British Spaceplane Skylon Could Revolutionize Space Travel (ieee.org) 226
MarkWhittington writes: The problem of lowering the cost of sending people and cargo into low Earth orbit has vexed engineers since the dawn of the space age. Currently, the only way to go into space is on top of multistage rockets which toss off pieces of themselves as they ascend higher into the heavens. The Conversation touted a British project, called Skylon, which many believe will help to address the problem of costly space travel. According to IEEE Spectrum, both BAE Systems and the British government have infused Skylon with $120 million in investment.
When I see "could" in a headline ... (Score:2, Insightful)
When I see "could" in a headline, I add "but it probably won't/doesn't" to the end.
I think fundamentally this is closely related to Betteridge's law.
Re:When I see "could" in a headline ... (Score:5, Funny)
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And quotation marks:
Headline: "British spaceplane will revolutionize space travel"
Intro: Some obviously biased guy somewhere said his spaceplane will revolutionize space travel.
Translation: we're terrible 'journalists' who lack the competence, fortitude and integrity to come up with a headline we actually stand by. If not, we'd have written a headline like: British company developing spaceplane.
We need more than Betteridge's law. We need Betteridge's law book.
Re:When I see "could" in a headline ... (Score:4, Insightful)
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Actually, blowing up people in an experimental aircraft should be a crime worthy of jail time all up the line, given that we could be blowing up autonomous piloting gear instead.
Re:When I see "could" in a headline ... (Score:5, Interesting)
I have followed Skylon for several years now. The engines are very interesting, in fact, the whole design, including the wings is very cool. The wings take the gravity load off, which for something that takes that long to get to orbit is quite an advantage.
They actually get more energy out of the hydrogen than they would get from just burning it. The reason is that they run the compressor on the temperature difference between ram air and the LH2 flowing to the engines. Burning hydrogen gives about 50 kWh/kg, it takes 20 kWh/kg to make it into a liquid.
You might note that everyone who has been given the full inside information, including the USAF, agrees that it will work as a SSTO. If anyone wants to build power satellites, Skylon is the only thing that is likely to get the cost to where power satellites could undercut coal.
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If anyone has studied the history of the UKs aviation and space industry will simply say I will believe it when I see it.
The modified rule has versions for battery tech or mass storage tech. I will believe it when it ships.
Re:When I see "could" in a headline ... (Score:5, Insightful)
I believe there is a quote from Arthur C Clark regarding this
"Every revolutionary idea seems to evoke three stages of reaction. They may be summed up by the phrases: 1- It's completely impossible. 2- It's possible, but it's not worth doing. 3- I said it was a good idea all along."
That's not to say that one should buy into every idea that someone is trying to peddle, but many of the technologies we take for granted today (aircraft, cars, PCs, engineered lumber, etc) were seen as prohibitively expensive, unnecessary and/or dead ends before they became widespread. Air breathing rocket engines of some sort are very likely to be the future of spaceflight, whether or not Skylon will be that future we will have to see.
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In the scale of things, it wasn't all that odd for the computer that I had in my house, counting all the peripherals, was more costly than my new car in the driveway. I think my first laptop was about $10,000 and had an external tape drive (that had an internal 40 MB HDD IIRC and used proprietary tapes), had a docking station, had an external modem, and I think it had an internal 40 GB drive as well as the ability to use an external monitor.
The PC on my desk was only slightly less expensive and I think that
Stupid article (Score:5, Interesting)
Skylon's idea is to use oxygen from the air, rather than taking the oxygen as fuel for the initial part of the ascent. A well known idea that is being worked on elsewhere.
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The two extremes are 1. shoot straight up out of the atmosphere, then straight tangential to the local surface (horizontal) and 2. Stay at sea level until you achieve orbital velocity, then head straight up. The space shuttle accent is closer to (1), popping out of the atmosphere t
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Stay at sea level until you achieve orbital velocity, then head straight up.
Hitting about 8km/s at sea level sounds hazardous to health.
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Skylon's idea is to use oxygen from the air, rather than taking the oxygen as fuel for the initial part of the ascent.
Skylon's stupidity is to insist on combining a jet and rocket motor, whereas the jet could be attached to a separate vehicle, flown back independently. Just leave the LN gear in the atmosphere, please.
