RobGoldsmith writes "The TAAS Company have released details on their new Orbital Space Plane. The new design has many attributes to set it apart from its rivals. One highlight is the integrated Safety System; this is where an escape vehicle can eject from the main body of the craft then fly home safely. They claim: 'With the system's performance capability, economical first stage tow and independence from ground launch facilities, it can offer the lowest price. It also offers the safest flight.' Could this spaceship rival Virgin Galactic's SpaceShipTwo?"
Reader wooferhound points out related news from XCOR Aerospace (which we've discussedpreviously), that they're beginning to take orders for seats on their own suborbital flights, with test runs planned for 2010. Seats will be going for around $95,000 each, less than half the cost of the first tickets for SpaceShipTwo.
"The TAAS Company have released details on their new Orbital Space Plane."
Is the word "orbital" being used in some context I don't understand? This vehicle does not appear to be anywhere close to capable of reaching orbit. "Suborbital space plane," I can get behind.
From the article: "We discussed their plans to reach suborbital space and scale this up to orbital flights..."
They didn't go into any detail on the scale-up.
What was there about what little information given about the vehicle that suggests to you that the vehicle "does not appear to be anywhere close to capable of reaching orbit"? I'm not an aerospace engineer, but it seems like there's too little information to say how close it is.
Ah. Thank you for your deeply insightful and very informative response. I understand the design's failings much better now. In retrospect, even I should have seen them.
But mainly the lack of a heat shield would prevent them from ever achieving orbit and coming back in one piece.
Never mind the fact that it basically looks like a commercial private jet "re engineered for orbital travel" AKA just a bunch of snake oil. Where are the technical details besides the marketing jumbo?
Orbit required much higher speed than suborbital spaceflight. You don't just need to get high enough, you must also go fast enough to stay in orbit. The ISS for example is moving at 27,743 km/h
(17,239 mph). A modified jet with a rocket engine will just not have room for enough fuel, I think.
the article talks about the use of a tow plane. if they use the tow plane to get the space plane to high sub-orbital altitudes, then the rocket fuel stored in the space plane could be enough to help it reach low earth orbit. it's really not all that different from the launch methods used by X-15 or SpaceShip One.
besides, have you taken a look at the design diagram [robsastrop...aphy.co.uk]? nearly 2/3rds of the fuselage is taken up by the plane's two propellant tanks.
Yeah, I thought so too. The tanks take up most of the "space plane". And you just stick a rocket motor at the end of the it and it goes whoosh into suborbit ? Possibly it just occured to me that maybe your tow plane comment is the missing piece of the puzzle : they'll tow it into orbit and then let it go there ! Then it can fart around all it likes since the problem of getting into orbit has been solved ! (that's sarcasm for you sarcasm-impaired out there).
I don't see anything with this design that would allow for re-entry, which would rip off the wings of a normal airplane.
The sub-orbital designs by Armadillo, Scaled, and XCor at least show some resemblance to real vehicles that are intended to go into space and made by real rocket designers. Keep in mind that the real innovation that Burt Rutan made wasn't the fuselage of Spaceship one, but rather the "shuttlecock" system that allowed for atmospheric re-entry in a passive mode that would re-orient the spac
Well, it clearly wasn't RobGoldsmith's fault. The article does indeed claim this business-jet sized craft will reach orbit. The first stage would be a tow plane.
I'm just not seeing this. The tow plane can get the vehicle to a moderate altitude, but nowhere near orbital velocity (delta-v=20,000 km/hr, after drag?). You'd need a mass ratio of 10-to-1 on propellant ("easy" with a capsule that jettisons everything behind it; much harder with a space plane), and you'd have to be using something with an extraordinary Isp, around 320. That probably means cryogenic propellant. So this plane is made of cryo-compatible low-weight, reusable materials? Are there turbopumps on board? I don't see a rocket engine, I see a nozzle. OMS? Reentry heat shield? How do you restart your engine for a controlled reentry burn? Do you keep propellant in those tanks for that? Have you accounted for O2 slosh?
This just doesn't LOOK like an orbital vehicle. To build an orbital craft with that profile and no significant 1st stage would require ludicrous developments in materials science.
And his answers come across as insanely naive.
"Our proposed flight profile from launch to orbital insertion enjoys the same level of safety as conventional aircraft."
No, it can't possibly. You don't even have a prototype, so I can't even entertain such a statement.
"Towing aircraft is common and NASA successfully demonstrated towing a space plane."
NASA hasn't demonstrated a space plane, so how can they have demonstrated towing one? They may have demonstrated towing a REGULAR PLANE. It is true that NASA has launched orbital missiles from airplanes (not via tow, however, to my knowledge).
"One thought I had was that the complexity of this vehicle may actually cause more safety issues, I was told that its simplicity and reliability are un-matched in any other system."
Oh, well that settles that, then. Who wrote this?
"With regards to cost I was also told that a prototype would cost $4 million USD."
