Let's hear your cheap launch strategies

[neutrino_cannon]

For the wide-eyed futurist, the costs of slinging things into space is one of the least promising things about space. Depending on how you decide to work out the numbers, launch costs typically work out to the tens of thousands of dollars per kilogram. There is the question of whether there's much economically worthwhile to do in space at all, but that's a question that will not get answered unless the launch costs come down.

So, if you were in charge of this sort of thing (tm), what strategies would you pursue to reduce launch costs? Dump the money into fullerene research to make a space elevator? Develop simpler disposable rockets? Look into piggybacking rockets onto aircraft?

Spell out your plans to herald the dawn of cheap space travel, and justify them. If you say a new, re-usable launch vehicle, I will laugh at you.

[bjornart]

I'd rather put energy into developing moon based production and launch stuff from there. If we can't do that, there's no reason for us to be in space anyway.

[neutrino_cannon]

I'd rather put energy into developing moon based production and launch stuff from there. If we can't do that, there's no reason for us to be in space anyway.

And how are you going to get to the moon smartypants?

[Snow]

And how are you going to get to the moon smartypants?

Hitch a ride with the Chinese ;)

[NobbyNobbs]

Build a Ringworld, spin it up to speed, and just drop vessels off the side.


Enormous initial investment. Practically free space travel after that.

[Ocelot]

Currently piggybacking rockets onto aircraft (possibly lighter than air options e.g ATO) appears to be the most feasable method of reducing cost for small payloads. Being a wide eyed futurist I do like linear accelerators, space elevators, photonic power delivery and suchlike.

[Jimcalagon]

Orion.
//en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)

Providing you get some nice clean nukes for the initial atmospheric launch phase - or that reimagined version (there was a video floating around the net) which used a couple of dozen Shuttle SRBs to get above the atmosphere - youtube video - youtube.com/watch?v=V1vKMTYa40A

[genesplicer]

Personally, I see the use of Linear Motor Propulsion as the way to go. (It is similar to the Electromagnetic Aircraft Launch System (EMALS) planned for Aircraft carriers.) By having a huge ramp loaded with the proper magnetic induction technology, it should be possible to accelerate a payload to orbital velocity with little difficulty. The initial cost would be high, but launch costs would be no more than fairing structure and energy to run the magnets.

[Corsair 115]

I'd suggest resurrecting the Delta Clipper/DC-X rocket project from the early 1990s. It appeared to have quite a bit of promise, and was built with off-the-shelf technology available at that time.

[BenBurch]

http://en.wikipedia.org/wiki/Sea_Dragon_%28rocket%29

[patnray]

Personally, I see the use of Linear Motor Propulsion as the way to go. (It is similar to the Electromagnetic Aircraft Launch System (EMALS) planned for Aircraft carriers.) By having a huge ramp loaded with the proper magnetic induction technology, it should be possible to accelerate a payload to orbital velocity with little difficulty. The initial cost would be high, but launch costs would be no more than fairing structure and energy to run the magnets.

I like linear induction motors, too. That would work great from the moon or Mars. Not so good from the Earth's surface though. But it could be used as a first stage.

[Fnord]

I favor the idea of constructing a linear mass accelerator on the Earth's equator. The 'business end' would face east to exploit the Earth's rotation.

Obstacles include, but aren't limited to, finding enough friendly real estate on the equator to construct a 20-kilometer long rail gun, funding it, and keeping it under the control of scientists and/or commercial interests without any government getting their hands on it and using it as a launch system for WMDs.

[Doubt]

I favor the idea of constructing a linear mass accelerator on the Earth's equator. The 'business end' would face east to exploit the Earth's rotation.

Obstacles include, but aren't limited to, finding enough friendly real estate on the equator to construct a 20-kilometer long rail gun, funding it, and keeping it under the control of scientists and/or commercial interests without any government getting their hands on it and using it as a launch system for WMDs.

I like that one too. But also add to the problem list you need it placed so that a launch failure does not end up hitting a populated area. The launch location probably needs to be at the edge of an ocean or desert.

[Fnord]

Something else I read a while back - the mass driver would require some form of superconducting material, and a nuclear power plant to drive it.

Nuclear Material + Mass Driver + (Pre-Emptive strike by the "good guys" OR a terrorist takeover by the "bad guys") == a lot of dead people and poisoned landscape.

[Ziggurat]

Something else I read a while back - the mass driver would require some form of superconducting material, and a nuclear power plant to drive it.

Why on earth would the power plant need to be nuclear? That might be a good option, but unless you're planning on mounting the whole thing on a mobile platform, it won't matter.

Nuclear Material + Mass Driver + (Pre-Emptive strike by the "good guys" OR a terrorist takeover by the "bad guys") == a lot of dead people and poisoned landscape.

A nuclear plant that's destroyed before it's fueled (ala Osirik) won't poison anything. A nuclear plant that's hit post-fueling will cause problems (but actually probably not a lot of dead people - you could kill more by blowing up chemical plants) regardless of what it's powering. And the kind of mass drivers envisioned for orbital launching would not be very ammenable for use as improvised weapons. They'd be VERY easy to disable should anyone try to commandeer them.

[Fnord]

I think the article talked about a "dirty" load using spent fuel rods and other waste from the reactor, rather than the fuel itself.

I really wish I could cite the original article. 'Sorry, all.

[AgeGap]

Arthur C Clarkes space elevator. Need to move Sri Lanka to the equator and develop a very strong thread.

[neutrino_cannon]

If the development of linear accelerators proves too difficult or too expensive, I'm rather taken with the approach the Canadian government elected (http://en.wikipedia.org/wiki/Project_HARP). Aren't there still some mothballed Iwoa-class battleships to poach guns from?

[bjornart]

And how are you going to get to the moon smartypants?

Use existing launch technology. No reason to spend billions on pipe-dream launch strategies if you're only going to launch 20 times.

[neutrino_cannon]

Use existing launch technology. No reason to spend billions on pipe-dream launch strategies if you're only going to launch 20 times.

And supposing that someone from Earth wants to get to the launch facilities so conveniently placed on their nearest natural satellite?

[The Man]

Slingshot

Just need a big ass rubber band.

[The Man]

But, seriously until “Big business” finds something profitable in micro gravity production, unfortunately, space tourism will be the only driving factor for American businesses.

[Dr. Trintignant]

My other favorites have already been mentioned, so here's an interesting but rather unlikely one:
http://en.wikipedia.org/wiki/Nuclear_lightbulb

It's a nuclear rocket with no waste products in the exhaust. Instead, it runs the reactor at a very high temperature and transfers energy to a working gas (hydrogen is one of the better choices) via UV radiation. The reactor is contained with fused quartz.

Beyond that, it's just an ordinary rocket. The hot gas shoots out the rear and the rocket goes up. But there's so much energy in the fuel that you can built in a lot of redundancy, and therefore safety. And of course it's also reusable, since there's more than enough fuel to use powered landings, DC-X style.

- Dr. Trintignant

[Myriad]

Why stop at a space elevator? Once you have the engineering problems solved, you can go on to build an equatorial rotor (using the earth as the stator) tethered to the moon for power generation.

Be aware of the downsides, though: if the rotor jams and the tether snaps, you have a problem of at least the magnitude of a major natural disaster; and the side effect of slowing the earth's rotation would make it imperative to move on to other space-based power technologies within a few centuries.

Respectfully,
Myriad

[Dr. Trintignant]

and the side effect of slowing the earth's rotation would make it imperative to move on to other space-based power technologies within a few centuries.

That seems unlikely. According to this calculation, the kinetic energy in Earth's rotation is ~2.5x10^29 joules:
http://en.wikipedia.org/wiki/Rotational_energy

And according to this page, annual world energy use is ~5x10^17 btus, or ~5x10^20 joules:
http://www.eia.doe.gov/oiaf/ieo/highlights.html

That is 500,000,000 years worth of energy at current rates. Even assuming massive growth in energy use, a couple of centuries would have an absolutely minuscule effect on Earth's rotation (especially since the velocity term in rotational energy is squared).

I suspect that the problem with your scheme is not in the amount of energy to be tapped :).

- Dr. Trintignant

[BenBurch]

Arthur C Clarkes space elevator. Need to move Sri Lanka to the equator and develop a very strong thread.

Ecuador has good geography for that.

