This is hardly beyond standard practice in the industry.
The SLS is going to orbital flight with no flight testing. Heck the Falcon Heavy launched a car past Mars' orbit on it's first flight. I think SpaceX's main goal was to refine their manufacturing process and make sure they can achieve a certain level of consistency in building these things. The fact that they installed all these Raptors before even doing a pressure test tells you they are far more confident in their processes than they were even 6 months ago.
I hope it goes well, but I'm concerned that they've never done a test flight or a full-duration 33 engine static fire on the first stage booster. SpaceX has always been about real-world testing and rapid iteration based on the (often catastrophic) results of that testing. I worry that the lack of testing is due to a business desire to avoid the (stunning) cost of building and losing 33 Raptor engines on each failed test article, rather than an engineering judgement that such tests are not needed.
What you've missed here is that failure points can only be guessed or simulated prior to testing. That analysis is often more expensive than the cost of a test and test article.
So SLS does a LOT of analysis and manages to find and rectify failure points prior to flight. They pay a lot in analysis and inflexible design to do this.
SpaceX does some analysis, but then flies to confirm the analysis early. That way they identify actual failure points and can use sensors to see how close they got to failure.
For instance today I'm sure they learnt a lot from each failed engine, parts on the booster that stopped working, detailed telemetry on ship behavior on flight and sensors for the non-separation of booster from ship.
SpaceX builds to the same high tolerances as other rocket manufacturers, but they don't try to avoid testing through overly rigorous analysis. They also don't gold-plate their manufacturing, instead making tradeoffs to allow cheaper volume production with recovery instead.
So I listened to a podcast about this... but SpaceX and Boeing/NASA are explicitly taking two different approaches to proving their rocket will work. Obviously we know SpaceX is proving their rocket through system level tests. But for SLS the plan has been to use a long accepted NASA approved method of proving their design where individual parts are so thoroughly tested and proven to work that they don’t need many flight tests of the full system. In fact I believe the original plan was one flight test without humans and then have the second flight be a manned mission! So they really aren’t supposed to fail like this.
So at the core are two different approaches to proving their system, where SpaceX totally expects some failures and SLS is supposed to be proven before it even flies. Personally I’m a fan of the SpaceX method but I can understand why the old guard space developers would choose this slower more cautious method.
I don't have any problem with them adopting a test flight heavy methodology, however it is extremely misleading to suggest that this is the methodology which gave them the Falcon 9.
The falcon 9 succeed on it's first launch, it was not a test flight heavy program.
The falcon 1, SpaceX's only orbital rocket prior to the falcon 9, did fail on it's first three flights, however it was never intended to and that nearly bankrupt the company. They destroyed third party payloads on flights 1 and 3, because these were intended to work, not be test flights.
Long after it was in production the falcon 9 did begin a "test-flight" heavy program, but that was for developing the ability to recover boosters after they had successfully delivered a customer payload in an operational flight, not for developing the rocket itself.
SLS proponents have been claiming that all of the extra time and money spent on process and formal verification would lead to a rocket that works without having to do lots of trial-and-error like SpaceX. Heck, even the name of the test campaign, the "Green Run," kind of reflects this hubris and shows that NASA expected the tests to largely be a formality.
The thing is called "progress" and is the reason for doing these tests. If you really care about this I suggest looking back in the development history of SpaceX' current cash cow, the Falcon 9. Look for similar explosive events and compare that to the current ease with which they seem to launch and land and relaunch these things now. Now fast-forward another 10 years and imagine the same happening with this new rocket which is poised to bring down the price of launching mass to orbit by another large factor.
Typically, but SpaceX has made rather a habit of ignoring expensive space-grade components in favour of consumer-grade ones they test themselves for a fraction of the cost. I guess we'll see.
> SpaceX uses a different testing strategy where a lot more stuff is tested as a complete system.
I'm sure they are tested as integrated systems, but they are also exercised extensively ahead of that. The Super Dracos used for the launch escape system have been test-fired since well before the Crew Dragon got its name.
SpaceX has a "test as you fly" philosophy. It's the same approach that built the Soviet Union's excellent rockets (including the Soyuz).
Unlike the Soviet Union, SpaceX can afford to fund their version of the "N1" moon rocket: at around $1 million per Raptor engine (and 3 Raptors per Starship hop test) the R&D program is still relatively affordable, even with the failures.
