NASA Eyes Shuttle Replacements 353
jonerik writes "According to this article at Space.com, NASA yesterday released a status report on the first year of NASA's Space Launch Initiative; the search for a space shuttle replacement, currently planned to begin operating ten years from now. The competing contractors - Boeing, Lockheed Martin, and a team consisting of Northrop Grumman and Orbital Sciences Corp. - have their work cut out for them. NASA is looking for both a ten-fold improvement in per-pound launch costs (from $10,000 per pound to $1,000) and massive improvements in crew survivability."
In related news, Rubyflame writes: "Aviation Now has a
story about four new kerosene-fueled rocket engines being developed by Aerojet, Pratt & Whitney, Rocketdyne, and TRW. These are engines that will produce a million pounds of thrust, intended to outdo Russian designs in reliability and launch cost, and one of them may power a new reusable launch vehicle. Kerosene has the advantage that it's denser than hydrogen, so the fuel tanks can be smaller."
Haiku (Score:4, Funny)
Takes off like a pile of bricks
Lighter craft required
Just another NASA bait'n'switch (Score:2, Interesting)
They just want gobs of money to spend on technology development programs (read "new toys"). The ultimate goal of upper NASA management these days is to reach retirement without having any disasters (like Apollo 1 or Challenger) on their watch -- the easiest way to avoid that is to launch things as infrequently as possible.
(Note, there are probably a few naive engineers and rocket scientists still at NASA who believe the PR and have honorable intentions. But they're not the decision makers.)
Re:Just another NASA bait'n'switch (Score:3, Funny)
Note, there are probably a few naive engineers and rocket scientists.
Funny, I always thought the terms "naive" and "rocket scientists" were antithetical.
Re:Just another NASA bait'n'switch (Score:3, Insightful)
Naivete? (Score:3)
Only if you equate wisdom with cynicism. Being cynical never got anyone to the stars.
I'm naive, and damn proud of it.
NASA's justification for existing (Score:5, Insightful)
American tax dollars are working to make these "new toys". The primary justification for NASA's funding is that the technologies that come out of these "technology development programs" push the cutting edge of modern tech.
It's been a long time since Congress has thought about the values of "exploring space". That's just an side-effect of research spending.
It's like those robot-construction competitions where they have to get all the balls into the goal. The contest isn't to designed to solve the great "yellow ball problem", it's to build and explore ideas in technology.
Congress views funding NASA the same way; by funding NASA they're advancing America's technical know-how. Not to mention that NASA contracts go to high-tech american industries.
There's not some sort of conspiracy to keep regular people out of space here. NASA's just doing its job.
Sweat
"advancing american know how" (Score:2)
Currently the money goes to a couple of aerospace companies that keep all of their important developments in secret.
And all those advances in know how are so esoteric they are quite useless for most Americans.
The primary justafication for NASA's funding is to feed powerufl contractors. Luckily we can get some important science done as a byproduct of that.
Re:NASA's justification for existing (Score:2)
That may have been true in the Apollo era, and even for a little while after, but it hasn't been the case for years -- at least, not in the launch vehicle category. (I agree that some of the Centers do useful research, but that's a small fraction NASA's budget compared to what gets eaten by Houston, the Cape, etc.)
If you want "spin off technologies", you get a much better pay off by focusing on those, not on wasting the money pretending you're spending it on innovative launch vehicle design. (The X-33 project is a classic example, with that thoroughly stupid oddly shaped composite propellant tank that couldn't stand up to internal pressures (because of the odd shape) without reinforcing it so much that it was heavier than a metal tank would have been. Among other design stupidities, like VTOHL, which means you have to design for perpendicular load paths, and have no safe abort mode immediately after launch.)
As for "not some sort of conspiracy to keep regular people out of space" -- they tried pretty damn hard to keep Tito out of the International Space Station when he bought a ride on a Russian vehicle.
I tend to agree with you (Score:2)
Instead the Russians still do things cheaper (and so far quite reliably) with their Energia rockets.
It is really hard to believe that those contractors are actually trying to make things cheaper.
Re:I tend to agree with you (Score:2)
Most of launches in last 10 years are Soyuz and Proton. These are relatively cheap rockets.
Energiya flew only couple of times, taking Buran into orbit in one of those flights. But it became obvious that Buran would be a financial black hole (exactly as Shuttle is), and the Buran program was stopped (with no ill effects, as we see today). Energiya rocket was mostly developed to launch Buran, and therefore it got shelved too.
What about the XB54? (Score:2, Interesting)
Give NASA a chance!
Re:What about the XB54? (Score:2)
There is some research right now on using plasma to reduce drag on aircraft. Evidently the Russians are using it for their next generation of MIG's (they are using it mostly for stealth, since the plasma absorbs radar).
Anyway, they've done windtunnel tests with welder's torches, and they have found that it reduces drag by up to 30%.
Ramjets can only get up to about mach 5. What if you attached one of these plasma generators onto a ramjet? It might be able to get to Mach 7.
It seems like with such a setup you could use the ramjet to get up to Mach 7, and then use a kerosene rocket to get to orbital velocity.
I figured with a kerosene/LOX fueled rocket motor at 350 seconds, you should be able to reach orbital velocity with about an 8/1 fuel to payload ratio.
Re:What about the XB54? (Score:2)
They've had their fucking chance. More than once. Space launch costs more now than it did in the sixties -- completely counter to all other technology trends.
Give somebody else a chance.
about time (Score:3, Insightful)
Websurfing done right! StumbleUpon [stumbleupon.com]
Re:about time (Score:2, Informative)
There's been only one major accident (challenger) in those 30 years
No one else has a reusable launch vehicle (that I know of...I don't think russia does, pretty sure no one else does either
--Jubedgy
Re:about time (Score:2)
Russia used to have a shuttle called the Buran or some such. Buran means Snow Storm, IIRC. I doubt if they fly it anymore, some enterprising Russian Engineer probably carved it up and traded the scrap metal for vodka.
One feature it was supposed to have that the US shuttle doesn't is some power on landing, allowing a wider margin of safety in landings.
