There was a flurry of activity last year when the upper stage was being tested. And then… nothing much. Of course there was a lot of 'FAA regulatory ‘stuff’, but it seems that’s been at least somewhat sorted.
Has he run into some showstopper technical problem, I wonder?
He needs permission from NASA. There are semi-legitimate conspiracy theory rumblings that they put up all sorts of obstacles so as to not have him show up Boeing and their inept over-priced engineers. For example, they delayed crewed Dragon as long as they could but when Boeing’s first unmanned capsule test went haywire, they couldn’t delay any longer.
So theoretically he will get his launch license this summer. He’s been preparing and testing and modifying newer versions of his Starship - pressure tests, static fire, stacking, etc. (See teslarti dot com). He said the ship would launch in July, but that’s on Elon time, which as everyone knows clocks run at a different speed due to relativity,
The first test will allegedly launch and orbit almost once, the Starship stage coming down near Hawaii where it will pretend to land until it hits the water. The booster - this time - will be discarded. Future ones they will try to land like the Falcons.
NASA doesn’t regulate commercial launches, and SpaceX doesn’t need NASA’s permission. The FAA is responsible for licensing launches. They will provide permission when needed. Cite.
There are lots of conspiracy theories that NASA’s admin put pressure on the FAA to delay SpaceX. But I would doubt that. That sort of thing is career limiting at best.
The FAA are painted as the bad boys in the entire saga of approving the Boca Chica launch facility, with delay after delay. But SpaceX would never have made the early mooted launch dates with even the best of luck. But the FAA have done SpaceX the favour of making sure that the approvals process is as bulletproof as possible. Random interest groups can’t reasonably take legal action against the FAA for providing permission because they were too hasty or didn’t take account of every piece of input for the process. This has all been a bit of a beat up with Elon’s usual flair for being a public relations disaster. But the outcome is very much in SpaceX’s favour.
It’s not just a matter of "tighten a few bolts and try to launch. The individual pieces go through a number of tests. For example, here’s what Teslarati says about the current version of Starship, with both booster and ship rolled out to the launchpad:
Booster 7 and Ship 24 got off to fairly rocky starts when they began a less risky phase of proof testing in May and June. Apparently caused by improper sequencing or a small design flaw, a large steel tube meant to carry liquid methane fuel through Booster 7’s liquid oxygen tank and double as a storage vessel for landing propellant violently imploded when a vacuum formed inside it. It took SpaceX several weeks to repair the damage but, defying the odds, the tube was eventually repaired and Booster 7 completed another two proof tests soon after.
So they build a version, do a few tests, fix what failed and then analyze to see if it was a design or manufacturing problem, then try again. There’s a number of tests before they actually launch an assembled rocket, up to and including test-firing the engines - a few or all at once - for a few seconds to ensure the systems work.
The process moves much faster than other NASA rocket makers, but they still make sure they have done enough tests before committing.
No, there haven’t been any showstoppers. It’s only been a year! That is an instant in aerospace time. The Starship tests last year, while impressive and necessary, were only a small part of the entire program.
Since then, they have built several iterations of the Super Heavy booster. Although in some ways it’s simpler than the upper stage (due to the lack of orbital reentry hardware), it is still a gigantic rocket stage using the most advanced engines made yet.
The Raptor 1 engine has been iterated into the Raptor 2. Some teething pains, but it appears to be coming along. A static fire of the booster is expected soon.
They’ve built a robotic launch tower with movable “chopsticks” for moving and stacking the stages. They call this “stage 0” since it’s effectively a part of the launch system itself. They’re partway done with building a duplicate in Florida.
While the FAA delays may have forced SpaceX’s hand in some ways, it probably ended up sending SpaceX down a better design path. The Raptor 1 specifically was not quite good enough; it needed to be iterated into the Raptor 2 (cost, performance, reliability, simplicity, etc.). The thermal protection on the first Starship prototypes needed a lot of iteration.
They have been very busy down in Boca Chica, but it may not be apparent due to the lack of test flights. That will probably change soon.
Optimistically but not unrealistically, Starship should make its first orbital attempt in August. That assumes no big issues crop up, of course.
