Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [ssme]

SSME is the acronym for the Space Shuttle Main Engine. Sometimes called the RS-25, or RS-25D.

4
votes
1answer
66 views

Actuators for gimbaling of engine in rockets and launch vehicles

For controlling the rockets to stay on course, continuous engine control is require which is done by using gimbal actuators. What type of gimbal actuators have been used on SSME, Rocketlab's ...
1
vote
0answers
45 views

What is the geometric dimensions of turbo pumps present in SSME?

Here is a really well documented and detailed explanation of the SSME engine. Looking through this, one can notice that there are no details of the dimensions. I would like to know about the ...
5
votes
2answers
253 views

What is the purpose of the “shaft” and “block” in these two different engine gimbal joints?

This question refers to the device which transfers the thrust force from the engine to the vehicle while allowing the engine to swivel - the "gimbal joint". Both the F-1 and SSME have a bolt- or ...
8
votes
1answer
243 views

STS: How much thrust did the nominal post-MECO LOX dump produce?

Following up to some questions asked in comments to the answer to this question: With pressure-fed engines, is any measurable thrust generated by venting the pressurant out the engine bell after ...
3
votes
0answers
65 views

SSME propellant duct routing

The low pressure propellant ducts in SSME are routed around the engine in a somewhat complicated way. Both fuel and oxidizer lines leave the low-pressure turbopump, go around, down and then turn back ...
0
votes
1answer
199 views

How does the Space Shuttle's SSME engine's thrust vary after ignition?

After writing the question Do Blue Origin's BE-3 engines need to run for 7 seconds to “warm up”?, I took a look at the YouTube video SSME ignition sequence (found in What are the small gas jets at the ...
6
votes
1answer
208 views

Disposal pool during RS-25 engine test?

Nasa recently did a test firing of an RS-25 rocket, and released a video of it. Here's a frame grab: Note that pool of water at the bottom right, with a pipe leading to it, and clouds of steam coming ...
7
votes
1answer
443 views

RS-25 Hot Fire Test

Yesterday, NASA Stennis successfully completed a hot fire test of Aerojet Rocketdyne RS-25 a.k.a SSME. It was noted in the webcast before the test started that they were testing the 'engine controller'...
4
votes
1answer
951 views

Theoretical Max G forces on Shuttle Launch?

Reading this question Why are rocket engines operating above 100% often considered nominal? leads me to a question about throttling back the SSMEs in the later stages of a Shuttle Launch to limit G ...
4
votes
1answer
174 views

Why does the shock wave in this new 2017 RS-25 test also have a “bump” on one side?

In last year's question Why does the luminous blue shockwave from the RS-25 engine appear to be rectangular? I showed images of an RS-25 engine test from 2015, and what I believe to be a test of the ...
1
vote
2answers
202 views

Can SLS use subcooled LOX?

The SpaceX Falcon 9 FT is using subcooled liquid oxygen. I understand that LOX gets significantly denser at lower temperatures so more propellant can be filled in the rocket's tank. Can NASA SLS RS-...
4
votes
1answer
523 views

Is it possible to estimate the nozzle characteristics of the Rocketdyne HG3 engine?

Boeing and the Marshall Space Flight Centre brought to pass many studies of improved Saturn V launch vehicles. The rockets proposed under the MLV and ELV projects would feature longer stages for more ...
18
votes
3answers
3k views

How was fuel crossfeed achieved, between the main tank and the Shuttle?

Whenever a fan of Kerbal Space Program mentions the super-efficient 'asparagus staging' in any professional context, the automatic response is 'That won't work. KSP fuel pipes are pure magic.' The ...
4
votes
2answers
767 views

Which STS mission raised the normal engine throttle above 100%, and what change to the SSME made that possible?

As indirectly stated in an answer to How long does Max-Q last?, during later Space Shuttle launches the main engines were operating at above 100% of their nominal maximum thrust. Specifically from ...
16
votes
1answer
2k views

What does “in the bucket” mean?

I've heard this expression a couple of times before. It seems related to the engines, but I can't find any information on it, except in the context of testing them. Here's two videos where it occurs: ...
18
votes
1answer
2k views

What are the small gas jets at the rims of the Space Shuttle Main Engines?

As can be seen in close-up footage of SSME ignition, such as the video below, there are small jets of an unknown gas/vapor emanating from specific points around the ...
5
votes
4answers
516 views

Space Shuttle and SSME Servicing Procedures for Re-Launch

There's been a lot of discussion about SpaceX's ~30% price reduction from re-use of the first stage, which got me to wondering: why exactly was the Space Shuttle so expensive to service and prep for ...
18
votes
2answers
3k views

Was the third shuttle engine any different from the others?

The space shuttle used three SSME, organized in a triangle with two next to each other closest to the external tank, and one on top of those. I am pretty sure the first two engines were close to ...
7
votes
1answer
202 views

How do they simulate the SLS engine environment?

I was reading an Aviation Week article about the restart of SSME (RS-25E) production for SLS. There is a paragraph in it that is interesting to me. On the SLS, the engine inlets will receive ...
11
votes
2answers
1k views

How will the SLS first stage be supplied with engines? Copy manufacturing the RS-25 or replacing it?

The SLS is a very opinionated subject among bloggers. I'm looking for what substance there might be behind the following general claim (without specific source). Is it truthful and if so, what is the ...
6
votes
2answers
281 views

Was the notion of using an air-started SSME on Ares-1 a reasonable idea?

For whatever reasons, it seems like the standard upper stage engine in the U.S. inventory is the RL-10. A high performance engine with nice specific impulse (Isp = 450-465 s), but very low thrust (25 ...
2
votes
1answer
1k views

What are the costs of the various different engines in current use?

This may be impossible to answer, since the data is often not disclosed. But in an article, about ULA getting RD-180's from Russia it claims: Each engine reportedly costs between \$11 to \$15 ...
9
votes
2answers
1k views

Have SRBs or SSMEs ever launched without a space shuttle?

It seems to me that the April 12, 1981 launch of Columbia (STS-1) was the manned spaceflight with the most untested hardware of any manned space launch. Even the Vostok and Mercury launch systems had ...
19
votes
2answers
1k views

Can I drink the water from the plumes of SSME?

Shuttle's SSME uses cryogenic Hydrogen(LHX) and Oxygen(LOX) as their propellent to give hot water vapour. If I somehow manage to get the exhaust plume and condense it to liquid, Can I drink it ...
15
votes
1answer
2k views

Why not use Sparklers on Delta-4 Heavy launches to burn off the hydrogen?

With three CBC (Common Booster Core) modules firing their RS-68A engines simultaneously, a Delta 4 Heavy launch is an impressive sight. The RS-68 is a LOX/LH2 engine. As part of the launch sequence, ...
16
votes
3answers
2k views

In a cryogenic fuel rocket, at what pressure is the fuel injected into the engine?

The pressure in the Space Shuttle's main engines must be very high to get the vehicle off the ground (with the SRB assist, of course). With such high pressures inside the engine, how do you inject ...