I'm sure somebody has more info, or check google for "buran shuttle"
You mean Tthey "had" a "shuttle-like" prototype (Score:2)
It now sits as an amusement park exhibit that you can walk through, and as for it "not flying anymore"...well, it never really flew in the first place in a practical sense.
I don't know why people constantly bring up Buran. There is no comparison between this pseudo-prototype craft that was never practically used, and the shuttle, which has over two decades of nearly perfect mission records.
Re:You mean Tthey "had" a "shuttle-like" prototype (Score:5, Funny)
Because we like to torment you. It obviously bothers you.
I also heard that France was working on a shuttle. Portugal has been flying their shuttle for years, though it's not widely publicized. Mexico scrapped their shuttle project in favor of their rail-gun / light-sail combination system with which they've manage to supply migrant workers for the asparagus farming on Venus.
Re:You mean Tthey "had" a "shuttle-like" prototype (Score:2)
One shuttle was completed, but never actively used - it performed an unmanned orbit and return, admirably.
There is a flight test prototype currently on display in Sydney I believe (that's where it was when I last looked anyway), but was never space capable.
There is at one other almost complete space capable shuttle in storage (named Ptichka (Little Bird)) along with the one that orbited - Buran. Three more (unnamed) were under construction when the program finished.
They were obviously externally designed in the same way as the american shuttles with one major difference. They don't have engines. Instead to launch they are strapped to the back of one VERY powerful rocket system - an Engergia.
Anyway, this site [k26.com] is the best place for all your Buran needs.
Re:You mean Tthey "had" a "shuttle-like" prototype (Score:2)
Because the Buran program is interesting? Yes, Buran does come up ever six months or so here. I learned quite a few things during those discussions.
I didn't know that the Burans had considerably larger payloads than the American shuttles. I didn't know that the Buran crew had ejection seats.
I hadn't really realized that the main reason the Buran program was stalled was that the Soviet Union totally ran out of rubles.
Here are some of those previous slashdot threads.
Russia Revives Buran Space Shuttle [slashdot.org]
Own Your Own Russian Space Shuttle [slashdot.org]
Yes Russia does (Score:2)
I think it has only flown once. After that they parked it on a runway and it has been there ever since AFAIK. I think one of the fuselage models used for testing is a tourist attraction in moscow.
The Russians dont use it because it is much cheaper to use their rockets.
Umm no (Score:2)
There is a fully functional prototype that flew one orbital mission before funding ran out and is currently mothballed somewhere in some hangar (probably not a ranway).
So i dont know where i was "totally ill-informed".
Re:Umm no (Score:2)
Can you provide a link? I remember the Soviets working on a Shuttle-like vehicle, but I'm with the rest of the audience here... I only heard about them making a prototype. I've NEVER heard of anyone launching a Shuttle/reusable space vehicle except for the U.S.
Re:Buran sits in a parking lot among weeds. (Score:2)
The Russians built several Buran-class shuttles (another one was named something like Ptichka, "bird"). There was a structural model, that's the one sitting in the park, equivalent to the Pathfinder now sitting in Alabama. There was a manned flight test vehicle that flew numerous approach and landings (like the Enterprise) but unlike the US Shuttles, it had jet engine pods so it could take off on its own and do self-ferrying. And of course the Buran itself which flew in space and did a hands-off fully automated landing (something the US Shuttle has never done).
Re:about time (Score:2)
You're right about the safety record...it's enviably good. But just because the rocket is reusable doesn't mean it's cheap.
Re:about time (Score:2)
You don't need these guarantees with unmanned payloads. Mostly because it's not economic.
Let's say you have a $50 Million Satellite you want to launch.
If you can build a disposable rocket with a 99.999% chance of success per launch, but it will cost you a cool $2 Billion per launch, why would you do that if you can build a rocket with a low 95% chance of success per launch for say, $200 Million?
Even if you loose the rocket and the payload on the pad, you're still ahead money-wise of the 99.999% launch vehicle buy building and launching the dangerous rocket *seven times*!
On the other hand, though, would you willingly get into a craft that you knew had a projected 1 in 20 failure rate?
*THAT* is why the shuttle is so expensive. The closer to 100% safe you get, it's an exponential curve in cost. The current effort to create a second generation reusable craft won't eliminate the curve, but it will (hopefully) lower it because of the lower costs of newer technologies.
As for reusability being a crock, that's not really true either. Although the shuttle is horrifically expensive (and I hope I just illustrated why) a disposable craft with similar capabilities would be even more costly. Not only that, but how do you create a craft that can retrieve satellites from orbit to the earth without replicating something like the shuttle? Once you've got something large enough to do that coming back to the earth as the crew return vehicle, it becomes more economical to refit that and relaunch it than it does to throw it away.
Re:about time (Score:2)
Problem is that Shuttle is practically designed to break on every flight. (SRBs, ET, etc). Then the whole thing is decertified for flight as soon as it lands.
Air travel would be expensive too if the plane had to be reinspected for a new Certificate of Airworthiness between every flight, let a lone doing a full overhaul on the engines.
Re:about time (Score:2)
What seems more embarassing to me is that the Russians have a much more appropriate and cost effective system to launch humans into space -- and it uses 45 year old technology.
Embarassing compared to WHAT? (Score:2)
So please tell me why the shuttles are an embarassment. As far as I can see they're still the only space craft that lands on wheels.
Re:Embarassing compared to WHAT? (Score:2)
Well, that's one reason right there. What the heck is the point of wheels on a spaceship? It doesn't take off using those wheels, or the wings either for that matter. Total dead weight, useful only for landing -- and then only after you've got high enough and light enough that the wings will lift and the gear won't collapse.
Fscking stupid way to design a vehicle. Hell, how many helicopters have wheels? (not counting the tiny ones to make it easy to drag the thing around on the tarmac).
Re:about time (Score:2)
Any mistake that causes the whole system to explode and kill people is a _major_ mistake. No matter how seemingly trivial it was, it ceased being trivial when the whole damn thing blew up.
Crew survivability? (Score:2, Interesting)
No, I didn't read the article, but, assuming this poster is reasonably accurate with his description text, why is this necessary? Aside from Challenger, have we had any significant (or even insignificant?) problems with shuttle crews surviving the trip?
