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Re:SpaceX will soon fire up its Super Heavy booster for the ... by barbegal on Thursday July 15, 2021 @01:06PM (#27847001)
I don't understand how it can be an order of magnitude cheaper. There are more rocket engines to maintain, far more fuel, a more expensive launch structure and generally more expense in all the ground operations. In a world where this can be launched for $2M, Falcon 9 can be launched for less than $1M.
Re:SpaceX will soon fire up its Super Heavy booster for the ... by SEJeff on Thursday July 15, 2021 @01:29PM (#27847299)
The Falcon 9 can not be launched for less than $1M. Falcon 9 does not reuse the second stage. Elon has said that the second stage is approximately 20% of the cost of a Falcon 9 launch. A Falcon 9 needs to have some work done between each launch. Some of the Falcon 9 parts are not actually reusable (crush cores for the landing legs as an example). This is why they can not ever simply fill up a landed Falcon 9 booster, put a new second stage on it, and launch it again. The Starship / Superheavy combo is designed to be able to literally just refuel and go. The Falcon 9 booster is mostly made of aluminum, which is up to 60% more expensive than stainless steel. The Starship / Superheavy are stainless steel.

Methane (Starship fuel) is massively cheaper than Kerosene (Falcon 9 fuel). Methane also has a much higher specific impulse, which means you can use less of it to get the same increase in velocity. Methane can be stored in liquid form in same temperature as oxygen, which means less insulation the two propellant tanks. Inversely, Kerosene will freeze at the temperatures required to get oxygen into liquid form.

Basically, nothing you said is accurate.

Re:SpaceX will soon fire up its Super Heavy booster for the ... by Tuna-Fish on Thursday July 15, 2021 @02:01PM (#27847860)
> Elon has said that the second stage is approximately 20% of the cost of a Falcon 9 launch.

20% of the cost of the whole rocket. With no reuse. Now that reuse has cut the cost of launch way down, the second stage is much more than that of the cost.

Re:SpaceX will soon fire up its Super Heavy booster for the ... by dredmorbius on Thursday July 15, 2021 @05:02PM (#27850095)
Reuse follows a parallel of Amdahl's law.

Long-term marginal cost is determined by the nonreusable component cost + minimum refurbish & refit costs per launch. Effectively, the benefits of reuse offer diminising marginal benefit per reuse. Though designing for long-term use (say, a personal automobile vs. a rocketship) can still make sense.

An automobile used for daily commute with a 5 year life sees ~1,000 re-uses. You can vary the parameters to get different results. There are fuel, maintanance, garaging/parking, tax/registration, and insurance costs as well.

Re:SpaceX will soon fire up its Super Heavy booster for the ... by SEJeff on Thursday July 15, 2021 @02:10PM (#27848012)
Oh very good point. The GP’s $1 million number per falcon 9 launch was ludicrous.
Re:SpaceX will soon fire up its Super Heavy booster for the ... by Robotbeat on Thursday July 15, 2021 @03:04PM (#27848711)
I don’t think it is. A medium lift vehicle that is fully reusable could be made to have a $1 million launch price. I don’t know that Falcon 9 could do that, but some MLV could.
Re:SpaceX will soon fire up its Super Heavy booster for the ... by bryanlarsen on Thursday July 15, 2021 @07:11PM (#27851184)
I'm not sure that a falcon 9 sized medium lift vehicle would have any room for cargo after using its margin for re-entry shielding, landing fuel and hardware.

Something New Glenn sized definitely could.

Re:SpaceX will soon fire up its Super Heavy booster for the ... by SEJeff on Thursday July 15, 2021 @03:08PM (#27848758)
Ok. Why has no one done it? The economics would surely be there if someone could.

Seemingly, SpaceX is the current best in the world and they couldn’t do it.

Re:SpaceX will soon fire up its Super Heavy booster for the ... by Me1000 on Thursday July 15, 2021 @03:35PM (#27849089)
It's amusing how quickly we start taking things for granted.

Right now SpaceX is the only company that recovers their orbital class booster. And that didn't happen until 2016! Prior to that, everyone dismissed landing rockets as impossible. Given the lack of competition for launch vehicles + the fat defense contracts being awarded, there wasn't much incentive for the incumbents to even try to bring the cost down.

Designing a rocket that can land and be reflow is a multiyear process. As other comments have said, more design changes would been needed to F9 to make it more reusable, those changes have tradeoffs. Instead, SpaceX chose to invest in a new design and more capable vehicle.

Other launch providers like RocketLab and Blue Origin are pursuing reusable vehicles.

