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Following Elon Musk's and SpaceX's recent announcements of their spacesuits being tested to "double vacuum pressure", there's been some speculation on what this meant.

It got me wondering - do NASA, ESA, or other agencies have a standard test protocol? And could someone post a short description of it?

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  • $\begingroup$ You're asking about ground tests, right? Because there is a procedurally built in leak check after suit donning at the beginning of a spacewalk. $\endgroup$ – Organic Marble Aug 24 '17 at 12:24
  • $\begingroup$ In an answer to this question space.stackexchange.com/questions/13331 , different operating pressures were given: "The Shuttle extravehicular mobility unit (EMU) has an operating pressure of 4.3 psi (30 kPa) and the Shuttle crew escape/launch/entry suits operates at a maximum of 3.5 psi (24 kPA). All Russian spacesuites, in comparison, operate at 5.8 psi (40kPa) to minimize or avoid decompression sickness or other risks." The pressures used for a test may be different too. $\endgroup$ – Uwe Aug 24 '17 at 12:52
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    $\begingroup$ @organicmarble any and all would be good - especially if the ground test protocol(s) vary from pre-EVA checks in orbit $\endgroup$ – HorusKol Aug 24 '17 at 13:47
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    $\begingroup$ @uwe - but how are they tested. I'm assuming that failure pressure is a much higher rating than operating pressure (much like a submarine crush depth is below its operating maximum) $\endgroup$ – HorusKol Aug 24 '17 at 13:50
  • $\begingroup$ @HourusKol : But the safety factor used for the construction of a submarine might be much higher than that used for rockets and space equipment. $\endgroup$ – Uwe Aug 24 '17 at 15:36
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Pressure tests are done on-orbit as part of the EMU CHECKOUT procedure, and during airlock depressurization prior to extra-vehicular activity (EVA).

During the EMU CHECKOUT procedure, the suit is pressurized to a delta pressure of 4.3 psia (its normal working pressure) and the suit caution and warning system monitors for a drop in pressure.

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During the airlock depressurization prior to an EVA, the depressurization is halted when the airlock pressure reaches 5 psia, and again, the suit caution and warning system monitors for a drop in pressure.

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Source: the shuttle-era EVA checklist is online here.

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  • $\begingroup$ But that is not a one time post manufacture pressure test. Doing a burst pressure test with a suit worth some million $ is a different thing. But during design some parts may have been tested destructively. $\endgroup$ – Uwe Aug 24 '17 at 15:31
  • $\begingroup$ @Uwe Please notice that I asked the OP in a comment if they were interested in on-orbit tests, and they said yes. So your comment is not constructive. $\endgroup$ – Organic Marble Aug 24 '17 at 15:35
  • $\begingroup$ Excuse me, but the spacesuits tests to "double vacuum pressure" were ground tests and no in orbit tests. HorusKol was also interested in the ground test. $\endgroup$ – Uwe Aug 24 '17 at 15:44
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    $\begingroup$ It's not a dumb question. The suit has a positive pressure relief valve that opens when the suit pressure is > 4.7 psi above ambient. So as the airlock pressure drops, this valve would be cracking and releasing gas from the suit to maintain that delta p. When the suit is in a vacuum environment, this valve protects the suit from overpressurization. $\endgroup$ – Organic Marble Aug 25 '17 at 11:55
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    $\begingroup$ @uhoh the ACES suit you were asking about in a different question also has a PPRV, I updated my answer there to talk about that. $\endgroup$ – Organic Marble Aug 25 '17 at 12:03

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