Re:Crew survivability? (Score:5, Interesting)
Please note that during the first 2.5 minutes of every shuttle launch, there are NO abort modes that are survivable. If there are any problems with the SRBs, they cannot be turned off. If there are any catastrophic problems with the ET, it doesn't matter, you must continue your launch profile until the SRBs have stopped.
Three engine shutdown during SRB burn? Shuttle disintegration.
ET rupture? Shuttle disintegration.
Pretty much anything, dead astronauts.
The russians use 40 year old technology, but at least they have survivable aborts throughout the entire flight profile.
Re:Crew survivability? (Score:3, Informative)
Re:Crew survivability? (Score:2)
No. The problem with solid rockets is they don't have an "off" switch; you must wait for them to finish burning (run out of the solid fuel) before you can separate from them. The connection between the SRB and the Shuttle is under a lot of stress while the SRBs are firing, and it is very nontrivial to cleanly break that connection under load; and then you have the problem that the exhaust coming from the SRB's will probably destroy the Shuttle (the external tank is sort of like a big bomb).
Liquid boosters would have been a lot safer, and should have done the job well. I don't remember why NASA went with the solid boosters. It may have had something to do with which Congressional district the SRBs are built in.
steveha
Gragarin's reward? (Score:2)
Let me see if I understand what you are suggesting. Are you saying that even though Gragarin's missions seemed successful to the rest of the world, he did something that displeased his masters, and they had him beaten up, and allowed photos of him with the marks of these beatings still on him?
This is all news to me. But I remember during the buildup to the main attack in the Gulf War, a number of pilots were shot down. When the Iraqis allowed pictures of these airmen, there was a lot of speculation in the press that they too had been beaten. Then I heard someone less charged with emotion who said that being bounced around during a really rough landing could leave bruises on an airmen's face that looked like those one might get from being beaten up. This sounds reasonable to me, so I am going to assume, unless you can muster up more evidence, that any facial bruising you see in photos of Gragarin was due to a really rough landing.
Re:Crew survivability? (Score:2, Insightful)
The probability of any of them going wrong is actually fairly low (as our record as indicated with 10 deaths, and only 7 in the shuttle) and our ability to recoup is actually pretty good, but I think NASA wants a system in which *if* something does go wrong, they won't loose an astronaut.
Re:Crew survivability? (Score:2)
The Soviet Buran, which was not a knockoff of the American Shuttles, had ejection seats for a certain number of crew members. Were the lives of Soviet Cosmonauts more valuable than those of American Astronauts?
Build a goddamn Sänger-type launcher! (Score:3, Interesting)
A German concept, AFAIK. Way more reusable than anything NASA has come up with
The days of vertical launches are over.
Re:Build a goddamn Sänger-type launcher! (Score:2)
Nah. I say we just make a giant slingshot.
Multi-stage Launch (Score:5, Informative)
At first you may think that two-staged launches are a waste of money, but some of it does at least look promising.
The design from Boeing is an interesting one. It looks like a smaller shuttle attached to a jumbo jet. It's then flown near the limits of space where the top ship would then come apart and finish it's journey into space on it's own.
The jumbo jet would then return to the launch site.
I must admit that I would love to see a 1 stage space craft.
Aren't both Boeing stages identical? (Score:4, Informative)
Its true though that all of the designs share some characteristics...one stage to get you off the gorund, one to get you into orbit. Obviously this isn't by accident...the physics of the problem and materials/fuel presently available must dictate this design.
Re:Multi-stage Launch (Score:4, Insightful)
I honestly don't think we'll ever get SSTO going with conventional chemical propellants. You simple have to carry too much weight in fuel, which means you need a bigger rocket, which means more fuel, then a bigger rocket...you get the idea. What we need is a way to extract more energy from whatever fuel we use. One way to do that is to go nuclear.
Nuclear rockets have been proposed in the past and always shot down by the enviro-Nazi, anti-nuke crowd. Seems you can't split an atom these days without attracting a lot of attention from this fringe crowd that cringes at the very word "neutron". Yes, nuclear technology CAN be dangerous. So can a lot of other things. NASA has an enviably safety record given the hazardous work they do, and I have no doubt that if the nuclear engine project were ever to become reality it would be a paragon of safety.
Of course, there could always be something flying out of left field here like some sort of teleportation technology or anti-gravity, but I doubt it in my lifetime.
And if we ever get REALLY serious about getting off this planet, the ONLY way to fly would be a space elevator. A monumental engineering task to be sure, but once in place it'd be the cheapest ride into low Earth orbit that we could come up with.
Re:Multi-stage Launch (Score:4, Insightful)
You do realize that opposition to nuclear propulsion comes from rational concerns about its safety as well as irrational hatred of everything nuclear, don't you? I don't have particular problems with nuclear energy in general, but I have serious reservations about any flying nuclear system. A nuclear powered spacecraft is not like the radiothermal generators that have been used in spacecraft so far. It would require a large amount of quite hot material, so any accident could spread a lot of radiactive contamination over a very wide area. I'd want to be damn sure that there were adequate safeguards against that before signing off on such a thing.
Re:Multi-stage Launch (Score:2)
Launch fail rates are at what now? 1 in 20? 1 in 30? Contamination isn't just a knee-jerk reaction its a real statistical risk with the liability outweighing the benefits.
What's wrong with multiple stages anyways? If the next shuttle is going to ride on the wing of a high altitude plane and lauched like a missile then so be it. Aesthetics can wait.
Re:Multi-stage Launch (Score:4, Interesting)
> propulsion technology a single-stage-to-orbit
> (SSTO) isn't terribly practical. They made some
> prototypes and actually flew a scaled down
> prototype in the desert, but ultimately they had
>tremendous problems with the extremely high
>performance rocket engine they had to use, couple
>with the experimental composite cryogenic fuel
>tanks.
No. This isn't the case; I was talking to some engineers that worked on the Roton just last weekend. They indicated that they knew of no problem that would have precluded the design from working. The composite cryogenic fuel tank THEY used (as opposed to the X33 debacle) - it worked fine in all testing; including something like 50 pressure cycles IRC.
