3 ms·
They've done extended, multiple relight tests of the second stage as part of their Air Force mission rating tests. I don't think it is anywhere near designed t
by NikolaeVarius 7y ago
They've done extended, multiple relight tests of the second stage as part of their Air Force mission rating tests.
I don't think it is anywhere near designed to stay usable after multiple days of staying cold, that is a completely different mission profile from what the second stage was designed to do, aka earth orbit missions.
I would expect the stored cryogenics would not take well to it.
- m4rtink 7y agoExactly, the main issue is the liquid oxygen on board - withou either active cooling or very clever isolation, there will not be any left after a while, as it will evaporate. The soviets did experiments with a blok d upper stage that was also kerosene/LOX and were able to push it to a couple days, maybe up to a single week. So really multiple weeks are not doable due to LOX alone withou turning your already mass limitted upper stage to an advanced orbital propelant depot. Also longer term you will start hitting also other issues, such as battery power (might need to add solar panels), stuff getting too cold/hot, long term exposure of electronics to cosmic radiation, lack of ulage fuel, etc.
- ChuckMcM 7y agoThis was the ULA paper I read about 5 years ago : https://www.ulalaunch.com/docs/default-source/extended-duration/micro-gravity-cryogenic-experiment-opportunity.pdf https://www.ulalaunch.com/docs/default-source/extended-durat... There are a number of papers on the ULA site describing fairly innovative ways to keep the LOX from boiling away. As this stage would not have a "payload" in the traditional sense it could have a refrigerator attached :-)