Rockets are not expensive because they use lots of fuel. Sit down and actually compute how much propellant is needed, and how much it costs. It's CHEAP, especially if you use LOX + hydrocarbons (as Falcon 9 and Heavy do).

The actual amount of energy needed to reach LEO is about the same as the amount of energy needed to send the same mass to New Zealand from the US by airliner.

The reason launch is expensive is because the launchers were thrown away. SpaceX radically reduced the cost by reusing the first stage multiple times. And there's more juice to be squeezed from that lemon, as the second stage is still being expended.

> The actual amount of energy needed to reach LEO is about the same as the amount of energy needed to send the same mass to New Zealand from the US by airliner.

Yeah but rockets use a lot more fuel mass compared to aircraft whose engines are airbreathing. Rocket engines need to carry their own oxygen in the fuel tanks and are less efficient as a result. Surely fuel costs are no trivial concern.

> The reason launch is expensive is because the launchers were thrown away.

Well I agree that it's stupid to just throw away the rockets into the ocean but I thought NASA just didn't have the capability to reuse them. A comment below says the US congress forced them to reuse old parts which makes no sense to me.

Are you blaming the cost on liquid oxygen? Sorry, but LOX is very cheap. It's the second cheapest industrial liquid, after water (or water containing cheap dissolved substances). The cost of the LOX is small compared to the cost of the fuel that it combusts with.

When people have looked at airbreathing launchers, they quickly discover that the designs optimize to 0% airbreathing, 100% rocket. LOX being so cheap and dense is a big part of that.

Indeed NASA doesn't have the means to reuse them, which makes it sad that NASA is being forced to play to their own incompetence in the SLS program. NASA originally wanted to get back to the moon with commercial launchers.

That's exactly pfdietz's complaint. NASA employs the same types of humans SpaceX does. If reusability was a design constraint they would have solved it like SpaceX did. But they didn't consider it a priority or even a goal to make regular moon travel feasible so they continue throwing away billions with such limited impact.

> they didn't consider it a priority or even a goal to make regular moon travel feasible

That's insane. Isn't it literally their mission to advance spaceflight technology?

I assumed there was a good reason they were not reusing the rockets. Are you seriously telling me it's due to politics and corruption?

NASA was always a public works program, that's one of the reasons LBJ was its biggest high level booster back in the 1960s, it had an explicit mission to uplift the US South. Per the guy who invented the reentry vehicle, the lack of one or more staging space stations along the way for Apollo came from that spending "a billion dollars" more in Texas, call that $10 billion today.

After the end of the Apollo Project, "politics and corruption" were all that was left, as should be obvious from the lethally ridiculous design of the Space Shuttle.

Wow that is disappointing.

> as should be obvious from the lethally ridiculous design of the Space Shuttle

Can you elaborate? Everyone here is calling it stupid but I don't really understand why. I thought it was retired due to expenses, NASA defunding or something like that.

As a general principle, the Space Shuttle program was massively capital constrained, so many trade-offs were made that compromised safety and operating expenses. I suppose the latter helped in limiting the number of flights, but then again half the fleet and their crews were lost.

Perhaps start with what killed two shuttles and their crews? Besides no provisions for escape unlike all other "capsule" based craft, solid rockets are _dangerous_ because you can't turn them off, whereas liquid fuel rockets will effectively turn themselves off in many disaster scenarios.

So for a get me out of here tower escape system a solid rocket makes a lot of sense, see also their use in ejection seats. But mounting some number of them (more than one unless used alone because you need symmetrical thrust) on the sides of your system means they must work perfectly every time.

The reentry heat shield protections which along with the wings etc. came from a requirement the Air Force says they never really wanted or needed, a single polar orbit mission returning to the launch location which thus required a lot of maneuvering in the atmosphere because the Earth turned while it was up there resulted in the infamously fragile tiles and some more refractory stuff for hotter locations (and eventually a bunch of tiles in a cooler location were replaced by something else).

Rear end heat shields are protected during the launch of a capsule, it's all hanging out there with the Shuttle. Change the foam and larger parts of it may break off, hit, and fatally compromise a part of the insulation system.

Now going from personal worry points and speculation:

The Space Shuttle Main Engines (SSMEs) are for institutional reasons extremely high performance and required a rebuild after every mission, so the SLS "throw away half a billion worth of engines every flight" would need to subtract that labor and parts.

That said, they were fired up and the SRBs not lit until it was clear the SSMEs were running fine, that resulted in three legit aborts and two from faulty sensors. Two failures after launch, split between both causes, noting catastrophic or mission endangering. But, still, you have all their complexity and SRBs.

