Watching pieces of the ship melt off, but then seeing it make a relatively controlled landing, is perversely confidence building. If it can survive that kind of damage on a control surface maybe it's a quite robust craft.
Exactly. Everyone was worried about reentry, but perhaps more concerning than the question of whether the headshield tiles work was the question how well the material below can handle failures. Now we know significant failures of tiles do not have to lead to mission loss.
It's also worth noting part of the craft flew (intentionally) without heat tiles, and another part with thinner tiles.
They're gathering a ton of data to make it robust! Many of these engineers built Falcon 9, and I have a pretty high degree of confidence they'll shake out the issues. SpaceX operates very differently from traditional aerospace, so we'll likely see many more issues come up before Starship is human rated.
Two tiles were intentionally left out, in a non-critical area (the anticipated damage was still bad for re-usability, but tolerable for re-entry) and instrumented with sensors to collect data like just how hot it gets.
Getting it human rated is likely much harder than reusing the upper stage a couple of times. The difficulty is that Starship has 1) no launch abort system, and 2) the belly flop landing is much more dangerous than conventional and proven capsule based landing. To get the system human rated, they may have to fly tens or even hundreds of flawless cargo missions first.
Not just perhaps wrongly, definitely wrongly by NASA's own late security analysis, which led to the early discontinuation of the Shuttle program. The Space Shuttle is a major reason why the security standards for human rating anything is now much higher than for initially human rating the Space Shuttle.
> Getting it human rated for landing on Earth seems infeasible.
Why? For NASA, human-rating - for either Earth launch or Earth re-entry - requires a very detailed engineering analysis of probability of loss-of-crew (LOC), and then NASA has some maximum LOC probability they allow (for NASA Commercial Crew, both launch and landing it is 1-in-500, which is 0.2%-for whole of mission it is 1-in-270). That analysis is based on engineering data, which can include simulations, data collected from actual flights, and data from ground-based testing. If SpaceX can demonstrate N successful uncrewed landings (with maximum G forces within acceptable limits for crew, etc), for sufficiently high N, logically the LOC probability will fall beneath NASA’s threshold, and then NASA will human-rate it. However, they don’t actually have to land it 500 times - all they need is an engineering analysis which calculates the LOC probability as being below threshold, and then NASA’s own engineers review it, and once NASA’s engineers are confident it is correct, the human-rating will be approved
> However, they don’t actually have to land it 500 times - all they need is an engineering analysis
That very analysis will include the fact that they have no launch abort system like normal capsule based systems and that the belly flop landing is much more dangerous than landing a capsule. Space Shuttle memories may come to mind. So the only realistic way to get the 1 in 500 confidence would probably be to really land hundreds of times for unmanned missions and not mess up even once. Granted, they may eventually get there, but I estimate this would take about two decades, if Falcon 9 is any indication.
> That very analysis will include the fact that they have no launch abort system like normal capsule based systems and that the belly flop landing is much more dangerous than landing a capsule. Space Shuttle memories may come to mind.
You are talking about this as if it is based on feelings as opposed to probability calculations. SpaceX will present a probability calculation to NASA, who then either accepts it or disagrees with it on engineering grounds, not "memories". There is no formal requirement for a launch abort system in NASA's safety standards – just a requirement that the probability of death be below a certain threshold. A launch abort system is one way to get that probability below the threshold, but if you don't have one, that's okay so long as you have some other way of getting there.
> So the only realistic way to get the 1 in 500 confidence would probably be to really land hundreds of times for unmanned missions and not mess up even once.
What they do is list every possible failure mode, give it a probability of happening and probability of a lethal outcome if it happens, multiply those two probabilities together, and then add them all up. If the result is above the threshold, they will fail certification. If the result is below it, they then have to convince NASA engineers that (1) their probability estimates are accurate and have sufficient evidence to justify them (2) there are no failure modes they've omitted in the analysis. For (1), actual flight experience is a valid source of evidence, but there are others as well – such as simulations and on-the-ground testing of components. There is no minimum number of flights required to gather sufficient evidence, it all depends on how much non-flight evidence is available and how NASA engineering evaluates that non-flight evidence (which is going to depend on the component or failure mode we are talking about).
You are looking at this from a "big picture" perspective, whereas NASA will be looking at it scenario by scenario, component by component
Starship separation from booster could be the launch abort system. There is no landing abort system.