That won't even pay for your propellant. For reference, a new Lear Jet STARTS at $5 million. That's off-the-lot; all development costs behind it. So an orbital space plane costs less, including R&D than a Lear Jet? How about the tow plane? Does that come free?
"The design can easily be scaled up, both in terms of the first stage capability and the capability of the parent vehicle."
No, spacecraft do not "easily" scale up. You pick your target orbital payload mass/velocity and you do whatever it takes to get you there. You can't build an orbital, man-rated spacecraft, and then just multiply the entire thing by 1.3.
"The project is currently getting a team together and looking towards getting funding."
So, really, no design yet?
I read up a bit on Robert Talmage. His expertise seems to be in rescue/escape vehicles. I think this entire thing is a publicity stunt for his cockpit-jettisoning escape system (which is all they really talk about in that article; they don't mention fuel or engines once), which, for the record, seems to depend on lifting surfaces:
"After separation, the EV (which is designed to fly at higher dynamic pressures than the parent vehicle) will naturally pitch down and accelerate. Releasing the forward weight of the EV will cause the parent vehicle to be out of balance. With the center of gravity now well behind the center of lift, the parent vehicle will be unstable and pitch up. The high drag configuration of the unstable parent vehicle will provide good horizontal separation from the EV."
...so it wouldn't even work in orbit.
I'm sure Mr. Talmage has some hand-wavy answers to all of these questions, and I would LOVE to get my hands on a $4 million space ship. But I think it's safe to say this guy has his head in the clouds, not his hardware.
I agree with almost everything you say, with a couple minor exceptions. Mild cryogens like LOX and methane aren't at all hard to deal with, even in lightweight structures. Highly reusable carbon fiber tanks are still not readily available, but they appear to be within range of a reasonable R&D effort. Lightweight aluminum or fiberglass tanks are readily available. Hard cryos (LH2) are an entirely different story, because the insulation is difficult.
320 seconds vacuum Isp isn't a big deal for a close
single stage or single stage plus tow plane to orbit on a winged vehicle is not reasonable for the forseeable future
I wouldn't dismiss it out of hand. Getting from level flight at (say) 30,000 feet and 700 miles/hour (300 meters/sec) to low orbit is a very different proposition than getting there from a standing start on the ground. There's a lot less air resistance at that altitude for a start.
You need somewhere around 7 KM/second for LEO. The X-15 made about 2 KM/second, with a lot less fuel on board
I'm well aware of the numbers; I've looked at them in some detail. IAA Rocket Engineer, though trajectories and whole-vehicle performance aren't something I've focused on.
If you make grossly optimistic assumptions about mass ratios and engine performance, it's plausible. The problem is that 7kps is a *lot* harder than 2kps. If you don't require wings, then the problem isn't that bad. The original Atlas missile demonstrated the required performance. It had one set of tanks, a central engine optimized fo
You're right, the author is completely delusional about development costs, ground support, and a number of other things. I was speaking more to the general design problem, since the original article is so far off base as to not be worth much discussion.
Lox being heavy is a good thing. In general, tank mass is related to mass stored and pressure * volume. For pump-fed rockets the structural constraints are substantial enough that it taking less space (denser) doesn't help the tank mass that much, but it d
Nice to see the escape module. Bearing in mind that even NASA - and the Russians, Chinese etc. - have had some spectactular & sad blow-ups, it would seem likely that some of these less well resourced attempts will have the same. Shame there was not one in the shuttle - I seem to remember it was in the original proposal?
Neat idea also to tow the thing up, therefore avoiding the need for a special launch aircraft like Rutan's designs. Still, he did get there first, and this thing's only on paper...
On the other hand, escape modules of this type have been tried in aircraft and largely proved unsuccessful - mostly because they are very, very heavy and require a large parachute and a sophisticated deployment system.
Shame there was not one in the shuttle - I seem to remember it was in the original proposal?
The first four flights had modified SR-71 ejection seats, but they'd only be useful in the last stages of descent, and were only there because they were test flights.
Escaping from dying spacecraft is rather harder than it looks. It's only in the first 45 seconds or so after launch when a rocket's going slowly enough to eject from. Challenger broke up about 70 seconds into flight, at which point it was already travelling at over a kilometre per second --- and the breakup wasn't caused by the explosion; it was caused by the explosion wrecking the shuttle's aerodynamics to such an extent that it started tumbling, and then the hypersonic wind tore the vehicle apart. You don't eject into that. Most fighter aircraft ejection seats can only be used at speeds of 300 metres per second or so (although I'm sure someone can quote me something really esoteric that works at faster speeds).
The shuttle does have an escape protocol; you put the vehicle into a stable glide and jump out the door (using a frankly ludicrous system to avoid hitting that huge wing). They put that in after the loss of Challenger. It wouldn't have helped.
