EXPOSED TO LUNAR ENVIRONMENT ON THREE EVAS.
Beta cloth and thermal shield segment, approximately 6 x 9 inches, with 6 metal snap-buttons along edges.
PART OF THE OXYGEN PURGE SYSTEM COVER USED ON THREE EVAS ON THE LUNAR SURFACE, AND ONE TRANS-EARTH EVA. The OPS supplies oxygen purge flow and pressure control in the event of a failed of the Portable Life Support System (PLSS) during extra-vehicular activity. As DAVE SCOTT explains in his SIGNED provenance note, "the OPS is an assembly of two spheres of oxygen mounted as a unit on top of the [PLSS] strapped to the back of the astronaut on the lunar surface or carried separately attached by straps to the lower front torso of the suit to supply oxygen during emergency EVA transfer from the Lunar Module to the Command Module in lunar orbit." Scott certifies that "the segment of beta cloth included with this letter partially covered the [OPS] that I used for three EVAs on the lunar surface during Apollo 15 ... The OPS with this beta cover segment was also used by Al Worden during his Trans-Earth EVA" In completing his three excursions to Endeavor's scientific instrument module bay, Worden retrieved film cassettes from the panoramic and mapping cameras, performing the first deep-space EVA, and reported his personal observations of the general condition of equipment housed there.
The present section of OPS cover was exposed to the lunar surface for over 18 hours, and to the vacuum of space for 38 minutes.