Linked Questions

16
votes
6answers
4k views

What are the criteria to put the oxygen tank above or below the fuel tank for a given stage of a rocket?

Inside a rocket, tanks are put one above the other. This make sense as it may be a good compromise between tanks shape and the aerodynamicity of the whole rocket. In some rocket stage, the oxygen tank ...
11
votes
1answer
929 views

Falcon-9's subcooled LOX is continuously refrigerated in-situ, what about its subcooled RP-1?

@Uwe's answer to Why would sub-cooled LOX tanks need to “topped-off” until the last minute or so? explains how subcooled LOX is kept cold and dense by "in situ refrigeration"; helium is bubbled ...
10
votes
2answers
2k views

How much liquid oxygen is lost during a Space-X Crew Dragon launch abort?

The tanks of the Space-X rocket should be emptied after a launch abort. I assume the liquid oxygen is pumped back to the storage tanks at the launch pad. But how much oxygen is lost by evaporation? ...
12
votes
3answers
647 views

Does ISRO's Cryogenic Upper Stage have restart capability?

Does the CUS of ISRO have restart capability? If so why was it not tested in the recent GSLV-D5 flight? Maybe by restarting the stage after S/C release? What enhancements are required to make a ...
5
votes
1answer
520 views

How do they know how much liquid propellant is in a rocket just before launch?

In this answer I wrote: In other words, a few tons here or there could depend on something as simple as the weather, or trying to squeeze a little extra propellant in for a given mission with a tight ...
6
votes
1answer
692 views

Why can’t cryogenic propellants be storable, at least on the ground, via refrigeration?

Cryogenic fuels (liquid hydrogen, liquid methane)1 and oxidisers (liquid oxygen)2 are the rocket propellants of choice where raw performance is the overriding concern, due to the very high performance ...
9
votes
1answer
184 views

Will the New Shepard be able to sit for long holds when filled with passengers?

In the Blue Origin YouTube video Replay of New Shepard Mission 8 Livestream, the first of several hold starts at T- 03:00 when the video is at about ...
7
votes
3answers
256 views

Can Falcon 9 be fueled slowed to delay the instantaneous launch window?

DM-2's first launch attempt was scrubbed at about T−17 minutes due to bad weather at the instantaneous launch window, even though the weather was predicted to clear up as early as T+10. It was ...
5
votes
1answer
143 views

Loading the LOX into Falcon 9 V1.1 and Falcon 9 Full Thrust

It is clear from the spaceflight101.com that there is difference in Launch sequences of Falcon 9 FT and Falcon 9 V1.1. Clearly, Spacex has found a way to load the tank in 30 minutes (falcon 9 FT) as ...
4
votes
1answer
111 views

Role of ground-supplied helium in S-1C stage

In this answer, the attached quote, says that ground-supplied helium was made to bubble up through LOX lines which mixed it and kept it from boiling and geysering. What exactly this means? By ground ...
1
vote
1answer
141 views

Could in situ (in-rocket) evaporative cooling/refrigeration be used for methane or hydrogen cryogenic propellants?

@Uwe's excellent answer to the question Why would sub-cooled LOX tanks need to “topped-off” until the last minute or so? explains that the LOX is sub-cooled in situ within the rocket's tank using ...
3
votes
0answers
139 views

Is the outside surface temperature of a Falcon 9 below freezing? How is the LOX insulated?

This answer explains how the liquid oxygen in a Falcon 9 is evaporation cooled to maintain a temperature well below boiling, by bubbling helium through it. The temperature difference to the ...
2
votes
0answers
109 views

What about recycling the helium used for sub-cooling the LOX in the tank of a rocket before launch?

Helium is a rare and expensive noble gas. When it is loaded into a rocket to be used after launch, it is not possible to recycle it. But the helium used for sub-cooling the LOX before launch (see ...