The best way of escaping during launch is to fire the entire crew capsule free. Mercury, Apollo, Soyuz and the upcoming Orion, if it doesn't get cancelled, all used/will use escape towers; a set of solid fuel rockets on the crew capsule designed to get the capsule clear of an impending explosion in a hurry. But they're intended to work on the ground, and get ejected about 50 seconds into the flight.
You might be interested to read up about Soyuz 18a [wikipedia.org]; the second stage hadn't separated when the third stage fired! The Soyuz capule was jettisoned, reentered normally, and landed safely. But that accident happened much later, when the whole vehicle was out of the atmosphere in a suborbital trajectory. Not having to worry about atmosphere makes things far easier.
Escaping on reentry is much harder. Columbia broke up while travelling at about *eight* kilometres per second, through atmosphere. I don't know of any way to survive an event like that.
At least one successful ejection has been made from an SR-71 at mach 3, which is roughly the speed that Challenger was doing when it broke up, assuming that your 1km/s figure is correct. The reason why this was survivable is because what kills an ejecting pilot isn't speed, but rather dynamic pressure caused by speed. Dynamic pressure increases with the square of speed,but it also drops off with altitude. Your 300m/s figure is correct, but that's assuming a sea-level ejection. If you're at a high altitude then the true speed goes up accordingly. (If you're familiar with aviation terms, it's the indicated airspeed that kills you, not the true airspeed.) I don't know how high Challenger was when it broke up, but if it was more than about 12 miles then it's conceivable that ejections from it could have been survivable.
Not to take away from your post overall, as you make many excellent points, I just wanted to elaborate on that one thing.
You might be interested to read up about Soyuz 18a; the second stage hadn't separated when the third stage fired! The Soyuz capule was jettisoned, reentered normally, and landed safely.
Except it didn't reenter normally. The LES fired, increasing it's downward velocity while it's lack of horizontal velocity meant a steeper than normal trajectory. The result was a high temperature, high G loading reentry.
In addition to your excellent response here is in regards to the Soyuz T-10-1 [wikipedia.org] launch that was the only realistic use of the launch escape tower as intended.
In that launch, the launch vehicle began to explode due to a fuel spill on the launch pad just a few seconds before the launch was supposed to happen.
As for the astronauts surviving re-entry from orbit for a situation like existed for the Columbia, about the only plausible method of survival would be some sort of personal extreme-altitude sky-diving suit
Nothing in the article on it being a Lear for sure, but they probably just picked something more or less at random. Here's a link to their website with more on the escape pod:
Sorry for being that cybernerdish-childish, but when I saw TAAS and space I immediately associated at Tessier Ashpool (yeah have all the books here but lazy to check the correct spelling) corporation from the Gibson books.:)
TAAS: Who? No matches to TAAS or Talmage when searching Personal Spaceflight http://www.personalspaceflight.info/ [personalspaceflight.info] or Encyclopedia Astronautica. The latter is particularly notable, as the NASA history office recommended it to National Geographic when they were looking for some historical data. TAAS apparently recognizes itself though: taascompany.com
Stability: "With the center of gravity now well behind the center of lift, the parent vehicle will be unstable and pitch up." All true, basic aerodynamics. Specifically AEROdynamics. This will be true in the atmosphere. If the vehicle is in the atmosphere, there's no reason to rely on structural aerodynamics, because the vehicle has control surfaces. A much safer ejection sequence would be to kick the capsule forward, lower the flaps for aerobraking, trigger any other brakes that may exist, lower the elevators to "nose" down the main vehicle. Bring it down and away from the capsule under control is far safer than hoping instability won't backfire and somersault the tail over and forward, into the capsule.
Wings and Reentry: "Wings are the most efficient means of air transportation and air-breathing engines are the most efficient form of propulsion. A vehicle that takes advantage of these two components will be the most efficient. The wings also play a role in orbital transfer maneuvres and reducing thermal loads during re-entry."
The fastest atmospheric speed ever achieved was Mach 9.6 by NASA's X-43. The "wings" were integral to the airframe. Nothing that pokes out from the body like those imagined for the TAAS thing would stay attached at anywhere near that speed. And nothing running at lower Mach could possibly make it outside enough of the atmosphere to accelerate to orbital speed unless it were carrying an enormous fuel load to make up for lack of lift since the wings wouldn't be working any more.
As for reentry, the wings would absolutely be a hindrance. The greater surface area (as compared to the body alone) would result in much more aerodynamic compression heating than any amount of radiative cooling that could possibly occur. Now, if they were to use the wings as ablative cooling, by having them absorb heat and then get ripped off by the high Mach forces, it might just bear itself out to be as silly as the rest of the article.
A couple details to put some of this in context: Low Earth orbit speed is around Mach 25. The temperature of the X-43's leading edges approached 4,000 degrees. The SR-71's reached 3,300 at Mach 3.3. The nonlinearity in the speed/heat comparison was due the the X-43 flying much higher (110,000 ft); less air, less heat generated.
If an airplane was a good design for an orbital vehicle, it would have been done already.
