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SpaceX's giant Starship Mars rocket nails critical 10th test flight

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Re: SpaceX's giant Starship Mars rocket nails critical 10th test flight

#331

Post by jjk166 »

FireBeyond wrote: post #300
jjk166 wrote: post #286

Earlier quoted context omitted.

> What, exactly, is that guy doing for those five years? Waiting to be rescued. We're not talking about sending one guy to mars for funsies, we're talking about one person left after an emergency. In the book he gets off mars by going to the launcher staged for the next mission, which again is a case of prepositioning extra hardware before sending someone to the planet. If you assume a team of 5 people with an intend…

> In the book he gets off mars by going to the launcher staged for the next mission, which again is a case of prepositioning extra hardware before sending someone to the planet. There's a "world" of difference between the Eagle returning to Apollo 11 in low lunar orbit, and prepositioning a interplanetary vehicle capable of Mars-Earth ( after getting from Earth to Mars), landing it (and without live feedback/guidance…

Actually in this case it is an Eagle-like launcher meant to rendevous with a craft in orbit. I'm not sure why you are arguing this when you're completely unfamiliar with the premise being discussed.

Re: SpaceX's giant Starship Mars rocket nails critical 10th test flight

#332

Post by jjk166 »

ricardobeat wrote: post #309
jjk166 wrote: post #284

Earlier quoted context omitted.

You couldn't start launching things in 30 days, you need to wait for a launch window, which happens every ~2 years. The transit times are on top of that.

The launch windows are for the most fuel efficient transfer. You can still launch outside of the window if you’re willing to pay the cost elsewhere.

Higher energy transfers can widen the launch windows, but their frequency remains unchanged. The frequency is due to the synodic period of Earth and Mars. It doesn't matter how fast you can get to a point in Mars' orbit if Mars doesn't happen to be there when you arrive. Any given trajectory will only work when the planets are in one specific configuration relative to one another; having more delta-V to play with means you can choose from a broader range of possible trajectories.

In the limit, there are hyperbolic trajectories that would basically give you such wide launch windows that you could launch whenever, but you're not doing that with chemical rockets.

Re: SpaceX's giant Starship Mars rocket nails critical 10th test flight

#333

Post by peterfirefly »

jjk166 wrote: post #276
lordofgibbons wrote: post #193

Earlier quoted context omitted.

> After the Shuttle program ended in failure, work on reusable launch systems stopped for decades Did it really stop for decades? I think SpaceX and Blue Origin were both already working on re-usable launch systems around that time

SpaceX started with the business plan of low cost, mass producible single use launchers. Falcon 9 was not designed with any level of reusability in mind. There was a major redesign to add landing hardware, but the whole reason for Starship being a totally new design was the reusability that a Falcon "super-heavy" derivative could never achieve.

They tried to use parachutes to slow the boosters down on the first two flights. Turned out it didn't work: the boosters burned up/disintegrated before the parachutes could deploy.

Re: SpaceX's giant Starship Mars rocket nails critical 10th test flight

#334

Post by peterfirefly »

WalterBright wrote: post #225
iwontberude wrote: post #145

Earlier quoted context omitted.

[flagged]

Selling rockets to the government is not receiving gifts of taxpayer money.

Especially not when they are cheaper and/or better than the competitors!

Re: SpaceX's giant Starship Mars rocket nails critical 10th test flight

#335

Post by jjk166 »

GMoromisato wrote: post #287
jjk166 wrote: post #272

Earlier quoted context omitted.

> Either they can never get the heat shield to be reliable, or they can't get cost down below Falcon 9 (meaning, refurbishment costs are too high). There are a lot of other potential technological problems (dozens of engines, stainless steel construction, the belly flop maneuver, etc). Ultimately if Starship would were to fail for technical reasons, it would only indicate the particulars of Starship's implementation…

Rocket Lab tried the alternative: low-cost, mass-produced expendable rockets, and Peter Beck famously ate his hat when they pivoted to reusable. Partial reusability won't get the cost down to the ~$100/kg range. And it definitely won't do that and still loft ~100 tons to orbit. Falcon 9 can get 15 tons to LEO for $45 million, and that's already the lowest price on the market. To hit $300/kg they would need to build a…

> Partial reusability won't get the cost down to the ~$100/kg range.

I don't see why $100/kg is a particularly important threshold.

> Falcon 9 can get 15 tons to LEO for $45 million, and that's already the lowest price on the market. To hit $300/kg they would need to build a 2nd-stage, launch, recover (on a drone-ship) and refurbish for $4.5 million. That's just not going to happen.

