The shuttle had a 2/135 death rate. If Starship becomes the core infrastructure for Starlink, it'll be able to afford hundreds of launches before putting humans on it. You won't have to trust some theoretical calculations, you'll just be able to see in practice what the risk of a Starship launch is.
Design flaws that you don't know about yet are still design flaws.
I'm sure there are plenty of "accepted design flaws" in SpaceX vehicles. Hopefully SpaceX engineers are better at calculating the probabilities than NASA was, but I would not volunteer for early missions.
The two programs don’t manage risk the same way. You’re picturing a younger NASA trying to do the same process as led to the first space shuttle launch.
With the Challenger disaster, the contractor's engineering team that developed the booster gave a no-go for launch and NASA administrators showed off their engineering skills by using social engineering to trick an unqualified and unapproved employee of the contractor into signing the form to go for launch. That's far worse than being bad at calculating the safety risks; the specifically overruled the decision by the people that were good at calculating the safety risk.
Source: Truth, Lies, and O-Rings by Allan J. McDonald, James R. Hansen, and Jonathan Yen
dumb question, but at what point does the cost of fuel start to become an issue with such frequent launches? today I imagine launch cost is dominated by the price of the nonrecoverable parts, but fuel will become the floor no?
Starship is more efficient than F9 but in terms of multiple launches per day, the supply chain is indeed a factor. An hourly launch cadence is going to consume roughly as much natural gas as Houston.
All back of envelope here just to get a rough order of magnitude:
Starship needs 10kg (0.5mcf) of methane and 36kg of oxygen per kg to orbit. The oxygen takes 22kWh to liquefy or about (0.16mcf to generate that onsite). So 0.66mcf/kg to orbit and 66,000mcf from to fully fuel.
That is the daily gas usage of a midisze city, say 200k population, per launch.
For liquid oxygen, Spacex is building an air separation plant at its facility in Texas to grab it from the air.
For methane, didn't know this but looked it up, methane is one of the cheapest propellants, but rocket grade methane needs to be purer (starship is estimated to cost $300k to $1 million to refuel)
Sure but it doesn't launch or land humans on Earth, which is the hardest part. And that's fine for now. Once it's launched and landed a few hundred times we can think about launching people on it.
I like the rocket less, imho solids have no place in human spaceflight, but the Orion has a LES, which elevates it to being more safe than any spacecraft without one.
Liquid fueled rockets are intrinsically safer than solid fuel rockets. There is a floor on just how low you can get the risk level with solid fuel, you can't test the rockets you fly, and the failure mode is catastrophic blow-up à la Challenger.
It's like saying flying is safer than driving per passenger-mile. It is. By orders of magnitude. I don't care how safe your new Volvo or electric vehicle is, flying in a helicopter is still safer, and a passenger jet vastly more so.
"But Starship blew up 5 times!" Yes, and flying a test plane is dangerous too. Apples to oranges. Starship and SLS have vastly different design certification strategies. SLS spends 100x as much to deliver something that works as reliably as it ever will by the second or third launch. SpaceX gets Starship flying quickly and discovers bugs in prod. So you see more failures. But even now, Starship is probably safer than SLS ever will be. If not now, then very, very soon.
You're telling me starship is safe for humans when they failed to land the booster?
How about we let them succeed first before pressuring them to perform and inevitably embarrass themselves because the silly SpaceX fans were too smug on the internet.
SLS has an abort mechanism. That alone mitigates most risks of the first stage in a way starship never can, meaning the latter has to fight an uphill battle to deliver the same safety through flight numbers and experience.
> But even now, Starship is probably safer than SLS ever will be. If not now, then very, very soon.
Any failure to orbit is essentially a guaranteed loss for Starship. Any booster explosion or total engine failure on starship would also be essentially a guaranteed loss. Even the space shuttle had better backup options than the current version of starship.
Idk about you, but if I'm the astronaut I'd take 1-(P(SLS failure)*P(LES/parachute failure)) over P(superheavy success)*P(Starship to orbit)*P(Raptor relight) every time.
SLS might be less safe than some hypothetical future version of starship, but in reality the current starship's most recent flight had a 15 minute window where a no-go for orbit was called and the mission plan would have resulted in a loss of crew. Safe crewed launches and earth landings are not a priority for them and likely won't be for a long time. Even then, SLS+Orion have the advantage of an LES and the option for unpowered landings essentially anywhere, both of which are fundamentally unworkable with starship's design.
