Apollo TMG Boot

I'm not exactly certain as to what this boot is, but my best guess is that it's an early Apollo (perhaps A6L) thermal-micrometeoroid garment (TMG) boot. It certainly has a number of differences from the A7L/A7LB boot which was actually worn in the program.

In the A7L, the pressure boots were part of the pressure garment assembly (PGA). The PGA boot had a hard sole and heel, similar to the one on this boot. The ITMG boot zipped to the lower leg portion the ITMG and covered all of the PGA boot except the sole and heel (with a system of loop tape and lacing cord to secure the ITMG boot to the PGA boot).

The material on this boot is cuffed at the top, seeming to indicate that this boot was meant to be removable during the mission; straps and buckles on the ankle and instep also give the impression that this boot was meant to be donned and doffed.

It's possible that this boot is one from the A6L suit, which predated the A7L/A7LB suit actually worn on the Apollo missions. Early A6L suits had a separate pressure garment assembly (PGA) and external thermal/micrometeoroid garment (ETMG); the ETMG would have been donned prior to walking on the lunar surface. The ETMG looked like heavy winter garments, with separate pants, jacket with a hood, gloves or mittens, and boots. The jacket was sometimes referred to as a "lunar parka".

The A6L suit did not consist of a single configuration, but rather a range of concepts which evolved as NASA and the vendor conducted testing and performed reviews. Changes accumulated until, one day, it was agreed that the now-current configuration was sufficiently different from the first A6L to warrant calling it the "A7L". See this auction lot and ILC Space Suits & Related Products for photos of the early A6L ETMG. Later A6L suits were very virtually indistinguishable from the A7L suit, other than for the lack the integral boots, as shown in this Smithsonian photo.

The Franklin Institute displays what it calls an "A7L Prototype cover". The ITMG in this display has legs which are cuffed, with no visible zipper, and so may be from a similar design as these boots.