>I honestly don't think we'll ever get SSTO going
>with conventional chemical propellants. You simple
>have to carry too much weight in fuel, which means
>you need a bigger rocket, which means more fuel,
>then a bigger rocket...you get the idea.
No, the simulations converge- SSTO is definitely possible. I've seen atleast 2 hard and fast designs for SSTO vehicles- the Roton and Mockingbird. The Roton would have carried 3 tonnes to LEO; the Mockingbird design didn't have a payload of any note, but was really tiny (1.5 tonnes), and cheap. I've studied both concepts extensively; they both appear workable.
The biggest argument against SSTO is that it may be more expensive. TSTO may be cheaper. Still, the argument isn't totally watertight. There's a lot of ground processing for TSTO that SSTO doesn't require and that's going to cost something. Although SSTO designs use more fuel- fuel is cheapest bit of the whole rocket by far.
>What we need is a way to extract more energy from
>whatever fuel we use.
Another thing I saw on the weekend- I was at a presentation by a guy talking about a laser powered launch system. The idea is you take a large bank of lasers and point it at a hydrogen powered launch vehicle, which has a heat exchanger it uses to heat the hydrogen. The ISP is about 600 seconds, which is plenty for reaching orbit. The laser bank was priced at about $1 billion but its dropping at about 30% a year currently- only cheap semiconductor lasers are needed, and they're getting cheaper and cheaper.
Re:Multi-stage Launch (Score:3, Informative)
>with the experimental composite cryogenic fuel
>tanks.
No. This isn't the case; I was talking to some engineers that worked on the Roton just last weekend. They indicated that they knew of no problem that would have precluded the design from working. The composite cryogenic fuel tank THEY used (as opposed to the X33 debacle) - it worked fine in all testing; including something like 50 pressure cycles IRC.
It's good to hear that someone's worked on the problem a bit. Still, I'm sure it's quite expensive.
>you need a bigger rocket, which means more fuel,
>then a bigger rocket...you get the idea.
No, the simulations converge- SSTO is definitely possible. I've seen atleast 2 hard and fast designs for SSTO vehicles- the Roton and Mockingbird. The Roton would have carried 3 tonnes to LEO; the Mockingbird design didn't have a payload of any note, but was really tiny (1.5 tonnes), and cheap. I've studied both concepts extensively; they both appear workable.
I will point out that the payload capacity you're speaking of is about a tenth of what one Saturn V can hurl into LEO. It's like comparing an old big-block V8 with a 4 barrel carb versus a high-winding multicam, turbocharged, intercooled 4 cylinder engine. Both will make gobs of horsepower, but the latter is going to be much more expensive than the former AND generally more prone to failure. The Shuttle main engines are a case in point with their trouble-prone turbopumps. The J5 engines on the Saturn only had to work once, thus were much cheaper AND more reliable.
>What we need is a way to extract more energy from
>whatever fuel we use.
Another thing I saw on the weekend- I was at a presentation by a guy talking about a laser powered launch system. The idea is you take a large bank of lasers and point it at a hydrogen powered launch vehicle, which has a heat exchanger it uses to heat the hydrogen. The ISP is about 600 seconds, which is plenty for reaching orbit. The laser bank was priced at about $1 billion but its dropping at about 30% a year currently- only cheap semiconductor lasers are needed, and they're getting cheaper and cheaper.
I've seen this concept demonstrated with computer simulations, but I'm still skeptical of it. Ground based lasers will always be subject to thermal blooming due to atmospheric attenuation. By the time you're 50 miles up, that's got to be a tremendous power loss, meaning you'd have to have incredibly powerful lasers chewing up gobs of power. You'd need a nuclear power plant on site just to power the darn thing most likely.
Laser launchers. (Score:4, Informative)
Interesting. Is this caused by the lasers or just natural artifacts of the atmosphere? Incidentally power is the cheap bit in the equation, and you need less of it delivered at altitude due to g-limiting anyway; so it may not matter.
Atmospheric. You have two effects happening. One is that minute particles in the atmosphere scatter the laser beam. This is unavoidable, and causes exponential attenuation over long distances. The second is that the atmosphere absorbs some of the light you're sending, and heats up. This causes optical mayhem that defocuses the beam.
Compounding the problem is the fact that you'll have to fire through a *lot* of atmosphere. Your craft needs most of its velocity to be tangential, and you want as long an acceleration path as you can get away with to keep the acceleration to something that a) you can provide and b) won't damage your cargo. This means a grazing path through the atmosphere, which means your lasers will be firing through hundreds or possibly thousands of kilometres of air (i.e. as far as you can manage).
The only practical scheme I can think of for very long distances is to have multiple stations along the flight path and to fire a converging beam, so that heating problems are only significant for the last little part of the beam path.
On a couple of other points: You'll be using a laser array, not a single laser, so the cost will be directly proportional to the power required. More power means more cost.
Also, I have doubts about a heat-exchanger system working. Throughput tends to be low compared to the power flow required to get high ISP, and a heat exchanger means a heavier craft. The most practical craft design I've seen suggested, which has flown in small-scale tests, has the bottom of the craft being a curved mirror with a central projection. The laser is focused by the mirror and heats air immediately below the central projection, which is shaped to force the air to move away from the craft.
Laser launchers are a neat idea, and avoid the problem of carrying most of your reaction mass when set up in jet mode, but there are formidable engineering problems to overcome before they're practical.
Re:Multi-stage Launch (Score:3, Interesting)
Yeah. So? The S-V cost per kg was 1/10 that of the shuttle to begin with! The shuttle is NOT cheaper than the 60's era moon rockets -- not by a LONG shot. All that throwaway booster work was actually easier to deal with than the constant launch-inspect-refit-launch cycle that the shuttle goes through. Go look up NASA's data on the subject. It's all there.
>Ground based lasers will always be subject to thermal blooming due to atmospheric attenuation.
Interesting. Is this caused by the lasers or just natural artifacts of the atmosphere? Incidentally power is the cheap bit in the equation, and you need less of it delivered at altitude due to g-limiting anyway; so it may not matter.