It isn't. As another poster pointed out, you will never reach escape velocity in a single-stage vehicle of that type. Also, wings might bring "aerodynamic stability", but pushing those wings at 17,000 mph through even thin upper atmosphere would be too much work and too much heat.
But this might be enough to do sub orbital. Pop up just high enough to call it space, and head back down again. The plan is not for orbital flight - but our early space program did just what these people are looking to do: an air launched rocket plane that glides back. These folks just need enough thrust to get to the appropriate altitude and return. Escape velocity, and the high mach numbers associated with reentry from that speed don't factor in. Tis probably much lower speeds than the early X-planes
Gosh. I find myself getting really riled up by this article. I work on the Shuttle External Tank, so I see every day how demanding, how difficult and precise manned space flight has to be.
I have a lot of respect for the suborbital tourism industry, and for SpaceX, since they're both doing very difficult things, too (getting a human to the boundary of space, and getting a payload to orbit without government funding, respectively).
And here, this guy just waltzes in and claims he can do all of that and more for a low, low cost of $4 million and a bad Photoshop of a Lear Jet with "rocket" and "propellant tank" drawn on the fuselage? Cripes!
Sounds like the initial Space Shuttle proposal in some ways. I actually read something like $100,000 per flight for "routine" Shuttle operations and a turn-around time of 1 week. But that goes back to the 1970's and was wildly optimistic before any real hardware was built, much less any real engineering design took place.
While I think that manned spaceflight can be a couple orders of magnitude cheaper than the Shuttle, there still is some basic physics that seem to be missing from this initial proposal by
I think you underestimate how much effort and attention to detail goes into the Russian spaceship/parts/program.
Spaceflight is very complicated, mainly because of the need to keep things as lightweight as possible, while still able to withstand very high temperatures and forces.
As far as the shuttle goes. It's design is deeply flawed due to the extreme requirements that were put on it, but as far as execution goes, it's still a marvel of engineering, almost 30 years later.
Manned space flight will have to be demanding and precise no matter who does it. You're right that the "difficult" part may have more to do with NASA than anything.
Otherwise, I totally agree. The shuttle was deeply flawed, and NASA is a deeply dysfunctional organization. But for all its flaws, the shuttle is real and not imaginary.
Of course, the shuttle has cost real dollars and real lives, whereas this fellow's fantasy ship hasn't hurt anyone and probably never will (because nobody would fund it). So I gue
Thanks for your work on the Space Shuttle!:) Sorry to see it go. I fondly remember the time when every Space Shuttle launch was broadcast on television!:)
I live in Germany!:) Here, in the 80ies, they interrupted regular programming for every shuttle launch and broadcast it live, from the preparations to the actual launch, often accompanied with interviews with NASA staff and scientists. Nowadays, shuttle launches aren't broadcast live anymore here, sadly, but at least we have Space Night every night on BR3 (a Bavarian television channel), they broadcast NASA footage all night every night. That's a lot of fun also!:) - I hope that NASA will get a foot into
Don't get me wrong, I'm not going to defend the ridiculous proposal in the article. For all its faults, at least NASA actually flies stuff! My only point is that experience with the Shuttle and what it requires does not necessarily convey to everything else.
The real problem with the Shuttle was simply that it was a $10 billion craft with a $5 billion budget. Everything else stems from that. If Congress had funded it more fully or if NASA had managed to realize early in the game that they were only going to
I can see the need for commercialized flights to sub-orbital and even to orbit.
But really, what's next after this? I'd like to be able to get to the ISS for a not insane sum, like MAYBE 200 thousand dollars.
But, failing that, OK, you're in orbit. Now what? I think that "space tourism" will only be genuinely successful is if there is a destination in orbit. The whole "space hotel" thing makes a LOT of sense in that it is a destination AND a safe haven if the vehicle can safely reenter.
In the anime Eureka 7, they would take their ship (the Gekko-go) into low orbit to travel across great distances faster. When you don't have to consider things like weather, turbulence, etc. you can travel a lot faster and a lot safer. I wonder how practical this is in reality.
You want to look at Bigelow Aerospace [bigelowaerospace.com]. By the time companies like XCOR and Virgin are offering orbital rides, Bigelow is quite likely to have an orbiting hotel for your destination. Note that Bigelow has a launch listed on the SpaceX manifest [spacex.com]. They're quite serious, and well funded. They don't always get as much press, because they don't make hot flamey stuff, but they're just as important.
So... all it takes to build an orbital space-plane is to mount a rocket engine on the back of a Lear Jet? I WANT MY TAX MONEY BACK NASA.
Apparently you don't even need the rocket *engine*, just a nozzle...
I remember drawing a lot of these kind of things about thirty years ago. I was ten years old and hooked on space stuff. The drawing would be based on something common, an airplane or a car, and I would put in neat little arrows pointing to all sorts of bizarre 'devices'.
