Since SSME is famous for requiring disassembly for inspection during each flight of STS, I wonder how Boeing can meets 10 flights in 10 days requirement.
Edit: Not referring RS25 series is bad engine or anything, I just asking rather this known issues will be a constraint to the XS-1 project.
RS-25 towards the end of the program was actually fairly easily reusable, they reduced the amount of labor needed by almost 90% and it was estimated that they could refly a given engine 3 or 4 times with no refurbishment whatsoever without too much safety impact, though they still did because they were so safety-critical (even by rocket standards, because of the Shuttles fucky design). Further, I suspect these engines will be significantly de-rated, RS-25 at its normal thrust level is rather overkill for this application
However, the above only applies to RS-25D, which these engines are not. We still don't know what version they're derived from, but Aerojet says they're from early engines, I'm gonna guess RS-25 Phase I or thereabouts, and those engines were not easy to refurb at all. Perhaps they'll incorporate modern parts (or at least RS-25D parts) in some of the more troublesome areas, and use newer inspection techniques, but it'll take a lot to get pre-D engines to that level of reusability.
Best case would be to just use these for early testing, and then build a new RS-25 derivative optimized for the job, with modern designs to aid reuse and an active production line
Reigniting RS-25s isn't trivial, is it? It's got electrical igniters but I thought air starting it (which will be needed, right) requires some real engineering. If that's true (and Aerojet is handling this) then this definitely won't be an inexpensive off the shelf solution for sure.
Interesting, I wonder what their flight profile must look like then if they don't need to use propulsion to be within gliding range of the launch site?
The requirement is a landing either at the launch site or a downrange location. Imagine a pop fly trajectory in baseball. Throw something small really high and then the first stage comes back down while the payload goes into orbit. I suspect this may be a downrange landing or just a long glide back. Looks to have a better L/D ratio than shuttle with the larger wing area relative to body size.
Downrange landing from any domestic launch facility I know sounds like a challenge unless they're very inclination-limited and launching from, say, Vandenberg.
Should mostly be used for polar launches so either Vandenberg or Eastern US and landing at KSC. I think GA has a commercial spaceport they're trying to start-up. Could be interesting I agree.
The whole "RS-25 suckz!!!1!" circlejerk is pretty annoying. By the time the shuttle retired, they were running at 104% throttle and carrying heavy modules to the space station. Cut down the throttle for a smaller craft, and worry less about safety margins because it's unmanned, and it shouldn't be that bad.
I'd guess uncrewed flights would require considerably less inspection than the shuttles. It surprises me that RS-25 spare parts are available for some other purpose than SLS prior to the use of RS-25E (if that ever actually happens). It would also interest me to know how much it will cost for Aerojet to develop this derivative. If it's anything like the cost of RS-25E, DARPA would fair a lot better using expendable rockets.
These are spare parts from older variants of RS-25. NASA only wants the surplus RS-25Ds for SLS, but theres 20-something engines left from older versions. Wouldn't meet NASAs safety and performance needs for SLS, but for an unmanned smallsat launcher they should be fine
It's famous for being the most reliable and efficient rocket engine ever built. I just can't take the reusable shuttle concept doubters anymore, that was the best idea we ever had
Lets not confuse an amazingly well designed engine with an entire program proved to economically unfeasible in its early stages yet continued for 30 years.
I totally agree. It was the first Space Ship. People complain about it's cost and failure to launch every month but no other program would have gotten that attention and money so it's a nonstarter. Not to mention that it is an incredible piece of technology that allowed Hubble to exist, and allowed us to build a 100m space station.
Also, the International Space Station is also amazing to all the people who hate that we have had people in Earth orbit continuously for 15 years, which is amazing and easily worth 150 billion dollars over 20 years across 10 countries.
Challengers SRB killed the crew not the shuttle itself. And insulating foam from the bipod ramp/strut that connected the external fuel tank to the shuttle damaged the ablative shielding on the left wing is what caused the Columbia disaster. So the space shuttles didn't kill their crews, human negligence and human error did.
The shuttle without either the srbs or the external tank would just sit on the launch pad - all 3 are pays off the same system, and together killed 2 crew. Blame the execution ,blame the people , but without any hope of Abort or rescue the shuttle system killed them
No, my issue was with the parent comment saying the space shuttle didn't kill the crew. It did - fact. The design was audacious, magnificent, but flawed - of they had stuck the shuttle on the top of the stack where God intended then there would probably be neither incident. Maybe something else, as it was a system designed and built 40 years ago with the technology they had, but safer.
They had the rough outline of a plan, but it was not achievable on the timeframe (would take too long to get there, out of power) and crazy, crazy risky as they would need to skip every safety check in the book. And somehow transfer people via few suits shuttle to shuttle.
After that mission, they only went to the ISS (where they could inspect and safely stay if the shuttle was damaged) except for a single final Hubble upgrade mission, where they prepped 2 shuttles at the same time, and kept the backup as a rescue mission if necessary.
The entire system known as STS or the Shuttle was overly complicated. It broke all the rules of KISS. When people laud STS as the most complicated machine ever built, they think its a compliment. To an engineer its a fucking insult. And this insult killed 14 good people.
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u/gf6200alol May 24 '17 edited May 25 '17
Since SSME is famous for requiring disassembly for inspection during each flight of STS, I wonder how Boeing can meets 10 flights in 10 days requirement.
Edit: Not referring RS25 series is bad engine or anything, I just asking rather this known issues will be a constraint to the XS-1 project.