The Interim Cryogenic Propulsion Stage (ICPS) of the Space Launch System is essentially the Delta Cryogenic Second Stage (DCSS) lifted from the Delta IV rocket. However, among other minor changes, the ICPS features most notably a stretched LH2 tank.

However, there is no corresponding increase in the amount of oxidiser being carried. Is it to allow for some boil off while loitering in Earth orbit or is there another reason?


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    $\begingroup$ @Starshipisgoforlaunch Why didn't they protect against something going wrong that makes it need more oxygen? $\endgroup$ Mar 1, 2023 at 23:12
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    $\begingroup$ @Starshipisgoforlaunch Oxygen is a propellant. $\endgroup$ Mar 1, 2023 at 23:46
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    $\begingroup$ Do you have a source giving the hydrogen and oxygen tankage capacities for DCSS-5 and for ICPS? $\endgroup$ Mar 1, 2023 at 23:49
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    $\begingroup$ All liquid-fueled rockets have more propellant than oxidizer, because oxidizer is a propellant. Propellant = oxidizer + fuel $\endgroup$ Mar 2, 2023 at 0:04
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    $\begingroup$ @Starshipisgoforlaunch unfortunately you don't get to define that. Despite what you and Humpty Dumpty think, words have actual meanings. Especially in engineering. $\endgroup$ Mar 2, 2023 at 0:33


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