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Modular Laser Launch Systems
BerntB writes "I don't think Jordin Kare's NIAC article has been covered? It's about using new laser tech to build modular
laser launch systems. The modular nature makes it easier to test and build. The only other launch ideas as cool are the Orion Project and the space elevator."
...that offers a built-in light show and 1600x DVD burning.
Just so cool to watch the meter go from "000350 Number of Hits Since Mar 10, 2000" to "000501" in a mater of seconds (by hitting reload). Mesmerizing!
I miss seeing more hit meters around the web.
Oh. Nevermind...
Show me on the doll where his noodly appendage touched you.
has gotten more visits in 5 minutes then it has in 4 years...
I need a sig.
cheap labor conservatives - they want to keep you hungry enough to be thankful for minimum wage.
a) the vehicle may blind by reflected light at a considerable distance (100m - 1km or more- think of the wildlife [handwring]).
b) it ideally uses pure liquid hydrogen fuel; this means that the fuel tank ends up pretty heavy relative to the fuel (heavier than the space shuttle, because the Space Shuttle tank also holds LOX, so the average propellent density is rather better.) The ratio of the vehicle weight full/empty is critical in a high performing rocket- so this rocket doesn't perform as well as you would hope- it's not a SSTO solution, not quite, so he has a drop tank or two.
c) got a few billion? The lasers are very expensive... note that conventional rockets can be designed for *well* under a billion if you don't do anything fancy (see SpaceX)
d) it works best when you are launching a lot, but then again, just about any launch system gets cheap real fast if you launch a lot; and this one is expensive up front, so you have to launch even more to offset this.
Still, it's a very cool idea, and he's still working on it. But I can't shake the feeling Jordin has missed something that will move the idea up one more notch.
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"Since the prior story is about Carnegie Mellon its rather ironic that the most intriguing launch technology was left off entirely -- and it is out of the robotics department of CM: the Rotovar(tm) by Hans Moravec.
Seastead this.
Kare, who's been plugging this idea for decades, writes "A rule of thumb for laser launchers is that the unit payload is 1 kg per MW of laser power." The Apollo lunar module (all the stuff that went to the moon) massed about 6500 Kg, of which 2500Kg made the round trip. So we're going to need several gigawatts of laser power for a moon shot.
Kare is talking about using continuous diode lasers in the 1KW range. These don't exist, but 60W units are available, so this isn't totally unreasonable. Kare proposes to use maybe 150 of these future 1KW units in a prototype. That only launches a 150g craft.
Launching something the size of the Apollo lunar module would take six million such units, and about 12 gigawatts of electrical power for several minutes. This is twice the power output of Grand Coulee Dam, the biggest single power source in the US.
The power storage problem might be overcome using ultracapacitors. You can get 2600 farad capacitors (not ufd, farads) at 2.5V today, and you can take current out fast. Auto engines can be started with six of these things, weighing a total of about 3Kg. With a big budget, a laser launch system could have enough energy storage to do the job.
Six million lasers, though, is a bit much. The prototype doesn't put enough mass in orbit to be useful, and the real version is too big.
If you want to launch a microsat, you call Orbital Sciences Corporation, and they launch a Pegasus rocket from a L-1011 for you. The X-prize guys get all the press, but Orbital actually puts stuff in orbit. They've launched 45 payloads so far. Click here for their user manual.
Project Promethius
Promethius is not a launch solution. It's a nuclear powered Ion Drive. Energia Vulkan, Sea Dragon, and the Gas Core Nuclear "Liberty Ship" are all cool launch solutions he forgot.
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Here's a similar, but more interesting article: http://science.nasa.gov/newhome/headlines/prop16ap r99%5F1.htm
;-) A flying saucer that flies straight up by creating a vacuum above it that literally sucks it upward. Plus, it uses no propellant at all, which means significantly less weight to lift.
j an%5Fen virorocket.htm
Now that's cool.
Quote:
"You could go halfway around the world in 45 minutes, or from the Earth to the Moon in about 5-1/2 hours."
