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How well does an airliner's pressurization work at extremely high altitudes (extremely low atmospheric pressure)? Does the system provide an absolute pressure differential, or is the differential a factor of the ambient pressure?

For example, consider an airliner in an environment where the atmospheric pressure is 1155 Pa (0.1675 psi). Such an environment may be found at an altitude of approximately 100,000 ft on Earth, or in the Hellas Basin on Mars. What cabin altitude could the airliner simulate?

When at 41,000 ft (pressure 2.6 psi) above the Earth's sea level an airliner simulates a cabin altitude of 8,000 ft (10.9 psi), which is 4.19 times the pressure of 2.6 psi at FL410. So if we took $0.1675 \times 4.19$ it would mean an airliner could provide an onboard pressure of 0.7 psi, the pressure around 68,000 ft MSL. Is it correct to assume that you have to multiply by 4.19 to get the result or did I miss something?

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    $\begingroup$ This is borderline off topic for me as you are asking about an impossible situation. An airliner cannot get to the altitudes where they would experience near vacuum. $\endgroup$
    – GdD
    Commented Jun 7, 2022 at 15:21
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    $\begingroup$ I think you have a fundamental misunderstanding about how airliner pressurization works. $\endgroup$
    – GdD
    Commented Jun 7, 2022 at 15:24
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    $\begingroup$ @Giovanni I don't understand what you expect us to say about "providing pressurized air if it were possible (which it isn't but that doesn't matter)". If it's not possible, how can we write a meaningful answer? Such speculation is off-topic. $\endgroup$
    – Bianfable
    Commented Jun 7, 2022 at 15:32
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    $\begingroup$ I think it's far more possible to get a Boeing 737 up to 100 thousand feet than get it to the surface of mars @Giovanni. $\endgroup$
    – GdD
    Commented Jun 7, 2022 at 16:21
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    $\begingroup$ @Giovanni - Which impossible things are you willing to ignore? If pressurized air comes from bleed air from the engines then the engines must be running. 737 engines won’t run in the Mars atmosphere. And I‘m pretty sure they’d wouldn’t be able to run at 100,000 ft on Earth. Without them you get no pressurization. $\endgroup$
    – Jim
    Commented Jun 7, 2022 at 17:49

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PSI differential (pounds per square inch) is relative, so the difference in psi is comparable as you suggested. So you can do around 10.9 - 2.6 + .1675 or around 8.4675 psi or around 13,000 feet. This is a bit better than 68,000 feet, which is above the Armstrong limit where full space suits must be worn.

But why not check out what the Virgin Galactic Spaceship 2, New Shephard, Dream Chaser, or Space Shuttle could do.

Any rapid decompression of an airliner cabin would be almost instantly fatal to unprotected passengers under those conditions$^1$. Forget about dropping oxygen masks, air pressure on Mars is way to low to get sufficient O2 into your body, even breathing pure oxygen, unless you have a pressurized suit.

Shuttle astronauts routinely worked in shirt sleeves throughout much of their missions.

$^1$ even if a 737 was capable of doing it

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    $\begingroup$ Metal bodied airliners are generally limited to about 8+ psi differential. The carbon 787 goes to 10 as do some high altitude corporate airplanes. 8.3 psi gives you an 8000 ft cabin at 41000 ft. $\endgroup$
    – John K
    Commented Jun 7, 2022 at 23:47

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