SpaceX (general discussion)

Dagger said:
1. Even in the 1960's this launch would not have been called a qualified success.

2. I am getting more and more disappointed with the way SpaceX is working on Starship/Booster.
It's just trial-and-error like Wernher von Braun did in the 1940's, but in those days they did not have 80 years of experience with rocket launches like we have nowadays.

3. The first Saturn V launch was a success, only 25 years after the first successful A-4 (aka V-2) launch.
Saturn V could bring astronauts to the moon and bring them back.

4.The second Starship launch was a failure, 81 years after the first successful A-4 launch.
Starship is merely a two-stage rocket. Yes, it is big and heavy but that does not change the basic design principles.

5. Everything can accurately be calculated and simulated nowadays, but if that is done by young enthusiastic, overconfident, but inexperienced engineers working under extreme time pressure then the results are full of mistakes. It's no different in my world (process design) where also most calculations and simulations done by young coworkers have to be corrected by more experienced engineers. Seems to be a result of the modern education system.
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Wrong on every point.

1. The first Atlas launch was called a success that even though it flipped and had to be destroyed by the RSO, it validated the balloon tank concept by remaining intact during the flips.

2. Nobody had tried to fly a fully reusable system from the beginning. If this was a test of an expendable vehicle, the booster was 100% successful. It only failed after the primary mission and during the recovery phase.

3. There were 4 non flight stages built for testing of each stage of the Saturn V. One each for static fire, structural load , facilities and ground dynamics testing. Why don't we wait on the fifth Starship before passing judgement.

4. NASA has crap loads of money to build test facilities, pads, manufacturing buildings, etc and 3 different companies doing the stages. Of course it could be done quicker. SpaceX is spending a small fraction of what NASA did and it is SpaceX's own money. You have no say in how they are doing it.

5. No, everything can't be calculated and simulated. That is why there is ground validation tests. That is why proofloading is done. That is why wings of airliners are loaded to 150% of flight loads on the ground. SpaceX chooses to bypass some of this ground testing for flight testing. They are hardware rich and have great telemetry systems. SpaceX has more test points inflight than Saturn did in its ground tests.

You really don't know what you are talking about.

Also, I am not a SpaceX fan, but I know what the reality is
 
Here's a video from TheSpaceBucket about how the Starship launchpad held up during and after IFT-2's launch:


After around 7 months of building, testing, and waiting for approval, yesterday morning Starship lifted off for a second time. While the launch itself was very exciting, a lot of people's attention shifted to the pad right after the mission had ended. This has to do with the fact that the pad was damaged quite severely on the first launch which took up time in a few different ways.
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Since then, SpaceX put a lot of time and effort into creating a new pad protection system meant to not only withstand one launch, but many. This consists of a massive water-cooled steel plate positioned under the 33 Raptor engines of Super Heavy.
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At this point, comments from SpaceX along with pictures of the pad suggest that it held up very well to this second attempt. Here I will go more in-depth into the current state of the pad, what damage if any it suffered, what to expect in the coming weeks, and more.
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Triangles
Byeman said:
4. NASA has crap loads of money to build test facilities, pads, manufacturing buildings, etc and 3 different companies doing the stages. Of course it could be done quicker. SpaceX is spending a small fraction of what NASA did and it is SpaceX's own money. You have no say in how they are doing it.
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Ahem

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WatcherZero said:
Triangles


Ahem

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You don't even understand the chart. SpaceX is not getting money from NASA for Starship. SpaceX is getting money from NASA for supplying services, whether they are launch services, cargo services to the ISS or crew services to the ISS. This is no different than SpaceX getting money from Loral or Eutelsat for launch one of their commercial Comsats. NASA is paying for a service that SpaceX provides using Falcon Launch vehicles and Dragon Capsules.
 
TomcatViP said:
Successfully but both stage blew up soon after.
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Umm, no, the booster blew-up as it was initiating its boost back burn (Scott Manley talks about this in his video) after clearly some structural damage to the thrust-section plumbing (Clearly G-force induced) while the Starship failed just as it reached SECO IIRC (Minutes after separation of the stages).
 
The fact that the first stage velocity apparently went negative might indicate the hot staging kick back caused a fuel slosh related problem. But it is doubtful that the hot staging has any connection to the starship failure.
 
Josh_TN said:
The fact that the first stage velocity apparently went negative might indicate the hot staging kick back caused a fuel slosh related problem.
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A good point however three of the Booster's engines were still burning when staging occurred.
 
NMaude said:
A good point however three of the Booster's engines were still burning when staging occurred.
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Two of those also flamed out, but I think that happened well after the flip, which probably points to that being the problem.
 
Byeman said:
You don't even understand the chart. SpaceX is not getting money from NASA for Starship. SpaceX is getting money from NASA for supplying services, whether they are launch services, cargo services to the ISS or crew services to the ISS. This is no different than SpaceX getting money from Loral or Eutelsat for launch one of their commercial Comsats. NASA is paying for a service that SpaceX provides using Falcon Launch vehicles and Dragon Capsules.
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2021 SpaceX received a contract from NASA for the Starship Human Landing System, a US$2.89 billion contract to design, prototype and qualify a disposable variant of Starship and the superheavy booster then provide two lunar descent flights from Gateway station to the lunar surface followed by a US$1.15bn contract in 2023 for one flight from Earth to Gateway station on a Starship HLS. Its paying $100m a seat for 4 seats on each flight and the rest is R&D funding.

