Spaceplane or rocket family?

[Nibb31]

The advantage that SpaceX has over Skylon is that it's funded by an eccentric billionaire who believes wholeheartedly in the advancement of humanity in space. If Elon Musk put his money behind Skylon, it would be flying two years from now.

SpaceX is mainly funded by NASA and based on a lot of proven technology and past experience. Skylon has no significant funding, uses unproven techniques for just about every part of the vehicle, and all of Elon's fortune wouldn't be enough to build it.

That being said, though, the Falcon family of rockets is looking VERY promising for dropping launch costs.

It is promising for dropping the cost of launch hardware. That is only a very small portion of the total cost of a launch.

Edited October 6, 2013 by Nibb31

[magnemoe]

The worlds best bet for this right now is Space X. Simply, once they have all of the falcon rockets functional and reusable, then we will be truly set for our advancements into space, as well as privatization. This will certainly happen long before the development and finishing of the Skylon. And if the Skylon works, then perhaps rockets may use it's reaction engines to power rocket launch stages.

Yes, benefit of spaceX is that they can do this is many small steps. Major step was getting falcon 9 running, reusable first and second stage,and falcon heavy / reusable version is less steps.

And they can develop them while having income from the previous steps. Yes they have governmental funding in the way of payment for bringing cargo into orbit. No different from any other company who does business with the government.

High chance that skylon need falcon or other reusable rocket system to be economical at all, with cheaper access to space you will get far more activity. In this setting an launcher with high investment cost and low running cost makes sense. This is an standard thing, an 300.000 ton oil tanker would be pretty useless 100 years ago, yes they used oil but the tanker would be to large for the demand.

[rkman]

I'd go with existing technology rather than a technology that might exist at some undetermined time in the future.

[DerekL1963]

I agree, but in turn those items, avionics computers, attitude control, docking adapters, also benefit from economies of scale.

Since those aren't the expensive bits, that's like saving a penny a pound on the ten or twenty pounds of nails (at a buck a pound) that go into your $250,000 house.

The Russians benefited from economies of scale by series production of common elements (TKS, DOS, Proton, Soyuz...) instead of building a super duper launcher to launch it all in one flight.

Well, since the only one of those actually built in quantity was the Soyuz (booster), your point is what exactly? Equally, as for "launching in one flight", that's precisely what they Russians did, many times. Heck, they even built two of the world's three biggest super-duper all-in-one-go launchers - N1 and Energia. (And quite a number further down the scale.)

"Economy of scale" is a real term for a real effect, not a buzzword and it decidedly does not mean "stuff they built a lot of over the course of many years".

[jwenting]

even if NASA's budget were doubled they'd be incapable of doing anything. That entire extra budget would go towards paying for "risk assessments", "environmental impact studies", "liability insurance", "legal defense funds", and other things non-essential to anything except keeping the bureaucracy expanding.

Maybe a 100 fold increase would see a few million dollars available for actual space exploration.

[Nibb31]

"Economy of scale" is a real term for a real effect, not a buzzword and it decidedly does not mean "stuff they built a lot of over the course of many years".

Economies of scale apply as soon as you decide to build more than one unit of a standardized design. Of course, in the space business, it's more about small series production runs than actual mass production, but the idea is that it will be cheaper to produce 28 (near-)identical Merlin engines for a Falcon Heavy than 3 RS-25s, 2 SRBs and a couple of RL-10s for an SLS every 2 years. If all goes well, SpaceX plans to produce those Merlins at a rate of 400 per year. Even at 200 per year, the unit cost will come down substantially compared to other rocket engines. In terms of space hardware, that is mass production.

(Incidentally, this is also the reason I'm a bit skeptical about the usefulness of a reusable Falcon. At current launch rates, reusability flies in the face of economies of scale.)

Add in the infrastructure costs, which will be spread over at least a dozen launches per year, compared to SLS which will have to maintain the VAB, the crawlers, the MCC and LC-39 for one launch every 2 years.

My point is that a launching 3 Falcon Heavies with 53mt to LEO each is going to cost way less than a single 100mt SLS (I doubt the Block II well ever be funded). Of course, this is based on optimistic estimates for SpaceX, but the same is true to a lesser extent for ULA launchers. You could probably afford 4 or 5 Delta Heavies or more for the cost of a single SLS.

[rkman]

even if NASA's budget were doubled they'd be incapable of doing anything. That entire extra budget would go towards paying for "risk assessments", "environmental impact studies", "liability insurance", "legal defense funds", and other things non-essential to anything except keeping the bureaucracy expanding.

Really. Then how do you explain NASA has done and is doing quite a lot other than the things you mention, on their current meager budget?

http://en.wikipedia.org/wiki/List_of_NASA_missions

[Nibb31]

even if NASA's budget were doubled they'd be incapable of doing anything. That entire extra budget would go towards paying for "risk assessments", "environmental impact studies", "liability insurance", "legal defense funds", and other things non-essential to anything except keeping the bureaucracy expanding.

Maybe a 100 fold increase would see a few million dollars available for actual space exploration.

You might think that the "bureaucratic" overhead work is useless, but certification, quality audits, risk assessment, studies and so on are all jobs that need to be done. The private sector does those things too. It's part of the cost of doing business. If NASA didn't do it, they would have to outsource those jobs to private companies, who would probably charge them more for the same (or less) work done in China.

[camlost]

Everybody is talking about launch costs yet launch cost only comprises of a small fraction of the total cost. All the satellites, spacecrafts etc are considerably more expensive than a rocket.

Lack of ambition in space is stalling human kind's progress in launch vehicles, that's true, but I don't see how lowering launch cost will turn that if the payloads are still expensive.