My concern is that the flip maneuver is just too risky for landing with people on board even if Starship manages to do 200 perfect landings in a row (that would be a better record than the Shuttle).
I guess one factor which makes it less bad is that Starship can throttle its engines to hover (Falcon 9 can only throttle them down completely in a "suicide burn", which leaves no possibility of hovering in place). Starship also uses multiple engines for the landing. So if one fails, it still has a few others left, and perhaps even enough time to start another one.
> But… why go to all that effort when you can just pop the capsule and land in a thing that is not full of highly explosive fuel?
SpaceX wants NASA to human-rate Starship because their long-term plan is to retire Falcon 9 / Dragon.
How I expect it will happen: SpaceX will run their own internal analysis of loss-of-crew probability for launch and re-entry. No point going to NASA until they've convinced themselves they are going to meet the standards for human-rating. Once they believe they are, then they'll decide when is the right time to try to convince NASA of it too.
Obviously they are already doing this for lunar landing/launch. Some of that is going to be transferrable to Earth landing/launch. Other parts are unique – e.g. probability of surviving re-entry – but they need to estimate that anyway for non-crewed use cases.
I love that they are deliberately tempting failures with the no and thin tiles.
In a lot of ways they will learn far more from the heat shield burn through around the flap(s) than they would have if they had been "lucky" and it had all gone perfectly.
You during testing you want things to fail, that is the point of testing. If it's all successful you only learn that under those conditions your design works, but if it fails, you learn another way to not do things.
That's an often underappreciated aspect of engineering.
When parts last longer than expected, it is considered something that needs "fixing". It is a signal that the part can be made cheaper, lighter, etc... If SpaceX had gone with heavy, thick tiles, and they did their job because they were overspecced, it is that much less payload capacity.
Even value engineering, which is often criticized when it comes to consumer products is a good thing. Yes, your new dishwasher is not as robust as the one made in the 50s, but it is also 10x cheaper (inflation-adjusted), and it can still wash dishes for maybe 10-15 years without repairs, at which point you may want a new one as technology has improved. Note that I am talking proper engineering, having a single point of failure that prompts a replacement is planned obsolescence and terrible engineering, there should be no single point of failure with good engineering.
It'll still be orders of magnitude cheaper than the nearest competitor for many years. They don't need to fix it before gaining very extensive experience flying it.
You have to be careful how much wisdom you glean from fiction.
The sheer hostility of space kind of precludes the "she's a good ol' ship" trope. When your door doesn't shut on your pickup, you can bang on it a bit. When your door doesn't shut on your spacecraft, you've got a ship full of corpses that look like a blob fish brought up from the Marianas Trench.
So how can that work for air seals? Have a big robust air storage that can replenish losses from your half-broken door? How many other systems like that do we need? And all that extra weight somehow doesn't get you stranded in space when your badly maintained, low efficiency engine can't move it and your payload with the fuel that fits in the tanks? I get the principle, it just seems literally impossible to achieve (without, maybe, a radical step forward from chemical propulsion).
Same way rusty old cargo ships keep the sea out. Redundancy. Compartments. Emergency doors that close. Crew that run around patching leaks. Spare parts and welding equipment.
I think the definition of workable old ship is going to be different in space, but ultimately you can expand workable envelope for it by over-engineering critical parts. That's kind of what I mean. Right now we don't quite know how to do that efficiently or effectively.
Still remember that at one time moving faster than 15mph was considered insane and pushed the limits of materials and vehicle design. Same for high altitude flight, McMurdo station, deep ocean diving, etc.
In a lot of ways very deep ocean diving is harder than space. The pressure differentials are a lot worse.
The hard part about space is really launch and delta-V budgets.
Everything's relative. People a century ago would probably have felt uncomfortable at the idea of DIYing a multi ton vehicle being accelerated by a extremely high power pistons pounding up and down thanks to creating a controlled explosion inside a tight little box, that you can then hop in and cruise around at 80MPH+. And indeed if something goes critically wrong, you're dead. We just work to reduce the number of ways that things can go critically wrong.
I can't find the details now bit in the early 19th century an MP introduced a bill to parliament to make it illegal for trains to go over 30mph because in his opinion it would be impossible to breath at that speed.
The real problem are the storms, as a naked human you won't survive in an ocean storm any longer than in vacuum.
