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Blimps... In... Space...
LandGator writes "MSNBC reports a California company with an alternate launch site in Texas, JP Aerospace, is on their third test of a blimp system specifically designed to fly to space. Blimps. To Space. At payload costs around a dollar a ton to LEO. Their concept, first unveiled at the Space Access '04 conference in Phoenix last month (with a blog report here, include the Ascender, a ground-to-near-space blimp, which docks to a helium-inflated two-mile-long station at the edge of space, over 20 miles up. Another ship, also a blimp but specifically designed to reach orbit, takes the payload from there to LEO, using well-proven electric propulsion (AKA 'ion drive'). That trip to LEO would take up to nine days, but that's a good thing; for, what goes up fast, must come down fast, and speed is energy which must be bled off by either massive amounts of expensive and explosive rocket fuel, or through ablative heat transfer which has its own problems (as we have seen before). JP Aerospace has flown many PongSats -- micropayloads the size of a ping-pong ball -- for balloon or rocket-launch. Over 1,500 PongSats have flown to date, which demonstrates a track record in near-space few of the X-Prize contenders can approach. Oh, yes, the Air Force is interested."
Well, if they can truly get cargo to space at a single US dollar/ton, this is orders of magnitude cheaper than current costs which run approx $10k/kg. Which could very well result in a total destabilization of the space launch business. (a little chaos now and then is a good thing.....yes?). Of course we also have maglev and space elevators which could also provide this a run for the money, but I suspect maglev would be more expensive and due to helium costs, space elevators might be cheaper still.
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What's even more amazing is they have only been around since 2002. Going from start-up company to your 3rd test flight in that amount of time is.. well.. impressive.
Hmmm.
Eh? That's the coolest thing I've seen in a while, if it's at all possible. Kinda blows the x-prize away.
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Second, LEO isn't just *up*, it's also speed that keeps you falling back to earth. That kills the up-fast-down-fast idea. Are these space blimps (inflatible tech! Dr. Schlock would be proud) going to manage to accelerate a load from a relative standstill to LEO speeds using an ion engine (which has very weak acceleration) in just a few days? Unless I'm missing something, that doesn't seem very likely.
That aside: Cool idea. This sort of infrastructure wouldn't be as awesome as a space elevator would be, but it sure seems a hell of a lot more likely (cheaper, safer, possible without huge leaps in materials, etc). Once you're moving tons of material to orbit for a very small price (costs more to ship something across the ocean!), it seems like space exploration is ready to take off (no pun inte... oh, who am I kidding?) in a very real way.
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I can't way until they offer nine day cruises to near-space.
Imagine the view...
Seriously, this is a good stepping stone to space tourism.
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I'm sure they have thought this out, but:
Can you really accelerate a big inflated condom to escape velocity with an ion drive? I mean, it can only get so high on He, and I'm assuming that at its apogee there will still be an appreciable amount of atmosphere. Would an ion drive be able to overcome the drag force? Anyone willing to do the math?
Space elevators are something we will need better materials science to accomplish. Blimps we can do now. Space elevators also have a problem evading space junk and satellites, although I have read a proposal to introduce harmonics to the cable so it vibrates around them. I suspect that giant, slow moving blimps may have a real problem with space debris.
;-)
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They actually claim one dollar per ton per mile. And I'm sure that doesn't include accelerating it to an orbital velocity... So it's cheaper, to be sure... but not quite that cheap.
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That trip to LEO would take up to nine days, but that's a good thing; for, what goes up fast, must come down fast
What goes up fast must come down fast? Unless I'm missing something, low earth orbit still means going several thousand miles an hour. The rate you ascend at has nothing to do with how quickly you'd come down at.
AccountKiller
Recall in the very beginning where the Vickis are riding in a blimp where the bag is full of vaccum instead of any gas? It seems to be that this would be an elegant one-stage-to-orbit vehicle, since you don't have to worry about things like gas expansion.
Anybody care to take a guess as to what sort of advanced materials would be needed for this sort of structure?
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Hydrogen is half the density of Helium, not 1/4. And it wouldn't give anything like twice the buoyancy, either. If you're confused as to why this should be so, I recommend doing a little web research on the following terms: "monatomic gas", "chemical mole", "ideal gas law". "density of air".
-Mark
Folks, you can't just lift something up to a few hundred kilometers for it to be in 'orbit' -- you have to accellerate to around 8 km/s at altitude. Show me a blimp that can do THAT!
This isn't competition for rockets, it's an alternative for hoisting a sensor platform to an altitude which would serve as well as if it were in orbit.
If anything, should tools like this prove successful, there will no longer be a commercial or military need to lift heavy payloads into 'permanent' Earth orbit. If that happens, say goodbye to those space dreams.
You might very well be witnessing the beginning of the end of the space age.
That's a long trip- 9 days to go 100 miles or so. But at $1/Ton/Mile, I'm sure it would be possible to create a single-man spacecraft that could be attached to this launch system-say just a space suit, a titanium box, and enough food/water/air for 9 days.....
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A very readable John McPhee nonfiction book.
Synopsis: Zealots (both religious and technological) try to revive airships for use in inexpensive air transport, fail badly a couple of times, succeed technically on last dime, go broke. No one pays attention afterward.