[Nephf]

Let's say NASA's budget is doubled tomorrow.

It would be the end for SpaceX.

[Captain Sierra]

It would be the end for SpaceX.

Not necessarily. The SLS may be twice as powerful as the Falcon 9 heavy, but let's not forget that they have plans for the Falcon X, X heavy, and XX using more powerful Merlin 2 engines. I have seen NASA make the payload and then outsource the launcher. If anyting, it could actually help NASA as they have a plan B for when even the SLS isn't enough (They can finally orbit half a space station at once like us!)

[SargeRho]

How about both? Heavy lift if you need to lift something really heavy, and Spaceplanes like Skylon for people and smaller cargo.

[magnemoe]

Everybody is talking about launch costs yet launch cost only comprises of a small fraction of the total cost. All the satellites, spacecrafts etc are considerably more expensive than a rocket.

Lack of ambition in space is stalling human kind's progress in launch vehicles, that's true, but I don't see how lowering launch cost will turn that if the payloads are still expensive.

Part of the reason why satellites and spacecrafts are so expensive is the launch cost and low launch availability. This is espesialy true for NASA probes who tend to be seriously gold platted as they are worked on for years and years before launching. Yes this gives very reliable probes with stunning results however not sure how cost effective it is.

Some of the same is true for satellites, as they have to be build both small and very reliable this drives prices up, an larger satellite could be build cheaper.

Part of the problem is also scale of production, how much does the iridium or gps satellites costs?

[Vaebn]

You know what I'd like to see? A nuclear powered spaceplane!

It goes like this. It would combine the concept of a Nerva Engine, with the concept of a Nuclear Scram/Ram/Jet, in what would hopefully be the exact same engine.

Just imagine a SR-71 with two large intakes or something (it always was so sci-fi of a design, wasn't it?)

A normal jet engine sucks air in, heats it up by burning fuel, then tosses it the other way.

Similarly a nuclear ram/scram/jet would suck air in, heat it up because getting hot is what nuclear reactors do, and toss it the other way.

( Such ramjets have been proposed in the past for the likes of Project Pluto and such, albeit the observant fellow might notice that they were parts of nuclear cruise missiles meant to go boom at the end and kill all of russia or something. Let's ignore that. )

The advantages of such a thing are that:

a) it doesn't need "fuel" for atmospheric flight. The innate warmth of the engines themselves does all the job.

it doesn't need "oxidizer" or in other words "oxygen". All it needs is to such non-discript "air" in order to warm it up and toss it the other way.

Intuitively then, such a thing would be able to go much, much higher than the layers or the atmosphere where oxygen becomes scarce. And as the atmosphere would thin out, it would also go faster and faster, which it would pretty much -have- to do, so that it can still gather "air". All too convenient.

I have no idea how high such a thing would operate, but I suspect it would be high. Really high. Keep in mind that a reason a lot of "normal" scramjets heat up, is because they have to confine themselves in the layers of the atmosphere with oxygen. This doesn't. If it existed you'd simply pull the stick and watch it go up and up, and going faster and faster.

So, oxygen burning aircraft pretty much "stop" at 30km or so which is the world, jet flying record. (the U2 was flying at 21km).

I like to think that such a thing would make, well into the mesosphere (80km) easily. Possibly higher.

Somewhere along then, it would start using its engine as a Nuclear Rocket rather than a Nuclear jet, using on board propellant.

Since, oxidizer is irrelevant, even that propellant mass would probably end up more efficient than any rocket's.

(What would be really awesome, would be for the craft to be able to collect and store propellant in-flight. After all, with no oxidizer need, pretty much any gas will do, no? Although I guess there's reasons Hydrogen is concidered the most efficient fuel, even for Nerva style engines. Probably because of how much you can compress it or something)

And that's pretty much the most awesome, futuristic, but not alien technology I can think of. Basically a Skylon, minus all the in-atmosphere flight fuel, the oxidizer, and with more specific impulse in space.

And of course it will never be done, because if it went boom in low-attitude, it would irradiate everything in a 200 mile radius.

So uh. I'll just select the option for rockets in the poll I guess

Edited October 10, 2013 by Vaebn

[Anton P. Nym]

Since those aren't the expensive bits, that's like saving a penny a pound on the ten or twenty pounds of nails

Oddly enough, that's why I voted for "rocket family" over spaceplane... because the most expensive "bits" come from labour costs, not material. What killed the Shuttle's economics was the amount of labour needed to refurbish the bird after every launch, and though with today's technology it should be easier to turn a spaceplane around it still is going to take a lot of highly-skilled staff to do it. With Big Dumb Boosters (or, the better alternative of a modular booster family) the skilled labour problem is much less severe.

Equally, as for "launching in one flight", that's precisely what they Russians did, many times. Heck, they even built two of the world's three biggest super-duper all-in-one-go launchers - N1 and Energia. (And quite a number further down the scale.)

Much as I'm a fan of heavy-lift boosters, neither the N1 nor Energia are good supporting arguments given how they fared...

-- Steve

[Whirligig Girl]

You are welcome for showing you that video (don't lie and say you didn't find that Niel Degrasse Tyson vid from my forum post)

[Drunkrobot]

You are welcome for showing you that video (don't lie and say you didn't find that Niel Degrasse Tyson vid from my forum post)

Darn it! My secrets have been revealed!

[3_bit]

You guys should check out the SASSTO. It was a rocket designed to take a Gemini Capsule into orbit and land. It would have been a VTVL SSTO. Quite a beautiful craft, doable in the '60s. I'll bet we can make one that's nearly twice as efficient today.