totm nov 2023 SpaceX Discussion Thread

[mikegarrison]

22 minutes ago, tater said:

I don't see any reference specifically to the number of test flights. Whatever the minimum is, it is effectively a minimum of "one" for Boeing/ULA, since the first ever Atlas V with the upper stage in question will be the first unmanned CST-100 flight. If they have the same standard, then Atlas if given credit for it's great success rate in the past, but ignoring the fact that the actual LV with CST-100 on top will be a substantial variant---more different from other Atlas Vs than block 5 is from block 4 of F9.

Have you ever participated in an RFP? The proposals that come in are often quite varied.

I suspect (but don't know for sure) that the requirement was something like "get crew-rated under standard XYZ.123.6789" or whatever. And perhaps SpaceX read the standard and said "we can do that with seven flights." Maybe Boeing read the standard and said "we can do that with one flight". And NASA believed both of them, so gave them what they asked for.

[IncongruousGoat]

Just now, Scotius said:

Something occured to me after re-watching FH start and reading NSEP's link. I wouldn't be surprised at all if BFR met the same fate as Falcon Heavy. A lot of publicity, long development process during which elder\smaller brother ITV will receive a lot of modifications and upgrades. And then test flight, followed by a gradual fall into obscurity... because said brother ITV turned out to be able to conduct most of the missions planned for BFR, while being cheaper and sufficiently versatile. And there might be already even better and more promising project of a new spaceship, born out of data gathered during ITV testing and usage.

ITV? Are you talking about the BFS, or some sort of smaller Raptor-based lifter? Because neither F9 nor any potential derivatives can be modified to fill the same role as BFR.

[mikegarrison]

2 minutes ago, Scotius said:

Something occured to me after re-watching FH start and reading NSEP's link. I wouldn't be surprised at all if BFR met the same fate as Falcon Heavy. A lot of publicity, long development process during which elder\smaller brother ITV will receive a lot of modifications and upgrades. And then test flight, followed by a gradual fall into obscurity... because said brother ITV turned out to be able to conduct most of the missions planned for BFR, while being cheaper and sufficiently versatile. And there might be already even better and more promising project of a new spaceship, born out of data gathered during ITV testing and usage.

ITV is no more.

[tater]

Seems like there should be a more objective standard.

That or SpaceX should have been able to say, "we can do  it in 7 for 2.whatever billion (what spaceX got), and in one for 4.whatever billion (what Boeing got paid).

[insert_name]

The first launch is booked for late 2020

https://www.sncorp.com/press-releases/snc-nasa-dream-chaser-launch-window/

[Scotius]

23 minutes ago, mikegarrison said:

ITV is no more.

Oh, great. Not only i totally mixed ITS with its derivative BFR - but also i used last-year data Too many donuts for Fat Thursday caused early onset of sclerosis? Or did i suffer an ordinary brain-fart? LOL.  Thanks for setting me straight.

Edited February 8, 2018 by Scotius
A typo.

[mikegarrison]

Another thing to consider is that companies that are now part of Boeing were the main contractors on Mercury, Gemini, Apollo, and the Space Shuttle, as well as building modules for the ISS and more than half the world's airplanes. SpaceX, which has done some impressive work so far, has never flown a crewed mission of any type, as far as I know.

Maybe the proposals simply reflect the previous experience each company has in-house. Perhaps SpaceX themselves are less comfortable with quickly jumping to crewed missions than Boeing is.

[tater]

39 minutes ago, mikegarrison said:

Another thing to consider is that companies that are now part of Boeing were the main contractors on Mercury, Gemini, Apollo, and the Space Shuttle, as well as building modules for the ISS and more than half the world's airplanes. SpaceX, which has done some impressive work so far, has never flown a crewed mission of any type, as far as I know.

Maybe the proposals simply reflect the previous experience each company has in-house. Perhaps SpaceX themselves are less comfortable with quickly jumping to crewed missions than Boeing is.

It still seems like the standard should be objective.

The CST-100 upper stage has flown exactly once, for example. What if, for example, there is a problem with the CST-100 unmanned test flight? Will they just fix it, or will they then need to fly X flights of a fixed CST-100 stack first? Could SpaceX say after 4 block 5 flights that they are confident, and skip the other 2? (I'm not really arguing with you, I think you are likely right, I'm just curious).

Orion/SLS will not have flown at all when crew first climb aboard. EFT-1 was a boilerplate, basically. EM-1 won't have the flight article anything, except the core stage and SRBs.

Regarding institutional experience, the last US crew vehicle was designed in the 1970s. There were incremental improvements made to the last orbiter, built in the very early 1990s, almost 30 years ago. I'm sure some of those late 80s, early 90s people must still be employed, but not many, and none from the 70s at all (initial shuttle design). Given that NASA would not hide any lessons learned from new crew contractors, it's not like that knowledge is proprietary.

[Shpaget]

3 hours ago, CatastrophicFailure said:

 Most people, well... simply don’t care at all. FH got zero news coverage here, and we even have a SpaceX facility in the area. 

Interesting.