Come to think about it; if my name was Shampoo I would have been famous...
Orbital? (Score:2, Informative)
"The TAAS Company have released details on their new Orbital Space Plane."
Is the word "orbital" being used in some context I don't understand? This vehicle does not appear to be anywhere close to capable of reaching orbit. "Suborbital space plane," I can get behind.
Re: (Score:2, Funny)
Re: (Score:2)
From the article: "We discussed their plans to reach suborbital space and scale this up to orbital flights ..."
They didn't go into any detail on the scale-up.
What was there about what little information given about the vehicle that suggests to you that the vehicle "does not appear to be anywhere close to capable of reaching orbit"? I'm not an aerospace engineer, but it seems like there's too little information to say how close it is.
Re: (Score:2)
Trust me, that vehicle isn't getting into orbit any time this century.
Looks more like a hack job to me.
Re:Orbital? (Score:4, Funny)
Ah. Thank you for your deeply insightful and very informative response. I understand the design's failings much better now. In retrospect, even I should have seen them.
Parent
Re: (Score:3, Insightful)
I know, my comments are filled with wisdom.
But mainly the lack of a heat shield would prevent them from ever achieving orbit and coming back in one piece.
Never mind the fact that it basically looks like a commercial private jet "re engineered for orbital travel" AKA just a bunch of snake oil. Where are the technical details besides the marketing jumbo?
Re: (Score:3, Informative)
Re: (Score:2)
the article talks about the use of a tow plane. if they use the tow plane to get the space plane to high sub-orbital altitudes, then the rocket fuel stored in the space plane could be enough to help it reach low earth orbit. it's really not all that different from the launch methods used by X-15 or SpaceShip One.
besides, have you taken a look at the design diagram [robsastrop...aphy.co.uk]? nearly 2/3rds of the fuselage is taken up by the plane's two propellant tanks.
Re: (Score:2, Insightful)
Kinda smell something funny in this one since if
Re: (Score:2)
I don't see anything with this design that would allow for re-entry, which would rip off the wings of a normal airplane.
The sub-orbital designs by Armadillo, Scaled, and XCor at least show some resemblance to real vehicles that are intended to go into space and made by real rocket designers. Keep in mind that the real innovation that Burt Rutan made wasn't the fuselage of Spaceship one, but rather the "shuttlecock" system that allowed for atmospheric re-entry in a passive mode that would re-orient the spac
Re:Orbital? (Score:5, Informative)
Well, it clearly wasn't RobGoldsmith's fault. The article does indeed claim this business-jet sized craft will reach orbit. The first stage would be a tow plane.
I'm just not seeing this. The tow plane can get the vehicle to a moderate altitude, but nowhere near orbital velocity (delta-v=20,000 km/hr, after drag?). You'd need a mass ratio of 10-to-1 on propellant ("easy" with a capsule that jettisons everything behind it; much harder with a space plane), and you'd have to be using something with an extraordinary Isp, around 320. That probably means cryogenic propellant. So this plane is made of cryo-compatible low-weight, reusable materials? Are there turbopumps on board? I don't see a rocket engine, I see a nozzle. OMS? Reentry heat shield? How do you restart your engine for a controlled reentry burn? Do you keep propellant in those tanks for that? Have you accounted for O2 slosh?
This just doesn't LOOK like an orbital vehicle. To build an orbital craft with that profile and no significant 1st stage would require ludicrous developments in materials science.
And his answers come across as insanely naive.
No, it can't possibly. You don't even have a prototype, so I can't even entertain such a statement.
NASA hasn't demonstrated a space plane, so how can they have demonstrated towing one? They may have demonstrated towing a REGULAR PLANE. It is true that NASA has launched orbital missiles from airplanes (not via tow, however, to my knowledge).
Oh, well that settles that, then. Who wrote this?
That won't even pay for your propellant. For reference, a new Lear Jet STARTS at $5 million. That's off-the-lot; all development costs behind it. So an orbital space plane costs less, including R&D than a Lear Jet? How about the tow plane? Does that come free?
No, spacecraft do not "easily" scale up. You pick your target orbital payload mass/velocity and you do whatever it takes to get you there. You can't build an orbital, man-rated spacecraft, and then just multiply the entire thing by 1.3.
So, really, no design yet?
I read up a bit on Robert Talmage. His expertise seems to be in rescue/escape vehicles. I think this entire thing is a publicity stunt for his cockpit-jettisoning escape system (which is all they really talk about in that article; they don't mention fuel or engines once), which, for the record, seems to depend on lifting surfaces:
I'm sure Mr. Talmage has some hand-wavy answers to all of these questions, and I would LOVE to get my hands on a $4 million space ship. But I think it's safe to say this guy has his head in the clouds, not his hardware.
