Single-track’s space, rockets and astronauts thread

I think the lumps of concrete were ripped from the ground beneath the pad structure…as was the sand that followed after.

Poundshop 39A 🤣

My one takeaway from this launch was how slow it left the pad (yes I know the engines were not all lit at the same time) – what happens when it’s loaded with 100 tons of “stuff”?!

Marcus House analysis https://youtu.be/eCWUCkLYToo

On the ‘slow’ launch it was still doing around 100 km/h as it cleared the tower

Think people mean slow to move rather than the speed once it had started moving. Must’ve been ~5s of full throttle without really budging?

It dod seem to just sit there for at least that

I just remembered that they were only ever going to run the engines at 90% max thrust  this flight.

Scott manley analysis

So I’m sure it’s going to take a month or so to find out from spacex what all the problems were, but the damage to the launch pad does suggest they need a rethink there it seems. I’m looking at the pads damage and would think it needs tearing down and rebuilding all over. This time with a lot more water deluge AND a flame diverter trench. The only other thing that comes to my mind is, could it lift off with the engines at significantly lower throttle? Then power up once away from the tower. I believe it used twice the thrust of Saturn v, so I would think even at half throttle it should lift reasonably swiftly, but I’ve not checked the weights.
It wouldn’t surprise me at all if many of the problems were caused by debris from the pad, and perhaps a lower power lift off can be programed quite easily. However its going to take some time to build a new pad. Didn’t they take a couple of years building the first? 2 years to build, destroyed in 10 seconds.

I think they may have some repairs to do to the tank farm too…..and somebody’s minivan

This time with a lot more water deluge AND a flame diverter trench.

Not at that site apparently. The wetlands are protected and the water table really high, so no massive digging projects are likely to get the nod. Could look at building up, but $$ and massive delays as they’ll also have to rebuild the tower too.

Seems like the story is just getting going now, but less about the rocket itself and more about stage 0. Anyone know why Starship has always been based in Texas instead of Florida? Just keeping it out of the way of the regular launches?

The amount of debris and damage is pretty crazy, obviously not tolerable- just look at the big ejecta when it first fired! That’s serious bits of debris being thrown 50 metres or so in the air, the visible stuff’s got to be microwave to fridge size or we wouldn’t even see it. The dust and damaged pad are a way smaller problem than that, all it takes is one big chunk in the wrong place… (is that what happened to those outer rockets?) I wonder how much they already have planned and how much they’ll have to change- apparently there was already a plan for a water-cooled steel plate to protect the foundation but it wasn’t quite ready.

But even the small stuff is going to need a lot of work to resolve, FAA won’t authorise another launch like that (and they’re going to be looking very closely to see how much of a surprise it was…)

sharkbait
Free Member

My one takeaway from this launch was how slow it left the pad (yes I know the engines were not all lit at the same time) – what happens when it’s loaded with 100 tons of “stuff”?!

Does it launch at full power? I can’t find any actual info but I had the impression from somewhere that it basically tiptoes off the pad then throttles up once it’s clear.

Here’s a pretty cool video showing how fast it actually departs- (released then hastily unreleased by spacex, some people reckon you can see damage to the tail just at the end)

The launch as seen from the tower
by u/Harry_the_space_man in SpaceXLounge

It does seem really slow to actually start to move though… It sits there burning for about 5-6 seconds before it departs and that was part of the launch plan, presumably awaiting and then throttling up but you’d think that even on reduced power the time lapse would increase blast and heat stress by loads? Or maybe there’s a little “make sure at least X rockets are burning” check with an option to abort on the pad, or something…

That’s obviously another problem, I know they’re saying it can make it to orbit with 2 tubes not lit but that’s not going to cut it, for manned missions, 100% is going to be the acceptable expected number for every launch (because if you’re normalising 97 or 94%, sooner or later you’re going to get 91 or less) And besides, while margins for error are good, it’s hardly the spacex way to just accept that level of efficiency, they’ll definitely be planning to get 100% and then lose the safety margin for extra cargo. Was interesting to see some of them manage to relight… But was that blowout on the side impact damage or rocket damage?

Next time, explode it lower down so we can see better.