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Whoops, I meant liquid helium gear, even worse. Think of all the party balloons that could be harmed.
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Welcome to the 1970 or so plan for the Space Shuttle. A flyback booster was in the original concept, but it didn't pan out. Now, materials engineering and manufacturing processes have improved dramatically since then, so maybe something is feasible today, but I have my doubts.
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Oxygen is only a small part of the possible advantage of an air breathing rocket engine. Reaction mass is a much larger advantage. Standard rocket engines have to carry all of their reaction mass. Jets carry only their energy source (fuel) and use the atmosphere and external oxygen as an additional reaction mass. I believe a 747 for example sucks in and expels over 5,000 lbs of air a second. That is why jet engines have such a major advantage over rocket engines in terms of Isp (specific impulse: IE fu
Re:Stupid article (Score:5, Insightful)
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They save mass that conventional rockets expend almost immediately in their flight, pay a big price in aerodynamic drag instead, and additionally pack on lots of extra mass in air breathing equipment and various HOTOL related structure that they then need to take to orbit. They compensate for that and for the efficiency losses of SSTO by claiming a structure and thermal protection system that are basically magic, and gloss over all the additional operational expenses. And no, they don't avoid the need for p
Re:Stupid article (Score:4, Insightful)
So let me get this straight; you think you have spotted a major flaw in their design that was not spotted by various governments, space agencies and aerospace companies that have thoroughly analysed this project? Have you done the sums and found that the precoolers have more mass than the oxygen saved? Have you worked out the losses due to drag?
I was talking about integrating stages, not payload. SpaceX still have to and always will have to do that. The TPS isn't magic either They are already talking to manufacturers about how to build it. Most importantly though is due to the aerodynamics of the vehicle it will have a much milder re-entry than the Space Shuttle, only needing the same kind of thermal protection it has in certain critical areas.
And no, SpaceX does not have a reusable vehicle that actually exists. They haven't yet recovered a first stage, never mind reflown one.
Please, could people actually investigate this project, its history and the major players who have invested in it before dismissing it out of hand based on intuition?
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Please, could people actually investigate this project, its history and the major players who have invested in it before dismissing it out of hand based on intuition?
Funded by the UK govt is all you need to know about them... ;^(
Of course the "visionary" behind this is Alan Bond whose major claim to fame is Project Daedalus [wikipedia.org]. I think that was some sort of contest winner (on par with Mars One)...
His previous actual efforts was HOTOL and that was canned by the UK govt before it got off the drawing board... Skylon is basically HOTOL-3 (HOTOL-2 was proposed, but it didn't even get past the proposal stage)...
Okay, my 2cent internet investigation is complete. Your turn...
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So let me get this straight; you think you have spotted a major flaw in their design that was not spotted by various governments, space agencies and aerospace companies that have thoroughly analysed this project?
Of course he does, this is Slashdot. Most of the blowhard armchair experts on here would look at that article and genuinely think they have some insight to offer that would steer the people working on this project better or get them to chuck it in. Simple arrogance of ignorance at work.
Re: Stupid article (Score:3)
Your thinking is akin to two grave diggers. One uses a shovel to cut the earth and remove dirt (Skylon) making it an easy job to reach 6', while
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Skylon is reusable? So was the shuttle. Skylon saves propellant? Propellant is cheap. Reusable and low propellant consumption are not the key factors - maintenance costs are. And how Skylon will fare in that regard is very much an unknown at this point.
Part of the problem with building these sorts of reusables is that they're such low volume that you never achieve economies of scales or significant stocks of parts, and have a lot more trouble refining the design with time. SpaceX's approach where the rocke
Re:Stupid article (Score:5, Insightful)
Once more, saving 250t of liquid oxygen is absolutely nothing to do with cost! Its to do with reducing the take off mass - which is what enables the performance required for SSTO.
Oh, and the Space Shuttle wasn't reusable, it was rebuildable.
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Oh, and the Space Shuttle wasn't reusable, it was rebuildable.
By that sense, so is any airplane. They still need to be inspected after a flight, and parts repaired and replaced on a continuing basis. I would say instead that it is a vastly lower quality of reusability with much higher cost and turn around time between flights than a normal airplane.
As to Skylon, I hear that even with air breathing engines, it requires a very efficient mass fraction better than any current rocket stage (with the stage filled with low density LH2).