It's a natural effect of firing a laser through something other than a vacuum. The air molecules, water molecules, and even airborne dust all absorb and/or scatter the beam. Add to that the fact that a spacecraft isn't going to go straight up into orbit, it's going to follow a slanting path that could have a laser firing through 100-200 miles of atmosphere before it even touches the spacecraft, and THEN it actually has to still have enough energy to propell the craft. This is a HUGE problem that simply cannot be gotten around by anything other than brute forcing the laser output. Even adaptive optics will only get you so far. The power requirements would be orders of magnitude beyond anything even on the drawing board today, and the cost would be appropriately astronomical.
And let's not forget that if you had a ground based laser that powerful, it'd make a nifty weapon for zapping LEO satellites and space stations. I'm sure there's some hyper-concerned pacifists out there that would have an absolute conniption fit over such a thing.
Re:Multi-stage Launch (Score:4, Informative)
Ion engines are wonderfully efficient in converting mass to thrust, but they won't get you off the ground. The key issue for launch vehicles is the ratio of total impulse (ie, thrust x time) to system weight, where the system weight is not just the propellant mass but also that of the tanks to hold the propellant (this is where LH2 loses out, too bulky), the engines, thermal shielding, etc.
At least you qualified with reusable single-stage launchers. Several simple thought experiments using existing technology provide examples of workable (but not necessarily reusable) SSTO vehicles. E.g. a Shuttle External Tank with six SSMEs. Or a Saturn-II stage (with the bulkhead moved for the different mix ratio) with the 5 J2's replaced with an SSME.
Of course those are both LH2/LOX examples -- high Isp on the engine but crappy structural weights because of the size of the hydrogen tanks. Convert the engines to something like a LCH4/LOX (liquid methane/lox) cycle (easily do-able with RL-10s, probably require a massive redesign of something like SSME) and you lose some seconds of Isp but gain back because the CH4 is so much denser than LH2 that the tankage is much smaller.
Cheap, one-shot boosters, designed for low cost rather than reusability
This sounds good, but the problem is that, unless they are way overengineered (ie heavy) or you're willing to accept a few blow-ups, "cheap" and "one-shot" are mutually contradictory since a one-shot is inherently untestable, therefore you have to inspect quality in.
Max Hunter (rocket scientist, designer of the Delta's daddy, Thor) beat all this to death years ago, didn't anybody listen to him?
Re:Multi-stage Launch (Score:3, Informative)
There are two contentions that I'm making.
1) SSTO doesn't make sense, because you have to schlep a lot of dead weight into orbit with you. Once the fuel tank is empty, it's just drag and extra mass. Pitch it.
2) Reusable hasn't yet made sense, because it's almost less expensive to build a new one than to re-certify one for flight (where "one" is "whatever launch system we're discussing"). It may be that in the future, we'll have engineering technology such that we can re-certify the spacecraft with less intrusive inspections, but I don't think that the expense of that process is warranted, particularly for a system that's just for throwing big stuff into orbit.
Your point is well taken. Manned vs. unmanned shots require very different engineering constraints. I think it's unfortunate that NASA seems to be totally hell-bent on making one system that does both things well. And you're right, a large payload return module would be a useful thing to have in the inventory. But there's no reason to take it up there every time you launch.
the usual suspects...defense contractors (Score:5, Interesting)
Now, I am coming from a background where I am not incredibly familiar with either U.S. capitalism or with issues of defense. Basically, there are a handful of these companies that compete for every government contract. To maintain "competition," the government will try to spread the love around, going with different companies for succesive contracts.
But each individual contract is too big for a single company to fulfill on its own, so whomever ends up winning the contract will turn around and outsource some of the work to...the same "competitors" whose bids they beat out!
As a retired rocketman, I am the first to support expansion and improvement of any nation's space program. I just wanted to point out that the notion of "who will build the next generation shuttle" should be taken with a grain of salt.
You seem a little naive for a retired rocketman (Score:2)
Large scale aerospace and military projects have operated as such for decades. This really isn't news.
Re:the usual suspects...defense contractors (Score:2)
It's about time (Score:2, Interesting)
I find it kinda ironic how they're doing this only a year or two after canceling practically every alternative-launch-system project NASA had (X-33, X-34, and a few others that I can't remember). I'd think it would be cheaper to just finish a few programs at once rather than stop and restart them constantly, as NASA seems to be doing lately.
Re:It's about time (Score:2)
Reminds me of this: (Score:5, Funny)
hehe...
Fore more quotes from that movie go here [atlyrics.com]
George Bush calls on NASA to put a man on the Sun (Score:3, Funny)
With everything that's been going on lately, you might have missed this important piece of 'news'.
Anyway, here's the link [bobfromaccounting.com].
Re:George Bush calls on NASA to put a man on the S (Score:2)
When asked how they were going to deal with the intense heat likely to be encountered on any journey to the sun, NASA responded "no problems, we'll send them at night"
Here's an idea... (Score:2)
Who knows, mybe that crazy Englishman [bbc.co.uk] with his "Thunderbird" rocket made from plywood will astound us all.
Or not.
Crew and Cargo Seperate (Score:2, Interesting)
Need For Shuttle? (Score:3, Interesting)
I would hope that they start by questioning the need for a shuttle to begin with. Manned orbital flight is pretty well handled with the ISS and the Russians have a cheaper, time proven method of transport to/from ISS that is pretty hard to beat.
As far as repair of orbitals, has that proven to be worth the expense? Maybe it is, especially if they use such a vehicle to do trash collection. Again, I'm no expert but I hope those who are will be considering these things.
It would seem to me that some of the would be costs of new shuttles would be better spent on upgrading the design of Soyez/Progress and making them even more efficient. The rest of the money could be better spent on other projects including unmanned deep space research or manned missions to other planets (assuming those make sense).
-1, Naive (Score:2)
First off, how is the ISS a solution to manned orbital flight??? Secondly, giving up manned spaceflight to the Russians is idiotic on many levels.
They aren't dependable.
They don't have the funding to pursue future programs.
They have nuclear weapons pointed at us.
Cost growth (Score:3, Interesting)
The Saturn V was cheaper than the Shuttle in cost per pound to orbit. Which is embarassing.