Ah, the long wait time on the pad is because they light the engines off in groups, rather than a readiness check before throttling up- apparently it was supposed to be faster, but they can’t (yet?) get that to work. So it’s not throttled, it’s just not fully lit. Which would also make any debris way riskier, since obviously the rocket thrust can deflect debris but not if that particular engine’s not lit. But equally means it’ll be basically hovering for a bit before it actually departs, which is frickin awesome.

Oh, <allegedly> the original launchpad team were personally fired by Musk for being too traditional, because obviously a flame trench wasn’t needed and would slow the construction too much.

why Starship has always been based in Texas instead of Florida?

It is based in California, but they wouldn’t let him do the flights and testing that he wanted so he bribed the Texans to massively increase the ex Beale Aeronautics site. They’re completely fine with his particular brand of half assed shit.

I can’t speak for SpaceX but many rockets are held down on the pad with bloody great arms while the engines throttle up and are then released several seconds after engine start. If I remember correctly Saturn V also dragged great steel rods through narrowing dies as it took off to control the initial ascent.

SpaceX has a set of hold down clamps. They were expected to releasea second or 2 after main ignition but everyone was wrong, they were just a safety thing to stop it toppling. They were actually released at T-15 mins.

I’ve been wondering about stage O for the last couple of years, and how it would work. It always looked way under sized compared to a traditional launch pad. Seems like it needs a complete rethink!

As said it seems digging down isn’t really an option so that leaves building up. If that isn’t an option then the whole facility will need to move unless spacex can come up with other clever ideas. Right now I’m doubtful that the next test will be July as musk tweeted. I fear this will be the cause of a quite considerable delay. Next flight, 2025? This could make nasa look sensible.

As said it seems digging down isn’t really an option

Why not? Even with a low water table you can still dig below it and build a concrete trench.

Why not? Even with a low water table you can still dig below it and build a concrete trench.

This.  It will be expensive with lots of dewatering required but they can, and probably will, go down this route.

They had been test firing raptors against various blocks of material, including concrete, and I wonder if they just got the specification wrong?

Why not? Even with a low water table you can still dig below it and build a concrete trench.

It’s not a technical issue. Rather an environmental one as the wetlands are protected leaving to little room to build the proper trench system

someone on pistonheads found a pic of the car that got hit

Elon reckons 1-2 months to repair the launch pad (chinny rec)

3 months ago, we started building a massive water-cooled, steel plate to go under the launch mount.

Wasn’t ready in time & we wrongly thought, based on static fire data, that Fondag would make it through 1 launch.

Looks like we can be ready to launch again in 1 to 2 months.

— Elon Musk (@elonmusk) April 21, 2023

I’ve seen videos of the water deluge system being delivered and wondered why it didn’t seem to be being used. – I also thought that steel plate might work but assumed they knew what they were doing.

Obvs too keen to get on and launch!

I also thought that steel plate might work

As an old school back of fag packet engineer I’m going with……….er….no.

Too much heat and too much thrust against a flat plate whether or not it’s cooled isn’t going to work I wouldn’t have thought. It needs a diverter channel…..

Analysis of the launchpad:

https://www.barrons.com/news/giant-spacex-rocket-leaves-crater-serious-damage-at-texas-base-bb567f22

someone on pistonheads found a pic of the car that got hit

Meh, that’ll buff out… 🤣

I see the simps have talked amongst themselves and decided that the pad was obsolete and that the damage is irrelevant. Even though Musk says they’re going to repair it and reuse it. Schrodinger’s launchpad damage. The next test is supposed to go off it, I think, and musk is saying it’ll be repaired in 1-2 months so based on that, I bet 420 scottish pence it’s not within 6 months- especially since they don’t just have to fix it, they have to convince the FAA that the upgrades will work.

If I understand the metal plates idea correctly they’re not just internally or back cooled, it’s a sort of solid water deluge concept with perforations and water forced through it at pressure. But it all just seems like iterations of trying to fix a problem that they could have avoided? Diversion and dispersion is always going to be better than just trying to take it on the chin.

But then I suppose the musk fanboys also all know that JeT fUeL cAnT mElT sTeEl!on!E

Diversion and dispersion is always going to be better than just trying to take it on the chin

I’m sure they know this, and they will build a trench if they have to, but the whole idea is that IF starship was to go to Mars then it wouldn’t have a launch pad with a lovely flame trench to take off from.