[dahduh]

I would develop the cheapest possible solid rocket fuel, wrap it up in cardboard composite, and make standardized solid fuel boosters in volume so as to bring down production costs. I would then cluster these together into various launch configurations, put the guidance mechanisms at the top, and kick the whole thing to 3km/s @ 40,000ft (or thereabout) using a reusable jet-engine booster. I would then run like hell.

[Sunstealer]

As a materials engineer I'm obviously interested in the possibility of using carbon nanotubes to produce a space elevator which would be the best solution but I think a mass driver/railgun is more feasible given current developments. But you never know, we might come on leaps and bounds within the next few years.

[this charming man]

mac and cheese plus hotdogs

uhh what?

oh launch...sorry

[BenBurch]

dahduh,

Absolutely. Big Dumb Boosters is the way to space. Look at the Sea Dragon link I posted above; Truax was going to have the first booster stage built in a shipyard using shipbuilding techniques. It had no pumps; Just pressurize the tanks to a prescribed pressure before launch and as the pressure in the tank decays the thrust drops off, which is just what you typically want to have happen as fuel is burnt.

And I really do believe that it would be much, much cheaper than this Orion vehicle we are now committed to.

[R.Mackey]

I would develop the cheapest possible solid rocket fuel, wrap it up in cardboard composite, and make standardized solid fuel boosters in volume so as to bring down production costs. I would then cluster these together into various launch configurations, put the guidance mechanisms at the top, and kick the whole thing to 3km/s @ 40,000ft (or thereabout) using a reusable jet-engine booster. I would then run like hell.

There's quite a bit more validity to this position than you may realize...

There are several vehicles at or near deployment that push launch costs down into the $10M range for moderately sized payloads -- total cost is often more important that "dollar per kilogram." To wit, I could design an Orion for you that launched 1,000,000 tons at 100 dollars per kilogram, but you couldn't afford it. But I digress.

Most of the new wave of low-cost launch systems are dumb, constructed simply, and use (at least some) solid propulsion. Solids are preferred for low-cost launches primarily because of the ease of handling. You don't need a tank farm, you don't deal with so many cryogenic fluids, and your operations are much simpler. The tradeoff is that solid rockets are generally less powerful in terms of specific impulse.

The Rutan spaceplane uses an interesting "hybrid" fuel, basically a bed of rubber that is solid and relatively inert which reacts with liquid nitrous oxide. Because the combustion components are safe and inert, relatively speaking, the rocket's design is straightforward and hence inexpensive. This approach is not quite ready for prime time, but it's a good example of newer thinking.

Totally reuseable vehicles are not practical at the moment, though. Materials technology simply hasn't caught up. Simpler propulsion will lead to lower demands on materials, however, although there is still the problem of re-entry.

In the extremely long-term, it seems most feasible to me that we will develop power transmission methods of launch -- targeting extremely high-energy lasers or masers on ablative targets covering the underside of our "launch vehicles," perhaps a highly inert ceramic that generates thrust as it is melted away. The advantage here is that the main lift engine remains on the ground, and safety is nearly 100%. Such a technique is also scalable to virtually any size, provided the key challenges can be overcome. (The main challenge is how to get that much power through the plume, once the burn begins, followed by creating beams with that kind of efficiency.) It would, however, require an enormous capital investment, one that would only pay dividends after a fantastic number of launches.

At some point it isn't worth making the launch vehicle cheaper. The cargo itself has to come down in price as well. Rad-hard computing, precision instruments, maneuvering, tracking stations, software, testing and certification costs -- to say nothing of environmental control for crewed birds -- are still comparable to the cost of the launch vehicle. All this has to get cheaper too, or else we're already approaching the point of diminishing returns in launch costs (for uncrewed systems only). Of course, economy of scale will help here as well.

I don't believe space elevators will ever be practical. Orion doesn't strike me as practical unless we're faced with a one-time desperate need, though I know other professionals who disagree with me on this point. Railgun launch is a maybe, but I've never heard a good way to deal with the atmosphere -- you kind of have to launch from a vacuum.

NASA scientist, by the way, though opinions here are mine alone, as always.

[BenBurch]

R. Mackey,

Can you say much about the old Truax boilerplate booster idea? Yes, its a cryogenic oxidizer, but you don't have to build a launch pad for it, and you use a tanker ship to fuel it rather than a tank farm. In fact you would really only need to load the oxidizer out at sea as the RP-1 is stable.

And I suppose you could go to a H2O2 and RP-1 combination, lower your Isp, and dispense with cryo entirely, but 100% H2O2 fills me with dread as I had nearly killed myself with it in my teenage rocket building phase...

-Ben

[R.Mackey]

I only know a little bit about Captain Truax and the Sea Dragon concept, so take my commentary with a grain of salt...

You actually need more than a tanker ship. Liquid oxygen takes quite a lot of refrigeration. You will need a substantial tank farm somewhere, be it at port or wherever. The purpose of sea launching is to get the most favorable trajectory and assistance from the Earth's rotation, not to eliminate the ground processing problems. Those are actually made more difficult because now you have to unload a gajillion tons of liquid oxygen onto the ship, and then fuel the rocket from there, adding a new and somewhat hazardous step.

In terms of using pressurization instead of boost pumps to power the rocket, this concept has been used elsewhere, in some places with considerable success -- the Atlas (http://en.wikipedia.org/wiki/Atlas_%28missile%29) being the best-known example. Atlas is so thin-skinned that most of its structural integrity comes from being pressurized, and it cannot even support its own weight without positive pressure. Atlas also used LOX and RP-1, and is among the more successful launchers ever made.

We use pressurization in smaller systems, such as interplanetary stages on robotic probes, all the time -- typically using gaseous helium (GHe) as a driver gas. Safe and simple. Problem is that you lose efficiency, partly because now you have to lug around another tank, and partly because you don't dare lean out your engine. This is minor for an upper stage, where the relative size of the proplulsion system is small and precision is important, but it's hard to fathom a Saturn V-sized launcher without a positive flow system. The amount of propellant flow for a big launcher is almost unbelieveable.

The cost-to-lift claimed for the Sea Dragon is suspicious, but it's important to note that such figures naturally drop as one builds a bigger launcher. While Sea Dragon is out of family, so was Saturn V, and for largely the same reason.

Hydrazine and hydrogen peroxide are pretty dangerous, and we'd like to get rid of them completely. Probably won't happen for a long time. However, you have to keep this in perspective... the early Wehrner von Braun Mars concept (http://www.astronautix.com/craft/vonn1956.htm) called for hydrazine and pure nitric acid as its bipropellant!

[BenBurch]

Even inhibited Nitric Acid in a pre-passivated tank scares me to death.

But less so than 100% H2O2. (BTW I made my own in a freezer. I figure I had 98% concentration... Yes, I was immortal owing to youth.)

[Soapy Sam]

Atom bombs.

And if you're not nice, guess where we'll build the launch site?

[BenBurch]

Atom bombs.

And if you're not nice, guess where we'll build the launch site?

Then why build a spacecraft? We'll just fly the planet around.

[R.Mackey]

Even inhibited Nitric Acid in a pre-passivated tank scares me to death.

But less so than 100% H2O2. (BTW I made my own in a freezer. I figure I had 98% concentration... Yes, I was immortal owing to youth.)

As well it should...

I sympathize, by the way. A friend and I made an "engine" loosely based on the Me-163 propulsion system -- water-alcohol and hydrogen peroxide, using samarium as a catalyst. Ours was probably no higher than 85%, to be honest, but more than enough to be hazardous.

He entered it in a science fair project. The judges didn't believe him. He sent a nice, foot-long tongue of flame over the exhibit tables, and that was the end of that argument. Good times.

[BenBurch]

Here is a little story for you R. Mackey;

We used to own an old roadhouse out here in what used to be rural western Cook County, IL. We are Germans and so the place was known as a German place and we'd get many visitors from Germany into the place.

One evening my brother was tending bar and an old fellow ordered a beer and a hamburger and they started talking. My brother is a pilot and was reading "Flying" and he and the old fellow started talking about aircraft. And he revealed that he had been training to operate the Me-163 when the project ended and that he had flown the aircraft.

My brother asked him what it was like and he said "It was a kick in the pants."

[Loss Leader]

Have we absolutely given up on the existence of gravitons?

[Soapy Sam]

Shoot a grapnel into the moon, then climb up.

Or indeed, down.

[BenBurch]

Have we absolutely given up on the existence of gravitons?