Parent
Re: (Score:2)
I agree with almost everything you say, with a couple minor exceptions. Mild cryogens like LOX and methane aren't at all hard to deal with, even in lightweight structures. Highly reusable carbon fiber tanks are still not readily available, but they appear to be within range of a reasonable R&D effort. Lightweight aluminum or fiberglass tanks are readily available. Hard cryos (LH2) are an entirely different story, because the insulation is difficult.
320 seconds vacuum Isp isn't a big deal for a close
Re: (Score:2)
single stage or single stage plus tow plane to orbit on a winged vehicle is not reasonable for the forseeable future
I wouldn't dismiss it out of hand. Getting from level flight at (say) 30,000 feet and 700 miles/hour (300 meters/sec) to low orbit is a very different proposition than getting there from a standing start on the ground. There's a lot less air resistance at that altitude for a start.
You need somewhere around 7 KM/second for LEO. The X-15 made about 2 KM/second, with a lot less fuel on board
Re: (Score:2)
I'm well aware of the numbers; I've looked at them in some detail. IAA Rocket Engineer, though trajectories and whole-vehicle performance aren't something I've focused on.
If you make grossly optimistic assumptions about mass ratios and engine performance, it's plausible. The problem is that 7kps is a *lot* harder than 2kps. If you don't require wings, then the problem isn't that bad. The original Atlas missile demonstrated the required performance. It had one set of tanks, a central engine optimized fo
Re: (Score:2)
You're right, the author is completely delusional about development costs, ground support, and a number of other things. I was speaking more to the general design problem, since the original article is so far off base as to not be worth much discussion.
Lox being heavy is a good thing. In general, tank mass is related to mass stored and pressure * volume. For pump-fed rockets the structural constraints are substantial enough that it taking less space (denser) doesn't help the tank mass that much, but it d
Re: (Score:3, Funny)
Re: (Score:2)
Not much room, but good to see the escape module (Score:4, Informative)
Funny - looks a little like the original Learjet.
Nice to see the escape module. Bearing in mind that even NASA - and the Russians, Chinese etc. - have had some spectactular & sad blow-ups, it would seem likely that some of these less well resourced attempts will have the same. Shame there was not one in the shuttle - I seem to remember it was in the original proposal?
Neat idea also to tow the thing up, therefore avoiding the need for a special launch aircraft like Rutan's designs. Still, he did get there first, and this thing's only on paper...
Re: (Score:2)
On the other hand, escape modules of this type have been tried in aircraft and largely proved unsuccessful - mostly because they are very, very heavy and require a large parachute and a sophisticated deployment system.
Re:Not much room, but good to see the escape modul (Score:5, Interesting)
The first four flights had modified SR-71 ejection seats, but they'd only be useful in the last stages of descent, and were only there because they were test flights.
Escaping from dying spacecraft is rather harder than it looks. It's only in the first 45 seconds or so after launch when a rocket's going slowly enough to eject from. Challenger broke up about 70 seconds into flight, at which point it was already travelling at over a kilometre per second --- and the breakup wasn't caused by the explosion; it was caused by the explosion wrecking the shuttle's aerodynamics to such an extent that it started tumbling, and then the hypersonic wind tore the vehicle apart. You don't eject into that. Most fighter aircraft ejection seats can only be used at speeds of 300 metres per second or so (although I'm sure someone can quote me something really esoteric that works at faster speeds).
The shuttle does have an escape protocol; you put the vehicle into a stable glide and jump out the door (using a frankly ludicrous system to avoid hitting that huge wing). They put that in after the loss of Challenger. It wouldn't have helped.
The best way of escaping during launch is to fire the entire crew capsule free. Mercury, Apollo, Soyuz and the upcoming Orion, if it doesn't get cancelled, all used/will use escape towers; a set of solid fuel rockets on the crew capsule designed to get the capsule clear of an impending explosion in a hurry. But they're intended to work on the ground, and get ejected about 50 seconds into the flight.
You might be interested to read up about Soyuz 18a [wikipedia.org]; the second stage hadn't separated when the third stage fired! The Soyuz capule was jettisoned, reentered normally, and landed safely. But that accident happened much later, when the whole vehicle was out of the atmosphere in a suborbital trajectory. Not having to worry about atmosphere makes things far easier.
Escaping on reentry is much harder. Columbia broke up while travelling at about *eight* kilometres per second, through atmosphere. I don't know of any way to survive an event like that.
Parent
Re:Not much room, but good to see the escape modul (Score:4, Informative)
At least one successful ejection has been made from an SR-71 at mach 3, which is roughly the speed that Challenger was doing when it broke up, assuming that your 1km/s figure is correct. The reason why this was survivable is because what kills an ejecting pilot isn't speed, but rather dynamic pressure caused by speed. Dynamic pressure increases with the square of speed ,but it also drops off with altitude. Your 300m/s figure is correct, but that's assuming a sea-level ejection. If you're at a high altitude then the true speed goes up accordingly. (If you're familiar with aviation terms, it's the indicated airspeed that kills you, not the true airspeed.) I don't know how high Challenger was when it broke up, but if it was more than about 12 miles then it's conceivable that ejections from it could have been survivable.