Re:Cost growth (Score:3, Interesting)
The sad truth is that the Saturn V was probably the most effective and efficient heavy lift vehicle this planet has ever seen. The Russian Energia system is damn close but I haven't had a chance to really compare the two on the fine details of cost and payload. Suffice to say, though, that if we'd spent the last 20 years upgrading and perfecting the S-V design, it would undoubtedly be the pre-eminent heavy lift vehicle in the history of manned spaceflight. The space station would've been DONE by now and we'd be starting on a lunar colony. And it would've been done BETTER, FASTER, and CHEAPER than anything NASA is fielding right now.
Discover magazine had a huge expose on this whole subject about 10-15 years ago where they showed how NASA had systematically rejected "Big Dumb Booster" (BDB) ideas, not because they were technically or economically unfeasible but because they weren't sexy, or didn't provide some congress-critter's home district with enough jobs, or other nonsense. And the original shuttle idea had some HUGE differences from the final product, like air-breathing engines for power landing, no solid rocket boosters, etc. etc.
We need to scrap the shuttle and scrap all manned missions that do not actually involve setting up humans PERMANENTLY somewhere else in the solar system. The space station should be scrapped in favor of a permanent lunar colony -- after all, why cart all that aluminum, silicates and titanium up to orbit when there's billions of tons of it already on the moon? Low lunar gravity is an EXCELLENT place to stage interplanetary missions to Mars and the asteroid belt.
Space station has its purposes (Score:2)
As to the possibility of launching interplanetary missions from the Moon, as I understand the orbital mechanics that only works if you actually construct your spacecraft out of lunar materials, requiring a *very large* industrial infrastructure on the moon. If you build your spacecraft on Earth, the fuel you'd use stopping your craft on the Moon for refuelling (no aerobraking on the Moon, unlike Mars, remember) is greater than the fuel you'd use going to Mars in the first place.
Re:Cost growth (Score:2)
Of course they did. Many here seem to forget that NASA is, at its core, a government bureaucracy, and the fundamental imperative of any bureaucracy is to perpetuate itself. Mind, NASA has been particularly good at PR, painting itself as high tech innovators. (To a degree they are, but look at the results compared to their budget.)
But there's no reason to believe that NASA is going to be any more efficient at its stated mission than any other goverment bureaucracy. (INS anyone?)
How soon until we have ships built in space? (Score:2, Interesting)
My only concern is using such a vessel for travelling to other planets, we'll need something like the shuttlecraft from countless sci-fi series and movies to move from orbit, to surface, and back.
Of course, build the ship large enough (perhaps a standing crew of 50 - 100) and with a large cargo space, and part of the problem may be solvable about setting up colonies offworld. The cargo space can house a dropship that can deploy into a base. Just a notion I've been toying with in my (still unpublished) stories.
¿¿¿ Roton ??? (Score:2)
CNN's bit (Score:2, Interesting)
"They must be developed and operated by private industry."
Now maybe I am misinterpreting what "operated" means, but that sounds like NASA is planning for someone else to run these bad boys. Could this the first step towords commercialization?
If only... (Score:2)
Anyway, didn't Bush start talking about pushing nuclear propulsion in space (maybe ala NERVA)? Does anybody think there's a snowball's chance in hell of one of the competitors for SLI to team up with General Atomics or Electric Boat or anybody else with experience in portable nuclear power plants? After all, a rocket that simply can't explode has got to do wonders for crew survivability, not to mention the weight savings of not having to carry around LOX.
Yeah, and while I'm dreaming we can use those rockets to send manned missions beyond Mars...
Fission powered rockets don't work well. (Score:2)
I recall reading about back in the 50s someone built a nuclear powered cruise missile. The thing would kill anything it flew over as it was entirely unshielded to save weight...
Re:Fission powered rockets don't work well. (Score:2)
Hey that would work along the same lines as the shuttle, ie a reusable vehicle. All you would need to do is send it off fly over a few terrorist training camps then back to base. Then you can refueld it and be ready to send it off on other missions. Of course you would have a rather high turnover of base personall, but think of the material savings!
Re:If only... (Score:2)
If you want to efficiently burn kerosene (or mostly anything, to that matter) you need liquid oxygen. That's where a cryogenic gas tank might be of use.
Just a thought..... (Score:2)
Let's face it, if there were very few to no regulatory hurdles to creating private space travel, colonies, etc coupled with low enough taxes for the venture capital to be there, we could accomplish NASA's "goals" in about half the time. Telling corporate America, "you see that big, beautiful, mineral-rich asteroid worth 2 trillion USD? Well if you can get to it, you can mine it for free!" would spur space R&D faster than NASA ever could.
No generation of Americans has ever had simultaneously the kind of economy we have and the scientific know-how. The only thing keeping us back is the government. The national debt's interest alone consumes 13% of the budget! If we got rid of it, filed the charters of 70% of the federal agencies in file 13, booted the majority of people off social security and medicare (keep only those that even if they stuck only to survival, could not pay for medical care) and cut the taxes to something minimal who knows what we could accomplish. There would be so much money availible for private research grants that it would be mind boggling.
Re:adendum (Score:2)
Check out those concept animations. (Score:2, Funny)
Airbreathing engines are needed (Score:3, Insightful)
At these low altitudes, air resistance is a major factor and, due to the heavy fuel-load still onboard, a great deal of power is required.
Conventional rocket motors suffer from the need to carry their own oxidizer (O2) but if the first stage of flight used air-breathing engines then far less of this heavy fuel element would be required. The result would be a lighter "wet" vehicle that required less power to fly.
This is why NASA and other researchers are spending such huge amounts of money on things such as the SCRAMJET and Pulse Detonation Engines [aardvark.co.nz].
Unfortunately it appears that there's still a big gap between laboratory and launchpad as far as these new engine designs are concerned.
Liquid-fueled rocket engines will always be risky and fuel-hungry. The magnitude of improvement in safety and price-performance being sought will probably have to wait until they're perfected.
Re:Airbreathing engines are needed (Score:2)
Airbreathing engines do you no good anywhere but during the first few minutes of takeoff; after that, they are extra mass you have to push around. Also, a design with both airbreathing engines and rockets is more complicated than a design with just rockets.
Liquid oxygen is cheap. It takes up little room onboard. Carrying a bit extra is no big deal.