Well, if Mass indeed does derive from the Higgs Mechanism, then you need a particle to mediate that transaction and that would be the Graviton.

But even if we can prove it is there, how can we *do* anything with that fact?

And you know, if you have a graviton, why do you need to have mass curve space-time? I've never been quite clear on that.

[BenBurch]

R.Mackey,

Did you ever run into Maxwell Hunter?

I've always liked his arguments in favor of developing an H2/F2-fueled launch capability.

I have had his little book "Thrust Into Space" since I was a sprout and it has guided my thinking on propulsion systems.

There are two roads to cheapness it seems to me; Big Dumb Boosters, like Sea Dragon, All-solid clusters, or OTRAG's system, OR making the smallest possible booster by using the highest possible energy chemical fuels. In the former case you build a crude but effective cheap rocket, in the latter you build a VERY complex, extremely carefully designed rocket that has to be PERFECT, but which is so much smaller than its conventional rivals that it is actually cheaper.

[Loss Leader]

Well, if Mass indeed does derive from the Higgs Mechanism, then you need a particle to mediate that transaction and that would be the Graviton.

But even if we can prove it is there, how can we *do* anything with that fact?

And you know, if you have a graviton, why do you need to have mass curve space-time? I've never been quite clear on that.


I don't know what the hell you're talking about. On Star Trek, they had gravitons.

[mhaze]

Even inhibited Nitric Acid in a pre-passivated tank scares me to death.

But less so than 100% H2O2. (BTW I made my own in a freezer. I figure I had 98% concentration... Yes, I was immortal owing to youth.)

You must be referring to a production process not a concentrating process.

[BenBurch]

You must be referring to a production process not a concentrating process.

No, you can make it in a domestic freezer at 20-30 below.

You start with 35% H2O2, freeze it, pour off the unfrozen liquor. Repeat with the product. You can get to a very dangerous 70% concentration with just this. I then further sparged the H2O2 using CO2 with terrible yield to get to get what I believed was 98%, but that is what I computed at the time and I was a kid...

Let me tell you a little about this stuff. I had some in a beaker and a loose hair fell in and it flashed into flame and the beaker cracked. And that beaker had just been decanted into a storage flask and only had about a ml in it.

This is when I stopped playing with H2O2.

[mhaze]

No, you can make it in a domestic freezer at 20-30 below.

You start with 35% H2O2, freeze it, pour off the unfrozen liquor. Repeat with the product. You can get to a very dangerous 70% concentration with just this. I then further sparged the H2O2 using CO2 with terrible yield to get to get what I believed was 98%, but that is what I computed at the time and I was a kid...

Let me tell you a little about this stuff. I had some in a beaker and a loose hair fell in and it flashed into flame and the beaker cracked. And that beaker had just been decanted into a storage flask and only had about a ml in it.

This is when I stopped playing with H2O2.

Sparging, I see now.

These are not to be done by amateurs.

The issue here was the stabilizers in the 35%.

[BenBurch]

These are not to be done by amateurs.


Amen.

Some day I'll tell you about the fulminating silver explosion I caused when I tried to silver a telescope mirror by the traditional method... Actually, thats all there is to tell. It went pop! and my arms were stained with black spots for weeks.

Yeah, I was stupid.

[R.Mackey]

R.Mackey,

Did you ever run into Maxwell Hunter?

I've always liked his arguments in favor of developing an H2/F2-fueled launch capability.


No, I'm not familiar with him. I'm not really a propulsion guy, although I am involved in some seeded-fault testing of solid and hybrid rockets this year...

I do, however, have some experience with H2 - F2 reactions. One of my professors (http://journals.cambridge.org/action/displayAbstract;jsessionid=04282E51C8455B8B1373325 78BEE5D3C.tomcat1?fromPage=online&aid=377592) at GALCIT runs a fascinating facility designed to study fluid mixing at high Reynolds numbers. Fluoride reactions are about the only chemistry that works fast enough to provide visual evidence of the effect. As a result, he kept a stock of HF gas on hand... Still not exactly what I'd call a "safe" propellant. :D

[Jimbo07]

At the risk of sounding like a broken record, I'll have to go with the space elevator.

;)

[TjW]

Mine's a little complex:
It involves a 747 or larger sized tug with a payout winch, a 10-20 km carbon-fiber cable, a high aspect ratio "launch platform", and the rocket to be launched.

The payload is placed on the launch platform, which is pulled aloft by the tug in a conventional aerotow. At the tug's service ceiling, the cable is paid out, allowing the launch platform to kite higher. If the launch platform needs additional true airspeed to climb (the indicated airspeed would be fairly low at high altitudes), the tug can turn, and the launch platform can play "crack the whip" by flying to the outside.
At maximum altitude (say, eighty to a hundred thousand feet), launch the rocket.
The cable is reeled in, and tug and platform land separately, the launch platform as a glider.

"Service ceiling" in this case would mean the altitude at which the tug's engines can still produce enough excess thrust to keep the launch platform climbing. With the cable extended, the tug could even start a shallow dive to trade off altitude for additional cable tension.

The advantage is that the engines are down where there's enough oxidizer to do some good without any terribly exotic design, while the launch platform is high enough to be out of a good portion of the atmosphere. The launch platform has some additional speed, though not much in terms of orbital velocity, and the whole assemblage can fly toward the equator during the climb to gain what advantage it can there.

[Myriad]

That seems unlikely. According to this calculation, the kinetic energy in Earth's rotation is ~2.5x10^29 joules:
http://en.wikipedia.org/wiki/Rotational_energy

And according to this page, annual world energy use is ~5x10^17 btus, or ~5x10^20 joules:
http://www.eia.doe.gov/oiaf/ieo/highlights.html

That is 500,000,000 years worth of energy at current rates. Even assuming massive growth in energy use, a couple of centuries would have an absolutely minuscule effect on Earth's rotation (especially since the velocity term in rotational energy is squared).

I suspect that the problem with your scheme is not in the amount of energy to be tapped :).

- Dr. Trintignant


I agree that it's not the only problem. But your assessment of the effect as miniscule is optimistic. With such an abundant and clean energy source, usage would increase dramatically. Let's say a hundredfold in the first century, and another hundredfold in the next century, with no further increases after that. Now it's 50,000 years worth of energy, and you're slowing the earth's rotation by about 1 part in 1000 per century, or nearly a second per year.

By then the nuisance of perpetual timekeeping errors would have been long since adjusted to (becoming significant to scientists by the end of the first century of use) but concerns about other side effects such as complete permanent breakdown of earth's magnetic field or other geoplanetary phenomena would make this far from indefinitely "sustainable." Much of the energy harvested would then have to be budgeted (or usage greatly increased again) to power the construction of the next energy supply, such as a solar power ring. (Which is also the logical first stage in ringworld building, so it fits right in.)

Respectfully,
Myriad

[Jimcalagon]

Is anyone familiar with the ATO - Airship To Orbit - idea being developed by JP Airospace - www jpaerospace.com ? Here is their description of the programme...

Balloons have carried people and machines to the edge of space for over seventy years. JP Aerospace is developing
the technology to fly a balloonor more accurately, their relative, the airshipdirectly to orbit.

Flying an airship directly from the ground to orbit is not practical. An airship large enough to reach orbit would not survive the winds near the surface of the Earth. Conversely, an airship that could fly from the ground to upper
atmosphere would not be light enough to reach space. The resulting configuration is a three-part architecture for using
lighter-than-air vehicles to reach space.

The first part is an atmospheric airship. It will travel from the surface of the Earth to 140,000 feet.

The vehicle is operated by a crew of three and can be configured for cargo or passengers. This airship is a hybrid vehicle using a combination of buoyancy and aerodynamic lift to fly. It is driven by propellers designed to operate in
near vacuum.

The second part of the architecture is a suborbital space station. This is a permanent, crewed facility parked at 140,000 feet. These facilities, called Dark Sky Stations (DSS), act as the way stations to space. The DSS is the
destination of the atmospheric airship and the departure port for the orbital airship. Initially, the DSS will be the construction facility for the large orbital vehicle.

The third part of the architecture is an airship/dynamic vehicle that flies directly to orbit. In order to utilize the few molecules of gas at extreme altitudes, this craft is big. The initial test vehicle is 6,000 feet (over a mile) long. The airship uses buoyancy to climb to 200,000 feet. From there it uses electric propulsion to slowly accelerate. As it accelerate it dynamically climbs. Over several days it reaches orbital velocity.

