SpaceX Tuesday...
Discussion
Flooble said:
Is there such a thing as a small leak, for a spacecraft?
I suppose it depends on what's leaking, where it is and the rate of loss.This is a helium leak apparently. Helium is used to help push the LOX and RP1 (kerosene) propellent through to the engine and displace the fuel as the tanks empty. There's all sorts of plumbing to facilitate this, although on the upper stage, the helium tank is located inside the big liquid oxygen tank.
They've haven't said if it's a pipework leak or the tank itself. If the tank is pissing out helium, it could potentially overpressurise the LOX tank and cause it to rupture. That's what they suspect to be the cause of both Falcon 9 total losses so far.
Interesting!
Perhaps it's always leaked but after the last failure they've put in some extra monitoring so can now see the leak ... the tweet from musk about go for launch subject to a check on pressure decay suggests they can monitor it at least.
Where's the tank for the "spin start system"?
Perhaps it's always leaked but after the last failure they've put in some extra monitoring so can now see the leak ... the tweet from musk about go for launch subject to a check on pressure decay suggests they can monitor it at least.
Where's the tank for the "spin start system"?
As I understand it, the upper stage engine doesn't have a dedicated helium tank attached to the back of the engine itself. They use the main helium pressurisation system to also spin up the engine's turbopumps before the fuel arrives.
If the helium pressure is too low, it could cause problems with that too, so if they detect a significant enough drop they'll abort the launch countdown with a minute to go. Helium is inert of course, so it's not a danger in itself.
If the helium pressure is too low, it could cause problems with that too, so if they detect a significant enough drop they'll abort the launch countdown with a minute to go. Helium is inert of course, so it's not a danger in itself.
This launch from 2015 was scrubbed because of the same issue.
https://www.youtube.com/watch?v=HgMXEs68VLo
https://www.youtube.com/watch?v=HgMXEs68VLo
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