Linked Questions

67
votes
10answers
46k views

Why is SpaceX considering Methane as fuel for their next engine, the Raptor?

Currently, SpaceX has developed the Merlin 1 family (1B (Falcon 1), 1C (Falcon 9 v1.0), 1D (Falcon 9 v1.1/F9-R/Falcon Heavy), vacuum versions and sealevel versions) which are LOX/RP1 based. (75-...
9
votes
4answers
4k views

Why can't cryogenic oxygen and cryogenic kerosene be “stored” together?

This question, to my knowledge, is only applicable to Rocket Lab's Electron, pressure-fed engines that use non-hypergolic fuels, and other engine cycles that don't use a fuel/oxygen-rich preburner. My ...
14
votes
3answers
5k views

Is the supercooled LOX used in Falcon 9 Full Thrust a first?

One of the changes made to the Falcon 9 v1.1 Full Thrust was using supercooled liquid oxygen at 66 K (-340 F) as well as chilled RP-1. I've seen various claims that this is a first in the industry. ...
11
votes
1answer
1k views

What is the density of supercooled LOX at −206 °C, as SpaceX uses it

I want to calculate the size in cubic meters of Starship's propellant tanks. The only figures for LOX I can find are at −183 °C. 1141.7 kg/m³ at −183 °C. Could somebody please calculate it at −206 °C,...
10
votes
1answer
798 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 ...
7
votes
3answers
5k views

Autogenous pressurization with sub-cooled propellant

In his IAC 2016 talk, Elon Musk said (at 28m 4s in the video) that the ITS booster tanks would use autogenous pressurization. This means there is gaseous oxygen resp. methane in the tank. To stay ...
7
votes
1answer
2k views

Vector-R's LP-1 and -2 engines use liquid propylene as fuel with LOX, advantages and distinctions from kerosene or propane?

@gwally's answer highlights the company Vector Launch Inc. and their Vector-R rocket, which uses three LP-1 18,300 lbf engines on the first stage and one LP-2 1,000 lbf second stage engine to put ...
10
votes
1answer
1k views

Function of the RL10 Oxygen Turbopump's Splined Shaft End

The oxygen turbopump in the RL10 upper stage engine has been openly discussed by NASA for some decades now, in publications like SP-8107. On page 8 of this document is a drawing of this turbopump. The ...
12
votes
1answer
798 views

Why NASA's sudden renewed (apparently) interest in Wax hybrid engines? Which property is so attractive now?

update: This answer links to Larry Russel Kellogg which links to NASA Tests Environmentally Friendly Rocket Fuel where images of Test firing of new Paraffin-Based Fuel at NASA Ames Research Center 1/...
3
votes
3answers
280 views

3* Tonnes Unaccounted for in Falcon 9 FT Weight Wikipedia Calculation?

On the Falcon 9 FT Wikipedia page, the fully fuelled weight of Falcon 9 is only 546 300kg instead of 549,054kg as stated on SpaceX website. 546,300 kg - Wikipedia ...
2
votes
1answer
545 views

ULA's plan for LH2/LOX 2nd stage that can maintain propellant for an extended period of time?

Business Insider's (long) article SpaceX's biggest rival has a 'genius' plan to cut its rocket launch costs more than 70% contains the statements sourced from ULA's CEO Tory Bruno: Vulcan should ...
4
votes
1answer
405 views

How would the Saturn V have differed if the first stage was using liquid methane and LOX?

We have seen here the excellent answer to the question: How would the Saturn V have differed if the first stage was also LH2/LOX? What if liquid methane would be used instead of kerosene? Would the ...
3
votes
1answer
183 views

What's the viscosity of chilled RP-1?

I would like to compare the viscosity of "chilled" RP-1 as it is used for Falcon 9 launches to that of some everyday fluids. However, I am unable to find this information elsewhere. Would you please ...
0
votes
1answer
623 views

Is the “cryogenic helium” system in recent discussions actually LHe for cryopumping?

I am wondering if the "cryogenic helium" system discussed in articles about the 1-Sept-2016 SpaceX Falcon 9 anomaly (see this answer for a good summary to date) is not actually related to the high ...
2
votes
2answers
166 views

Is it possible to load propellant during the lift off? [duplicate]

Falcon 9 rocket consumes approximately 30 tons of fuel for the first 15 seconds of flight while it's still less than 350 meters in altitude. Is it possible to build a giant tower near the launchpad, ...

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