Low cost bulk access to space

Scaleable Technology.
True reusability, multiple orbital flights before servicing.
Large structures can be placed already assembled in orbit.
Brings safety and reliability to reaching space.
Both the climb to orbit and reentry are slow controlled processes. No high reentry heating, no big fuel tanks to explode.

Opens up the solar system.

Once in orbit, the airship is a spacecraft. With its solar/electric propulsion, it can now proceed to any destination in the solar system.

It is happening now.
This is not fanciful speculation. The project is now over two decades in development with over eighty real hardware test flights and countless development tests. It is being built completely with existing technology.

It’s being built now.
The high altitude airship has been built and is awaiting test flights. Several Dark Sky Station platforms have been built and flown. Every piece of equipment for this system has been carried to 100,000 feet and tested in the environment.
The first crewed DSS is scheduled to fly in eighteen months. The ion engine 120,000 foot flight test for the orbital airship will be flown in the next five months.

It’s being paid for now.
This new way to space has not and will not require a massive pile of capital to accomplish. Each component has its own business application and funding source. It is a pay-as-you-go system. For example, funding the atmospheric
airship was provided by the Department of Defense for use as a reconnaissance vehicle. The DSS has multiple customers in the telecommunications community.

When?
We are seven years from completion.

It sounds feasible to me but then I'm not an expert.

There is a pdf detailing the program - www jpaerospace.com/atohandout.pdf

Any thoughts?

[R.Mackey]

140,000 feet is not "low orbit." It's well below the Karman line. While it may have the altitude to be considered "in space," it doesn't have the velocity to maintain orbit, and therefore is not "in orbit."

That's why actual satellites are higher. To stay "in orbit," they need to be going much faster. Going much faster at that altitude means tons of drag and a rapid descent back to Earth. So we boost them higher, about 400 km is the minimum.

Whether or not this concept is useful depends on what you want to do. A lot of commercial applications don't really need to be in orbit. Extreme-altitude UAVs make arguably better surveillance platforms than satellites, for instance. But this concept cannot be confused with spaceflight.

The only benefit to spaceflight would be if this "platform" could be used to launch an actual rocket. I'm skeptical of this point. Floating that much infrastructure does not sound economically feasible.

ETA: Using that plus solar-electric propulsion to float small payloads up to actual orbit is barely possible... the problem then is that to get more propulsion, you need larger solar panels. Larger panels means more drag. More drag means you need more propulsion. In other words, might be economical for a narrow range of small satellites, but will not scale to big birds.

Oh, and the type of solar-electric propulsion they're talking about doesn't work outside Earth's magnetic field.

[bjornart]

And supposing that someone from Earth wants to get to the launch facilities so conveniently placed on their nearest natural satellite?

Unless it's worth it to send up them up the expensive way, they'll be sod out of luck. We're at the bottom of a serious gravity well, and getting out of it is never going to be something we do cheaply.

[BenBurch]

What we really need is a very, very lightweight and strong superconducting electrical cable. Then your orbital vehicle is a hypertrophied resistojet with a cable reel it is playing out behind itself, and it can actually have an amazing Isp.

None of this solar butterflies nonsense!

[RecoveringYuppy]

140,000 feet is not "low orbit." It's well below the Karman line. While it may have the altitude to be considered "in space," it doesn't have the velocity to maintain orbit, and therefore is not "in orbit."
They referred to 140,000 feet as suborbital not low orbit. They propose launching a second craft from that station.

Oh, and the type of solar-electric propulsion they're talking about doesn't work outside Earth's magnetic field.
Where did you see enough of a description to make that judgement?

[R.Mackey]

They referred to 140,000 feet as suborbital not low orbit. They propose launching a second craft from that station.

My point is that the 140,000 foot platform is not really "suborbital," either. It lacks cross-range velocity. Standing on top of a 140,000-foot tower would not make one suborbital, and that's basically what this is.


Where did you see enough of a description to make that judgement?

I did not. I extrapolated from what else I know of solar-electric propulsion. And so, I may be wrong. Your objection is completely fair. Let me explain.

Ordinary solar-electric propulsion takes the form of an ion engine -- we just built one for the Dawn mission. Hughes and Lockheed have used them for years to boost commercial satellites in the form of xenon ion thrusters and arcjets; in the latter, monomethylhydrazine is burned and accelerated electrostatically, a mixed-mode thruster. More recently, Hall Effect thrusters are all the rage. You can burn these thrusters for weeks, building up a lot of momentum, a tiny tiny tiny bit at a time.

Now, all of these systems have high specific impulses, but very low thrust. To lift from a balloon, you're going to need a substantial amount of thrust. The minimum thrust is either equal to the spacecraft's weight (after buoyancy becomes negligible), or equal to the atmospheric drag created by the spacecraft and it's buoyancy assist -- which will be huge. Otherwise, your spacecraft has no hope of gaining altitude or gaining orbital momentum. I just don't see this happening with current ion engines, with the possible exception of the horrendously expensive VASIMIR.

So, I assume these folks -- if they're serious -- have come up with a system that essentially enhances buoyancy. They need a system with little or no reaction mass, and one that allows the spacecraft to float even higher than the balloon limit, but one that also can provide orbital momentum once the drag decreases further.

My solution is a magnetic sail, also known as tether propulsion. It can be run forever using solar power, provided your tether or wiring doesn't get hit or arc out, and provides comparable thrust to most ion systems currently in use. This approach actually does work in the solar wind as well, though it works far better in Earth's magnetic field. There have been some experiments but nothing really practical with this technology.

The text above actually does suggest ion thrusters instead, but as I stated before, I don't see this working. The consumable load would still be considerable, even if they have a very high powered ion engine in mind. On the plus side, perhaps they can recycle their helium as propellant...

I'd be interested to find out more. It seems awfully far-fetched to me, but I've been wrong before. :D

As always, all opinions mine alone, I do not speak for NASA, this post written on my own time with my own materials, void where prohibited, discontinue if headache persists.

[Gravy]

Ordinary solar-electric propulsion takes the form of an ion engine...[snip]

In fact, JP Aerospace does intend to use ion engines to get to orbit, as quoted above. (Edit: I see that you noted this)
The ion engine 120,000 foot flight test for the orbital airship will be flown in the next five months.Allow me to coin the term "failballoon."

After poking around their site and Googling for a while, I see no data or opinions from other aerospace experts like yourself that indicate that this idea is feasible from engineering or economic standpoints. Their list of sponsors (http://www.jpaerospace.com/sponsor_pg.html) does not inspire confidence that they'll meet their 7-year projection.

Still, I enjoy learning about ambitious private projects like this, and I hope their successes and failures are educational.

[R.Mackey]

Still, I enjoy learning about ambitious private projects like this, and I hope their successes and failures are educational.

Absolutely. I'm glad someone is trying this, although I hope they've crunched a few numbers.

If it so happens that they have come up with an ion engine with huge ISP and raw thrust, if it works, and if it's even moderately affordable, this would be a boon to the robotic science community (my folks). I hope it works, I just know it's a tough, tough problem.

[Dr. Trintignant]

But your assessment of the effect as miniscule is optimistic. With such an abundant and clean energy source, usage would increase dramatically. Let's say a hundredfold in the first century, and another hundredfold in the next century, with no further increases after that.

Hmmm. Do we really have uses for a 10,000-fold increase in energy? It seems likely that there is, at most, roughly another doubling of population in store. And bringing the world up to America's energy usage gives you maybe another factor of 5. So that leaves another factor of 1,000 over and above the average American.

Is that reasonable? Maybe my imagination isn't big enough, but even assuming regular space tourism, that seems like a lot. It may even be too much for the biosphere to sustain, though I guess Trantor-style heatsinks are possible.

So maybe the most natural use for that kind of energy is off-world megaengineering. In which case, constructing the next stage in energy production would be an obvious choice.

- Dr. Trintignant

[Jimcalagon]

My understanding of the JP Aerospace proposal is - a propeller driven airship, using a combination of lift derived from buoyancy and aerodynamic design, ferries cargo/passengers to a platform 140000 feet up. This platform is not orbital, just a high altitude transfer facility - some pressurised rooms suspended from balloons in essence. The research into these stages is being funded by bodies like the US Military who are interested in high-altitude observation/communication platforms.