So they are endeavouring to build a system that can take off from more basic facilities without incurring flight limiting damage.

I’ve heard people say that but it just seem irrelevant? Superheavy will never launch from Mars- let’s be honest, Starship won’t either, but if it did, it’s about 1/6th the max thrust lifting a fraction of the weight out of 1/3d the gravity. The problem is the sheer scale of the laden launch from earth gravity.

In reality all we’ll launch from mars at most is crew and experiment return vehicles, at least within the foreseeable phase of a mars program. Any heavier launches we might as well file in the same place as space elevators and railguns for now. But all that aside, if you can’t build a flame divertor on mars you also can’t build a blast-proof concrete pad… but the easiest sort of launch pad to build, would surely be something primarily dug out of the surface rather than entirely constructed. Same as it is here, it turns out!

It did strike me looking at the pictures of the damaged pad, that it reminds me quite a bit of Omega Supreme’s landing pad, and that every time he flew anywhere a pad always mysteriously appeared for him to land on. And then he could transform into the whole robot even though the rocket bit was really only his arms. So they should probably just use that well-established 80s tech, I don’t fully understand how it works but then I’m neither a rocket scientist nor an autobot

but the easiest sort of launch pad to build, would surely be something primarily dug out of the surface rather than entirely constructed.

Except to dig something out you’re going to need digging machinery.

Maybe it’s easier to construct something [that’s already partly constructed].

Anyway, I’d take the word of rocket engineers with a proven track record over “anyone else”.

I’d say they probably know what they’re doing.

sharkbait
Free Member

Except to dig something out you’re going to need digging machinery.

Maybe it’s easier to construct something [that’s already partly constructed].

Easier to construct/assemble, aye. But getting it there, not so much. How many tons of concrete and steel do you have to get to the surface to build a launchpad of any nature? And digging equipment is going to be required regardless.

Plus, nobody has ever cured concrete in mars conditions, so a plan that relies on really high strength high stress engineering concrete in that environment has a lot of unknowns of the sort that are really hard to turn into knowns, whereas a plan that relies more on geology (er, areology) and basically finding a suitable bit of rock and making holes in it then reinforcing it, is much more… knowable? Pre-knowable?

Though like i say, it’s all much of a muchness since this pad on earth has to handle 33 raptors and any future mars pad doesn’t. We already know how to make pads that can resist a smaller rocket launch (and landing).

And in practice, all of the first generations of mars relaunches will almost certainly be eagle lander-ish things that take their own launch infrastucture with them, followed by very small launchers that don’t. Any sort of sizable return launch is way way down the line- permanent-ish residence, moderate scale construction, some industry such as water production, that’ll all happen first.

(I know some people see this as a spacex vs old school thing, but it’s just an outcome of necessity- we won’t use a big return vehicle for a long while, simply because we won’t have anything big to return. Getting tons of stuff there is hard enough. By the time we get to that point, it won’t be starship, it’ll be some distant descendent or something else entirely. A mars-to-lmo specific vehicle built solely for that job, almost certainly)

sharkbait
Free Member

Anyway, I’d take the word of rocket engineers with a proven track record over “anyone else”.

The rocket engineers with a proven track record all say “make a flame trench”. The ones who said “build a pad without it” just now have a proven track record of failure. And that’s OK, nobody had a proven track record in reusing rockets or grabby arms or anything else like that and now they do… but you really can’t use “proven track record” to argue for this sort of pad, at this point

Flipping heck. 5.7 terapixel of Mars.

https://murray-lab.caltech.edu/CTX/V01/SceneView/MurrayLabCTXmosaic.html

Thread bump.

Lots has been happening with all sorts of space agencies and missions but I continue to be fascinated by space X and star ship.  Thought I’d bump the thread as star ship could go again very soon.  My understanding is that the ship,  plus super heavy booster,  is ready to go,  wet dress rehearsals done,  water deluge system fittedtothe repaired stage 0, the flight termination system is armed even.  Notams are in place and they are just waiting for the final approval to launch from the authorities… the environmental ones that got rather upset at the destruction around the launch site last time!

The big change to the rocket is a hot stage ring, so the plan now is to fire starship’s engines while still attached to the booster,  I believe the booster will be throttled back to just 3 central raptor while this happens.  Once separate the booster does a flip with those 3 engines burning then fires up the others for a boost back to bocage chica.  However the plan seems to be to ditch the booster and starship and not recover.

