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Second stage reuse seems the far more challenging problem. Other companies should have reusable boosters soon but if significant amounts of Starship continue to
by shirro 2y ago
Second stage reuse seems the far more challenging problem. Other companies should have reusable boosters soon but if significant amounts of Starship continue to ablate on the way down they could be faced with a disposable Starship competing with smaller and cheaper second stages that are well sized for typical payloads. We already knew boosters can be flown back to launch sites reliably with high accuracy. We don't know if it is possible to make rapidly reusable thermal protection systems that can operate on an orbital vehicle of Starship's size until it is demonstrated.
- api 2y agoDidn’t they look at all kinds of ideas earlier like squirting some propellant or water out over the skin on the way down, and wasn’t steel chosen for its thermal robustness? Did they get into the problem and realize it’s a lot harder and abandon those things for tiles? Maybe they will have to sacrifice more payload mass for active or passive shielding or more fuel for powered deceleration. That would yield a less impressive lifter but with full reusability.
- chasd00 2y agoYeah for rapid reusability tiles aren’t going to work, too fragile. Iirc it was with a lot of reluctance they went with tiles and will have to make breakthroughs on the heat shielding to get where they want to be.
- rini17 2y agoThey already plan refueling infrastructure in orbit. That would include stuff to "squirt" on the way down if necessary. If they can use one extra launch to reuse 5-10 starships that might be interesting. Noone knows yet if it's actually needed.
- wolf550e 2y agoThey dropped transpiration cooling, at least for now.
- WalterBright 2y agoInterestingly, the inside surface of a rocket nozzle is covered with tiny holes. Fuel is circulated in a jacket around the nozzle both to pre-heat the fuel and to cool the nozzle. Additional cooling of the nozzle comes from fuel leaking into the combustion chamber through those holes, carrying away the heat so it doesn't melt the nozzle. It's called boundary layer cooling. It was one of the technological breakthroughs of von Braun's team with the V2.
- philistine 2y ago> Other companies should have reusable boosters soon You're way too optimistic. Starship will deliver commercial payloads, with SpaceX phasing out Falcon 9 outside of ISS launches, before anyone has a reusable Falcon 9 equivalent. It pains me to say this, but SpaceX is in a class all its own.
- dotnet00 2y agoNew Glenn finally has flight hardware undergoing pre-flight testing. I think they're pretty likely to manage to fly in early/mid 2025, and they do aim to recover the booster in their first try.
- thinkcontext 2y agoThe Chinese could have a reusable booster before then. One of their companies is doing 10 km hop tests.
- signatoremo 2y agoSpaceX couldn’t manage the first Falcon 9 landing until 2015. The first Falcon 9 reuse wasn’t until 2018, so 3 years to achieve reusability. The Chinese prototype hasn’t yet succeeded at sub-orbital landing. I wouldn’t be surprise if it’d take them longer than 3 years to have a reusable rocket. Starship would have been routine at that time. Blue Origin plans to launch New Glenn in a month, with landing planned. They are a wild card.
- jiggawatts 2y agoI’m not saying they stole the plans through industrial espionage, I’m just wiggling my eyebrows suggestively while glancing in the direction of the suspiciously similar looking booster.
- ls612 2y agoIs this the same company that had their booster fly into the air when they were trying to static fire test it?
- audunw 2y agoI found Jeff’s Bezos interview with everyday astronaut really illuminating on this topic. Supposedly they’re working on both a reusable and cost optimised non-reusable second stage at the same time. And they don’t really know yet which one will end up being cheaper. You also see this kind of thinking with Rocket Labs neutron rocket. Where they focus on making the reusable booster do more, while making the second stage smaller, cheaper and simpler. I think if it wasn’t for the rocket engine this wouldn’t be a question at all. The tank doesn’t have much value. It’s just a thin shell and probably a fraction of the cost of the fuel. So I’m thinking, perhaps the optimal solution is something like this: the bottom part of the second stage with the engines separates, and a small engine and fuel tanks places the engines in a stable orbit. The tank itself is deorbited and burns up. At some point later something like the Starship collects several second stage engines and deorbits them safely to be reused. Or perhaps just the engines can be immediately deorbited with an inflatable heat shield and parachutes.
- cryptonector 2y ago> Second stage reuse seems the far more challenging problem. Sure, SpaceX has been doing first stage reuse for a long time now. But they have demonstrated landing the second stage successfully at sea twice now with the same sort of smoothness that they demonstrated once for the booster before they then caught the booster on the first real try. A partial list of unbelievably hard things that SpaceX has so far made seem easy: - building a rocket from scratch - landing Falcon 9 boosters - landing Falcon 9 boosters *reliably* - 3x weekly launch cadence (Falcon) - the bellyflop manoeuver - mass manufacturing(!) a rocket engine - catching the booster - simulated landings of the ship Catching the booster is really just like landing a Falcon 9 booster w/o legs, but clearly much harder. Anyways, if they can do all those things then it's pretty clear that they can catch-land the ship. There's still a huge list of crazy-difficult things that SpaceX say they want to do that are hard to believe are possible, except for the fact that SpaceX has already done so many unbelievably difficult things already.
- pfdietz 2y agoThe hard part of 2nd stage reuse is surviving entry at orbital speeds. They are close to having that solved.
- m4rtink 2y agoYeah, I would say they already made a lot of progress - looked a lot less crazy now compared to the previous flight. :)
- pfdietz 2y agoWith F9, they piggybacked refining S1 recovery/reuse onto commercial launches. This was a big help in reducing development cost. They could do the same thing with S2 recovery here.
- cryptonector 2y agoI would say they are there. Sure, they're having some burn through on the flaps, but they managed to hit their virtual landing spot anyways, and if they caught a slightly damaged ship they could study that damage better, repair it, and refurbish the ship. But I imagine that by IFT6 they'll have nailed the flap burn through problem.