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No, not at all. The Space Shuttle had to be substantially overhauled after *every single flight*. Airplanes don't. EasyJet for instance turns around a flight in under 30 minutes, which simply wouldn't be possible if it required more than a visual walk around by the crew between flights. I own an aircraft, and typically we only have to take things apart twice a year (and this is for an antique aircraft, too).
The Space Shuttle was not like this at all. It needed a full engine overhaul after every flight. The
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Oh, and the Space Shuttle wasn't reusable, it was rebuildable.
This is the best way of describing STS that I've ever seen. Not STS as it was designed, but rather STS as it was in practice.
And that was part of the problem: the orbiters were not designed to be disassembled as had to be done.
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Tankage mass is not generally that expensive, so reducing your tankage by reducing your propellant is not the huge money-saver you're envisioning. It's your engines and particularly all of the components that drive them that make rockets expensive. And Skylon involves totally new, rather complex engines that run in two different operating modes.
And really, you think Skylon engines wouldn't have to be taken apart, examined, and refurbished just like the shuttle engines? Like jet engines?
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Skylon's payload is comparable to that of the Falcon 9 V.1.1, but its engines are nonetheless still 70% the thrust of Falcon 9 V1.1 first stage. And a LOT more complex.
There's a number of other problematic things about Skylon. One is the very HTOL design itself. Rockets (including skylon) are cylinders under some degree of pressure - that's the natural shape for them due to wind resistance. This is a very strong design against loads along its length, not so much for loads applied by stubby wings in the midd
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On the contrary, propellant is damn expensive. Its mass winds up being most of the mass of the rocket, which you then have to lift.
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Carrying it around isn't.
That's why motor vehicles run on fuel that burns in air instead of a self-contained explosive despite such a thing being available in the late 19th century.
There is plenty on the net about using air when it is available and other things when it is not. Single stage to orbit sounds "simple" but requires moving a lot of leftover mass so why not use the best tool for the job in different conditions instead of a compromise? I don't know about this thing but the scram
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They aren't trying to save money on not needing as much LOX, the aim of taking a whole lot less LOX is that this can translate into increased payload and decreased vehicle weight.
Re:Stupid article (Score:4, Funny)
"They have a plan"
Even better - they have a cunning plan.
Only $240M? (Score:2)
Only $240M in funding? Last I checked, REL had specced the program as costing $12,000M.
This isn't even the first time they've gotten funding. They've gotten about $450M in several previous rounds. Did they pass some milestone to earn more funding or did they just get paid for the sake of not canceling the project? As far as I can tell the only component that's been tested is the intake air precooler.
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So where's their spaceplane? (Score:2)
SpaceX started in 2002; Reaction Engines Ltd started in 1989; SpaceX reached the ISS in 1012. Looks like Reaction Engines Ltd is 21 years behind, unless you count only their Skylon project, in which case it's almost 2 years behind.
Sorry. I'm massively unimpressed. Build something, already.
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LOX fueled rocket engines have been flying since 1926.
You're comparing "Tweak existing technology" with "Invent new technology"
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SpaceX reached the ISS in 1012.
Whoa, has Elon built a time machine?
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SpaceX started in 2002; Reaction Engines Ltd started in 1989; SpaceX reached the ISS in 1012. Looks like Reaction Engines Ltd is 21 years behind
You're forgetting that in 2024 Reaction Engines will steal SpaceX's time machine and use it to reach the ISS in 997 AD, beating SpaceX by 15 years. That will have, of course, triggered the time race between the two companies, which will have resulted in both going further and further back in time until they accidentally cause a mass extinction on Earth 66 million years ago.
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Re:So where's their spaceplane? (Score:5, Insightful)
Re:So where's their spaceplane? (Score:5, Insightful)
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So where is the flight hardware?
The flying prototype?
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So where is the flight hardware?
The flying prototype?
Parent is replying to a post that said they haven't made anything. "so where is the flight hardware" is a nonsensical response to that post.
They haven't finished it yet, so it's a waste of time - is that your argument?
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tlambert ridiculed the fact that RE is still in the lab/prototype phase after 25 years (note that he never claimed that RE has not built anything, just that their progress in 25 years is massively unimpressive).
EdgePenguin claimed that having tested a precooler in a lab is some kind of achievement.
I ask where the flight hardware &/or where the flying prototype is.