Proponents were plagued by systemic resistance to lighter-than-air technology (in addition to many, many other problems.) Interesting accounts of how the last Navy airship pilots proved their ships were capable of much more than heavier-than-air -- just before the DOD pulled the plug on military LTA vehicles.
Well let's make a brief calculation Of course, atmospheric pressure is by area. "using the ISA standard sea level conditions of P = 101325 Pa and T = 15 deg C, the air density at sea level, may be calculated as: D = (101325) / (287.05 * (15 + 273.15)) = 1.2250 kg/m3 " so say we have an ultra strong and light material that is about as dense and strong as aluminum and is 2700 kg/m3. Wow that's a lot! So let's say our balloon is only 1mm thick, the balloon need about 2200 times the amount of volume the material used in vacuum to be able to float up. 2200 times the volume, we know that the volume of a sphere is 4/3pi*R^3, so we can take R and find cross sectional area. Now we have the amount of pressure exerted on ALL sides (proportional to cross sectional area), 14.7 pounds per square inch of pressure at sea level. The math is long and tedious, but basically we are talking about no material known to man, needing something 1000's of times stronger than steel which comes to the point that the forces applied at this strength would probably be actually tearing apart molecular bonds much less the actual crystaline structure of most structural materials, in short it is impossible.
As far as i understood until now the main cost to put something in orbit is to vainquish the gravity potential well. So if the "blimp" put you at the right altitude even if it is a slow-mo ascent, the only stuff you have to have afterward is a slighty ascending booster to finish putting the payload in orbit.
In other word you would only need to lift a far smaller rocket up there , orient it correctly, and have it put payload easily in space. Thus far less cost in needed boost overall. Am I missing something ? Is it a naive thinking ?
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If enough money is put into the project, we can start space industrialization in a year or three, we don't have to wait until we find out if the space elevator is actually possible, we don't have to build giant rail guns for cheap space launches if the Elevator is unworkable.
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You forgot to figure in the ion drive- which very slowly accelerates the blimp as it goes up. In addition, we're talking blimps, not balloons (rigid structure, not inflateable tech) which, supposedly, can handle the vaccuum. You're not at orbital velocity until you're already in near-vacuum.
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A big bag of Helium won't stay filled long in the low pressure environment. Probably half the trips would be to just keep the Helium topped off.
Figure a fully outfitted luxury passenger module, including oxygen and other facilities, is ten tons per passenger.
That's $200 per passenger to get to the "edge of space", or $9000 per passenger for low earth orbit.
Space cruises for civilians now become feasible.
Pretty exciting.
Finding God in a Dog
Helium _might_ make sense for the first leg of the trip, if only to placate the "But the Hindenburg!" crowd. But past a few dozen thousand feet, there's no point. As you said, there's not really enough internal overpressure for the incredible diffusive properties of H2 to matter so much, and there's not even enough oxygen around for it to combust with! You'd quadruple your payload capacity at a stroke. And both H2 and He have liquification points far below the temperature around LEO, so no worries there.
Dyolf Knip
Carbon nanotube ribbons as mentioned might very well work (not an endorsement on my part) for the tension loads, but you have to consider the wind loads and oscillations they will induce. Does the name Tacoma Narrows ring a bell?
Wind engineering is serious business for just this reason. If the profile of the tether increases drag (thereby reducing terminal velocity), there will be a corresponding increase in susceptibility to wind forces.
Consider the tethered balloons (aerostats) in various US locations.
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I don't know if anyone has noticed this, but at the "dark sky station" stationed at 100,000 feet up, since the station is floating rather than orbiting, there is no issue with zero gravity. Weightlessness is caused by the fact that an object in orbit is "falling" to the earth--and missing. But the "dark sky station" is not in free-fall; it's held aloft via bouyancy, and so workers on the "dark sky station" will experience full gravity. No problems with muscle atrophy.
Furthermore, it's not like poeple haven't flown up to 100,000 feet up in balloons; what becomes technically interesting is building a permanent or semi-permanent station as a balloon at that altitude.
The best part is that the worlds record for the highest skydive is above that altitude. So theoretically in the case of a catestrophic emergency, people could simply get into their skydiving space suits, and jump.
Beware the horrible approximations that follow. . .
Assuming. . . . 100 Tons of Blimp (1x10^5 kg)
Assuming. . . . The ion drives expend 0.1kg of fuel per second (absurdly high for ion drives).
Recall conservation of momentum.
Recall kinetic energy. (k = (1/2)mv^2)
Plug some numbers. . . We need a force of (F = ma = (1x10^5kg)(0.1m/s)) 10,000 newtons.
Rocket thrust is roughly (dm/dt)(V)
dm\dt = 0.1kg
V is dependant upon our accelerating potential, but must be high enough to give 0.1kg enough momentum such that 10,000n = (0.1kg)(V), v = 100,000 m/s. Luckily this is non-relativistic which makes life easier. k = (1/2)mv^2 = 0.5 * 0.1kg *100,000m/s^2 = 5x10^8j
To summarize.
In order for a 100 ton blimp, to achieve an acceleration of ~0.1g, and a fuel expendature of 0.1kg/s (360kg/hour -> 8.64 tons/day). It would require 500MW of power generation.
The moral of the story?
Ion engines are useful only for low thrust applications. If you want to drop the mass expendature of that engine further, it will require an unfortunatly large amount of energy to power the damn thing and get a large thrust out of it.
Building a better backup.
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