SpaceX loses another Starship prototype as landing sequence fails
arstechnica.com
arstechnica.com
1. This landing procedure is not viable. Restarting an engine in the middle of a rotation like that, fuel sloshing around is really hard. Just restarting an engine in zero G has always been tricky, because the fuel is floating around and doesn't have gravity pulling it to the pump. This case is even more dynamic, and you have to get it right immediately.
or
2. If the raptor engine is too complex to be reliable.
Then again Falcon9 also failed to land many many times early on, and it has become rather routine. Though still not routine enough that you would want to be a passenger riding one down.
please nobody reply with "prototype" or "rapid iteration" we know, we have seen your posts 20,000 times here already :)_
The raptor engine on the other hand does seem like something that they are far from mastering the production of. Being the first full flow staged combustion, methane fuelled orbital ready rocket means that there is less to directly compare to so I'm not surprised that they are having reliability issues with it. I am optimistic that they will eventually overcome these challenges but I'm less certain if they will be able to meet their projected schedule.
Rather fail fast, than fail slow. SpaceX takes this to the next level of space hardware testing with their willingness to fail. Good on them.
Ps: it is a prototype (i said it!). It's expected to fail at some point. Otherwise it would be production hardware...
going to be tough, hope it works!
These test flights might be low altitude but the flip and landing is realistic.
I'm far from a rocket scientist, but I thought that rockets were kind of like soda cans - very strong on the long axis, but not at all perpendicular to that.
If you make them strong in both directions, I wonder how that doesn't make them prohibitively heavy.
Generally, of course this is more true when the stages are empty. If the tanks are pressurized, as they are during the whole flight, they actually become very stable in both directions.
Starship is specifically designed to survive a reentry (heating) into the atmosphere at an angle, just like the Spaceshuttle.
I was re-watching a series of videos doing a walk-through if the Apollo guidance computer over the weekend and one of the cute 'yes, they thought of that' bits that was mentioned was that before the main firing sequence begins on the LEM descent they perform an 'ullage' burn using the RCS to settle fuel in the tanks.
We should realize that after the first failure SpaceX already had built a couple of prototypes that were 'wrong'. So they had to basically do hacks to figure out how to fly them at all.
I would assume with the next generation they have really thought about how to do the header tanks and redesigned them and how the pressurization of those work. They are seemingly learning about some interesting things about liquid methane and bubble formation in liquid methane. The baffles they had apparently caused a vacuum bubble in SN8.
Can't the fuel be stabilized mechanically, e.g. as in a syringe?
But its not what any rocket designer would want to do. Having a mechanical system inside of a deep cryo liquid methane is hugely complex and very heavy. Even if you put it outside, you still have deep cryo liquid inside and that would make it even heavier.
Consider that 1kg extra weight on the second stage reduces payload to orbit by 1kg and payload to Mars by much more overall.
Helium was just temporary as well so once the actually design system is back with SN15 it should be better already.
The idea that Starship has is to use the fuel and oxidizer in its gas form. So the methane tank contains liquid methane pressurized by gaseous methane.
The benefit of this is that if the engine ingests some of that gaseous methane its less of an issue in terms of engine thrust compared to helium and its possible more recoverable of a situation.
It works for Mars rover tires too. Want rubbery tires? Use something like perfluoroheptane. Keep the vehicle cold during the trip, or mount the tires in disposable molds that wear away during use.
Think a radiator, lots of tiny fins, but all inward pointing in a tube. Coat the fins so they are '-philic' to the liquid. Get creative with the geometries of the fins. Surface tension / capillary-action spread over a lot of the fins in the tube will move the liquid to a sink, like the combustion chamber.
The procedure might be unworkable, the engine unreliable, or not reusable enough, tons of things. I think such an ambitious project is always a “maybe” until it’s done. But not in the general perception.
Seems totally reasonable to me. It's a new design of a new type of engine.
Also, as of their 25th Starlink mission last week they now have 1320 satellites in orbit. Approximately ⅓ of all operational satellites are now Starlink relays, which is kinda mind boggling.
I wouldn't be surprised if this Starship didn't incorporate all the improvements they learned about during last few launches (and booms).
"Next major technology rev is at SN20. Those ships will be orbit-capable with heat shield & stage separation system. Ascent success probability is high.
However, SN20+ vehicles will probably need many flight attempts to survive Mach 25 entry heating & land intact."
Surviving the orbital entry and landing is probably the most difficult challenge yet. After that the next major challenge is landing on Mars.
> Fortunately, as part of its iterative development program, SpaceX is building a Starship vehicle at a rate of every two to three weeks. So the next prototype—likely to be SN15 as the company skips ahead toward a more advanced version—may be ready to fly in several weeks. Still, SpaceX would have liked to have gotten this one back in one piece.
Is there going to be an ejection system in case of failure?
EDIT: Instead of just down voting my valid question you could please provide me with an answer so I can understand how such issues are going to be resolved. If the flip maneuver fails I don't want to die.
Vertical landing of the rocket seems to be the only rapidly reusable architecture for landing on other planets - the primary purpose of this rocket (eventually).
I'm not sure about other failure handling, you ask a good question and I don't have a great answer. But the mission requirements suggest that vertically landing the rocket is the only feasible landing method I think.
What was the backup for landing on the moon? What about Mars?
The moon lander didn't perform a complex flip maneuver.
Also you are wrong. SN9 actually used 2 engines for the flip, not 3.
They only swapped to 3 for SN10 and the flipped worked perfectly there. The problem with SN10 was the temporary helium system they put after SN8 in so the engine was ingesting helium.