If NASA wants to build a base on the moon, they need something similar to this. Even if technical problems make it difficult to lift people this way (i.e. excessive heat, microwave radiation, or G-forces), it sounds perfect for lifting heavy cargo and supplies into orbit or to the moon.
Of course, I like the candle-based rocket fuel as well:
http://science.nasa.gov/headlines/y2003/29
Do i understand this correctly? Nasa wants to use a high-power ground-based laser as the heating supply for the power needed to ignite the H2 fuel in the Primary Propellant Tank? And as such they gonna aim their laser over very large distances to a so-called Leighweight Heat Exchanger as a shooting target ? (see figure 1 on page 6).
:
There's some rather severe pitfalls to be considered with this method
1. if the spacecraft abusively rotates around its length axis, the power from the ground laser might not be able to reach/hit that Heat Exchanger target any anymore, hence the rockets drops its speed instantly, leading to even more fatal flight manouvring.
2. As the rocket is approaching large heights, the laser guiding system will be put to the real test. When the "lock-in" signal is lost, you loose everything.
3. The conventional iginition system should allways be present as a backup system. In that case the net effect is just that extra costs are introduced.
I personally see this project more as a nice step-up for developing and deploying guided high-power ground-based lasersystems, which can follow ("lock-in") their target to very large heights. a laser "lock-in" in the end might even be possible on rockets (targets) which are near the moon. Doesn't that closely resemble the "StarWars" program of former president Ronnie Reagan ?
Robert
When are lasers going to finally hit 'real' efficiancies?
This rocket skips the oxygen, which is heavy.
There is only hydrogen being boiled off by the laser.
Hydrogen is only 2 protons per molecule,
the same as helium, without the neutrons.
(plus some insignificant electrons, minus some
bits from e=mc^2, and so on)
At low altitude of course, all that hydrogen
will burn when it hits the air outside the rocket.
Oh well. So the exhaust catches on fire.
Dean Ing's "The Big Lifters" talked about this 15 years ago, with a prototype unit that used a maglev train to push the orbiter to just about transsonic, a short-lived ramjet booster to get upright, then hit it in the @$$ with a laser to get to orbit.
Ing talked about other interesting transportation options in that book, such as delta dirigibles to handle cargo off-load from moving trains, and engineering trucks for intermodal hauling over short distances that are better at city driving than highway. Good socioeconomics for hard sci-fi.
Design for Use, not Construction!
You are wrong.
LH tank weight is exactly the same problem with both shuttle and this approach (using LH as monopropellant + laser heating).
The main limitation of rocket propulsion is the weight of the oxidizer. Even with LOX (most weight-efficient oxidizer) the weight of the oxygen is 8x higher than the weight of hydrogen. And you need lotsa fuel/oxidizer to lift the weight of the fuel/oxidizer, etc. Any weight savings will greatly reduce the overal rocket mass and size.
Compared to shuttle (without SRBs) you would be flying the laser/hydrogen rocket with about the same tank of LH but without oxydizer.
If opportunity came disguised as temptation, one knock would be enough.
3^2 * 67^1 * 977^1
Make sure you bring enough extra batteries for the landing, rewelding the tower, and the second required flight.
Superconductive coils are better: Cost scales a little less than radius, but energy scales as radius squared. On the other hand there may be problems getting the energy out fast enough. (Problems like radially pumping ground water that rips open the coil container.)
Another possibility is gas dynamic lasers. They scale all the way up, and fuel/oxygen tanks are cheap.
Orbital's approach is insanely expensive and logistically apalling. It's fine for launching must-not-fail satellites serving lucrative markets, but worthless for the human conquest of space. What I want is the flying equivalent of Conestoga wagons.Funny, I've been seeing these asymmetric brown creatures running around - and things seem to be working better - the coffee is simply wonderful.
