Space Travel on the Cheap

[damocles]

Several startup space launch companies currently are investigating means to replace the space shurttle as an Earth orbiter/launcher.

Here is one example of a company hoping to obtain a NASA contract as a backup system to the next NASA shuttle-derived manned spacecraft abortion for which Lockheed and Norththrop compete the CEV.

http://www.transformspace.com/docume...ce_Summary.pdf

This describes Transformational Space Corporation's approach to the problem. I find the approach complex but sound. I think their cost estimates are wildly optimistic per launch though.

I would be interested in other alternatives and a discussion of this alternative as a viable exercise in near space exploitation.

Best wishes.

[UncleAl]

http://www.transformspace.com/
A large area planar faceplate separating a pressure differential is an incredibly bad idea. Using modern materials and engineering to kick NASA out of the political porkbarrel, er, monopolized space industry is a money-maker. The moon has no material resources. It is only useful as a platform - and it's a fantastic low-gee hard vacuum platform. Any entity - national, corporate or individual - continuously occupying the moon (presumably absent aboriginal or indigenous sentient species) has the right to declare it a sovereign nation with all the rights and privileges that entails. Legal precedent dates back to the late 15th century. If you try it, one imagines you had better have a big sharp sword to make it stick

http://www.transformspace.com/docume...ce_Summary.pdf
That's a nasty 3.4 MB pdf.

The world is overflowing with good ideas and money. It is government's task to minimize both.

[DietAnthrax]

Basically, there are only two choices:

1. Chemical rockets. Very inefficent at delivering payloads into orbit, but I suspect there's room for more refinements. Aircraft releasing the rocket seems like a very sensible refinement to me, for example.

2. Orion style drives. Slight increase in the background radiation versus the ability to efficiently hoist thousands of tons of payload into space - it all depends how badly you want it.

[BlameTheEx]

Originally Posted by DietAnthrax

Basically, there are only two choices:

1. Chemical rockets. Very inefficent at delivering payloads into orbit, but I suspect there's room for more refinements. Aircraft releasing the rocket seems like a very sensible refinement to me, for example.

2. Orion style drives. Slight increase in the background radiation versus the ability to efficiently hoist thousands of tons of payload into space - it all depends how badly you want it.

Err. Are you sure its just a slight increase?
Add the following to the list:

3) Linear accelerators or cannons. Electric or chemical powered.
4) Rocket powered by a ground based laser.
5) Scram jet.

Or combinations of the above. How about a 4 stage boost?:

a) Up to mach 3 via ground based accelerator (Think very fast train)
b) Mach 3 to mach 15 via scramjet.
c) Mach 15 to low orbital velocity via conventional rocket.
d) Arrive at the ISS. Fit payload with solar cells and ion drive. Then use ion drive for slow but fuel efficient boost to high orbit or wherever it needs to go.

These are long term answers. There can only be one direct replacement for the shuttle: a conventional low tech rocket. For this the Russians have the right technology at the right price. It makes economic and political sense leave it to them. The rest of the world just isn't going to allow the USA to have a monopoly for boosting satellites into orbit. They probably would let the Russians.

http://www.newscientist.com/article.ns?id=dn7901

America should concentrate on what it does well: The high tech packages such as satellites, interplanetary missions, and space telescopes.

[damocles]

Originally Posted by BlameTheEx

Err. Are you sure its just a slight increase?
Add the following to the list:

3) Linear accelerators or cannons. Electric or chemical powered.
4) Rocket powered by a ground based laser.
5) Scram jet.

Or combinations of the above. How about a 4 stage boost?:

a) Up to mach 3 via ground based accelerator (Think very fast train)
b) Mach 3 to mach 15 via scramjet.
c) Mach 15 to low orbital velocity via conventional rocket.
d) Arrive at the ISS. Fit payload with solar cells and ion drive. Then use ion drive for slow but fuel efficient boost to high orbit or wherever it needs to go.

These are long term answers. There can only be one direct replacement for the shuttle: a conventional low tech rocket. For this the Russians have the right technology at the right price. It makes economic and political sense leave it to them. The rest of the world just isn't going to allow the USA to have a monopoly for boosting satellites into orbit. They probably would let the Russians.

http://www.newscientist.com/article.ns?id=dn7901

America should concentrate on what it does well: The high tech packages such as satellites, interplanetary missions, and space telescopes.

1. Each one of those four segment element launch systems is a loss of mission engineering disaster that would scrag the space program.

2. Relying on Russia to provide America with ground to orbit launch capability puts America's strategic forces at the mercy of another nation. You need your own launchers to put up your own reconj satellites.