You falsely claim that "Parent is replying to a post that said they haven't made anything" & then misrepresent "no flight hardware" (in 25
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Building the hardest individual part and asking for more funding to make the full device, having shown that it works is a perfectly respectable strategy, unless you have a budget larger than most governments or can pull the whole thing of at once using magic, is that what you are asking for?
I thinnk the animation is the finished product. It indeed works pretty well.
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Re:So where's their spaceplane? (Score:5, Interesting)
If I remember correctly, Reaction Engines got severely dicked by the UK government (pulling funding declaring the engines covered by the Official Secrets Act), effectively ending private development.
The design was promising but had teething issues, and has been carried on as a garage project all these years.
That they've managed to get this far given the hurdles they've had to overcome is nothing short of astounding.
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That's a BAE/Rolls Royce project called HOTOL, which was co-created by the same designer. After HOTOL was canceled he started REL.
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Sadly, I don't think £120m is going to get them very far. They will need at least a billion to get this thing into orbit. 120M is just keeping some of the government's friends employed for another few years.
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Yes but they had to loop around the sun to do it :)
More seriously SpaceX is doing mostly what Grumman etc were doing earlier instead of something very different and they have more people as well as better funding than Reaction Engines.
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Not so fast (Score:4, Interesting)
Ultimately jet engines are just complex rocket engines that use outside air for the oxidizer. The reason commercial jet engines are more reliable, generally, is they aren't pushed to the very edge of what's possible, performance-wise, and they're produced in large quantities. But neither will be true for the Skylon SABRE engines. I don't see any reason to think they'll be any cheaper to maintain than the Space Shuttle Main Engines.
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Reaction Engines are not NASA, true. And as such they don't have any experience taking engines (of any sort) to space and back. And yes, other hydrogen engines have been cheaper. But they weren't designed to be reused, either.
It's not difficult to imagine an organization that can do things more cheaply than NASA. But just wishing away costs like that isn't going to work. Even assuming they get the damn thing to work at all, I will be shocked if their net $/kg figure is lower than SpaceX's.
Re:Not so fast (Score:4, Insightful)
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Your feelings aside, I think the reason most people don't take this project seriously is so far all they've actually produced is a pre-cooler.
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Re:Not so fast (Score:4, Informative)
Actually, the Skylon group predicted that the X--33 wouldn't work. They said that the X-33 was too tail heavy. And fixing it would mess up the payload fraction. And they were right.
It's difficult to get your head around just how far ahead these guys have been for about 20 years.
The ultimate reason is that they built a computer model of launch vehicles, which they fiddled with until they got a plausible vehicle. Then they did a back-back comparison with a pure-rocket vehicle, and found that there was no big advantage. Then they fiddled around more, and out popped Skylon, and then they found it *seriously* beats pure-rocket vehicles; it's not even close.
Skylon is looking at costs starting around $500/kg and then going lower. SpaceX won't be able to get down to that.
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Sure, at this stage of any project it's easy to be "looking at" very low costs. They haven't done anything yet. The nature of these kinds of projects is there are a whole bunch of costs, technical an regulatory, that aren't apparent until you actually start building something. The X-33 is actually pretty instructive - like REL, Lockheed Martin tried to pack a whole bunch of new technologies into a single program, and the failure of any of them would doom the program. And no, the X-33 didn't fail because
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This thing is going to be a whole lot more expensive than the sums they've penciled out. The only question is how much more.
Wow, predicting that a large and complex project will cost more than initially anticipated? You're all about the bold predictions. Now I know you're talking real sense. Go ahead, say they haven't built anything yet again.
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Actually, their team are were built from battle hardened rocket engineers, who had put stuff into orbit before.
I've looked at their design, been to lectures by them and asked questions. If it works, I will be absolutely gobsmacked if it isn't cheaper than SpaceX.
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No, more importantly than that they use outside air for the reaction mass, and this is what makes them so much more efficient than a rocket.
Ob. XKCD (Score:2)
https://xkcd.com/697/ [xkcd.com]
Skylon Pros and Cons (Score:3)
Pros:
A single engine that can transition from air breathing jet to scramjet to rocket, all the way from runway to orbit and back!
Cons:
A single ungodly complex engine that might transition from air breathing jet to scramjet to rocket, all the way from runway to orbit. Or not.