I’m not sure the FAA held them back at all. In fact, Elon might be secretly happy that they gave him an excuse for delaying, because Starship/Superheavy just wasn’t ready. Thry had production problems with Raptor 2, and needed time to build and test the launch tower, ‘chopsticks’, etc.
I suspect they also had issues with the thermal tiles, as they kept falling off after various tests. There have also been some recent design changes to the booster.
I think they will attempt an orbital flight soon - maybe not in July, but in August. But that depends if the test firings go okay. 33 Raptors firing at once will be ‘interesting’. They are in completely uncharted territory here. And while losing a Starship before meant losing three engines, now it’s 33 on the booster alone. They can’t afford a lot of blowups. So I suspect they will proceed a little more slowly and carefully from here on out.
There’s a decent chance the first attempt will not clear the tower. Also a chance it won’t survive the trip to orbit, and an even better chance it won’t survive re-entry. If Starship makes orbit and survives re-entry to a soft splashdown, it will be a huge moment for spaceflight.
Also, if Starship blows up on the pad it’s likely to destroy it, which would set SoaceX back more. So this isn’t a done deal. They’ll try to make orbit soon, but if anything goes wrong on the first attempt we might not see another one for the rest of the year, imo.
I think they could have pushed to fly some earlier versions of Starship+SuperHeavy. But it would have been a much higher risk without too much return. SpaceX is happy to take risks, but only when there’s some reasonable benefit to it. The FAA delays guaranteed that they could not have flown an earlier configuration, but there’s a good chance they’d have made that choice anyway.
I think the chances of taking out the tower are fairly low. This isn’t a situation like the Soviet N1, where they weren’t even able to test individual engines. All the Raptors here will have been through multiple test cycles before flying. And the computer control for what happens if an engine does shut down is much better.
Anything’s possible, of course, but the most likely failure outcomes, as I see it, are a performance shortfall that leaves it unable to make orbit (but just barely), a staging problem of some kind, or a reentry problem for Starship itself. The tiles really are almost untested (though some test tiles have flown on Dragon).
Neither vehicle is intended to really land, so failures there are not really considered. It’s certainly not unlikely that one or both vehicles will fail to come to a smooth halt over water.
As Elon in wont to say about early launches - excitement is guaranteed.
It is pretty hard to say things could have gone faster when they have still not even test fired the entire 33 engines together. As good as the modelling may have been, 33 engines all together is moving well into the unknown. No blast deflector is another. I would be quite prepared to put a modest amount down to bet that it doesn’t leave the pad in one piece. Hope it does make it, but this is a seriously risky launch.
The number of iterations we have seen wander past, only to be scrapped before use is telling about the pace of change, and also the apparent immaturity of design.
If there had been a fully ground tested stack sitting on a fully ready and tested launch system at the start of the year we might have said the FAA were the pacing item, but we didn’t. The launch vehicle is still not stacked for launch (as opposed to ground testing).
SpaceX are still beavering away, and nobody will be surprised if it is late in the year before a launch is attempted.
I’m not worried about individual Raptors. I’m more worried about complex interactions between 33 of them firing at once. Acoustic energy, vibration, etc. Does the tower now have a functioning water deluge system? I haven’t paid attention for a while, but last I heard Musk was saying he didn’t think they needed it.
I’m sort of interested in what happens when #23 decides to explode due to overrich or overlean mixture or whatever. How many more does it take out? Then what?
In the fighter world the F-14, -15, and -18 turned out to not be all that much more reliable than their single engine contemporaries. Because although there are many contained failure modes for turbojets/fans, there are also the shrapnel- or raging-fire-producing failure modes. And having the two engines mounted adjacent encouraged fratricide.
At least on Falcon 9, the engines are designed and installed in a way that prevents the explosion of one engine from taking out the others. Whether that works with 33 Raptors packed tight, I don’t know. Hopefully the static fire on the ground will unearth any issues. But this is a very complex domain, and there could be a lot of failure modes 5hat have yet to be uncovered when 33 Raptors fire together, or when one or more fails.
That’s one way to look at it. The other is that if SH is designed such that it can withstand one or more failures and still complete its mission, then lots of engines creates redundancy instead of increased failure risk. Having one, two or three giant engines means mission loss if any of them fails. Having 33 hopefully means that you could lose several and still complete the job.