The passengers (or cargo or whatever) are transferred from the platform into another airship. This airship is designed solely for very high altitude operation (i.e. very low atmospheric pressure) and could not operate down to sea level, which is why the transfer platform is necessary. The high altitude airship then ascends from the platform and accelerates gradually to orbital velocity over a period of five days using ion engines.

As I say, it sounds to me as though it might be feasible but I'm pretty much a layman. My concerns about whether it would work concern the high-altitude airship - would the ion engine(s) provide enough thrust to accelerate the airship against the resistance of the (admittedly quite tenuous at this altitude) atmosphere?

Surely there will be some point where the airship can't ascend higher because the atmosphere won't support it - are they going to bob along at this height accelerating gradually until they reach an orbital velocity? Won't they start tracing a series of shallow parabolic arcs when this happens - dipping deeper into the atmosphere and losing velocity to air resistance?

One thing is for sure - it's not rocket science!

[Michael Redman]

Ecuador has good geography for that.That's what I was thinking. Not only the equator, but at high altitude, so you can avoid most of the atmosphere.

[Michael Redman]

My idea: giant steel spring. Works both ways, too. You can use it to capture the landing craft safely, and reuse the energy on the next launch.

[Michael Redman]

Hmmm. Do we really have uses for a 10,000-fold increase in energy? Did we find a use for coal and steam?

I want a car that weighs 10,000 pounds and can drive 400 MPH.

I want a personal HVAC system build into my clothes.

I want windows made out of synthetic diamond.

I want to destroy documents containing private information by launching them directly into the Sun from my back yard.

I'm an American. Give me the energy. I'll use it.

[Myriad]

Hmmm. Do we really have uses for a 10,000-fold increase in energy?


That's a good question. I admit I hadn't thought it out very thoroughly, and I don't plan to do any calculations. However, there are a few areas besides space engineering where I can imagine greatly increased per capita energy use might have benefits.

Massive-scale desalination.

Replacement of all manufacturing processes that currently use high-energy (and generally nonrenewable) substances as raw materials with synthesis from basic molecules.

Personal flying vehicles (which would most likely be somewhere near Michael Redman's numbers).

Universal implementation of "perfect" waste processing systems (let's say, perfect enough for long-voyage spaceship use), with total breakdown of all organics and complete isolation of all reusable elements and all harmful by-products (e.g. traces of mercury removed and purified into elemental mercury instead of released as toxic compounds).

Thermostats set to 75 degrees F all winter!

The basic idea is to leave the biosphere alone as much as possible, such as by using desalinated water for irrigation and public water supplies instead of taking it from rivers, using flying vehicles instead of building more roads, etc. Those things are technically possible but can't do any good at present because the environmental cost of the energy required exceeds the environmental benefits.

But you're right, terraforming-scale refrigeration (with radiators) might be needed to deal with the excess heat (or, just for mitigation of already existing global warming), and that would use a good chunk of the power.

Respectfully,
Myriad

[Dr. Trintignant]

Some interesting possibilities... (gonna combine posts here).

Roughly speaking, a 1000-fold increase in energy use means 10 MW per capita (it's roughly 10 kW for an average American today). With that in mind:

Did we find a use for coal and steam?

We did, but consider this: just for basic survival, a human needs about 100 watts to survive. Millenia later, we're still only using 100 times as much. Can we two more factors of 100 in much less time? Maybe, but I don't really know.

I want a car that weighs 10,000 pounds and can drive 400 MPH.

How many horsepower do you need for that? 2,000, perhaps? That's about 1.5 MW. That's a pretty good chunk of the total, but surely it won't be used continuously.

I want a personal HVAC system build into my clothes.

Again, the human body uses around 100 watts. Cooling that should take a comparable amount (besides, you couldn't safely radiate much more than a few hundred watts long-term).

I want windows made out of synthetic diamond.

Sounds good, but once we get pretty good at it, the cost shouldn't be that much more than any other bulk chemical made from cheap materials.

Massive-scale desalination.

Current water use is about 5,000 liters/capita/day in the US, including agriculture--given current desalination technology, this is about 2 kW continuous. So not enough to make a dent. And I can't think of too many uses for massively increased water use (Americans eat enough as it is...).

Replacement of all manufacturing processes that currently use high-energy (and generally nonrenewable) substances as raw materials with synthesis from basic molecules.

This one's pretty hard to estimate. Ideally, the energy use would approximate the chemical binding energy of whatever you were trying to manufacture. I suppose an appropriate analog is the amount of fuel we burn currently. If we burn it now, we should be able to manufacture it with the appropriate molecular manufacturing tech for the same energy cost, roughly speaking. 3.5 tons per year of coal are burned per capita, per year--so it seems likely that we could get the same amount of "stuff" in return for the same cost. But I don't know how much stuff we can use in a year.

Those things are technically possible but can't do any good at present because the environmental cost of the energy required exceeds the environmental benefits.

Agreed. However, I expect that the cost may not be as much as you think. It may even be that efficiency improvements prove more important than increase in energy in the long run.

Though now that I think about it, weather control seems like an interesting idea. And that is most certainly a high-energy project.

- Dr. Trintignant

[MRC_Hans]

I favor the idea of constructing a linear mass accelerator on the Earth's equator. The 'business end' would face east to exploit the Earth's rotation.

Obstacles include, but aren't limited to, finding enough friendly real estate on the equator to construct a 20-kilometer long rail gun, funding it, and keeping it under the control of scientists and/or commercial interests without any government getting their hands on it and using it as a launch system for WMDs.I think the worst, and probably fatal, problem for an earth-based kinetic launcher is air resistance. As the space vehicle would have to leave the launcher at escape velocity and at a low altitude, and would even have to follow a tangential path (i.e. not the shortest path to space), it would have to travel a considerable distance through dense atmosphere at some 12km/sec. Constructing a vehicle that could survive this will be a far harder challenge than building the launcher itself.

Of course, this problem does not apply to a launcher on the Moon, where there is no atmosphere, and to a much lesser degree on Mars, where the escape velocity is lower and the atmosphere much less dense, however, even here, 5km/sec in 0.01 Bar of atmosphere is no joking matter!

Personally, I think airlifting to the edge of the atmosphere and rockets from there is the way to go, for the foreseeable future.



Hans

[uruk]

At the risk of sounding like a broken record, I'll have to go with the space elevator.

;)

How come nobody ever supports my space escalator system?

[TjW]

Wow. You wrote "Stairway to Heaven"?

[RecoveringYuppy]

Dump the money into fullerene research to make a space elevator?
Several people have voted for the space elevator option and I've got to wonder how anyone can know it's going to be cheap. Too many breakthroughs required to estimate a cost.

Even before the cost of the currently speculative materials required, construction costs running above 10 billion dollars are frequently cited for an elevator that can launch 10 tons to geo every two weeks. Those number don't really suggest low cost or high volume. They work out to about $2,000 dollars per pound just to recover the capital cost.

Develop simpler disposable rockets?

This would be my first option. And I'd add "built in countries with low labor costs".

[NoZed Avenger]

Can we just pretend that the "Let's hear your cheap lunch strategies" thread has already been done?










Oh. On topic. Cannons. The big, big ones like the ones that were being kind of developed in Iraq before the first Gulf War. Gradual acceleration through charges being used along the length, with the majority of costs being receoverable and reusable many, many times.

[uruk]

Wow. You wrote "Stairway to Heaven"?

As a matter of fact it plays continualy on the musak system.

I am still working out the bugs in the handrail to stair synchronization.

[BenBurch]

NoZed - Doctor Gerald Bull's space guns could have worked. No reason that they couldn't have, but the very high acceleration puts serious constraints on what payloads are even possible.

It's also not really clear how many cycles such a gun would have before it needed refurbishment, so we don't know if it would be cheap.

-Ben

[Roboramma]

I vote that we put them all together. A big cannon launches a cheap rocket that has a vacuum compressed "baloon" which opens as the vehicle slows down due to air resistence. It slowly floats up toward the edges of the atmosphere, and carries it over to the bottom of a cheaper version of a space elevator that doesn't quite reach the ground. The space elevator carries it up in to orbit, where the rockets go off and take it to wherever it's going.

Okay, that was all just stupid fun. But seriously, I don't know all that much about the space elevator idea, but could one be built that didn't extend all the way to the ground? If we can float up to 140,000 feet in an airship, would we save a great deal of expense and maybe even the need for such strong materials by building one that only extended that far down?