Over here, 8000+ km away, we had quite a bit of coverage. I don't really watch local TV or listen to the radios, but I managed to see and hear news about it on both. Furthermore, the local technical museum organized a lecture on SpaceX and rocket reusability, had to charge admission fee because of large interest, completely sold out, organized another one the next day and sold out that one as well.

 

[Scotius]

"Pinpoint landing at KSC." That sounds nice For crewed variant it would be even better. Crew would be delivered on the doorstep of ground facilities - no need for recovery operation offshore, having to pick up the capsule and people and transport them back to the shore.

[CatastrophicFailure]

28 minutes ago, Shpaget said:

Interesting.

Over here, 8000+ km away, we had quite a bit of coverage. I don't really watch local TV or listen to the radios, but I managed to see and hear news about it on both. Furthermore, the local technical museum organized a lecture on SpaceX and rocket reusability, had to charge admission fee because of large interest, completely sold out, organized another one the next day and sold out that one as well.

 

I saw it was front page on the BBC website. Watched two local broadcasts, not a word, and just one tiny article buried way down on news web pages. 

Probably cuz nothing exploded enough for them to sensationalize. 

[DAL59]

When does the Tesla cross lunar orbit? Remember, its not the farthest car until it does.  

Current Score

1. Apollo 15

2. Apollo 16

3. Apollo 17

4. Tesla

5. [formerly] Reliant Robin

 

[Ultimate Steve]

2 minutes ago, DAL59 said:

 

5. [formerly] Reliant Robin

If you were to ship any car by plane, it would go higher than that I think, but that would be the fifth highest rocket powered car.

[sevenperforce]

14 minutes ago, DAL59 said:

When does the Tesla cross lunar orbit? Remember, its not the farthest car until it does.  

Current Score

1. Apollo 15

2. Apollo 16

3. Apollo 17

4. Tesla

5. [formerly] Reliant Robin

The Tesla has already crossed lunar orbit.

[klesh]

20 minutes ago, DAL59 said:

When does the Tesla cross lunar orbit? Remember, its not the farthest car until it does.  

 

http://www.whereisroadster.com/

 

Its currently at 623,045km from Earth, with the moon at 384,400km.

 

Edit: spamming the "update" button really gives you a sense of how fast it's going.

Edit2:  Hey, 1,234 posts!

Edited February 8, 2018 by klesh

[DAL59]

Wow!  Its almost at Minimus

 

[GoSlash27]

10 minutes ago, DAL59 said:

Wow!  Its almost at Minimus

It's about 13 times farther than Minmus

*edit* it's nearly out of Earth's SoI altogether now.

Best,
-Slashy

Edited February 8, 2018 by GoSlash27

[Tullius]

1 hour ago, tater said:

It still seems like the standard should be objective.

The CST-100 upper stage has flown exactly once, for example. What if, for example, there is a problem with the CST-100 unmanned test flight? Will they just fix it, or will they then need to fly X flights of a fixed CST-100 stack first? Could SpaceX say after 4 block 5 flights that they are confident, and skip the other 2? (I'm not really arguing with you, I think you are likely right, I'm just curious).

Orion/SLS will not have flown at all when crew first climb aboard. EFT-1 was a boilerplate, basically. EM-1 won't have the flight article anything, except the core stage and SRBs.

Regarding institutional experience, the last US crew vehicle was designed in the 1970s. There were incremental improvements made to the last orbiter, built in the very early 1990s, almost 30 years ago. I'm sure some of those late 80s, early 90s people must still be employed, but not many, and none from the 70s at all (initial shuttle design). Given that NASA would not hide any lessons learned from new crew contractors, it's not like that knowledge is proprietary.

The minimum number of uncrewed launches before the first crewed launch is zero, as NASAs only requirement is a less than 1 in 500 risk of LOCV.

However, doing no tests of prototypes means that you need a lot of additional overengineering, error margins and paper work to get the certification.

But nobody wants to design to design the first rocket with a risk lowrr than 1 in 10.000, just to get the 1 in 500 for the first flight ever of it being crewed. So you are reduced to doing test launches that will prove that the rocket remains well within its specifications to get certification.

Less test launches means more overenginering and more paper work, and vice versa. Since the cost per flight for SLS is ridiculously high, NASA obviously wants to do as few test launches as possible (but not zero, as that worked so well for the Space Shuttle). On the other hand, if Falcon 9 is anywhere near as cheap as it claims to be, doing a few more test launches might seem to be a worthy tradeoff for less overengineering and paper work.

[mikegarrison]

6 minutes ago, Tullius said:

Less test launches means more overenginering and more paper work, and vice versa. Since the cost per flight for SLS is ridiculously high, NASA obviously wants to do as few test launches as possible (but not zero, as that worked so well for the Space Shuttle). On the other hand, if Falcon 9 is anywhere near as cheap as it claims to be, doing a few more test launches might seem to be a worthy tradeoff for less overengineering and paper work.