At least you are going to space in a sophisticated vessel full of redundant life support systems. People sailed the high seas in old, barely seaworthy wooden ships dangerously overloaded with cargo, which didn't even have a reliable way of determining where precisely they were, because no one could tell longitude at sea before the mid-1700s or so.
In fact, they did. Being a sailor was about the most dangerous profession that you could choose, including the military.
Until today, some jobs at sea are pretty dangerous. Being a fisherman in Alaskan waters is much more risky than being an (American, not Russian) soldier.
People still do it. Which convinces me that people will risk their lives going to Mars, and more than a few of them. Some people are just built that way.
> They don't risk their lives for high-risk, no-Reward explorations.
Sure they do. There’s a queue at the top of Mount Everest despite regular deaths; a couple rich folk got squished to pulp in the Titanic submarine last year. The free solo guy climbs Yosemite for the fun of it.
Do you believe that no one feels highly rewarded by exploring wilderness?
Generations of explorers, many of whom lost their lives for no gain, indicate otherwise.
Let us make a thought experiment. Let's say that Musk, tomorrow, declares "we are now creating a list of future Mars colonists, reasonably healthy individuals under 70 can apply from anywhere in the world, please send us your resumes".
Would they get fewer than 10 million applicants? I'd rather guess 50 million or so. Of course, some of those are going to get cold feet the moment they receive their one-way flight ticket in mail, but quite a few won't.
By your hypothesis, there would be approximately zero applicants. I don't believe that.
This is ridiculous. People risk their lives for pretty views and brief moments of adrenaline. I would advise you to touch grass, but you might not want to risk a cut.
Although space flight tends to have long periods of time where the craft can just coast. You have time to work the problem. A complete system failure could be worse on a plane in cloud than a spacecraft in orbit.
That's more of a movie trope. The ISS has had leaks, they are not explosive decompression. It makes sense too, the pressure vessel only has to hold in 1 atm, and we can manage to breathe a lot less than that.
That doesn't work IRL. Space is insanely unforgiving. While Starship has a vastly better chance than STS had of achieving rapid reusability, you really can't launch with a rocket that isn't up to spec because adding robustness adds weight. Unlike a multi-stage expendable rocket, Starship uses all its fuel to get to orbit. To go to the moon or beyond, it requires refueling by several other Starships that also just get to orbit. If the payload spec can't be met you need even more refueling launches. If reusability isn't rapid, you need a starship for each refueling launch. If cost goals are not met, the cost difference vs expendable rockets shrinks. Everything has to go right.
If you don't go very deep into the gravity well (said another way: high orbit of whatever planet you want to orbit) then the fuel cost is reduced compared to going down close to the surface.
The vast majority of the weight however is oxidizer which you could theoretically eliminate since the rocket is surrounded with various amounts of oxygen depending on launch trajectory.
A scramjet power first stage for example could overcome the tyranny of the rocket equation (at least on earth).
The issue is orbital velocity is an absolutely bonkers high velocity. Nothing can even come close to that velocity in the atmosphere. The SR-71, fastest air-breathing aircraft ever flow topped out at around 1/9th of orbital velocity.
Yes scramjets could certainly beat that speed, once they are developed but even if that doubles the speed of a SR-71 (which already was pushing the limits of heating) then you are still only doing 1/4th of the speed you need for orbit.
So you have a bit of a catch-22 situation - You can have plenty of oxygen for your engines all around you, or you can have the speed you need for orbit - But not both at the same time. Yes, a scramjet can reduce the amount of oxidizer required (by a lot) but to do this you need the extra weight of wings and everything else you need for proper aerodynamic flight.
A booster stage solves exactly that. I noticed in the launch yesterday that the booster was a hog - it was bigger, but it also had a lot of engines and a lot of work to do, so it burned through its fuel faster. This particular configuration is set up for the separation to happen pretty high, but one can imagine different configurations as well - a bigger ship and a smaller, fuel only booster that works only as long as there's atmosphere.
Or even better - keep the current setup but have a ring of air breathing engines in the booster that work as long as they can.
There's a lot of stuff some extra engineering can do, given enough time and resources. For now, SpaceX is going for the biggest bang for the buck, and they have a very healthy aversion of complicated solutions. But in time, adding a few air breathing engines may become simple enough to be worth it.
Right but the SR-71 had a pretty significant fuselage cross-section that is basically pure drag. If going for max efficiency, the entire nosecone of the rocket should probably be the air intake. Basically take one of the SR-71's engines put it vertical and mount the payload inside of it under the shock cone. TWR needs to be high enough to eliminate the need for wings.
