# What joints of Apollo 17 space suits did moon dust get into, making the astronauts arms difficult to move?

At about 02:45 the Curious Droid video Apollo, the Lunar Dust and NASA's Dirty Problem says:

During Apollo 17, crew members Harrison “Jack” Schmitt and Gene Cernan had reported that the dust was making it difficult fro them to move their arms around, because it had got into the joint of their spacesuits.

What suit joints is he talking about? All I see exposed is fabric.

Cued at 02:45:

• There's a long discussion of the adverse effects of the dust here hq.nasa.gov/alsj/a17/AS17Tech6.pdf but the EVA crew never say anything about it affecting their suits. They talk about the bad effects on the rover, on breathing it in, etc, etc, but nary a word about suit joints. Hard to prove a negative but... – Organic Marble Feb 25 '19 at 14:54
• @OrganicMarble it didn't sound right to me, that's why I posted. If you continue to feel the same way after further deliberation (i.e. just wait 24 hours and pretend you deliberates) then feel free to post a answer to the negative. – uhoh Feb 25 '19 at 15:20
• I'm not going to suffer through watching the youtube video so it doesn't seem fair for me to post an answer criticizing it. I'll limit myself to a comment. – Organic Marble Feb 25 '19 at 17:18

There are no joints to be seen within the arms assembley, only fabric.

But at the lower end of the arm there is the wrist ring.

This ring is used for a gas tight connection of the gloves to the suit. But there must be another function of this wrist ring, it should allow the rotation of the hands. I remember a video of the suiting procedure of an Apollo astronaut, he tested carefully the rotation of his hands, the movement was smooth and easy.

But if this wrist ring and its counter part in the gloves are contaminated with moon dust, rotation of the hands may be impaired. Between these two metal rings there must be a O-ring seal and some of the lubrication of these O-rings might been lost due to the vacuum during EVA. The remaining lubrication may have mixed with moon dust making rotation difficult.

All images from a NASA page about Buzz Aldrin's Apollo 11 Suit

In this report about space suits evolution rotary bearings are mentioned in the section about Space Shuttle suits on page 13:

The gloves incorporate a rotary bearing to allow wrist rotation,

In the section about the Apollo suits on page 7:

An example of this stiffness: inflate a large cylindrical balloon or the inner tube of a tire, the balloon or tube will become very stilt and almost impossible to twist or bend. Without these specially developed joints for the space suit, It would be virtually impossible for the astronaut to do useful work on the moon's surface. These special joints are installed Into the CMP A7LB suit at the knees, wrist, shoulders, elbows, ankles, and thighs.

From this PDF APOLLO OPERATIONS HANDBOOK EXTRAVEHICULAR MOBILITY UNIT on page 2-23:

The glove side-wrist disconnect is the male portion of the wrist disconnect assembly and features a sealed bearing which permits 360° glove rotation.

Figure 2-15 from page 2-44.

Lubricants were used for O-rings (page 2-78):

The lubricant pouch assembly contains eight fluorinated, oil­ saturated pads which are used to lubricate pressure sealing slide fasteners, seals, and "O" rings. The pads are held in place in the center pouch of the pocket assembly by whip­stitched Beta thread.

So a rotary joint is located in the wrist disconnect at the glove side.

• this is getting pretty interesting! – uhoh Feb 26 '19 at 12:40
• There are good pictures of the arm bellows joints in the pressure garment at this anti-moon-hoaxer page: moonhoaxdebunked.com/2017/07/… There was a rotary bearing at the shoulder but only a bellows joint at the elbow. – Organic Marble Feb 26 '19 at 13:58