You obviously dont understand the structure of NASA develop and provide contracts which are designed to stimulate technological development rather than being just transport contracts.
 
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zevets said:
that doesn't work for the nasa funded exploration missions - spacex needs to refill starship ~10x to get enough fuel onboard for human-scale interplanetary work, and at the timing/pace for that, you need to a full a return to sender
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I believe that the SpaceX bid includes building full booster+ship stack for each fuel mission. SpaceX will then try to get them back because if they do, they get to reuse the boosters for their own missions, but any lost boosters don't impact cadence unless they also take the tower with them when they die.
 
To Byeman:

Neither of us X-rayed the area where it failed—so who knows?

Shuttle orbiters were pulled about—but they were less like eggshells.

You are probably right…but do we know the loads chopsticks impart on structures?
There are materials now which show color when stressed.

I might like to see a replica of that…some type of modeling. Still very early.

I seem to remember some bladder that remained flexible when filled with LOX…and I also seem to remember materials that can become rigid when current is applied. Maybe that can help with sloshing….
 
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publiusr said:
I seem to remember some bladder that remained flexible when filled with LOX…and I also seem to remember materials that can become rigid when current is applied. Maybe that can help with sloshing….
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Little blue pills dissolved in methane. Who'd though that the solution would be so simple!
 
Byeman said:
Wrong on every point.

1. The first Atlas launch ..........

2. Nobody had tried to fly a fully reusable system from the beginning. If this was a test of an expendable vehicle ..........

3. There were 4 non flight stages built for testing of each stage of the Saturn V...........

4. ....... SpaceX is spending a small fraction of what NASA did and it is SpaceX's own money. You have no say in how they are doing it.

5. No, everything can't be calculated and simulated. That is why there is ground validation tests. ..................
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1. That was in 1957, not in the 1960's.
Moreover that 4A launch was rushed under extreme schedule pressure and I never read anywhere that that launch was considered a success.

2. It was not intended as a test of an expandable vehicle.
In the week before launch SpaceX replaced 3 of the 4 grid fins on the booster and added new tiles on Starship to replace some that had fallen off while still on the launch pad, because Heavy Booster and Starship were both intended to make soft landings in water. That did not happen, so that is a failure.

3 & 4. They can do it any way they want, but that does not mean that others are not allowed to question what they are doing. Insufficient ground testing does not mean that therefore failure in flight is not a real failure.

5. SpaceX is not doing tests, they are doing trials.
Validation tests are not trials but merely intended to confirm that design calculations and manufacturing techniques are as required. They should be a formality, not a learning experience. Imagine aircraft manufacturers building wings and fuselages that fail again and again in validation tests. That would be the end of those companies.

Objectives of this second Starship launch were that:
- the Heavy Booster would make a controlled soft landing in the Gulf. That did not happen, so that is Failure #1,
- Starship would re-enter the atmosphere successfully. That did not happen, so that is Failure #2,
- Starship would make a controlled soft landing in the Pacific Ocean near Hawaii. That did not happen, Starship exploded and debris landed in the Atlantic near the Turk and Caicos Islands, north east of Cuba, less than 3000 km from Boca Chica, some 31000 km and more than an hour flight short of Hawaii. That is Failure #3.

Failure #1 + Failure #2 + Failure #3 = Total Failure.

The objective was not merely that all engines worked and stage separation worked, although that's the impression that SpaceX and their many fans want to give us. That is not revolutionary in 2023 but was already routine in the 1960's, including hot staging.
 
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sferrin said:
Egg shells? Did you see the first flight?
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The first flight didn't have a bad weld that could come apart this flight though. Was that destacked as many times?

It might be that the nose came off for the same reason the tiles did...flex.

The first flight didn't lose a nose--this one did.

Now, all 33 engines lit for SH..so if there were any flow problems--they seem solved.

SuperHeavy will probably be dialed in first.
 
publiusr said:
The first flight didn't have a bad weld that could come apart this flight though. Was that destacked as many times?

It might be that the nose came off for the same reason the tiles did...flex.

The first flight didn't lose a nose--this one did.

Now, all 33 engines lit for SH..so if there were any flow problems--they seem solved.

SuperHeavy will probably be dialed in first.
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It didn't "lose the nose". The FTS went off, remaining propellant went boom, turning the propellant section into confetti, while the empty forward section stayed relatively intact. If anything it speaks to the strength of the structure, not weakness.
 
NMaude said:
Umm, no, the booster blew-up as it was initiating its boost back burn (Scott Manley talks about this in his video) after clearly some structural damage to the thrust-section plumbing (Clearly G-force induced) while the Starship failed just as it reached SECO IIRC (Minutes after separation of the stages).
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Clearly g-force induced? Nah, can't say that.
 