Cool idea on paper, but I see way too many moving parts over a huge performance envelope for me to believe this will ever be a robust engine. It just seems too complex to be a "fuel-up-and-go" engine. Looks more like a engine that would need to be torn down and inspected after every flight, assuming it works once. But best of luck to them all the same.
Re:Skylon Pros and Cons (Score:5, Insightful)
Wrong on multiple points
It never becomes a scramjet. Not being a scramjet is in fact the entire point behind the last few decades of research. You can either try to burn fuel in a supersonic flow through your engine (scramjet) or you can slow the flow to subsonic and compress it so the fuel can burn properly (ramjets etc.) - problem is, this compression superheats the air. SABRE dumps the excess heat into the cryogenic hydrogen the vehicle carries so that you can operate an engine at high Mach number without its insides melting.
As for too many moving parts; they precooler itself does not appear to have any moving parts. It needs a liquid helium cooling loop to connect it to the hydrogen supply, but that isn't overly complex. Everything behind that is well established jet/rocket engine technology. Even if you assume that each precooler + bypass is itself as complicated as enough engine, the spacecraft only has as many "moving parts" as an ordinary rocket with 4 engines. SpaceX happily flies a rocket with 9 engines and will likely be able to reuse its first stage in a cost effective way.
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SpaceX happily flies a rocket with 9 engines and will likely be able to reuse its first stage in a cost effective way.
I'll believe that when I see it. IMHO air breathing planes will never replace solid fuel boosters to get through the atmosphere.
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Re:Skylon Pros and Cons (Score:4, Interesting)
I've sometimes pondered the concept of a self-consuming rocket engine - basically infinite-staging.
Picture a spike (although the ideal shape would be different from an aerospike) comprised of small channels between aluminum - for example, assembled via fine aluminum wires or finely corrugated aluminum sheets, all the way through, thus leaving empty space between them. The wires or sheets would be joined together by having any surface oxide removed (or inhibited altogether by alloying agents), and heated enough in a non-oxidizing environment to braze them together. The channels would be filled with an oxidizer-rich polymer/ammonium perchlorate mixture (very mainstream as far as propellants go).
The engine would need to be lit off across its entire surface, so all channels ignite (or be designed such that neighboring channels ignite neighbors who fail to ignite).
The propellant mixture would burn down into the channels (as even fine aluminum wire/sheeting takes time to burn through) - lacking any area within the channels to expand into, it remains compressed and accelerates linearly as it moves through the channel (design parameters set such that the compression ratio achieved is the desired compression ratio for the engine). The angle of the channels would direct the stream largely along the spike, so that the gases expand along an ideal expansion profile for generating forward thrust. Since the entire spike would be comprised of channels, again, the ideal shape would be different form an aerospike; the exhaust gases don't simply come from the top.
As the oxidizer-rich propellant burns down, it progressively erodes the aluminum making up its channels (again, alloying agents in the aluminum may be used to help or hinder this process). Since the exterior ends of the channels would be exposed to the oxidizer-rich exhaust for the longest, they'd progressively burn down from their ends. Since the exhaust burns further as it flows (and the oxidizer would be more liberated), again the erosive potential of the stream would be highest near the end of the channels. So like a wick keeping pace with a candle as it burns down, the channels would be expected to erode away at approximately the same rate that the propellant burns down.
Aluminum metal is itself is a very energetic-burning compound - aluminum dust is often included in solid rocket mixes, so the erosion of the aluminum channels is a significant thrust contributor. Lithium-aluminum would be even better - lithium-aluminum is stronger than aluminum, and lithium is even more energetic than aluminum. It would also help neutralize the hydrochloric acid that occurs in most ammonium perchlorate-based solid propellants (although there are other techniques as well, such as burning magnesium and/or sodium nitrate with it).
In a naive implementation, the spike would change from the ideal shape to a progressively suboptimal shape as it burned down. But the rate of propellant burn and aluminum erosion could be controlled by tweaking the parameters of the system such that the areas of the spike you want to last longer can burn down slower than the areas you want to burn down faster. Hence the ideal spike shape can be retained as the engine burns down, all the way to right before it burns out.
