2
$\begingroup$

What is the pressure levels inside rocket liquid oxygen tanks, at launch time?

The question is for the minimum and maximum (known) levels of pressure inside such tanks.

I am asking for any rocket since such data is not really easy to find.

If the pressure inside Atlas V is X, then the pressure for Delta V should be similar, or at least in the same order of magnitude.

Similar questions:

Improve this question
$\endgroup$
0
5
$\begingroup$

According to the Flight Manual, the Saturn V upper stage LOX tanks were maintained at 38-41 psi (2.6-2.8 bar).

The first-stage LOX tanks were kept at lower pressure, 20-24 psi (1.4-1.7 bar).

It appears those values may have varied slightly on different flights.

Improve this answer
$\endgroup$
7
  • $\begingroup$ Why the pressure is higher în the second stage? $\endgroup$ – Joe Jobs Jan 14 at 2:54
  • 1
    $\begingroup$ Different engine designs, J-2 on the upper stages, F-1 on the lower. I don't know why the engines were designed for different inlet pressures. $\endgroup$ – Russell Borogove Jan 14 at 3:23
  • $\begingroup$ Interesting. First stage ~ same as shuttle. $\endgroup$ – Organic Marble Jan 14 at 5:08
  • 2
    $\begingroup$ @aroth The pressure is maintained by supplied pressurant in the ullage above the liquid; it has little to do with the amount of propellant. Higher pressure = heavier structure = less payload (although some pressure stablizes the tank); the lowest pressure you can get away with is used. $\endgroup$ – Organic Marble Jan 14 at 13:21
  • 1
    $\begingroup$ I’ve provided links in my answer which can yield additional information. $\endgroup$ – Russell Borogove Jan 14 at 16:17
4
$\begingroup$

The ullage in the space shuttle external tank liquid oxygen tank was pressurized by ground-supplied helium to its flight pressure level of 20-22 psig (1.4 - 1.5 bar) at 2 minutes and 55 seconds before liftoff. Before that its vent/relief valve was open and the tank was approximately at ambient pressure. After liftoff ullage pressure was maintained at the same level by tapping gaseous oxygen from the space shuttle main engines.

enter image description here

Sources:

Improve this answer
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.