Another big change is maxQ is expected much earlier,  20 seconds earlier,  so I guess they aren’t holding back on the raptors this time!

So, will it be any more successful than the first try?  I hope so but whatever happens I reckon its going to be exciting!

Space debris visualisation https://wayfinder.privateer.com/

Musk owns a high proportion of the working space objects.

Regulatory approval given.  Primary launch day is 17th nov with 18/19 as back up

what happened with the launchpad they trashed?

Hot staging just seems to make the most sense, it’s basically simple and the fast flip concept just seemed a bit mad tbf, people kept saying “it’s the same as how they deploy starlink” but that process happens slow and stately not on the way to orbit. Not sure what’s going on with the max q change though. That implies greater confidence in the motors, I guess? Are they so confident that it was launch/impact damage that caused all those issues, without having a subsequent flight?

The Fish and Wildlife approval was always a biggie- and it’s entirely spacex’s fault. Even leaving aside the debris issues, they crashed ahead with fitting and testing the deluge system without applying for discharge permits- and they’d applied for the same discharge permits for other wastewater purposes previously, so they were certainly aware they ought to do so. But as usual tried to go cut corners.

Now everyone’s blaming FWS for the delay in approval, politicians are applying pressure but if they’d applied for the permit, the environmental review for the deluge system would be complete by now. And while I do reckon they’ll eventually give approval, just because the entire approvals system around Boca Chica is so routinely lax, they could well demand changes… water runoff controls or other mitigations that are easy to install but take time, that spacex just hasn’t done because their plan is to be allowed to just dump fresh water into a salt water habitat. ie, things that they could already be doing if they hadn’t cut that permit corner. And going to a regulator having already deliberately bent the rules is not a good look- they just seem used to getting away with that.

It is getting pretty bad I think. I don’t want things to get held up, because spaceships are cool, but they’ve treated all the previous approvals much like carte blanche- the complaints from spacex (and their fanboys) are pretty much along the lines of “You let us set up in a fragile environment in a nature preserve so now we should be allowed to do anything we want” and “anything that slows this down is unacceptable, even when it’s of our own making”. A little bit of dealable-with consequence would probably do them a world of good. Some people and orgs can be trusted to use discretion when you give them leeway, others can’t, and ultimately doing more right first time will let them go faster, not all corners are safe to cut

Absolutely sick of hearing people whining about “letter agencies” and “just putting clean water in a swamp” though.

what happened with the launchpad they trashed?

It was rebuilt and now uses a water cooled steel plate protection system.

Musk owns a high proportion of the working space objects.

Your point is?

I hadn’t realised the approval still required was for the deluge ( or ‘Day-luge’) system.  They’ve tested it half a dozen times,  have they not been following rules?!

The FWS review isn’t just about the water runoff, it’s a wider environmental impact approval so also includes noise and debris, but the deluge system is a new matter for that approval and is ongoing for future launches and tests, whereas the other issues are supposed to be resolved. It’s the big live issue, essentially.

My understanding is that they definitely haven’t followed the state permit rules, the regulators have confirmed that there was no application. That’s only a paperwork violation really and unlikely to cause a problem in itself, but the main consequence is it leaves unresolved whether the water discharges are acceptable or not. And there’s both state and federal bodies involved with different remits and goals, but if they’d got the state-level approval they’d be much less likely to face any issues with the federal body.

Fundamentally they ignored the permit so they could proceed with testing without waiting, but they might have just banked that delay for later when it’s more disruptive.

FWS and the TCEQ both have the power to order cessation of the deluge system discharges, so getting to this point is pretty wild. It’s also added to the lawsuit against the FAA, which could also bite spacex both short and longterm. TBF the FAA look pretty shakey on this to me, the basic fact that they rubberstamped the change of use from “commercial launch site” to “test site” without requiring a new environmental assessment seems pretty indefensible.

Like I say it’s totally possible that they just give some warnings or future requirements, or maybe raise no concerns at all, and that spacex basically gambled right. But also possible that they end up just being told “no deluge system til you do X” and it causes them a totally avoidable delay, which of course everyone will blame on “regulation holding us back” and such nonsense. Like not applying for your passport for months, waiting til the last possible minute then complaining about a 1 day delay.