Landing ... well, that's another thing that's more complex or at least different although landing in the sea also has its issues: https://en.wikipedia.org/wiki/Mercury-Redstone_4

It's a hell of a lot more complicated aerodynamic body/system than a cylindrical rocket and capsule system so that work was harder and more error prone. IBM Federal Systems modified a lot of code between the first and second launches, and caught an introduced error that would have released just one SRB. There's a 1984 CACM issue devoted to all this https://dl.acm.org/toc/cacm/1984/27/9 and is now free to read online or download, I highly recommend it. A lot of programmers outside of that world were concerned the code wouldn't be up to snuff, what you'll read in those articles explains how they pulled it off.

And, again, no escape systems. Fly enough times and things go wrong, the Shuttle compounded this by massively increasing complexity for very little gain.

Rocket books are written by scientists, not economists or MBAs. Elon Musk's major innovation with SpaceX was to look at it from a business & economic angle rather than the angle of scientists or millitary industrial complex which thrives on Cost Plus contracts.

It turns out fuel cost rarely exceeds 10% of the cost of launch even with the tyranny of rocket equation. Traditional expendable rockets (including SLS) essentially throw away 90% of the cost of each launch - hence the push by SpaceX to some of the fuel to try and land the first stage.

I initially thought rockets were not reusable because it was literally impossible to reuse them. I thought the launch and reentry damaged them beyond repair. Reentry modules require huge heat shields to protect the craft from being destroyed by atmospheric ablation. How is it possible for these things to launch into high altitudes and not only survive reentry but land safely?

It does sound kind of stupid to just let the engines and stages free fall into the ocean now that you mentioned it. I'm not sure how advanced Musk's rockets are but if they can land safely after being staged then that's an amazing innovation. Why isn't NASA all over this if it's so revolutionary?

They are currently reusing the first stage which is sub orbital - ie. Much slower, less re-entry forces. Still a major economic benefit for overall rocket cost. That said, Starship is planned to land from orbit & be reusable - let's see.

NASA is all over it from what I see - SpaceX has essentially captured virtually all of the commercial launch market and a good chunk of defence and science markets except for hyper specialized requirements or non-US defence launches.

I however don't see how NASA could have developed it given the politics involved with its funding essentially incentives Project thinking over Product thinking - I actually use that as an example when I contrast Project vs Product at work. SpaceX had to blow a couple of dozen rockets AFAIK to get to a stage where they land reliably - doubt NASA could have justified that to the US Congress. NASA's funding incentives encourage a risk averse approach to engineering ever since the very high profile failures in space shuttle and the early Mars missions. Witness how the Mars helicopter was rated for a low single digit of missions and has now completed a few dozens.

> Much slower, less re-entry forces.

I should point out it isn't forces that matter for entry from orbital speed, it's heating.

Spacecraft that require protection from re-entry are going far, far faster than first stages, so slowing them down using atmospheric friction creates a lot of heat. The Falcon first stage gets to about 8,000 kph and reaches over 100 km before it starts coming down, not high or fast enough to create the stresses an orbital re-rentry vehicle sees. The other key to reusability is having enough leftover fuel to land, control surfaces and restartable engines. Restartable engines weren't proven to work until the Gemini program in the mid-1960s, if I remember right; I'm sure the Saturn rockets was well into development by that time and the engineering costs to make major changes the lower stages were too great. Sometimes government gets set upon a course and it's very hard to redirect it; that's why innovators like Space-X are so valuable.

There were quite a few proposals for how to reuse rockets stages - actually you can see more the farther you go.

Certainly it could have been partially due to not yet having enough experience with many real world launches.

But at the same time a lot of the funding was comming from ICBM programs that don't really care for reuse by design & from army and a high profile space race with USSR. That kinda favored the expensive get-it-done fast expensive MVP instead of a more complex reusable solution that could be much cheaper in the long run.

And then the status quo took root & reusable rocket proponens were no longer taken seriously because - what were they thinkig, this is how we have always been doing it!

"And then the status quo took root & reusable rocket proponens were no longer taken seriously because - what were they thinkig, this is how we have always been doing it!"

Disagree as someone who as a kid watched this happen in real time. The Saturn V follow on was always planed to be reusable, with a huge first stage booster that was something of a bigger brother of the stage that would make it to orbit. NASA was starved for capital after Apollo and this resulted in the horribly deadly and very expensive to operate kludge of the eventual Space Shuttle.