This philosophy is in stark contrast to the SLS (Space Launch System) which after decades of development has only just done a static fire. Also SpaceX's philosophy around the Starship test program is focused on building a factory that can manufacture thousands of Starships vehicles a year.
But I agree on the spectrum between "analysis paralysis" and "reckless" SpaceX is arguably a bit too far towards reckless at the moment.
I hope apparently wasteful R&D program yields better results soon. They need to start testing rapid reuse for Starship to be able to meet its cost goals.
"I'm still surprised they moved to this orbital fly so quickly without doing more tests."
I'll bet they're going to remove all 29 of these engines and re-attach them again later. I would expect they want much more testing than they've done to date (for example, pressure testing the tanks -- they have not done that with this booster, BN4, according to Reddit).
I just did a short search for the SLS test launches, but couldn't find anything. Is this SpaceX fail fast approach to test incrementally, and SLS was just launched the first time with payload, or did I just miss the test launches of that system?
And NASA will probably be very happy to use such a cheap system once they are convinced it meets their reliability standards. The point of SLS IMO is to keep a backup option if SpaceX has some horrific, unpredicted setback or design problem.
Surely people understand redundancy in aerospace right?
They’ve had two falcon 9 systems explode unintentionally. The CRS-7 system failed in flight, and AMOS-6 failed on the launch pad during fueling. They also unintentionally blew up a Crew Dragon capsule.
It is true that they do testing differently from Boeing. Boeing uses a NASA testing plan where hardware is verified on the ground through extensive part or subsystem-level testing. This method has a downside which is that many things end up needing a higher factor of safety than absolutely necessary due to uncertainty in the risk calculations.
SpaceX uses a different testing strategy where a lot more stuff is tested as a complete system. There is increased potential for full system failures, which we have seen, but the entire system can be vetted more quickly.
SpaceX's problem was they trusted the manufacturer who had certified the strut. So theoretically it was already being done by the vendor.
SpaceX is also pretty good about eliminating checks that have become redundant or otherwise redundant. For example they no longer do a static fire on the launch stand before every flight.
The big promise of Starship is the quantity of flights they envision. A thousand flights will give huge insight into reliability, insight that space flight has never had because most articles are never recovered and inspectes.
People need to understand this in context of rocket engine production.
For comparison, Blue Origin has sold the BE-4 to ULA many years ago. The are testing 2 qualification engines, they have 2 engines in production that hopefully will finish sometimes in a the next few months. We don't know how many are in production beyond that but likely not all that many. These engines will still cost around 7 million $ per engine.
That is a more normal production rate, one engine in a cycle of months or even slower.
SpaceX just for the test campaign alone is already on SN-100+. Most engines are never even produced in such numbers. SpaceX already has quite high production rates relatively to what would be considered normal.
What SpaceX is attempting to do here with the Raptor, and mass producing them in a cycle of a single day is something that has never been even approximated by anybody. This is not a relatively simple engine like to Soviets use for Sozus. This is one of the most complex and most powerful engines ever built.
SpaceX has some experience as the Merlin is already one of the most mass-produced engines, but its simpler and they never attempted to push the production quite to where they want the Raptor to be at.
What I also think is that some people might misunderstand is that this is not about producing a functioning engine, this seems to be really about how fast they manage to do it.
For something totally different, the biggest issue with launching Starship 2x per week is that they literally have no place to do that from. Even if the get approval in Boca, that's for 12 launches a year. Getting more then that might not be very easy.
The launch platforms from the ocean will likely not be ready.
The might be able to launch more from the Cape, but that is also quite contested. And they would have to duplicate the mechazilla launch infrastructure there as well.
I really hope the planning they are doing are not that tight. I can see how mass production of Starlink Sats could really bad a very tough cash burn if you can't launch them.
All that said I don't think its like SpaceX will fail anytime soon.
Edit 2:
SpaceX e-mails usually are not leaked so seeing this is quite surprising. I hope this is not a fake. It seem like it makes sense.
both test failures seem to have been during the booster rocket phase and they weren't even able to test or collect data on the missile component
Lockheed is in charge of development, just like the SLS program. I'm curious how hard it would be to have SpaceX make an attempt or if they would even be willing. Seems safe to say they know rockets far better than Lockheed
The largest rocket ever built just got to space for the first time. Even without re-entry this is a milestone.
They have a production line to build these things. They’ll roll out the next one and try again. It’s not like SLS where everything is expected to work perfectly.
reply