[R.Mackey]

NoZed - Doctor Gerald Bull's space guns could have worked. No reason that they couldn't have, but the very high acceleration puts serious constraints on what payloads are even possible.

It's also not really clear how many cycles such a gun would have before it needed refurbishment, so we don't know if it would be cheap.

-Ben

This is an important point. Past superguns (http://en.wikipedia.org/wiki/Paris_Gun) showed extremely high rates of barrel wear, and this goes up quickly with projectile speed. So too the cost and precision required to rebuild and recertify such a device would climb with performance and safety requirements.

Such a gun-launch approach (assuming we could armor the "projectiles" sufficiently) would perhaps be more reliable than current chemical rockets, but it's unlikely that they'd be any cheaper.

[jimbob]

If the linear accelerator is long enough, i.e. the length of a smallish railway line, it might do to reduce the fuel needed. It would probably need to be enclosed in an evacuated tunnel too, but that was proposed earlier for a Swiss high speed railway tunnel in thre mid 1990's too (an article in The Engineer IIRC).

For example a 250km accelerator at 5g would get to 5km/s in 100 seconds, or 7km/s at 10g (assuming g=10m/s/s). That should increase payload if nothing else.

[BenBurch]

Jimbob, a captive rocket sled is still likely much cheaper to build and maintain than a huge Linac like that. People who think such a thing would be easy have never worked at a particle accelerator lab.

-Ben

[Rasmus]

Okay, that was all just stupid fun. But seriously, I don't know all that much about the space elevator idea, but could one be built that didn't extend all the way to the ground? If we can float up to 140,000 feet in an airship, would we save a great deal of expense and maybe even the need for such strong materials by building one that only extended that far down?


Geosynchronous orbit is at about 26,200 miles. The cable would have to extend beyond that point - at least slightly. That equals 138,336,000 feet (or so tells me google).

You would save about a promille of cable and get a ton of other problems to solve. I doubt a space elevator could be used if the cable wasn't anchored to the earth somehow for once.

[NoZed Avenger]

This is an important point. Past superguns (http://en.wikipedia.org/wiki/Paris_Gun) showed extremely high rates of barrel wear, and this goes up quickly with projectile speed. So too the cost and precision required to rebuild and recertify such a device would climb with performance and safety requirements.

Such a gun-launch approach (assuming we could armor the "projectiles" sufficiently) would perhaps be more reliable than current chemical rockets, but it's unlikely that they'd be any cheaper.


You people are party poopers!!


And I am *not* talking about a big cannon as overcompensation for anything.


It's a matter of principle.


It's the Second Amendment. We all have the right to super cannons in our back yards, and the neighbors shouldn't have allowed their cats out to sleep in the barrel, so it's not my fault if something happened, not that there's any proof about what happened, anyway. Besides, I was just . . . holding it for a friend.

[stevea]

The idea of facing a rail-gun eastward for energy consideration is also an error committed by someone innumerate sci-fi writer. The tangential velocity at the equator is ~0.44km/sec and escape velocity is 11.2km/sec, so launching eastward from the equator save you a whopping 0.15% of the energy (100% * (0.44/11.2)^2). You'll lose that much by transport to the equator.

Energy is the thing in any launch. Why does anyone think a space-elevator is going to be more energy efficient than say conventional aircraft to 20km and then a solid fuel unit beyond ? The one energy saving possible is that the energy losses to the atmosphere are lower at lower speeds (well it depends on many factors to retain laminar flow rather then turbulent), but this is exactly what aircraft regularly do.

Some high altitude lighter-than-air ships have been designed in recent years than have a ceiling around 65k-70ft (~20km) These can be remarkably energy efficient to that altitude, limited but nontrivial payload. Still this just gets you past most of the atmosphere - barely touches the gravity well.

[Jimbo07]

Several people have voted for the space elevator option and I've got to wonder how anyone can know it's going to be cheap. Too many breakthroughs required to estimate a cost.

Well, of course, that's what Elevator2010 is all about... trying to draw a bound around those breakthroughs and costs. Should those breakthroughs occur, NASA will have gotten them for a song.


Even before the cost of the currently speculative materials required, construction costs running above 10 billion dollars are frequently cited for an elevator that can launch 10 tons to geo every two weeks. Those number don't really suggest low cost or high volume. They work out to about $2,000 dollars per pound just to recover the capital cost.

Current projections for the ISS put it over $100 billion. Even if estimates for the S.E. are out by 100%, it's still cheap by comparison to the current method of doing things.


This would be my first option. And I'd add "built in countries with low labor costs".

So... you don't know about S.E. development costs, but you advocate development of new rockets? ;)

[Rasmus]

Even before the cost of the currently speculative materials required,

What is required besides the cable that would need an actual breakthrough?

I know several things would have to be build and developed, but they all seem doable.

construction costs running above 10 billion dollars are frequently cited for an elevator that can launch 10 tons to geo every two weeks. Those number don't really suggest low cost or high volume. They work out to about $2,000 dollars per pound just to recover the capital cost.

I didn't find many examples - but the "Rockot" has a price tag of roughly 13 million $US per launch and can carry just under 2 tons. I make that to be 3250 $US per pound. I am not sure how often they could launch one of these - but there have been 12 launches or attempted launches since 1990, none closer than 3 month to each other.

I am not sure how you reached your numbers, btw. The building cost of the space elevator is a one-time investment. There will also be running costs, but those would be much, much lower.

[jimbob]

Jimbob, a captive rocket sled is still likely much cheaper to build and maintain than a huge Linac like that. People who think such a thing would be easy have never worked at a particle accelerator lab.

-Ben

True, but similar problems would begin to be explored with maglev trains, only about 100x slower...

I was also wondering what effect that the Earth's curvature would have on something like that.

[RecoveringYuppy]

Okay, that was all just stupid fun. But seriously, I don't know all that much about the space elevator idea, but could one be built that didn't extend all the way to the ground?
If you Google "tethers" you'll find lots of ideas for "partial elevators" in varous orbits.

[RecoveringYuppy]

Well, of course, that's what Elevator2010 is all about... trying to draw a bound around those breakthroughs and costs. Should those breakthroughs occur, NASA will have gotten them for a song.
Uhh, how can you know that without knowing what the cost is going to be?

Current projections for the ISS put it over $100 billion. Even if estimates for the S.E. are out by 100%, it's still cheap by comparison to the current method of doing things.
Well, the current projections about the SE are complete fantasy so who knows how off they may be. But I don't see the point of your apples and orange comparison of a station to a transport mechanism. And, as I pointed out in the post you are replying to, the cost and capacity and cited don't make me think it's going to be cheaper than what we're doing now. And since we can't build an elevator now comparing it to what we can do now is a spurious comparison.

So... you don't know about S.E. development costs, but you advocate development of new rockets? ;)
Can you tell me something about SE development costs? Not only can we not build an SE we can barely guess at it's cost. Advocating an SE is about like advocating building the Time Tunnel. Until some of the necessary breakthroughs occur it's pointless to "advocate" it.

When I compare current rocket prices against projected future costs and capacities for the imaginary space elevator I find that we've already built rockets that are close to those imaginary future prices. Seems to me that if we need more cheaper access to space the reliable way to get is to mass produce some current rocket design on an assembly line.

The number I calculated for SE costs based on the wiki article has already been matched by rockets. And that number assumed the SE had no operational costs.

[RecoveringYuppy]

I am not sure how you reached your numbers, btw. The building cost of the space elevator is a one-time investment. There will also be running costs, but those would be much, much lower.
I took a proejected cost and divided it by a projected capacity over an assumed lifetime. If you'd like me to repeat the exercise with numbers you prefer please provide the numbers.

How do you know the SE will be a one time investment? It will never need to be replaced? The first one will have all the capacity we will ever need?

How do you know what the operational costs will be?

If I said "No, elevator operational costs will be much higher" how could you dispute me?

Here's a link on launch costs. I'm on a slow connection and haven't checked multiple sources though.

http://cost.jsc.nasa.gov/ELV_INTL.html

[Rasmus]

I took a proejected cost and divided it by a projected capacity over an assumed lifetime. If you'd like me to repeat the exercise with numbers you prefer please provide the numbers.

I was just curious what numbers you used. E.g. what is the life time you assumed for the space elevator?

How do you know the SE will be a one time investment? It will never need to be replaced? The first one will have all the capacity we will ever need?