"Why has no one done it?" give it time... it will happen sooner than we probably expect.

Re:SpaceX will soon fire up its Super Heavy booster for the ... by Robotbeat on Thursday July 15, 2021 @03:18PM (#27848889)
SpaceX could absolutely do it. They chose not to in order to focus development resources on starship. It’s all about opportunity cost.

Also, you’d have to redesign F9 somewhat. Starship has the fairing integrated with the upper stage, which reduces recovery costs. Starship’s booster also does Return To Launch Site nominally, which means you don’t need a separate recovery droneship (Falcon 9 does that, too, but to make the most out of every expended upper stage, it makes sense to use down-range recovery). The F9 legs are sort of complicated logistically whereas Super Heavy is supposed to be recovered by the actual launch site, reducing turnaround time and costs. Also, using methane means less coking in the engines, which reduces turnaround costs and maintenance. Lots of things like that you’d need to reengineer to enable $1 million launch costs, but it’s feasible for an MLV. Relativity is planning to do it.

Re:SpaceX will soon fire up its Super Heavy booster for the ... by rbanffy on Thursday July 15, 2021 @05:49PM (#27850541)
In general, rockets work better the larger they get. Smaller rocket means more structure made per volume of fuel, which will translate to smaller proportional payload capacity. Manufacture cost is mostly a function of the surface while payload capacity is a function of the volume.
Re:SpaceX will soon fire up its Super Heavy booster for the ... by barbegal on Thursday July 15, 2021 @02:27PM (#27848241)
Indeed, I'm using the fact that it's ludicrous to make the case that a $2M starship launch is equally ludicrous.
Re:SpaceX will soon fire up its Super Heavy booster for the ... by btilly on Thursday July 15, 2021 @03:14PM (#27848848)
No, it is not ludicrous.

As Elon likes to point out, imagine how expensive it would be to fly if, after every flight, they threw away the plane. That's exactly what people traditionally did with rockets. The result is that the cost to fly a jet is mostly the cost of the fuel, while the cost to fly a rocket is the cost of the rocket.

Consider a Falcon 9 launch. Thanks to reuse, the cost to relaunch is in the neighborhood of $30 million. The cost of the fuel is about $200,000. Over 99% the launch cost is depreciation, maintenance, or having to replace what you didn't reuse.

The aim with Starship is to make the cost of a launch as close to the cost of the fuel as they can get.

Re:SpaceX will soon fire up its Super Heavy booster for the ... by simonh on Thursday July 15, 2021 @03:18PM (#27848895)
I’m not sure you understand the arguments being made here. $1m per launch for F9 is ludicrous because 20% of the rocket, by manufacturing cost, is expended on every launch. For Starship none of the rocket is expended per launch, the only costs are site operations, fuel and depreciation on the rocket over a hundred or more flights.

They are aiming for daily launches of starship, so the site operations costs would be divided by potentially hundreds of launches per year instead of the one or two dozen a year nowadays.

The cost model per flight of Starship is more like that of a jumbo jet than that of a Falcon 9.

Re:SpaceX will soon fire up its Super Heavy booster for the ... by oses on Thursday July 15, 2021 @01:46PM (#27847600)
The combination of Methane and the full flow staged combustion cycle also means significantly reduced coking in the engine, so it drastically prolongs the time between engine refurbishments.
Re:SpaceX will soon fire up its Super Heavy booster for the ... by ordu on Thursday July 15, 2021 @05:05PM (#27850132)
Do you know how a reduced coking works? I've read about the raptor engine[1] and it explains how fuel rich hot mixture leads to coking, it explains how USA solved this problem before (by using hydrogen as a fuel), but how Musk managed to solve it? Partially burned methane should produce free carbon atoms, shouldn't it? Doesn't it raise a coking problem?

[1] https://everydayastronaut.com/raptor-engine/

Re:SpaceX will soon fire up its Super Heavy booster for the ... by jjk166 on Thursday July 15, 2021 @06:18PM (#27850774)
In a conventional hydrocarbon fueled engine, you're using a fuel with hydrocarbon chains at approximately room temperature to cool the engine. With only a little heat addition, you get up to a temperature where these chains can shed hydrogens and convert their C-C-H bonds to C=C double bonds. These bonds in turn allow hydrocarbon chains to join together into larger molecules that can coagulate and stick to the walls.

Methane on the other hand is starting out at a much lower temperature, and it's very difficult to get methane molecules to react with each other to form large molecules as you're not starting with any single C-C bonds. Isolated free carbon atoms (soot) aren't much of a problem.