WatcherZero said:
2021 SpaceX received a contract from NASA for the Starship Human Landing System, a US$2.89 billion contract to design, prototype and qualify a disposable variant of Starship and the superheavy booster then provide two lunar descent flights from Gateway station to the lunar surface followed by a US$1.15bn contract in 2023 for one flight from Earth to Gateway station on a Starship HLS. Its paying $100m a seat for 4 seats on each flight and the rest is R&D funding.

You obviously dont understand the structure of NASA develop and provide contracts which are designed to stimulate technological development rather than being just transport contracts.
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Yes, I do very well. Those contract are back loaded. Again, they are milestone based. And I bet one of them is a fully successful test, so they haven't been paid.
 
Byeman said:
Clearly g-force induced? Nah, can't say that.
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Yep. There are too many things at play to make clear judgements from what we can see.

Assuming the telemetry is good, it really looks like the thrust of the ship impinging on the booster made it briefly accelerate backwards during the separation. I can't imagine that being great for the plumbing.
 
publiusr said:
To Byeman:

1. Neither of us X-rayed the area where it failed—so who knows?

Shuttle orbiters were pulled about—but they were less like eggshells.

You are probably right…but do we know the loads chopsticks impart on structures?
There are materials now which show color when stressed.

I might like to see a replica of that…some type of modeling. Still very early.

I seem to remember some bladder that remained flexible when filled with LOX…and I also seem to remember materials that can become rigid when current is applied. Maybe that can help with sloshing….
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I know because lifting doesn't induce such loads. The chopsticks is not imparting loads on the structure, it is not squeezing any thing. It is like a forklift and just raise the vehicle. The Starship is designed be reuseable and be lifted multiple times onto the Superbooster. The few times before this launch is in the noise.

You have nothing to base your claim on. Just a non engineer throwing out nonsense.
 
Dagger said:
3 & 4. They can do it any way they want, but that does not mean that others are not allowed to question what they are doing.
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True, like every other person doing this.
 

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Dagger said:
5. SpaceX is not doing tests, they are doing trials.
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So what and who cares?
SpaceX is getting more date from telemetry from more test points than were ever done on Saturn test stages.

Let's let them go through 4-6* test launches and see where they are on the 7th.

* 4 for the equivalent of the 4 non flight ground test stages (for each stage) built, tested and discarded for the Saturn Vs. And 2 for the two test flights, Apollo 4 & 6.
 
Dagger said:
Failure #1 + Failure #2 + Failure #3 = Total Failure.
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Really? Really???

Revised Flight Termination System - Ops Check Good!

(Much more immediate and effective than last flight. But, this test point having been adequately covered, we don't need to demonstrate it again.)
 
publiusr said:
The first flight didn't have a bad weld that could come apart this flight though. Was that destacked as many times?
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Destacking and stacking does not put undue loads into the vehicle. It is benign, it can happen dozens of times with no effect.
Also, this vehicle is supposed to be reused, so that means multiple stacking and restacking as part of the normal course of work.
 
Dagger said:
Moreover that 4A launch was rushed under extreme schedule pressure and I never read anywhere that that launch was considered a success.
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That test and the following one (6A) were partial successes which revealed useful data resulting in the redesign of the Atlas's thrust-section, from the Atlas A wikipedia article:

Analysis of telemetry data confirmed that the Atlas had malfunctioned due to hot exhaust gases being recirculated into the thrust section, which apparently caused failure of propellant ducting and engine shutdown due to LOX starvation. The pneumatic system also malfunctioned as tank pressure never properly transitioned to in-flight levels and along with propellant flow and pressure steadily decreased during ascent. The flight was considered a partial success because the missile had otherwise performed well. In particular, the Atlas's inflated balloon structure, which engineers doubted would even fly at all, had held together as the missile tumbled. The flight control system also worked well as it tried in vain to correct the missile's flight path.

Convair engineers decided that the Atlas needed a heat shield in the thrust section more substantial than the thin fiberglass one included on the missile. They proposed a modified heat sink made from steel and fiberglass, but the Air Force rejected that idea as the shield would be extremely heavy and also complicate booster section staging on operational Atlases. As one small modification, the pneumatic system was modified to vent inert helium gas down into the thrust section to reduce the risk of fire.
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These modifications were implemented and successfully tested in 12A, the third test-flight, more details can be found in the below 1957 4th quarterly status report:


Look at around 2:10 into the report.

IFT-2 wasn't a failure it was a qualified success which successfully passed a number of important milestones and the telemetry from it revealed useful data that will be used for IFT-3.
 
NMaude said:
IFT-2 wasn't a failure it was a qualified success which successfully passed a number of important milestones and the telemetry from it revealed useful data that will be used for IFT-3.
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for IFT-3 they need to find out and correct
1. what happen exactly in Superheavy B9, at restart the engines during boost back burn ?
2. what happen to Starship 25 near end of it SECO ?
 
Michel Van said:
1. what happen exactly in Superheavy B9, at restart the engines during boost back burn ?
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This will be easier to determine as the Booster was still transmitting telemetry when its' FTS activated while telemetry was lost just before SECO so determining the cause will be a little bit tricky.
 

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