3. Orion would launch dirty unless you developed a clean fusion bomb(vircator powered Z-pinch fusion trigger?).

Best wishes;

[DietAnthrax]

The 18 years of atmospheric nuclear testing (45 -63) weren't exactly catastrophic.

Sure, a clean fusion bomb is the holy grail of Orion drives, but I don't think the idea should be considered heretical even if this can't be obtained.

Explosive-powered cannons have no practical use for putting things into orbit - the g-forces are just too high.

There are numerous problems with ideas such as rail-guns and gauss-guns, but perhaps these can be overcome. Certainly, some kind of lunar-based EM accelerator would be a good idea, with the very thin atmosphere and shallow gravity well. I just can't see this being true on Earth, though.

[BlameTheEx]

Originally Posted by damocles

1. Each one of those four segment element launch systems is a loss of mission engineering disaster that would scrag the space program.

2. Relying on Russia to provide America with ground to orbit launch capability puts America's strategic forces at the mercy of another nation. You need your own launchers to put up your own reconj satellites.

3. Orion would launch dirty unless you developed a clean fusion bomb(vircator powered Z-pinch fusion trigger?).

Best wishes;

1) Could you say that in english?
2) a) Russia needs the money to badly to refuse to launch ANY package.
b) Provided America keeps control of key satalite technology Russia has no choice but to play ball.
3) I have never hear of this technology. Could you provide a link?
I might point out that such a bomb would eliminate the energy crisis. Excavate a very large underground cavity. Line it with concrete and fill it with water. Then drop in a bomb and you have the worlds biggest boiler. Just extract the power with steam turbines. All told if there was any real possibility of creating such a bomb I would expect it to be more widely publicised!

[BlameTheEx]

DietAnthrax

I agree that explosive powering is fraught with difficulties. Chemical powering is at least plausible. Not so much an explosion in a canon but more if a scramjet in a tube. Linear acceleration.

I have to admit that accelerating up to low orbital velocity with a ground based accelerator alone would mean a very long accelerator indeed. Not impossible, but probably only economic if we needed to ship the sort of tonnage necessary to colonise mars!

Composite systems using ground based accelerators as a first stage are more practical.

[damocles]

BlametheEx;

1. Mission failure sets for the various proposals you made for your four system approach is covered here in detail, especially for the LINAC and the scramjet solutions.

http://hypography.com/forums/space/3455-what-kind-launch-vehicle-manned-spaceflight.html

In summary it comes down to heatloading, explosive chemistry, aerodynamics, and materials stressloading limits.

2. You do not pay others to do what you can do for yourself. If you make yourself dependent on them they will hold you hostage to their service.

3. You have to put the pieces together;

http://en.wikipedia.org/wiki/Explosi...sion_generator

An explosively pumped flux compression generator (EPFCG) is a pulsed power supply that magnetically derives its energy from an explosion.

EPFCGs are popular as power sources for electronic warfare devices known as transient electromagnetic devices that generate an electromagnetic pulse without the costs and side effects of a nuclear weapon, a form of cyberwar.

[edit]
Characteristics
An EPFCG is a single-shot pulsed power supply; it can only be used once, and the device is destroyed in operation. An EPFCG package that could be easily carried by a person can produce pulses in the millions of amperes - tens of terawatts, exceeding the power of a lightning strike by orders of magnitude.

They require a starting current pulse to operate, which is usually supplied from a capacitor bank which has in turn been charged from batteries or the power supply of the vehicle carrying the weapon.(Read rest of the article....D.)
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http://www.ieer.org/reports/fusion/hishstat.html

Z-Pinch Drivers: These devices use electrical currents to evaporate a bundle of wires. The bundle is pinched by magnetic fields, causing the atoms to stop suddenly. This abrupt stop converts the kinetic energy of the particles into x-rays. The process is somewhat analogous to the conversion of the kinetic energy of a car into heat during sudden braking. Since x-rays can be used to compress a fusion fuel pellet, the high level of x-ray energy achieved by the wire-array z-pinch makes it very interesting to fusion researchers. The largest wire-array z-pinch is at Sandia National Laboratory in new Mexico.
(Read the report for the various avenues of research pursued since 1999...D.)

http://www.sandia.gov/pulsedpower/pr...rs/000191a.pdf

Recent success in producing intense x-ray sources with fast z-pinch implosions on the Sandia Zaccelerator (x-ray energies as high as 1.8 MJ and powers as high as 280 TW) has renewed interestin utilizing these x-rays to drive Inertial Confinement Fusion capsules.(Read rest of the abstract.....D.)

You put that together to form an architecture similar to an Ullam Teller bomb, but the problems to solve are FORMIDABLE.

Best regards