Not to take away from your post overall, as you make many excellent points, I just wanted to elaborate on that one thing.
Parent
Re: (Score:3, Interesting)
Challenger broke up at 48kft (14.6 kilometers or 9 miles).
Ejections seats for Shuttle ascent were rejected on three grounds, none of them related to dynamic pressure:
--and--
Re: (Score:2)
Escaping from dying spacecraft is rather harder than it looks.
Never thought it looked easy, although Sigourney Weaver managed it...
More seriously, thanks for the post, and also to 128...interesting
Re: (Score:2, Informative)
F-111 had an ejection capsule which protected occupants at high speeds, up to the top Mach 2.5 speed
http://www.f-111.net/ejection.htm [f-111.net]
Re: (Score:2)
The B-58 also had separate ejection capsules that were supposed to work at Mach2+. That was 50 years ago.
Re: (Score:2)
Except it didn't reenter normally. The LES fired, increasing it's downward velocity while it's lack of horizontal velocity meant a steeper than normal trajectory. The result was a high temperature, high G loading reentry.
Re: (Score:2)
In addition to your excellent response here is in regards to the Soyuz T-10-1 [wikipedia.org] launch that was the only realistic use of the launch escape tower as intended.
In that launch, the launch vehicle began to explode due to a fuel spill on the launch pad just a few seconds before the launch was supposed to happen.
As for the astronauts surviving re-entry from orbit for a situation like existed for the Columbia, about the only plausible method of survival would be some sort of personal extreme-altitude sky-diving suit
Re: (Score:2)
Nothing in the article on it being a Lear for sure, but they probably just picked something more or less at random. Here's a link to their website with more on the escape pod:
http://www.taascompany.com/slide1.html [taascompany.com]
Looks like they've got a patent, which surprises me since there's plenty of prior art...
http://en.wikipedia.org/wiki/Escape_pod [wikipedia.org]
TAAS - Tessier Ashpool (Score:2)
Sorry for being that cybernerdish-childish, but when I saw TAAS and space I immediately associated at Tessier Ashpool (yeah have all the books here but lazy to check the correct spelling) corporation from the Gibson books. :)
sub orbital plane? (Score:2)
These guys are 50 years too late. It has been tried [wikipedia.org] before [militaryfactory.com].
The Deam Is Way Too Alive Sometimes (Score:3, Informative)
TAAS: Who? No matches to TAAS or Talmage when searching Personal Spaceflight http://www.personalspaceflight.info/ [personalspaceflight.info] or Encyclopedia Astronautica. The latter is particularly notable, as the NASA history office recommended it to National Geographic when they were looking for some historical data. TAAS apparently recognizes itself though: taascompany.com
Stability: "With the center of gravity now well behind the center of lift, the parent vehicle will be unstable and pitch up." All true, basic aerodynamics. Specifically AEROdynamics. This will be true in the atmosphere. If the vehicle is in the atmosphere, there's no reason to rely on structural aerodynamics, because the vehicle has control surfaces. A much safer ejection sequence would be to kick the capsule forward, lower the flaps for aerobraking, trigger any other brakes that may exist, lower the elevators to "nose" down the main vehicle. Bring it down and away from the capsule under control is far safer than hoping instability won't backfire and somersault the tail over and forward, into the capsule.
Wings and Reentry: "Wings are the most efficient means of air transportation and air-breathing engines are the most efficient form of propulsion. A vehicle that takes advantage of these two components will be the most efficient. The wings also play a role in orbital transfer maneuvres and reducing thermal loads during re-entry."
The fastest atmospheric speed ever achieved was Mach 9.6 by NASA's X-43. The "wings" were integral to the airframe. Nothing that pokes out from the body like those imagined for the TAAS thing would stay attached at anywhere near that speed. And nothing running at lower Mach could possibly make it outside enough of the atmosphere to accelerate to orbital speed unless it were carrying an enormous fuel load to make up for lack of lift since the wings wouldn't be working any more.
As for reentry, the wings would absolutely be a hindrance. The greater surface area (as compared to the body alone) would result in much more aerodynamic compression heating than any amount of radiative cooling that could possibly occur. Now, if they were to use the wings as ablative cooling, by having them absorb heat and then get ripped off by the high Mach forces, it might just bear itself out to be as silly as the rest of the article.
A couple details to put some of this in context: Low Earth orbit speed is around Mach 25.
The temperature of the X-43's leading edges approached 4,000 degrees. The SR-71's reached 3,300 at Mach 3.3. The nonlinearity in the speed/heat comparison was due the the X-43 flying much higher (110,000 ft); less air, less heat generated.
Re: (Score:2)
This thing won't orbit. (Score:2)
It isn't. As another poster pointed out, you will never reach escape velocity in a single-stage vehicle of that type. Also, wings might bring "aerodynamic stability", but pushing those wings at 17,000 mph through even thin upper atmosphere would be too much work and too much heat.
