SLS and the RS-25 engines discussion

[Doug_G]

I really don't think you'll see some huge reduction in cost for a fighter jet. A lot of the cost is there for a reason.

Some years back I was on a team that designed an engine sensor for the F22 (a derivative version is on the F35). It's a glorified 4" piece of pipe that the oil flows through. No biggie, right? Well now we have to qualify it for flight. The performance of the sensor had to be analyzed to show that it would survive the qualification tests. Then you actually had to perform those tests. Aside from the obvious temperature, shock, vibration, electromagnetic compatibility, etc. etc., and things like analysis to make sure that the sensor could actually be maintained by the 10% sized female and 90% sized male mechanic, using only a limited set of standard hand tools, and that the sensor system would survive double the 5700 flight hours before refurb, and then after all that... it has to survive a battle. Which means that there could be an oil fire under the sensor and we had to not fan the flames by melting and dumping oil on it for a significant period of time, and we had to do a 2000 degree flame test to prove it (which we failed on the first attempt, but got it on the second try)...

Well you get the idea. The little 4" piece of pipe took millions to design and qualify. There was no "fat" in the program, all of this was all done for extremely good reasons.

 

[e-FTW]

Well, hot dang: they make it rain! Engine tests creates local rain conditions!
Chris B - NSF on Twitter

Clarkson getting rained on by an SSME test: Chris B - NSF on Twitter

Car wash:
Chris B - NSF on Twitter

Now, it makes total sense, as the plume is almost all water vapor. But it still tickled my geek muscle!

 

[jkn]

Unless I'm missing something, those are the same numbers I posted. I got them from the wiki post on Raptor.

I moved a number and changed its label on that wiki page.

So my question is: How much do you think it would cost SpaceX to build equivalent engines?
They don't seem to want to get involved in HydroLox engines, for very understandable reasons, but still. As you say $400M for an engine seems pretty ridiculous.

OFF TOPIC: I'm not trying to start a flame war (really), but what do you think it would cost a company with the esprit of SpaceX to build an F-35 equivalent? Or a Tomahawk missile.

Hydrogen embrittlement - Wikipedia may force use of expensive, difficult to process materials. SpaceX has been successful by using simple old design, modern materials and manufacturing. Raptor is step away from that.

 

[RDoc]

Hydrogen embrittlement - Wikipedia may force use of expensive, difficult to process materials. SpaceX has been successful by using simple old design, modern materials and manufacturing. Raptor is step away from that.

Raptor uses methane (natural gas) not hydrogen. There is a lot of industry experience with methane.

 

[jkn]

Raptor uses methane (natural gas) not hydrogen. There is a lot of industry experience with methane.

I understood that 'equivalent engines' means hydrogen engine.

 

[dpeilow]

This is more than SpaceX apparently spent on the Falcon Heavy program.

NASA spends $1 billion for a launch tower that leans, may only be used once

 

[Grendal]

It looks like they are changing strategy on SLS, yet again. Trump came into office and wanted the SLS to take astronauts on the first launch. NASA said no. Now it looks like they may be saying yes.

NASA may fly crew into deep space sooner, but there’s a price

 

[e-FTW]

It looks like they are changing strategy on SLS, yet again. Trump came into office and wanted the SLS to take astronauts on the first launch. NASA said no. Now it looks like they may be saying yes.

NASA may fly crew into deep space sooner, but there’s a price

"Get astronauts out there quickly!"
"Give us more money."
"Here you go, but employ my constituents with that money."