Falcon 9 reusable is 20 tons to LEO, and the cost SpaceX charges is what customers are willing to pay, not their costs incurred. Before they had reusability, the cost to make a complete, expendable falcon 9 rocket was $50 million. The marginal launch cost for a falcon 9 was approximately ~$15 million in 2020 when they were doing 20% of the launches they're doing now. They are very likely already below $500/kg. Remember this is a system that wasn't initially designed with any level of reusability in mind. A more optimized design that shifted more of the cost to the booster and which was produced at the appropriate scale would almost certainly see a further lower cost.

Falcon 9 boosters can fly back to an onshore landing pad, and Starship has already demonstrated landing back on the launch tower itself.

> If Starship fails, we are not getting $300/kg orbital costs for 1-2 decades minimum.

That's a substantially shifted goalpost. Even if starship succeeds we're still probably more than a decade out from $300/kg orbital costs being a reality. Rockets take a long time to develop, and longer still to mature. SpaceX has been working on Starship for over a decade already. Of course if we assume every rocket currently under development gets cancelled and something new needs to be started from scratch, it will take at least one full rocket development cycle time to bear fruit. But OP was worried that if Starship fails it will cause a loss of faith such that no one even starts working on another attempt for decades.

Re: SpaceX's giant Starship Mars rocket nails critical 10th test flight

#337

Post by jiggawatts »

wat10000 wrote: post #102
ralfd wrote: post #11

Earlier quoted context omitted.

You mis-copied the numbers for one launch. Wiki says: > Project cost US$6.417 billion (equivalent to $33.6 billion in 2023) > Cost per launch US$185 million (equivalent to $969 million in 2023) That a manned Apollo mission would/did cost under a billion dollars (todays money) is surprisingly cheap. A single Artemis launch using the Space Launch System (SLS) costs an eye watering $4 billions. Different metric: > [1966…

Part of the SLS cost comes from trying to save money. Yearly budgets are kept low, which spreads out the work over a long time. This makes everything cost more, but the politicians only care about the yearly spending. SLS is also a pretty weird design due to reusing Shuttle components for a completely different kind of launcher. This saves development costs (maybe) by using existing stuff that has already been develo…

"We're going to spend more to save money." is something I've heard said almost verbatim far too many times in government projects.

Re: SpaceX's giant Starship Mars rocket nails critical 10th test flight

#338

Post by boxed »

thesmart wrote: post #175
briandw wrote: post #41

Earlier quoted context omitted.

A starship mission to the moon will land over 100tons of cargo. Saturn V could get roughly 5tons to the surface. Its an entirely different class of operation.

That's LEO, not to lunar orbit and entry. Saturn V had a maximum lift capacity of 310,000 lb (140,000 kg) to low Earth orbit (LEO) and could deliver approximately 50 tons (45,000 kg) of payload to the Moon.

Well... no. The PLAN for the Starship lander is to have 100tons of cargo. That's why it takes so many refulings.

Re: SpaceX's giant Starship Mars rocket nails critical 10th test flight

#339

Post by boxed »

anonymars wrote: post #75
loeg wrote: post #16

Earlier quoted context omitted.

Looks like Starship test flights are already beating that $1 billion per-launch cost (I'm seeing estimates in the $100-500 million range), and they'd like to get the marginal cost down to ~$10 million.

I'm confused -- how is it meaningful to compare the cost of Starship test flights with operational Saturn V missions?

The test flights include R&D. The ~1b per flight of Saturn V was excluding R&D when the program was churning along.

I guess you could argue that it's never meaningful to compare anything that isn't a commodity though, which certainly isn't the case here. But I find that silly.

Re: SpaceX's giant Starship Mars rocket nails critical 10th test flight

#340

Post by boxed »

rozab wrote: post #271
GMoromisato wrote: post #169

Starship is like AI/LLMs in that success would revolutionize the world, but technological failure is very possible. And despite the confident predictions on the internets, we don't know which it's going to be. After the Shuttle program ended in failure, work on reusable launch systems stopped for decades. A similar thing would happen if Starship fails. Space would remain the province of the military and large governm…

The thing is, there is no demand to get that much stuff into space. Falcon 9 has massively brought down the cost per orbit, and even with the whole world as a captive market, every university in every country putting up cubesats, they still don't have nearly enough payloads to make the economies of scale kick in. Hence Starlink. The majority of SpaceX payload mass has been Starlink, something nobody was even asking f…

> The thing is, there is no demand to get that much stuff into space.

You mean no other company except SpaceX has such a demand. But SpaceX does in fact have such a demand and are using it to make a profit.

Small governments don't understand that they can have space science programs rivaling NASA for super cheap. That's what's holding demand back imo.

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