Basically, your rocket would be... no rocket at all; just propellant. The entire thing is consumed. It'd be useless for orbital maneuvering**, but to get to orbit, the rocket equation likes nothing better than non-stop continuous staging with no tankage or engine mass at all (a caveat in this regard: your gimbaling system and interstage would still have to be sized for when it's at full size and max thrust). No complex systems at all. No exotic manufacturing techniques needed. No exotic, expensive materials. Just aluminum and a not-particularly-unusual solid rocket propellant. Getting the details of the mix right to ensure 1) even ignition, 2) even burndown, and 3) aluminum erosion at the proper rate would take research and experimentation, but I would e
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This is a hybrid rocket engine.
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As mentioned, it's contained within the aluminum channels. A sizeable chunk of the mass of the "engine"/propellant would be aluminum metal (whether wires, corrugated sheets, etc, brazed together), meaning rather tremendous total structural strength. Each individual channel has little strength, but on the other side of each channel is another channel - the outward-pushing pressure from combustion in one channel is countered by the opposite pressure from the adjacent channels.
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The spacecraft only has as many "moving parts" as an ordinary rocket with 4 engines. SpaceX happily flies a rocket with 9 engines and will likely be able to reuse its first stage in a cost effective way.
And you do realize that even these "ordinary rockets" still do explode, even though the basic technology has been around since the 1960s? See Orbital, see the SpaceX Falcon 9 CRS-1 mission. And even some of the simple "technologies" (tank support struts) fail in these operational extremes.
Every component, moving or not, has a non-zero chance of failure. More parts, higher failure probability. Put those parts into an extreme operating environment, probability of something unanticipated biting you in the ass
Re:Skylon Pros and Cons (Score:5, Informative)
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An easy way to reduce the cost of getting cargo into space is to not send humans in the same spaceship. Making a spaceship safe enough for humans is expensive.
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That's rockets for you. Anything other than solid fuel stuff gets bits added onto bits to even out what the first bit does.
Yes.
Save the humans (Score:2)
It should read "leaving this planet is the only way of saving ourselves". I'm pretty sure the Earth will be here long after any sign of us has vanished.
Skylon = SkyNet + Cylon? (Score:2)
Seems like a company we can trust with people's lives.
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Thanks - didn't turn up in my web searches (except for disambiguation #5 on Wikipedia) and considering I was born in the same year as Land of the Lost started it's not surprising I wasn't aware of the link.
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Nope, it's a reference to the 1951 Festival of Britain [wikipedia.org].
Well (Score:2)
It's the web equivalent of an infomercial, completele with the "Everything now sucks, SUCKS SUCKS!
"But we here at Skylon, we have the improvement needed to transform those sucky rocket based systems into a awesome never look back Skylon System!"
Which by the way, in no way eliminates those rockets they go way out of their way to tell us - suck.
Come back when your web page wasn't designed and populated by the Marketing department and some ad agency.
Video unavailable due to location (Score:2)
I'll believe it when it happens (Score:2)
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News flash (Score:2)
Here's hoping (Score:2)
50% more than LEO, TO BE EXACT (Score:5, Insightful)
To get to low earth orbit, a vehicle needs to be travelling at 17,400 MPH (7.7 km/s). If it travels just bit faster, 25,000 MPH, you can head off wherever you want to go in space. Orbit is 2/3rds of the way to anywhere.
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To get to low earth orbit, a vehicle needs to be travelling at 17,400 MPH (7.7 km/s). If it travels just bit faster, 25,000 MPH, you can head off wherever you want to go in space. Orbit is 2/3rds of the way to anywhere.
Nice numbers, except that's not the way it works. Higher orbits are SLOWER than low ones. And then there's oblique verses circular, which comes from the way you are pointed when you are accelerating. Seriously, Orbital math is hard.
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Put down the Star Trek, pick up the physics and reality 101. For your own good.
Larry Krause implied this but not in those words. In a presentation he mentioned amount of energy it takes to accelerate a federation starship is way more than the mass of the ship (E=mc^2). I tried some basic calculations using KE=1/2mv^2, my values seemed quite low. However the concept seems valid (examine amount of energy it takes to put a measley 3000 lb (mass) into LEO.
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1. Skylon? Terrible name, sounds stupid 2. Great idea and hope they get it off the ground, but it's going to take another 15-20 years before this thing is doing anything but R&D and test flights. Getting the funding is going to take them half that time.
It's even older than that [wikipedia.org]