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I have an Idea, it's probably been proposed before but, i'm wondering if anyone with a better physics backround could verify or deny this idea. Basically For Satalites/already in space systems. Is it feasible to use some sort of lazer propulsion system? I.e Light energy is the most readily available source of power (through solar panel) Could A series of high powered lazers be used to hit an adjustable pannel (also attached to the satalite) with enough force to move the satalite. Thereby getting rid of any sort of fuel need? Considering that the satalite's mass is nearly 0 in space. Firing a lazer with enough force to propell the satalite would be simple. Or am I missing somthing here.??
AEnertia
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One nice thing about this approach, compared to many other systems, is that it could lend itself to distributed production which would spread wealth around to many companies and local economies rather than concentrating wealth in the hands of a few. The design requires over 2000 laser/telescope modules each in an intermodal container. Instead of having one contractor build them all, imagine having a hundred contractors (average two per state), perhaps many in university towns, each building 20 units to a common design. Move the factory to the workers instead of vice versa. Each production facility would have a large flatbed CNC mill, mirror grinder, welding equipment, and a small electronics shop or would be a consortium of local manufacturing shops with excess capacity (i.e. a machine shop and a welding shop). Many more smaller companies would produce subassemblies. Assuming that production was not continuous but came to an end, making them all in one factory would require large numbers of people to move to one city which would then have a large layoff and unemployment that the local economy could not absorb at the end of production. By spreading it out, local economies would be better able to absorb the layoffs. And the number of layoffs would actually be reduced because the 100 different companies could each have different transition plans to developing other products so you wouldn't need another project of the same magnitude to absorb the labor and manufacturing surplus at the conclusion of the project. The distributed surplus of manufacturing capability would then spur innovation in other areas. I am thinking that each factory would have, rather than single purpose fixtures, a more general purpose programmable production ability (such as CNC tools) that would need little retooling to work on other projects. Also, many of the manufacturers would be applying existing facility and labor surpluses to this project. Manufacturing the individual lasers would still be handled by a small number of plants with a few more turning them into laser arrays. Specialized tasks like silvering the mirrors might be cheaper to do by shipping an intermodal container based factory with metalization equipment to the various factories or by shipping the mirrors in to a central site. Mass producable electronics like tracking systems could be manufactured at a smaller number of plants and shipped to the individual plants. The honeycomb mirror blanks could be manufactured by the University of Arizona Mirror lab, Corning, or similar glass manufacturer and possibly spin cast to approximate curvature. When the booster modules are completed a tilt bed truck picks them up and transports them to the nearest railroad container facility to be put on a rail car for shipment to the final laser site.
The only huge scale production operation would be if you decided to build a nuclear power plant to power the system.
The individual launch craft would be small enough that their manufacture could be distributed as well.
The distributed nature would reduce cost overruns which are routine for large contractors since how many systems were ordered from each manufacturer would depend on the quality and cost of the systems they produced. The first (prototypes) would necessarily be built in small shops; this could be extended to final production and still keep a reasonable economy of scale by using flexible tooling and centralized engineering costs and by eliminating beaurocracy and monopolistic thinking and by reusing idle factory spaces around the country. The quantity of units isn't really high enough, anyway, to fall into the economy of scale of a fixed purpose production line (like for an automobile).
I imagine the laser site looking like a freight yard with perhaps 20 widely spaced parallel sidings with 100 containers each. The added expense of leaving rail cars under each container is offset by the ease of replacing modules although you could use a crane to move the container onto smaller wheel
Basically, there are two types of laser rocketry, as defined by fuel: air-burning, as used by Dr. Leik Myrabo and has been seen on tv; and soild fuel (usally a dense metal) burning, as being developed by Dr. Andrew Pakhomov at the University of Alabama in Huntsville. The problem with the Myrabo method is that the laser is tuned be absorbed by the air, and thus is inefficent over long distances. Ablative laser propulsion doesn't have this problem. It is however still very much theoretical: I've seen their first fight model; it's 3/4 of a cm tall...
;)
More info on Dr. Pakhomov: pakhomov.uah.edu
Simon