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Apollo Discussions => The Reality of Apollo => Topic started by: Allan F on March 20, 2023, 04:29:28 PM

Title: Ascent stage tanks
Post by: Allan F on March 20, 2023, 04:29:28 PM
I wonder if there's any numbers out there for the mass of the ascent stage tanks. Not the fuel/oxidizer, but the tanks themselves - also the mass of they helium pressurization system?
Title: Re: Ascent stage tanks
Post by: Obviousman on March 20, 2023, 07:44:42 PM
Can't help with that, sorry. NASA Technical Notes 7082 and 7143 have a lot of information about the LM and the Ascent Stage Propulsion System but not weights (that I could find).
Title: Re: Ascent stage tanks
Post by: JayUtah on March 21, 2023, 10:18:08 AM
I'll see if I can find this later. But for comparison, the dry mass of the O2 tanks in the SM is about 100 kg.
Title: Re: Ascent stage tanks
Post by: Allan F on March 21, 2023, 12:17:53 PM
Quote from: JayUtah on March 21, 2023, 10:18:08 AM
I'll see if I can find this later. But for comparison, the dry mass of the O2 tanks in the SM is about 100 kg.

Thank you. It's for a discussion about why the space shuttle couldn't go to the moon. Working backwards through the rocket equation, disregarding the mass of tanks and piping and pressurization systems, using only the OMS engines, I got a mass of the spaceshuttle including fuel before TLI to be around 26.000 tonnes, based on a 2.200 tonnes shuttle at reentry.

ETA: I suspect that with the added mass of tanks and equipment, the mass of such a vehicle would balloon beyond any reason.
Title: Re: Ascent stage tanks
Post by: onebigmonkey on March 21, 2023, 02:20:13 PM
Thomas J. Kelly's book 'Moon Lander' doesn't give weights for the ascent tanks*, but does give a figure of "25000 pounds" for the descent propellant tanks.



*that I could find on a cursory skim read.
Title: Re: Ascent stage tanks
Post by: Allan F on March 21, 2023, 04:33:22 PM
That number seems off, since the entire LM was about 14.5 tonnes full up.