Poll

Starship hasn't had another flight since May 2021 because....

It has many problems, none of which flight testing will help with.
28 (27.7%)
They didn't want to steal NASA's thunder over the SLS launch when they make orbit.
0 (0%)
They've had to accummulate enough of the same design of Raptors
4 (4%)
It has no problems. They are just waiting for Stage 0 to mature enough
41 (40.6%)
Something else.
24 (23.8%)
Starship is done but FAA license is extra-tough this time around.
4 (4%)

Total Members Voted: 101

Voting closed: 04/16/2023 11:53 pm


Author Topic: Starship hasn't had another flight since May 2021 because....  (Read 7897 times)

Offline john smith 19

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The polls closed and the people have spoken.  :)

Thanks for everyone who took part. TBH I figured by the time the poll closed we'd already be talking about Starships first orbital flight.

Obviously that's proved a bit premature.  :(  Hopefully by less than a week, if everything goes to plan.

[EDIT Well 50% right.  :(
Not the ideal outcome but Musk is a pragmatist. I'm sure he had the provisional staff for an MIB already selected before flight. This is not his (or SpaceX's) first rodeo.

On the upside the pad is intact. There's a rich crop of telemetry and imagery to be analysed. I'm sure the MIB will do a thorough job as quickly as they can, wheather it's results are ever made public is another matter.  :(
 I'll note the loss of so many engines on the booster so early in the flight once again shows that even "simple" things (like delivering low pressure propellant down some pipe to some engines) gets much trickier at scale.  :( I expect there will be some relatively obvious "low hanging fruit" (obvious in hindsight that is) that can feed straight into their next vehicles and then the deep study will begin.

I'll wish SX a speedy RTF  and full success with their next attempt.]

Intersting results

So the majority go along with the the view that it's all about stage 0 and once that's working everything wil run smoothly

However substantial minorities also thought a)It's got other problems flight testing won't help with (but not stage 0) and others reckon "Something else." Which could be said to argue that simulation and ground testing have advanced to such a level of fidelity that only at the extreme edge of performance is an actual flight test going to be needed.

Somehow I don't quite buy it.  :(

I was one of the 4 who thought producing that number of identical Raptor 2s might take a while.

Interestingly despite the legions of Musk's adulants none reckoned this six month delay after SLS finally made orbit was SX giving NASA a lap of honour moment before they got the launch licence, gassed up and went to orbit on the first go.

Intersting results, soon, I hope to be followed by some very interesting results IRL.

I'll certainly be crossing all my digits on a terrific spectacle.  :)
« Last Edit: 04/21/2023 06:51 am by john smith 19 »
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Lee Jay

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My thought was, there were problems with all of the above - stage 0, stage 1, some probably with stage 2, with the engines, they all needed work, and that's why it took so long.  That's why I voted "something else".

Offline john smith 19

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My thought was, there were problems with all of the above - stage 0, stage 1, some probably with stage 2, with the engines, they all needed work, and that's why it took so long.  That's why I voted "something else".
And it looks like you may be right.

Wiith the first stage having engine issues from takeoff and stage 2 not separating, so no idea if that was going to have any ignition issues.

TBH for some time now I've thought Musk has just kept pushing for higher performance from Raptor 2 because he could. Now I'm now starting to wonder if there's some reason why they don't just like higher performance, but they actually need it just to get throught the whole flight trajectory.  :(

Most disappointing they didn't even get to the interesting stuff, with SS re-entry from near-orbital velocity.

Still, every failure is a dress rehearsal for success.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Online TrevorMonty

My thought was, there were problems with all of the above - stage 0, stage 1, some probably with stage 2, with the engines, they all needed work, and that's why it took so long.  That's why I voted "something else".
And it looks like you may be right.

Wiith the first stage having engine issues from takeoff and stage 2 not separating, so no idea if that was going to have any ignition issues.

TBH for some time now I've thought Musk has just kept pushing for higher performance from Raptor 2 because he could. Now I'm now starting to wonder if there's some reason why they don't just like higher performance, but they actually need it just to get throught the whole flight trajectory.  :(

Most disappointing they didn't even get to the interesting stuff, with SS re-entry from near-orbital velocity.

Still, every failure is a dress rehearsal for success.
With so many engine failures it never managed to fly correct flight profile to allow 2nd stage separation. Question is what caused engine failures?. Debris from pad is looking to be the likely cause.

Offline john smith 19

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With so many engine failures it never managed to fly correct flight profile to allow 2nd stage separation. Question is what caused engine failures?. Debris from pad is looking to be the likely cause.
Well that sort  of sounds reasonable. But rockets aren't like cookers. They bring their own oxygen. So you can't "snuff out" the flame.

Since SH doesn't use vision during takeoff it won't care less if it took off in a huge cloud of cement dust.

OTOH if some of those chunks hit something sensitive, or a propellant line....

I've never quite got my head around why they went with flame trenches anyway. When concrete is subjected to a temperature rise rate of > 5c/minute it starts to exhibit something called "thermal spalling" and the surface peels off.  :(

Using concretes for high velocity hot jets seemed to be playing to its weaknesses, not its stregths

A thick water cooled metal plate was IIRC viewed as quite adequate up to the Saturn 1.

However it is is the pad construction that's the root cause of all of the trouble rebuilding it better makes all the problems go away.   :)

Keep in mind the previous test didn't get all the first stage engines firing either.

SS is the first operational vehicle to use a centralised source of ignition (Rocketdyne did this on some of their experimental linear plug nozzles). The theory seems simple enough. Replace chunks of valves, ignitors etc on each engine with a single set on a single combustion chamber and run pipes to each CC for hot gases to fire the mix.

The fact SH (at 50% thrust apparently) did not achieve all booster engine ignition suggests this might be a bit trickier to get right than it seems.

That said I do like the whole KISS ethos. A 21st century FFSC engine without an EMU?  Keep in  mind that (AFAIK) the UUSR built the NK 33 and 43 without one, and they were the benchmark for Kerolox engines for decades.
« Last Edit: 04/29/2023 06:39 am by john smith 19 »
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

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