You want a design that will work every time. A multiple-engine rocket, with enough engines that you can handle one or two engines failing, is what we need.
Note that in a two-stage design, it might make sense for the first stage to be air-breathing.
And that is all I know about air-breathing engines on spacecraft. I gleaned this by reading sci.space.* newsgroups on USENET.
steveha
Linear Aerospike Engine (Score:3, Interesting)
Re:Linear Aerospike Engine (Score:2)
Excellent question. Take a close look at Lockheed Martin's proposal [spaceflightnow.com]. See anything you recognise? :-)
Don't Poo Poo the Shuttle (Score:2)
As an aside, I'll bet you that the the SR-71 'Blackbird' replacement, the Auroura, was made possible by things learned by making the Shuttle - like the tiles. But as we don't know much about the Auroura, so I'm just pulling crap out of my butt.
Anyways, comerial rocketry is great for launching stupid XM radio satelites - the shuttle is great for learning and doing wacky things like fixing Hubble.
Shuttle tiles (Score:2)
There's been talk of reviving Buran, which would be good. It's a more modern design than the Shuttle.
That's because the shuttle is an utter failure. (Score:3, Insightful)
Secondly, the shuttle was originally supposed to save money vs. the Saturn V. It doesn't. It is at minimum an order of magnitude more expensive to run than the staged rockets it replaced. Just how expensive is not clear: it depends how much of the cost of its infrastructure you include in the cost of a launch. But the absolute minimum I've seen quoted is 300 million a launch, and that does not include infrastructure at all. Compare it to a cost of 20 million for a commercial flight of a Soviet space capsule, which includes both payments on infrastructure and a profit margin. And, because the shuttle was designed at the command of politicians and beaurocrats, the infrastructure is spread all over the country, to spread out the pork and give work to each of the beaurocrats' petty little domains. Why, for instance, didn't we just build the shuttle factory adjacent to the launch site, and cut out the cost of transporting it across the country? Why weren't the landing fields adjacent to the launch site from day one? Why use expensive and dangerous booster rockets? Why build the booster rockets using completely different technology than the main engines? Because it was a beaurocratic clusterfuck, that's why.
The shuttle was supposed to be reusable, so that it could be turned around quickly and relaunched. Instead, it takes months to refit a shuttle.
The shuttle was supposed to be safer than the systems it replaced. Obviously, Challenger blew up, the Saturn V's did not (the crew of Apollo 1 died in a ground test of the capsule, not the rocket). But also, one has to look at the underlying problem of operational complexity: the shuttle is just too damn complicated. It is a credit to the people involved that it has flown as safely as it has.
There were supposed to be many shuttles, flying every few weeks, which would have made each launch less expensive by spreading out the infrastructure costs more. Instead, there are a handful of shuttles, flying about once a year. They're too expensive to build, and take too much time to refit.
I'm not even going to talk about it landing at airports.
Lastly, when you look at Shuttle, you have to point out that at the time we stopped production of the Saturn V, we HAD THE SATURN V ALREADY. The space shuttle cost billions to develop, on top of what we had already spent to develop the Saturn V. Worse, it set the space program back at least 20 years. Hell, we still don't have a replacemnt for the Saturn V.
Jon Acheson
An important fact to consider (Score:3, Insightful)
However.......one of the single biggest problems with the Space Shuttle is also one that could be solved in the future by creating a market for them - with space tourism or somesuch.
When you decide to build something like the Shuttle or the Concorde and then you find yourself with one or two users and no need for any more beyond the origional production run, then you have serious problems down the line that drive up costs to an insane level.
Simply put, you run out of spare parts.
The Shuttle and the Concorde were built all at once. The factories churned them out one after another. They needed parts - lots of them - so factories mass produced them.
Then, there weren't any more Shuttles to be made, so there was no need for parts to be built.
Time passed.
Things broke down.
And they broke down again.
And again.
Guess what happened? They started to run out of things. But you can't retool an entire factory to make 100 more of something you need - and do this for every part. So, instead, when something breaks, you have to make it. If some parts of the Shutte go bye-bye, guess what? Someone has to walk into a file room, pick up the blueprints and make a one-off of that part by hand.
Sounds like excruciatingly time and money consuming fun, huh?
Well, it _is_
A growing market for a vehicle such as the Shuttle would mean more parts could be built, and for less. A permananet Shuttle maintence industry could be established, driving costs through the basement.
telepresence (Score:3, Insightful)
If we need real-time human intelligence for planetary exploration, telepresence from orbit is likely also a better choice than human landings: you reduce risks greatly, save on equipment, and still get real-time manipulation. But current planetary exploration goals are so modest that purely robotic systems are probably better.
So, let's scrap human space flight for the time being. We can do an enormous number of really neat exploratory missions in space for the cost of the shuttle program and its replacements. When we return to the issue of human space travel again in a few decades, we'll have much better technologies.
Don't mix passengers and freight (Score:3, Informative)
Okay, Britian has a long history of telling people what they ought to have built without actually putting very much together themselves. But it still strikes me as the right solution.
Re:BDB is the answer. (Score:5, Insightful)
Problem was the Saturn 5 was already paid for (million pound thrust kerosene engine -- didn't they call than the F-1?) while the Shuttle that replaced it required billions in development cost. Also, the Saturn could put 4 times the payload in LEO, making it half as expensive as the Shuttle per pound, and it could send stuff to the Moon.
Instead of punching around with the Shuttle in LEO and this Space Station which is the overpriced whatever, we could have kept Apollo going and evolving, and with the same money we have spent, we could have had a permanent human presence on the Moon by now.
What would that gain? Well, we could have a much more thorough evaluation of lunar resources (possible polar ice) and more thoroughly evaluated O'Neil's ideas of using the Moon as a source of construction materials for space-solar beamed power systems in geosynchronous or L-whatever orbits. Instead we are dinking around in LEO learning nothing.
The Big Dumb Booster by the way, was an idea to scale up the Lunar Module descent engine (had to be a KISS design to bring the astronouts down in one piece) -- they gave the job of building a prototype motor to some general construction contractors who didn't know the first thing about rockets, and they test-fired a successful motor. The thing would have been the size of a Saturn but much more cheaply (heavily) build -- payload would have been more in the Shuttle category, but the idea is that boiler and bridge makers could slap them together. Of course the Shuttle killed the idea.
if you think the space station is overpriced (Score:2)
Re:if you think the space station is overpriced (Score:2)
At least they would have worthwhile things to study on a moon base.