That’s the logic behind Falcon 9 - having nine engines increases the risk of any engine failing, but designing so that you can still succeed with two or three engines out means an overall increase in safety, just as having four engines on a jet increaes the chance of an engine failure while still increasing the overall safety of the flight.
Agreed 100% as to simple shutdowns. But not as to explosions which have a high potential for fratricide.
In the case of multiengine jets they try to place the multiple engines far enough apart that one coming unglued won’t throw shrapnel into the other. In fact on a 747 or A340 it would be both structurally and aerodynamically superior to place the outboard engines a lot further inboard than they are. They’re placed way out there on the wing to attain fore-aft stagger versus the inboard engine. So when either inboard or outboard throws shrapnel it’ll (probably) miss its wingmate.
I claim no expertise on the design of SH. But AFAIK adding much in the way of blast containment structure between each engine bay is both space- and weight prohibitive. So probably isn’t there.
Sure, that’s a concern, but any potential issues should be teased out via static fire. Same with any ground interactions. Significant issues could destroy the booster, but since it won’t be loaded with full tanks of propellants, a worst-case scenario won’t be the equivalent of a small nuclear bomb.
There is less inter-engine protection compared to the Merlins on a Falcon 9 (which have barriers between engines). The Raptors really are stuffed together at high density.
However, I think they have a pretty reasonable handle on the common failure modes at this point. Everyday Astronaut released another Musk walkaround interview, focusing on the Raptor this time. One thing that came up were the number of failed engines. Musk estimated around 20-30 full engines failures, as well as 50-60 combustion chamber failures.
Musk mentioned that a failed combustion chamber was a relatively “benign” event, though he later amended that to something like “benign in the context of rockets”. Anyhow, they typically didn’t destroy the engine because they can detect the problem and shut down gracefully before anything truly bad happens. In many cases they were able to reuse the remaining hardware.
He didn’t mention the nature of the other failures, but 20+ is a pretty good sample size, so I think they’d have a handle on the frequency of explodey type failures. Turbine failures seem the most likely to cause shrapnel (just watching videos of rocket failures, you can often see the turbines whizzing away at high speed). But full-flow staged combustion has relatively benign conditions for the turbines, so maybe that’s a less likely failure mode. It very much sounded like cooling failures are the most likely type, and those can be detected before the engine turns into a bomb.
Sorry; if it wasn’t clear from the above, these failures were from their Raptor 2 development program. It was mentioned that startup sequencing in particular was very challenging, since you have two separate pumps with complex interdependencies. One issue is that you can “go stiochiometric”, which essentially means passing through a point where the fuel and oxidizer are in the exact balance needed for complete combustion. For rocket engines, this is very bad, since it typically involves temperatures far higher than the materials can withstand. You generally want to run fuel rich or oxidizer rich. But if one turbine is delayed vs the other, the rate at which the propellants are coming in might coincidentally end up at a stoichiometric mix. That slags the engine.
In the first test, both stages are throw-away; so the loss during a launch is not a significant issue in terms of lost hardware setting back the build process. They plan to have more engines already in the pipeline. I guess it just means - how many times do they throw away 32 engines? The key is whether they have sufficient instrumentation to pinpoint what would have caused a failure. If I can think of that, of course the SpaceX guys have it covered as well as they can.
I assume they want to be assured of reliability before they tell many tons of steel full of explosive material many many miles up to “please come back, aim for the general area you left from…”
No, but losing the tower would be a big deal. Although they can build towers relatively quickly (i.e., relative to NASA contractors), they aren’t geared up to produce them at a high rate they way they are stages and engines. Last I saw, they were producing >1 Raptor 2 per day, which basically means a booster per month. They can’t produce towers at that rate, especially since the cleanup alone would be a big deal.
Back when the Falcon Heavy launched, Musk said he’d be happy if it just cleared the tower before exploding, and I imagine more or less the same is true here. The Soviet N1, after destroying the entire complex on the second launch, actually disabled its automatic engine shutdown systems until T+50 so that there was at least a chance that the remaining engines would send it clear of the ground facilities in case of failure. Pretty much anything is better than crashing back into the pad.