What about the micrometeorite protection layers of the Apollo suits used for lunar EVA? Was any hole found after landing on Earth?
Summary: There are no direct reports of holes in the outer suit layers. Microscopic analysis has shown some partial fraying of the outermost fabrics. Pressure is maintained by a rubber inner pressure garment layer, which leaked in varying amounts in the suits, especially Charles Conrad's.
The matter is simply not mentioned at all in the Apollo Program Summary Report or the Apollo Experience Reports.
This 2015 JSC lecture entitled Apollo A-7L Spacesuit Certification and Mission Operations Details was presented by NASA's former chief engineer of EVA systems. He was involved with every NASA spacesuit from Mercury through ISS. Although he does not mention holes or other problems in the outer layer, he describes numerous other issues with the Apollo suits:
- The pre-flight and post-flight leakage rates are reported for all suit pressure garment layers. (These are inside the suit; you asked about the outside.) Results were highly variable between suits, but only one suit was characterized as a failure.
- Thirteen sealing closures among ten suits needed to be replaced.
- The Apollo 7 astronauts shoulders and arms interfered with each other when seated in their couches.
- Apollo 7 astronauts recommended a Valsalva device, which was added to all future suits.
- The commander's pressure suit pants for Apollo 12 (Charles Conrad) were too short, and resulted in the only leak categorized as a suit failure.
- Prior to Apollo 14, the rubber pressure bladder in one boot failed. All boot bladders had to be replaced.
- And many other issues that arose during testing or for new mission needs.
The 2008 paper Lunar Dust Effects on Spacesuit Systems: Insights from the Apollo Spacesuits studied the outer-most layers of Apollo 12 LMP Alan Bean's and Apollo 17 LMP Harrison Schmitt's EVA suits, Schmitt's EVA gloves and boots, and the glove connector rings of Apollo 16 LMP Charlie Duke's EVA and IVA gloves. Methods included pulling samples off the surface using adhesive tape and examination with a stereo optical microscope. Bean's suit was also partial disassembled to obtain fabric samples, examined with a scanning electron microscope, and chemically analyzed.
A swatch from Bean's left knee showed
lunar soil particles are visible in-between the fibers and individual fibers show some crazing and fraying of the Teflon material. In places, it appears that soil particles have pushed fibers apart and caused individual fibers to fray, although no fibers appear to be completely broken. At the highest magnification, particles are visible embedded between fiber strands. Additional SEM secondary electron images in Figure 8 show stick-shaped particles of fiberglass present on the fabric. These particles are likely derived from highly abraded beta cloth fibers on adjacent or underlying areas of the ITMG.
A sample from Bean's left shoulder showed less wear than the knee sample. The American flag patch was carefully removed, and lunar dust particles were found embedded in the fabric underneath.
Bean's left and right EVA gloves showed
Among the observations were broken Chromel R metal threads that had been pulled out of the weave (Fig. 28a). The absence of separate thread fragments in areas associated with these broken fibers suggests either that the breakage occurred during manufacturing, or that the loose fibers, once pulled out of the weave, are easily broken by fatigue. Other features more likely to have been produced during the missions are sets of scratches and scoring perpendicular to the threads, especially on the “high points” of the weave (Fig. 28b). The consistent parallel alignment of the scratches and the relative hardness of the Chromel R metal fibers makes it more likely that these features resulted from handling or actuating high-hardness metal surfaces on tools or instruments, rather than having been the result of interaction with lunar rocks or soil. In addition to multiple, fine-scale scratches, isolated semi-circular “pits” were found on some fibers (Fig. 28c). Although initially considered to be a possible result of chemical corrosion, such an origin would most likely be associated with formation of oxidation layers or reaction zones, which are not observed. More likely, these features are a result of mechanical wear associated with impact, pulling or cutting against a sharp tool or instrument.
Optical microscopy of Schmitt's suit revealed partial fraying of the Teflon and beta cloth fibers.
Electron microscopy of the bearing balls in Duke's wrist connectors showed no significant difference between his EVA gloves (worn on the moon) and his IVA gloves (worn in the CM).