Re:if you think the space station is overpriced (Score:2, Interesting)
In low earth orbit, the only resource you have is solar energy. Everything else has to be trucked up from earth, at something like $10,000 a pound. It costs 2,500 bucks to shoot a Quarter Pounder into orbit. Astronauts eat the equivalent of 3 of those every day. Add to that the cost of air and water, and pretty soon a moonbase starts to look pretty good in comparison, especially given the stated lifespan of the ISS (at least a decade).
Would a moonbase cost more? Sure, in the short term. But over the long run, a moonbase would become essentially self sufficient - something the ISS could never do - and could then go on to pay for itself. Because lunar gravity is 1/6th that of earth, and it has no atmosphere, it would be much, much cheaper to launch payloads into earth orbit from the moon than it is to launch them from the earth. Using a moonbase to launch probes to the other planets, or giant communications satellites to orbit the earth, could save NASA and analogous space agencies around the globe hundreds of billions of dollars.
Ah, but they're going to lower launch costs with these new rockets, right? Well, that's the same line of bull Congress bought when they authorized the construction of the space shuttle back in the 1970's. The shuttle would be this reusable wonder that would drastically slash the cost of getting into orbit. Yeah, right. It costs more to launch payloads on the shuttle than it does on any other system currently in operation (and all of them are disposable). So if you truly believe this latest attempt to design a reusable booster will slash launch costs tenfold, I have a bridge I wanna sell you.
The ISS is a $100 billion boondoggle, a black hole that's sucking up NASA's budget and giving back nothing in return. It's like watching Columbus anchor his fleet just outside of the harbor at Palos and burn Isabela's money to keep warm, instead of sailing to the Indies. It's a pointless waste. Developing yet another generation of overpriced "reusable" rockets in order to support such misadventures is pure folly.
Re:if you think the space station is overpriced (Score:2)
As far as getting food from the moon even if moon farming is possible i am sure it will require many tons of machinery.
Launching satelites from the moon? Do you know how much a mosfet factory wighs? Making a satelite requires the best of earth industry, you want it to be made from the moon with localy found minerals.
Everything you are talking about is long ways off.
And the 100 billion ISS boondogle is nothing compared to what a moonbase would cost.
I agree that NASA is very unlikely to make a cheaper vehicle though.
Why does a moon base need to be 'metal'? (Score:4, Interesting)
The moon is a more practical environment to work in, the low G enables a person to remain there signifigantly longer than in the microgravity of space.
The Biosphere projects are partially aiming at researching the viability of building an enclosed, self sustaining habitat on the moon, but even if you build a moon base that requires resupplying like space stations do, it could easily be done for less money as long as you take advantage of the fact that you can always dig a hole use some plastic to make it airtight and cover it with a metal lid. Homsteaders used to build houses out of earth and mud where trees weren't available, so why should we build lunar bases out of 'industrial grade metal' when really the only part that has to be metal is the door.
Re:BDB is the answer. (Score:3, Interesting)
Almost all of the costs for the Shuttle are salaries for the huge army of people NASA employs. According to Henry Spencer, the Shuttle program's costs are nearly constant: they stay pretty much the same, no matter how many or few launches happen in a year. (So you might as well launch stuff.)
You are absolutely correct: NASA should have taken the working Apollo designs and incrementally improved them. If they had kept up a good improve/test/fly schedule, we would probably have several cool 2001-ish space stations and a moon base by now. But for whatever reason, NASA developed the Shuttle in a massive paper design exercise, to be a giant leap forward in spacecraft. No need to build X vehicles and test them! Just build the Shuttle, perfect the first time!
Maybe BDB is the answer. Maybe SSTO (single stage to orbit, a completely re-usable spacecraft) is the answer. I don't know. But I do know that NASA is past its useful life, and the answer simply will not come out of NASA.
What the government should do is promise to buy X launches at Y tons of payload per launch, perhaps with special tax credits or other bonuses. Then wait for launch vehicles to appear. The money will never be spent if working vehicles don't appear, and if they do appear they will be cheaper than anything the modern NASA can create.
steveha
Re:BDB is the answer. (Score:2)
It
Simple
Stupid!
That's what KISS stands for in this context.
Re:Kerosene? (Score:5, Informative)
On another article a few weeks back, someone posted an answer that cleared this up for me. (I'm too lazy to track down the posting now.)
Bottom line is: hydrogen is like a high-horsepower, high-RPM turbo racing engine; it's best for driving light vehicles at high speeds (upper stages). Kerosene is like a high-torque diesel truck engine, good for getting a lot of weight moving from a dead stop.
The difference has to do with the physics of exhaust density, speed, momentum, etc.
Re:Yes but... (Score:2)
Re:Yes but... (Score:2)
Re:about time.... (Score:3, Interesting)
Case in point:
Both the University of Queensland in Australia and NASA are developing SCRAMJET engines, or Super Sonic Combustion Ramjet. These are capable of doing extreme hypersonic speeds, up to escape velocity.
NASA has spent $500 million on it's program. It has only produced one failed attempt at SCRAMJET flight.
In contrast, spending only $500,000, the UoQ has already produced a successfull SCRAMJET flight.
NASA takes lots of money and doesn't get anything done. They funnel all their money into the worthless shuttle and space station programs. We don't need to spend money to send people into LEO. It's a cold or hot vacuum a few hundred miles out. Whoop-de-shit.
Before NASA worries about the space station, they should buckle down and actually get a spaceplane. Cancel the shuttle program. It's worthless.
When they have a low-cost spaceplane, they can breed all the rats in space they want, and plus a mission to Mars might become feasable.
Here, about 45 years after Sputnik, we still haven't gotten rid of our horribly expensive rockets.
Re:One big name missing? (Score:2)
When X-33 went a billion or so dollars over budget (really stupid design to start with) and was cancelled, Lockheed didn't have the guts to put its own money where its mouth was.