Re:SpaceX will soon fire up its Super Heavy booster for the ... by mr_toad on Thursday July 15, 2021 @07:53PM (#27851527)
> Partially burned methane

The raptors don’t run fuel rich, which should reduce that problem.

Re:SpaceX will soon fire up its Super Heavy booster for the ... by ordu on Friday July 16, 2021 @06:37AM (#27854817)
According to the link above they do. Full-flow means to have two pre-burners one going fuel rich while other going oxygen rich. Though I'm not a rocket scientist and I'd be grateful if proven wrong.
Re:SpaceX will soon fire up its Super Heavy booster for the ... by nautilius on Friday July 16, 2021 @12:44AM (#27853105)
Oh that’s interesting, do you have some more information or a link?
Re:SpaceX will soon fire up its Super Heavy booster for the ... by barbegal on Thursday July 15, 2021 @02:26PM (#27848227)
You raise a few good points. Falcon 9 launches could be 30% cheaper if fully reusable but that only reduces a launch cost down to $25M.

I am skeptical of the claim that they will just be able to refuel and go. Every reusable space vehicle has had that goal and always cost more than expected to refurbish for the next launch. Yes, we may get there eventually but not in the next few decades, the risks of a catastrophic component failure are too high to do no refurbishment.

The starship and super heavy are certainly cheaper to construct but that has more to do with fabrication techniques than the material cost.

Methane is less dense than kerosene so needs larger tanks but it does have more energy per unit mass. The overheads of using cryogenic fuel are reduced on a larger rocket but the performance gain is probably only 10% or so.

I am not aware of any significant insulation between tanks on the Falcon 9 and it certainly isn't a major cost factor.

Re:SpaceX will soon fire up its Super Heavy booster for the ... by Robotbeat on Thursday July 15, 2021 @03:08PM (#27848759)
> Every reusable space vehicle has had that goal and always cost more than expected to refurbish for the next launch.

There have only been 2 reusable launch vehicles ever, and both were only partially reusable. Shuttle and Falcon 9. Falcon 9 has already made massive strides in reducing any refurb costs between missions. there is no reason that you couldn’t build one that requires no maintenance in between flights for the same reason that there’s no reason you can’t make an upper stage that can do multiple firings per flight without any maintenance in between. Upper stage reuse will be trickier, but ultimately there’s no fundamental reason why refurb has to be done in between every flight.

Re:SpaceX will soon fire up its Super Heavy booster for the ... by rbanffy on Thursday July 15, 2021 @05:55PM (#27850589)
Upper stage reuse doesn’t require a landing. If you could refuel an upper stage in space, you could use it for deep space exploration.

Do they deliberately deorbit the Falcon second stage? Would be interesting if we could keep a couple parked in LEO and refuel them for different missions.

Re:SpaceX will soon fire up its Super Heavy booster for the ... by bryanlarsen on Thursday July 15, 2021 @07:15PM (#27851201)
But then you need a different vehicle to refuel the original one. If you're doing that, why not just use that second vehicle for the mission and forget about reuse?

Reusing second stages in space only really makes sense once you are making your fuel in space.

Re:SpaceX will soon fire up its Super Heavy booster for the ... by rbanffy on Friday July 16, 2021 @06:55AM (#27854933)
Making fuel on the Moon or on Mars is more or less the plan for any sustainable development of the solar system. Unless we get sci-fi grade engines, it’s just unfeasible to send fuel from Earth.
Re:SpaceX will soon fire up its Super Heavy booster for the ... by Robotbeat on Friday July 16, 2021 @09:35AM (#27856076)
An acquaintance of mine who works in the industry (not at SpaceX) called Raptor a “scifi engine.”

For a lot of purposes, Starship should make it extremely cheap to send propellant from Earth. $10/kg in LEO. Cheaper than any lunar mining proposal I’ve seen.

That said, I hope we do make propellant off-Earth eventually.