I suspect this is the heart of it. You can do risk mitigation by analysis or by testing. If testing is more expensive than analysis, then a company will try to do it by analysis. But if testing is relatively inexpensive and the company doesn't have decades of experience doing it by analysis, they may decide that it's cheaper to just do it by testing.

[sevenperforce]

41 minutes ago, Tullius said:

The minimum number of uncrewed launches before the first crewed launch is zero, as NASAs only requirement is a less than 1 in 500 risk of LOCV.

However, doing no tests of prototypes means that you need a lot of additional overengineering, error margins and paper work to get the certification.

But nobody wants to design to design the first rocket with a risk lowrr than 1 in 10.000, just to get the 1 in 500 for the first flight ever of it being crewed. So you are reduced to doing test launches that will prove that the rocket remains well within its specifications to get certification.

Less test launches means more overenginering and more paper work, and vice versa. Since the cost per flight for SLS is ridiculously high, NASA obviously wants to do as few test launches as possible (but not zero, as that worked so well for the Space Shuttle). On the other hand, if Falcon 9 is anywhere near as cheap as it claims to be, doing a few more test launches might seem to be a worthy tradeoff for less overengineering and paper work.

That makes a lot of sense. SpaceX will most likely happily trade paperwork for testing, since they can reuse Block 5 so well (supposedly).

[tater]

Except of course that the analysis is largely BS. SLS uses Shuttle parts (some that actually failed), yet claims to be 1:500, vs shuttle's actual 1:72? Seems a stretch to magically make it safer than it actually was. Or does NASA calibrate safety with dollars burned? Or is it safer the more districts produce parts . RS-25s have been test fired many times, and 405 individual engine full duration firings during launches. 7 times engines failed on shuttle launches (6 resulted in last second holds, and engines replacements).

Merlins have fired 459 times during launches (9 per F9). Each was also static fired at least once (were all also fired in TX, first?) Meaning that Merlin is demonstrably more reliable than RS-25. That doesn't even count restarts for landings (of which we know of one engine related failure so far, the recent FH core landing burn restart).

Likely we're talking well over 1000 firings of which at least 460 were full length burns.

I know there are other critical components, but SLS will not have tested anything like F9 has. They've landed them and reflown them---I think they are suitably overbuilt.

 

 

 

 

Edited February 8, 2018 by tater

[magnemoe]

3 hours ago, Scotius said:

Something occured to me after re-watching FH start and reading NSEP's link. I wouldn't be surprised at all if BFR met the same fate as Falcon Heavy. A lot of publicity, long development process during which elder\smaller brother ITV will receive a lot of modifications and upgrades. And then test flight, followed by a gradual fall into obscurity... because said brother ITV turned out to be able to conduct most of the missions planned for BFR, while being cheaper and sufficiently versatile. And there might be already even better and more promising project of a new spaceship, born out of data gathered during ITV testing and usage.

FH kind fall in an empty gap in an way, very nice for heavy payloads to LEO but not many customers, useful for heavy payloads to GTO however the fairly heavy second stage is an downside. Expendable its an heavy lift rocket with no missions, yes two missions could do an moon landing if you wanted it. 
BFR is another category, as in fully reusable heavy lift. You can do stuff like sending it to leo, have an 3rd stage who put an satellite into GTO, recover the 3rd stage and land. Most fun of all you can do this then taking tourist to a LEO cruise. 
 

[CatastrophicFailure]

8 minutes ago, tater said:

Merlins have fired 459 times during launches (9 per F9). Each was also static fired at least once (were all also fired in TX, first?) Meaning that Merlin is demonstrably more reliable than RS-25. That doesn't even count restarts for landings (of which we know of one engine related failure so far, the recent FH core landing burn restart).

Slight addendum: there was one engine failure in all that, CRS-1 I think, but the main payload still made orbit. 

Also, relevant: 

[tater]

3 minutes ago, CatastrophicFailure said:

Slight addendum: there was one engine failure in all that, CRS-1 I think, but the main payload still made orbit. 

OK, so a couple failures, where at least one is a restart (something RS-25 doesn't even do). 1 in 1000 vs 7 in 405.

The point is that the paper risk assessment seems pretty conjectural to me, and they have not even applied it to Soyuz. 1:500 vs 1:270, vs 2:75 (or whatever Soyuz is at this point---though you need to count all the Progress and sat delivery Soyuz LVs as well, I suppose, I was only counting actual LOC incidents).

I met Lori a few times years ago...

I somehow missed that SpaceX offered NASA a free ride on FH, and they refused.

I find it hard to believe that someone at NASA could not have cooked up some truly cheap yet interesting science to do with a free rocket launch with tons of excess capacity for them.

[YNM]

9 hours ago, sevenperforce said:

If anyone is wondering, my math gives the expendable Falcon 9 an impressive 7.7 tonnes to trans-lunar injection. If the Falcon 9 upper stage could coast for 3 or 4 days, it could even deliver a little over 4 tonnes directly into low lunar orbit.

F9 expendable is OP compared to "similar"-marketed launchers. I'm pretty sure though that there wil always be a small gap for some expendable launches, so perhaps every now and then you can ask for an expendable launch if it's really urgent.