I wasn't precise enough. The space elevator is believed to have relatively high building costs and relatively low operational costs after that. AFAIK most rockets or at least major parts thereof aren't reusable.

How do you know what the operational costs will be?

I don't. But it is a fair assumption to make that running a cabin up and down a piece of string will be cheaper than throwing it up and down sans the string.

If I said "No, elevator operational costs will be much higher" how could you dispute me?

I would have to remember a lot i forgot about maths, then compare how much energy each system would need to bring one pound of material into orbit. I could find out how much additional fuel a conventional rocket would have to bring partially into orbit.

It would, of course, still be possible that for some unknown reason the space elevator would have to operate far, far from an assumed ideal energy input - but i doubt that would be a reasonable assumption to make.

Here's a link on launch costs. I'm on a slow connection and haven't checked multiple sources though.

http://cost.jsc.nasa.gov/ELV_INTL.html

Cool, thanks.

[Jimbo07]

Uhh, how can you know that without knowing what the cost is going to be?

It's called protoyping. NASA has committed to a maximum payout of $4 MM by 2010, across both tether and climber competitions. Assuming the breakthroughs are made for sufficient prototyping, one can probably put +/- 100% bounds on costs, perhaps better. That's the goal of Elevator2010, basically... payout $4 MM so that preliminary cost estimates can be cobbled together.


Well, the current projections about the SE are complete fantasy so who knows how off they may be.

They're not complete fantasy. You'll have to do some follow-up reading on methodologies. Refer specifically to Brad Edwards's work, as he was the one who did the initial work for NIAC. Some of the estimates were done by analogy, but several come from known technologies. "Out there" maybe, but not complete fantasy. Again, refer back to Elevator2010 for movement toward better estimates.


But I don't see the point of your apples and orange comparison of a station to a transport mechanism. And, as I pointed out in the post you are replying to, the cost and capacity and cited don't make me think it's going to be cheaper than what we're doing now. And since we can't build an elevator now comparing it to what we can do now is a spurious comparison.

Actually, there are several comparison points. Is it the railroad, or necessary railroad towns/watering towers/facilities/etc. Both projects are infrastructure (although the utility of the ISS as infrastructure has become more limited through design revisions). Moreover, there is an apt scale comparison for large 'space engineering' projects.


Can you tell me something about SE development costs? Not only can we not build an SE we can barely guess at it's cost. Advocating an SE is about like advocating building the Time Tunnel. Until some of the necessary breakthroughs occur it's pointless to "advocate" it.

What breakthroughs are you referring to, exactly?


The number I calculated for SE costs based on the wiki article has already been matched by rockets. And that number assumed the SE had no operational costs.

All of your operational costs have to be divided over the number of launches. A space shuttle flies five times a year at the best of times. All of those salaries have to be distributed over that timeframe. If you could average those over fifty launches a year, you'd realize an order-of-magnitude savings/kg right there. The salaries example holds whether you're talking S.E.s or more rockets, however, you're not building a new S.E. climber every time.

I took a proejected cost and divided it by a projected capacity over an assumed lifetime. If you'd like me to repeat the exercise with numbers you prefer please provide the numbers.

How do you know the SE will be a one time investment? It will never need to be replaced? The first one will have all the capacity we will ever need?

No. In fact, your best savings are realized once you start using the first S.E. to start seeding others! That's an economy of scale!


How do you know what the operational costs will be?

Nobody does, but megaprojects have been done before. In my current industry, estimating takes data from pilot plants. Prototyping, of a sort...


If I said "No, elevator operational costs will be much higher" how could you dispute me?

We'd have to then go to how we've each come up with our estimates.


I wasn't precise enough. The space elevator is believed to have relatively high building costs and relatively low operational costs after that. AFAIK most rockets or at least major parts thereof aren't reusable.

Right. Moreover, those rockets which have reusable parts have not been as cheap as some would have liked.


I don't. But it is a fair assumption to make that running a cabin up and down a piece of string will be cheaper than throwing it up and down sans the string.


For many reasons.


It would, of course, still be possible that for some unknown reason the space elevator would have to operate far, far from an assumed ideal energy input - but i doubt that would be a reasonable assumption to make.

Many things tend to not operate at a preliminary ideal. However, the laser to PV system is providing interesting results!



Cool, thanks.[/QUOTE]

[Dr. Trintignant]

The tangential velocity at the equator is ~0.44km/sec and escape velocity is 11.2km/sec, so launching eastward from the equator save you a whopping 0.15% of the energy (100% * (0.44/11.2)^2).

If the difference is so minimal, why does everyone with a space program build as close to the equator as is practical?

First off, your calculation is wrong. You don't square the difference in velocities; you take the difference of the squares. Thus, the difference is proportional to (11.2^2 - (11.2-0.44)^2)/11.2^2, which is more like an 8% savings.

But it gets much better than that. The rocket equation is exponential with velocity, because every extra meter per second you need comes from the beginning, where you're carrying your entire fuel load.

That's why launching at the equator is so important, and why a rail/sled/etc. system would be so effective, even if it only gets you to a few hundred meters per second.

It's also one reason why space elevators are so promising. You don't need to carry your fuel at all--it just gets beamed from the ground. That in addition to no atmospheric or gravitational losses make for a big win.

I will grant that a fast, high altitude aircraft launch can have many of the same benefits as the rail launch, but it's more likely to limit the size of your rockets.

- Dr. Trintignant

[R.Mackey]

If the difference is so minimal, why does everyone with a space program build as close to the equator as is practical?

First off, your calculation is wrong. You don't square the difference in velocities; you take the difference of the squares. Thus, the difference is proportional to (11.2^2 - (11.2-0.44)^2)/11.2^2, which is more like an 8% savings.

But it gets much better than that. The rocket equation is exponential with velocity, because every extra meter per second you need comes from the beginning, where you're carrying your entire fuel load.

That's why launching at the equator is so important, and why a rail/sled/etc. system would be so effective, even if it only gets you to a few hundred meters per second.

Correct. In computing the rocket equation, it's momentum or total impulse, and thus delta-V, not energy, that matters.

Launching near the equator helps, but it's not make-or-break. The Kennedy Space Center is not at the southern tip of Florida, nor do we launch from Panama or what have you... The choice of launch site is primarily determined by the orbit you want to hit. Being close to the equator gives you large stretches of open ocean, allowing you to launch into a low inclination orbit without passing over population centers or radically changing your flight path.

But if you want a polar or sun-sync orbit, being equatorial doesn't help. Quite a few launches are from Vandenburg or even Alaska for this reason.


It's also one reason why space elevators are so promising. You don't need to carry your fuel at all--it just gets beamed from the ground. That in addition to no atmospheric or gravitational losses make for a big win.

I will grant that a fast, high altitude aircraft launch can have many of the same benefits as the rail launch, but it's more likely to limit the size of your rockets.

The major drawback to the space elevator is the capital investment cost -- launching the elevator itself is several orders of magnitude beyond any envisioned capability. If we already had one, different problem, but I just don't see it happening.

[Dr. Trintignant]

The Kennedy Space Center is not at the southern tip of Florida, nor do we launch from Panama or what have you...

True, and one has to keep in mind practical considerations, such as transportation costs. The latitude of KSC gets you ~88% of the benefit of launching from the equator. Compare to, say, France, which doesn't have such a favorable location (either in latitude or coastline), and launches from French Guiana instead.

But if you want a polar or sun-sync orbit, being equatorial doesn't help. Quite a few launches are from Vandenburg or even Alaska for this reason.

Also very true. My intuition is that these are relatively rare, but I honestly don't know the percentage.

The major drawback to the space elevator is the capital investment cost -- launching the elevator itself is several orders of magnitude beyond any envisioned capability. If we already had one, different problem, but I just don't see it happening.

I suppose the idea is that you can make a starter cable fairly cheaply--say, on the order of a billion dollars. You then increase the capacity by pulling up additional strands/layers. Capacity growth would be slow but exponential, and perhaps within several years could be at a point where you could carry cargo.

Of course, the first step in all this is building long, strong strands of carbon nanotubes. The second step is using them in more Earthly construction (say, a suspension bridge). Maybe then, the idea will be a bit more interesting.

In the meantime, I really, really want someone to build the Sea Dragon.

- Dr. Trintignant

[Father Dagon]

This might sound like knee-jerk libertarianism, but I would leave it to the market, seriously.