Some of the newer missiles like the BrahMos are designed like this and have a ramjet powered second stage to save on oxidizer. It doesn't reach anywhere near orbital speed, but with this design, the shock cone takes the majority of the heating vs. the SR-71 where there were many exposed parts and materials.
Scramjets require the engine to already be going pretty fast, so they can't be a first stage engine. Then, with a rocket, most of the speed to get into orbit is built up after getting out to essentially vacuum, so, again, a scramjet is not that useful.
At an abstract level, it's the same issue as with aerospikes, the idea has too many caveats, too much expense and not enough benefit to justify the relatively small improvements in efficiency.
This is unlikely. We don't really do this on airplanes, where servicing procedures and airworthiness criteria are very strict, and space is orders of magnitude more unforgiving than flying in the atmosphere at ~10km altitude.
If there's cabin decompression on a plane, you get an oxygen mask and land safely in the nearest airport. If there's cabin decompression on a spacecraft, you're dead. If there's a problem with engines on a plane, you can still glide and land somewhere. If there's a problem with engines on a rocket, guess what, you're dead.
I'm working on my PPL at the moment, and I found some pretty fascinating facts about certifications. Apparently there's a very very sharp divide between anything that can be constructed as "commercial" flight, aka somebody pays you to take them for a flight, and non-commercial, i.e. it's just you and maybe your friends. The former category has some pretty solid regulations like, for example, a continuous chain of service history. Once you decide a plane is no longer commercial, you can skip that, and it suddenly becomes less regulated than even your average car.
There are rust buckets flying out there without any issue. There's a guy on tiktok that bought a literal $200 plane and is documenting his work on it - and he started test flying it almost immediately.
I don't have enough experience in the field to tell myself if aviation tech is mature enough to be considered "rusty truck level", but we definitely have the data to know it.
Actually we do this on airplanes globally. There's many older aircraft or poorly maintained aircraft, as long as vital requirements don't fail, it's fine.
Yes it's different from a car's requirements, no the concept is not different, rusty pickup just means different things.
I would compare it to Airplanes, and there are not a lot of rust-bucket airplanes, because just like in space, failures can lead to unavoidable death very quickly. That’s not comparable to a reliable pickup
It really depends on where you are in the world. Poorer countries often have older aircraft that are in worse states of repair. Most aren't exactly rust buckets, but they wouldn't be legally airworthy in places like the US or EU. This does result in worse safety records, but it's still safer than driving the same distance in most places.
Those are getting overhauls in regular intervals though, it’s more like theseus airplane. Except for the structure itself, there is a lot of repair and replacement happening.
And they also have a less-than-great safety record (although that is also pilot related).
We also won't be ready for the sci-fi-style space age in real life unless there's a use case for it. Imagine Star Wars except there's no life on any reachable planets, what would they even do with their spaceships?
And Star Trek doesn't have "good old rust-bucket" ships in it, but the whole premise of it is that they found a way to move faster than the speed of light.
Here are a few likely use cases:
* in-space science
* in-space R&D
* in-space industry
* mining small rocks (asteroids) in space
* space-based power
* military applications
Long-term, we may see terraforming planets and minor planets.
Reminiscent of the booster in IFT-1 just doing spins in the air, refusing to break up even after the flight termination system was triggered. Completely unlike KSP with its wobbly rockets.
This is one successful landing. I think its robustness needs a lot more successful landings than this. Plus, its not even landing like it was originally designed to land, its just landing in the ocean like any other rocket expect with thrust vector control rather than parachutes.
It looked like plasma got between the flap and the body. I wonder if that means something broke/melted to allow that, or if the design just allowed it accidentally.
They've been concerned about burn through in that area for a while, but they didn't get to test it before now to understand how it'd perform in reality. IIRC they were even calling out that they were surprised that the temperature readings in other parts were in good agreement with the simulations, which is probably indicative of the limited confidence they had for that part.
It looked like the flap was starting to glow internally in the middle, right before the burn-through on the hinge point. I wonder if it maybe had a lost tile on the other side that evolved into the burn-through we saw in the video.
Part of the build up said that they had deliberately weakened / thinned some of the tiles in order to test what the tolerance was. It seems that they must have gotten some incredible data about the mode of failure.