Not only that, but Starship is a robust system from an architectural point of view (not saying they don't have some bugs to work out of it). As we saw in the previous launch, they can go to orbit with an engine missing. An engine down on the shuttle would have been a catastrophic situation.
The Shuttle did have limited engine out capability. The only in-flight engine-out (as opposed to a pad abort after SSME ignition and before SRB ignition, which happened five times) was STS-51-F with a successful abort to orbit. The various other engine-out contingency modes were never used, but they did exist.
Initially only single engine out was broadly survivable; after the Challenger disaster new abort procedures were developed that made two engines out survivable during all of flight and even all three engines out at some points.
The big caveat here is that most of these modes were never tested, and the risk of failure during the more demanding aborts was substantial. RTLS abort was famously not tested on STS-1 because it was considered riskier than going all the way to orbit on the Shuttle's first crewed flight.
To put it in perspective, the Falcon 9 has had 702 launches and has only lost one payload during launch. A couple didn't make it into the right orbit, but there's contingencies to deal with that in manned missions.
Since 2022, there have been 601 booster landings, with two losses. (https://en.wikipedia.org/wiki/List_of_Falcon_9_first-stage_b...) That means that if you could have snuck onto one of the last 600 Falcon 9 boosters, with appropriate life support gear, your chances of survival would have been over four times higher than if you had snuck into the cargo bay for an SLS (space shuttle) launch, and that's with the SLS being designed to be manned, unlike the Falcon 9 booster.
Bad things happen, and spaceflight is a hard problem. But that’s not what killed two Shuttle crews.
I'm sure there are plenty of "accepted design flaws" in SpaceX vehicles. Hopefully SpaceX engineers are better at calculating the probabilities than NASA was, but I would not volunteer for early missions.
Source: Truth, Lies, and O-Rings by Allan J. McDonald, James R. Hansen, and Jonathan Yen
Propellant for a Falcon 9 launch is ~$500K.
Starship needs 10kg (0.5mcf) of methane and 36kg of oxygen per kg to orbit. The oxygen takes 22kWh to liquefy or about (0.16mcf to generate that onsite). So 0.66mcf/kg to orbit and 66,000mcf from to fully fuel.
That is the daily gas usage of a midisze city, say 200k population, per launch.
For methane, didn't know this but looked it up, methane is one of the cheapest propellants, but rocket grade methane needs to be purer (starship is estimated to cost $300k to $1 million to refuel)
I like the rocket less, imho solids have no place in human spaceflight, but the Orion has a LES, which elevates it to being more safe than any spacecraft without one.
It's like saying flying is safer than driving per passenger-mile. It is. By orders of magnitude. I don't care how safe your new Volvo or electric vehicle is, flying in a helicopter is still safer, and a passenger jet vastly more so.
"But Starship blew up 5 times!" Yes, and flying a test plane is dangerous too. Apples to oranges. Starship and SLS have vastly different design certification strategies. SLS spends 100x as much to deliver something that works as reliably as it ever will by the second or third launch. SpaceX gets Starship flying quickly and discovers bugs in prod. So you see more failures. But even now, Starship is probably safer than SLS ever will be. If not now, then very, very soon.
How about we let them succeed first before pressuring them to perform and inevitably embarrass themselves because the silly SpaceX fans were too smug on the internet.
Any failure to orbit is essentially a guaranteed loss for Starship. Any booster explosion or total engine failure on starship would also be essentially a guaranteed loss. Even the space shuttle had better backup options than the current version of starship.
Idk about you, but if I'm the astronaut I'd take 1-(P(SLS failure)*P(LES/parachute failure)) over P(superheavy success)*P(Starship to orbit)*P(Raptor relight) every time.
Initially only single engine out was broadly survivable; after the Challenger disaster new abort procedures were developed that made two engines out survivable during all of flight and even all three engines out at some points.
The big caveat here is that most of these modes were never tested, and the risk of failure during the more demanding aborts was substantial. RTLS abort was famously not tested on STS-1 because it was considered riskier than going all the way to orbit on the Shuttle's first crewed flight.
Since 2022, there have been 601 booster landings, with two losses. (https://en.wikipedia.org/wiki/List_of_Falcon_9_first-stage_b...) That means that if you could have snuck onto one of the last 600 Falcon 9 boosters, with appropriate life support gear, your chances of survival would have been over four times higher than if you had snuck into the cargo bay for an SLS (space shuttle) launch, and that's with the SLS being designed to be manned, unlike the Falcon 9 booster.