The dark side of NASA is not the bloated costs per se, but that they set a standard. "Everoyne" can point to the costs and conlcude that space travel is expensive business, something that only the state can pay for.

And the costs isn't high beacuse of evil or some plan, it's in the small steps. It's the same every Christmas. I always buy gifts for some 10-20% more than I first budgeted for. But on the other hand I can lower my expenses in other fields as I usually gets books, clothes and films for Christmas. Leftovers from the Christmas-dinner helps too. Now imagine Christmas-splurging without lowering any costs in any field at all, all around the year on every imaginable department.

[RecoveringYuppy]

It's called protoyping. NASA has committed to a maximum payout of $4 MM by 2010, across both tether and climber competitions. Assuming the breakthroughs are made for sufficient prototyping, one can probably put +/- 100% bounds on costs, perhaps better. That's the goal of Elevator2010, basically... payout $4 MM so that preliminary cost estimates can be cobbled together.

The tethers and climbers coming out of 2010 are extremely unlikely to be realistic prototypes of a space elevator. And that 4MM you cite is unlikely to be the final price tab on the breakthroughs required?

They're not complete fantasy. You'll have to do some follow-up reading on methodologies. Refer specifically to Brad Edwards's work, as he was the one who did the initial work for NIAC. Some of the estimates were done by analogy, but several come from known technologies. "Out there" maybe, but not complete fantasy. Again, refer back to Elevator2010 for movement toward better estimates.

I've read all that and still can't past the fact that the crucial bit of technology required can't be produced now and can't reasonably be viewed as scaling up any existing technology.

What breakthroughs are you referring to, exactly?

Power transmission, radiation shielding for the long trip through the VA belts, cable or tether stability of thousands of miles. There are others.


All of your operational costs have to be divided over the number of launches. A space shuttle flies five times a year the best of times. All of those salaries have to be distributed over that timeframe. If you could average those over fifty launches a year, you'd realize an order-of-magnitude savings/kg right there. The salaries example holds whether you're talking S.E.s or more rockets, however, you're not building a new S.E. climber every time.

Well, actually to justify the numbers I gave earlier you would have to build a new climber each time. To be generous to the SE concept, I left out the time it would take for the climber to come back down.

And how long does it take a climber to go up and come down? The first SE certainly isn't going to be taking up payloads weekly.

No. In fact, your best savings are realized once you start using the first S.E. to start seeding others! That's an economy of scale!

Have you heard to old joke about the business man who loses a nickel on every sale but makes it up in volume?

Can you cite some numbers that make bootstrapping or "economies of scale" a plausible idea?

Using the first SE to build a second only makes sense if the SE can lift stuff cheaper than it's competition. And it looks to me (see link I posted earlier) that rockets are already nearing some of the hypothetical costs claimed by SE enthusiasts.

And what economies of scale do you see operating on an SE? Are we ever going to mass produce SEs?

IIRC the lowest launch cost in that link I cited was about $650/pound for a rocket that was custom built only a few times. You were talking about prototyping earlier. That rocket really has been prototyped and flown. So have most (all?) of the rockets on that list. If we need cheap abundant access to space then we should produce one of those rockets on an assembly line.

[jimbob]

Jimbob, a captive rocket sled is still likely much cheaper to build and maintain than a huge Linac like that. People who think such a thing would be easy have never worked at a particle accelerator lab.

-Ben

OK, this has given me an idea for an implausible launch strategy.

To get to the stars,why not do a "fantastic voyage" and then fire the resulting scientists out of a synchrotron?

I admit that there are technological hurdles, but hey...

[Jimbo07]

The tethers and climbers coming out of 2010 are extremely unlikely to be realistic prototypes of a space elevator.

Care to share why not?


And that 4MM you cite is unlikely to be the final price tab on the breakthroughs required?

Actually, you're exactly right. Altogether, the competing teams will spend more than NASA is paying. I didn't say it was a good financial deal for every team, I was just telling you how I had a guess on what costs are going to be. I also know the dollar amount my team has spent.

Spaceship One cost more than the X-Prize award of $10 MM. Such is life...

...

Anyway, I have to admit that you have me on the ropes. I don't have the resources to give this the rebuttal it deserves. I'm leaving work soon this afternoon, and won't have work access for 5 days, nor home internet access for 2 weeks! Maybe we can take this up later? :D

[RecoveringYuppy]

Sure. I'm on a slow connection due to holiday travel also.

The 2010 conference is unlikely to produce a prototype simply because the breakthroughs required can't be scheduled.

[TjW]

Even if you build a space elevator, you're going to need a cheap launch strategy to build the first one.

[jimbob]

How many gigatonnes of carbon would be needed for a space elevator, plus the extra to initially launch it into geostationary orbit?

Would you really want someone to steer a carbonaceous asteroid into geostationary orbit?

Of course it worked in "Red Mars"...

[RecoveringYuppy]

Presuming the desired material becomes available, most elevator designs are not billions of tons. Thousands of tons, more likely.

[BenBurch]

Well, we do have a lot of carbon...

But I think the one think that dooms any beanstalk is space flotsam and jetsam. There is no way that it will not suffer many high speed collisions and that it will be degraded and eventually destroyed by them.

Not only would we have to capture and ground every single satellite now in earth orbit, but every fleck of paint, every explosive bolt cover, etc., but also we would have to look for and deflect small (and large) asteroids, and the bottom end of size of concern would be quite small.

[quarky]

the solution is tiny.

why send large items into space?

if space ships ever do arrive on earth, I suspect they will be smaller than lady bugs.
nano-tech devices will rule. why send humans? imagine launching 1 gram payloads from high altitude balloons.

[jimbob]

the solution is tiny.

why send large items into space?

if space ships ever do arrive on earth, I suspect they will be smaller than lady bugs.
nano-tech devices will rule. why send humans? imagine launching 1 gram payloads from high altitude balloons.
You mean like this:
OK, this has given me an idea for an implausible launch strategy.

To get to the stars,why not do a "fantastic voyage" and then fire the resulting scientists out of a synchrotron?

I admit that there are technological hurdles, but hey...

[quarky]

forgive me, jim bob. I didn't know about the fantastic voyage. I was confused by your statement, frankly, because of a paucity of american pop culture knowledge.

but now i get it.


regardless, I suspect that space exploration by earth-humans is so far off in the future, that we may as well concentrate on genetic manipulations.
we would engineer a human to accomodate the mission.

perhaps just sperm and eggs.


long space journeys need people that are used to being immobile...not arnold-stalone types. stephen hawking types. with no legs. or smaller.

space exploration, with humans in a ship, is the woo of science.

its also the excuse of endless growth capatalism:
that we aren't in a closed system here on earth, because our destiny is beyond our solar system. manifest destiny, and what not.

I wonder what % of people here believe that we will ever populate other planets?

I doubt if another human will ever step on the moon.

Is this too negatory?

[OnlyTellsTruths]

I was about to say Space Escalator (http://www.kestsgeo.com/pages/tmpmt2.html) jokingly, until I checked google (http://www.google.com/search?hl=en&q=%22space+escalator%22&btnG=Search) and found I wasn't the first.

[Ocelot]

http://www.theregister.co.uk/2007/12/03/mhd_turbo_jet_nasa_ajax_research/

[BenBurch]

http://www.theregister.co.uk/2007/12/03/mhd_turbo_jet_nasa_ajax_research/

One way to ionize all that air is to have the intakes lined with short-half-life radioisotopes...

[biomorph]

This has to be my favorite...:D

[bokonon]

Advocating an SE is about like advocating building the Time Tunnel. Until some of the necessary breakthroughs occur it's pointless to "advocate" it.
Damn, that was my cheap launch strategy - build a time tunnel, which would transport the payload back in time a week, at which time the earth would have been in a different position, neatly depositing the payload in empty space.

My second choice is an anti-gravity tunnel, that punches the gravity well inside out, "dropping" the payload into space.

Third, a transporter.

The details are left as an exercise for the reader...

[T-Diddy]

I advocate researching the Black Arts. Don't even try to tell me that there isn't a powerful wizard somewhere who could lick this problem in a heartbeat. ;)

http://www.gameweb.gr/lordoftherings/photos/images/gandalf.jpg

[BenBurch]

Heh, don't ask Gandalf! He'll tell you "yes" and "no" in the same breath and then make you trudge 1000 miles through the wilderness!