The point is that you have engine out capability both on the flip and during landing. Of course over time SpaceX need to test some of these profiles in more detail, just as they did for Falcon 9 where they tried various ways of landing.
What happens if all the engines fail?
What happens if it flies into a mountain?
now they light all 3 and turn 2 off when one lights.
Orientation, I expect, would be determined by some kind of gyro (ring laser gyro? or super precise accelerometer?). How about altitude? What is the feedback mechanism(s) to know where the ground is in the moment before touch down?
Radar
Not true. They know exactly where most of the pieces landed!
They lose 3 raptor engines per crash and that hurts. A lot.
[0]: https://twitter.com/elonmusk/status/1179107539352313856
It makes sense at $10 mil since they are pumping these out like mad.
Also NASA awarded $135 mil for the starship design so it can’t cost $100 for each of these sn’s right!?
The best assumption would be that the author of the $180M figure has no idea what they're talking about and derived at this number from a lack of information and through bad analogies and misapplication of scaling laws.
The Starship prototype cost is a big variable, but assuming it's somewhere in the (log scale) middle of the 10 to 180 million range it's not unreasonable to think that SpaceX can afford to keep producing these things at a rapid rate for quite a while without going broke.
That'd mean a Raptor engine would cost less than $1 mil and that just can't be true - that'd be about half the price of a much smaller and less complex Merlin engine...
But even if it were $2m, there's 3 engines, that's $6m, leaving $4m for a bit of steel out of that $10m budget.
Well, they are shooting at a per Raptor cost of 100k long term 250k short term. Even assuming it is 4x as much now, that is about 3m for the engines.
The stainless steel only cost a couple 100k$ at most.
Add in some bits and pieces, like flight termination system, thruster system and tanks, sensors and so on, add another couple 100k$, lets say 1 million. All of these are already produced by SpaceX in pretty large numbers.
Then manufacturing cost, is a bit hard to calculated, they are producing one prototype every couple of weeks and most of the labor is in welders and most of the machines are welding robots. Labor cost being the dominate cost.
A large part of the cost would likely be the launch site construction itself, and how you want to amortize to an individual prototype is hard to say.
Then there is another bunch of cost for operations and fuel add another couple 100k.
So I would assume a cost of 3 million to 20 million. I'm giving this a pretty large range because its a guessing game. Over the course of a year they tested about 10 increasingly complex prototypes. That would at the high end be a cost of 200 million for one year of this process, if we ignore the design cost.
Consider that NASA SLS has a budget of about 2.5 billion a year including ground system (and that has been going on for 10+ years and will go on for many more), SpaceX is basically nickel and dimming a launch vehicle of that size.
Elon Musk has a couple of saying along the lines of 'if its long its wrong' regarding development. Spending 50% less time while blowing up prototypes regularly is cheaper then spending longer on the project overall. A lot of the things SpaceX does is novel, so no matter how much design work, nobody has ever flipped a deep cryo methane tank and started a full flow staged engine with torch igniter.
Working the perfect design for this on paper would take incredibly long and even then you might have to start over again and once you finally test it.
This is certainty an expensive program, but compared to Starlink is seems less insane in terms of cash burn. Doing both together is a bit extra insane, but on the other hand if you have Starship, the cost of Starlink drops to pretty absurdly low level.
Starlink has an insane cash burn during deploy, indeed, but after that it's a cash cow. People are paying through their noses for shoddy satellite internet, and Starlink is orders of magnitude better quality and way lower priced...
That's some super optimistic numbers you chose there. There's no reason to believe that at this point in time a Raptor engine is only half as much as a less complex Merlin engine.
The loss of three engines per test is by far the most costly part of the operation. How much an engine costs right now, I don't know of course, but I'm very confident it's more than $2 million a piece.
And in the next tweet, he mentions his concern is about "secondary structure", which I take it to mean all the infrastructure that you would need to build and operate to make that rocket fly.
Find me a tweet where he actually states that Raptor is at V1.0.
Raptor already seems to have a production rate comparable to Merlin.
And btw, in my final estimate I gave a larger range. Even assuming 3 million per Raptor, that would fit within the 20 million I mentioned.
10 successful landings or 20 or 50 ???.
Apollo did 6 launches (bar the first one - cabin fire) before it was manned.
Even if you start from the first Starhopper launch, that gives SpaceX until 2025 to be technically ready for the first crewed launch.
Is it correlated to the success of the mission or just a coincidence.
By saying that SpaceX "must provide adequate notice of its launch schedule", they are basically saying that it's unreasonable for anyone to try a fast-paced space development program. SpaceX has to slow down so the FAA isn't inconvenienced by having to hire a local inspector, or having the inspector wait idle a few days, or keep their phone on and travel on short notice, or figure out remote inspections. Which is just the epitome of government bureaucracy.
I have no doubt spacex would love to do that so why isn't it possible?
We'd do well to keep in mind that the Washington Post is owned by Jeff Bezos, who also owns Blue Origin, a rival spaceflight company. That doesn't necessarily mean that the reporter's information is false, but he's potentially biased.
At the risk of letting politics intrude into the discussion: the Washington Post also exhibits a conflict-of-interest pattern of behavior elsewhere. Bernie Sanders is a vocal critic of Amazon and their treatment of workers, and the Washington Post is often harshly critical of Senator Sanders. Again, there's no proof that Jeff Bezos is influencing the editorial content of the Washington Post, but there's a pattern of behavior and a financial incentive.
Huh? What does Trump have to do with Bezos owning the WaPo?
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