It'll never fly, Orville.
Re: (Score:2)
But this might be enough to do sub orbital. Pop up just high enough to call it space, and head back down again. The plan is not for orbital flight - but our early space program did just what these people are looking to do: an air launched rocket plane that glides back. These folks just need enough thrust to get to the appropriate altitude and return. Escape velocity, and the high mach numbers associated with reentry from that speed don't factor in. Tis probably much lower speeds than the early X-planes
Re: (Score:2)
The rest of the argument still holds, however. Materials would not hold up, nor would current chemical propulsion be adequate.
This proposal is irritating (Score:5, Interesting)
Gosh. I find myself getting really riled up by this article. I work on the Shuttle External Tank, so I see every day how demanding, how difficult and precise manned space flight has to be.
I have a lot of respect for the suborbital tourism industry, and for SpaceX, since they're both doing very difficult things, too (getting a human to the boundary of space, and getting a payload to orbit without government funding, respectively).
And here, this guy just waltzes in and claims he can do all of that and more for a low, low cost of $4 million and a bad Photoshop of a Lear Jet with "rocket" and "propellant tank" drawn on the fuselage? Cripes!
Re: (Score:2)
Sounds like the initial Space Shuttle proposal in some ways. I actually read something like $100,000 per flight for "routine" Shuttle operations and a turn-around time of 1 week. But that goes back to the 1970's and was wildly optimistic before any real hardware was built, much less any real engineering design took place.
While I think that manned spaceflight can be a couple orders of magnitude cheaper than the Shuttle, there still is some basic physics that seem to be missing from this initial proposal by
Re: (Score:2)
I think you underestimate how much effort and attention to detail goes into the Russian spaceship/parts/program.
Spaceflight is very complicated, mainly because of the need to keep things as lightweight as possible, while still able to withstand very high temperatures and forces.
As far as the shuttle goes. It's design is deeply flawed due to the extreme requirements that were put on it, but as far as execution goes, it's still a marvel of engineering, almost 30 years later.
I've did a master in material scien
Re: (Score:2, Informative)
Manned space flight will have to be demanding and precise no matter who does it. You're right that the "difficult" part may have more to do with NASA than anything.
Otherwise, I totally agree. The shuttle was deeply flawed, and NASA is a deeply dysfunctional organization. But for all its flaws, the shuttle is real and not imaginary.
Of course, the shuttle has cost real dollars and real lives, whereas this fellow's fantasy ship hasn't hurt anyone and probably never will (because nobody would fund it). So I gue
Re: (Score:2)
Re: (Score:2)
Re: (Score:2)
Re: (Score:2)
Don't get me wrong, I'm not going to defend the ridiculous proposal in the article. For all its faults, at least NASA actually flies stuff! My only point is that experience with the Shuttle and what it requires does not necessarily convey to everything else.
The real problem with the Shuttle was simply that it was a $10 billion craft with a $5 billion budget. Everything else stems from that. If Congress had funded it more fully or if NASA had managed to realize early in the game that they were only going to
Looks really old..... (Score:2)
I was first struck with how it looked straight out of the 50s X planes...the X-1 http://upload.wikimedia.org/wikipedia/commons/3/33/Bell_X-1_color.jpg [wikimedia.org]
Compare that to:
http://farm3.static.flickr.com/2238/2215031466_18acd44909.jpg [flickr.com]
Oh yeah. How did they get around the reentry stabilization problem? Or do they actually leave the influence of atmosphere?
Now, seriously. (Score:3, Insightful)
I can see the need for commercialized flights to sub-orbital and even to orbit.
But really, what's next after this? I'd like to be able to get to the ISS for a not insane sum, like MAYBE 200 thousand dollars.
But, failing that, OK, you're in orbit. Now what? I think that "space tourism" will only be genuinely successful is if there is a destination in orbit. The whole "space hotel" thing makes a LOT of sense in that it is a destination AND a safe haven if the vehicle can safely reenter.
Re: (Score:2)
Re: (Score:2)
In the anime Eureka 7, they would take their ship (the Gekko-go) into low orbit to travel across great distances faster. When you don't have to consider things like weather, turbulence, etc. you can travel a lot faster and a lot safer. I wonder how practical this is in reality.
Re: (Score:3, Interesting)
Re: (Score:2)
http://wooferhound.home.mindspring.com/ [mindspring.com]
Re: (Score:2)
So... all it takes to build an orbital space-plane is to mount a rocket engine on the back of a Lear Jet? I WANT MY TAX MONEY BACK NASA.
Apparently you don't even need the rocket *engine*, just a nozzle...
I remember drawing a lot of these kind of things about thirty years ago. I was ten years old and hooked on space stuff. The drawing would be based on something common, an airplane or a car, and I would put in neat little arrows pointing to all sorts of bizarre 'devices'.
Come to think about it; if my name was Shampoo I would have been famous...