the base of the craft a bit (especially toward the left). This lip overhang might have caught the blast and been blown out.
The reason for these panels was thermal shielding of the equipment in the AEB. That equipment included the ascent stage batteries and the sublimator for the electronics cooling system. And, of course, the outboard corners of the AEB supported the aft RCS quads.
The panels served their primary purpose, which was to provide thermal shielding of the AEB during TLC, lunar orbit, descent and surface stay. The amount of time the ascent stage spent after those panels were damaged (which did expose the AEB to higher-than-normal temperatures) was relatively minor. Even though the temps were higher than normal, they didn't have time to rise so far that any equipment was permanently damaged.
Besides, they were planning on just crashing the thing into the Moon as soon as they were finished with it. Why worry about some damaged panels in that case?
References
- ↑ Apollo 16 lunar module damage, nasaspaceflight.com Historical Spaceflight forum, 22/2/2007