Re:SpaceX will soon fire up its Super Heavy booster for the ... by SEJeff on Friday July 16, 2021 @08:49PM (#27862750)
Yeah if I remember correctly, I read that the solar panels required to ISRU make enough methane on Mars for a starship return flight would be two football fields worth and it would take them a few years to do it.
Re:SpaceX will soon fire up its Super Heavy booster for the ... by Robotbeat on Saturday July 17, 2021 @10:37AM (#27866082)
Area is just not a huge problem on Mars or in space in general. It’s not really a relevant figure of merit, unlike mass and pre-deployed volume
Re:SpaceX will soon fire up its Super Heavy booster for the ... by bryanlarsen on Friday July 16, 2021 @08:32AM (#27855566)
That's a chicken and egg problem. Making fuel off of Earth is going to require so much mass for infrastructure that it won't be feasible until we have fully reusable vehicles.
Re:SpaceX will soon fire up its Super Heavy booster for the ... by crawshaw on Thursday July 15, 2021 @01:08PM (#27847027)
A falcon 9 launch expends the upper stage. Building the upper stage is now most of the cost of its launch.
Re:SpaceX will soon fire up its Super Heavy booster for the ... by slownews45 on Thursday July 15, 2021 @01:10PM (#27847050)
Fairing recovery on Felcon 9 is not perfect. Rumor was that alone was something like $5M per launch flushed.
Re:SpaceX will soon fire up its Super Heavy booster for the ... by thinkcontext on Thursday July 15, 2021 @01:30PM (#27847316)
The key to the price is that Musk is projecting it will be able to be reused many more times than Falcon 9, as well as a reusable 2nd stage.
Re:SpaceX will soon fire up its Super Heavy booster for the ... by nickik on Thursday July 15, 2021 @10:03PM (#27852332)
Rocket engines shouldn't be that cheap to maintain, they are designed to be very reusable, unlike Merlin they were designed for the beginning to be reusable.

The whole reason for the full-flow staged cycle is to have much more reasonable internal temperatures. Methane as well was picked partially because its far more clean burning.

There is no reason rocket engines couldn't be as reliable a jet engines.

> far more fuel

RP1 is very expensive. Methane is much cheaper, and they can even produce it local. Ox is very cheap and is basically gone turn into the cost of electricity and they are using local solar to make it.

Helium is also a very expensive part of the Falcon 9. Starship avoids the use of helium.

Additionally the Falcon 9 used TEE-TAB that is also expensive.

And it used nitrogen as well, that not expensive but just one more thing to worry about.

Falcon 9 has 6 different different consumables, Starship has 2.

> generally more expense in all the ground operations

This is wrong. The Falcon needed to have drone ships operating and tug boats for them as well, to catch the fairing they have another 1-2 boats out there to collect the fairing.

Then the stages need to be brought into port, transported back to the launch site and so on. The fairing have to be refurbished as well.

In additional Starship has multiple design upgrades that make it actually easier. Unlike Falcon 9 Upper stage, the Starship will be fueled from below, meaning there is no secondary fuel infrastructure for the upper stage. Not requiring the fueling of the consumables above also makes it much easier.

Plus they were able to apply everything they learned from Falcon 9 and ground operations to this new launch vehicle and launch site.

> In a world where this can be launched for $2M, Falcon 9 can be launched for less than $1M.

Falcon 9 can not do that. First of all, you need to build an upper stage that cost you 5-10M. You can't build that Upper stage fast enough to reach the required flight rate. Falcon 9 is also more difficult to launch and prep for launch. It wasn't designed to be fully reusable and still need more checks and refurbishments.

Now $2M is extreme, even if it is $10M or $20M that only really matters for stuff like Mars. If you can launch it anywhere under $100M its revolutionary vehicle for space flight.

Re:SpaceX will soon fire up its Super Heavy booster for the ... by simonh on Thursday July 15, 2021 @01:15PM (#27847112)
They expect each vehicle to cost $200m and to fly them 100 times each. Hence $2m per launch. Falcon 9 costs a lot more than that because the upper stage is expended each time and that costs mid single-digit millions, and the first stages may not last much beyond a few dozen launches without significant re-engineering which would also make them heavier.
Re:SpaceX will soon fire up its Super Heavy booster for the ... by Robotbeat on Thursday July 15, 2021 @03:12PM (#27848818)
Actually, Elon once told me that they might be able to build Starship launch vehicles for less than Falcon 9 (say about $80 million new):

https://twitter.com/elonmusk/status/1094793664809689089?s=20

100 reuses is not the limit either. The first stage in particular may be made for a lot more.

Re:SpaceX will soon fire up its Super Heavy booster for the ... by throwaway316943 on Thursday July 15, 2021 @02:28PM (#27848268)
Boy I hope they park them in orbit on the last launch and use them to build space habitats.
Re:SpaceX will soon fire up its Super Heavy booster for the ... by rbanffy on Thursday July 15, 2021 @05:58PM (#27850609)
There was a plan to do that with shuttle tanks. If we used them, the ISS could have a humongous ring of habitable former tanks.