The American Drive

Popular Mechanics ^

[RightWhale]

Heinlein's stories focus on self-reliance like Ayn Rand's massive novels, but are much more entertaining.

The Rolling Stone. Flat cats.

[Brett66]

Here's some links on Gas Core Nuclear Rockets:

Astrodigital.org

Here's one of my personal favorites, Project Orion:

Project Orion: Its Life, Death, and Possible Rebirth

Here was a real contender for Mars propulsion Sytem, until NASA cut funding for it last year:

VASIMR: The Plasma Rocket

Basically, everytime scientists say "here, we figured it out! We can get you to Mars in three months or less"
NASA says "thanks, but we really weren't serious"

[The_Victor]

Cool!

Question: Does anyone know about the ability of the reaction to be throttled, or at least turned on/off? Seems to me, that would be a necessity for space travel.

[B-Chan]

The cool thing about californium is that it emits neutrons much more profusely than do most radioactive atoms. As a result, its critical-mass requirement is quite small -- a few grams. Herman Kahn's book On Thermonuclear War describes a hypothetical nuclear weapon utilizing californium fuel: an "atomic six-gun" the size of a regular revolver shooting hollow-point californium-tipped bullets. Upon impact, the kinetic energy of the bullet crushes the hollow-point tip into a critical mass and boom -- a nuclear explosion in the sub-kiloton range, one per bullet.

[Brett66]

If they could develop a small reactor that puts out a lot of power using Americium, it could be used to power a VASIMR drive. The VASIMR can reach an Isp of 30,000. That's up there with inertial fusion propulsion. I don't know if it would be better for direct propulsion or as a power source, but either way we could accomplish remarkable things in space travel if we had the will to do it.

[Brett66]

I looked around using a google search and couldn't find anything about proposed engine designs. I just saw one quote that stated a rocket could achieve a speed of 80Km/sec using such a propulsion system.

[techcor]

If they could develop a small reactor that puts out a lot of power using Americium, it could be used to power a VASIMR drive.

That's what I figured (read an article in Pop. Sci. on several different drives-that seemed best because of low and high drive gears). Check out B-Chan's post about atomic bullets. I always wondered if that was possible and now I have a source for it. Great!

One last thing before I go. Sometimes I have a couple of beers with friends and we discuss what groups could terra-form Mars. Well, the Clintonistas cames up as a group. Basically, it would be : " Bill Clinton: Porn King of Mars". Where he sells tapes of himself doing the Kama-Sutra with 480 of the top porn stars (mostly women) to raise money. They use Californium and call themselves the "Californicates". After that we decided to stop drinking so much.

Take it easy. And thanks for the links to the "gas-core" technology.

[MarkWar]

>Heinlein's stories focus on self-reliance like Ayn Rand's massive novels, but are much more entertaining.

Yes, Heinlein is very, very good.

On the topic of Mars, however, I seem to recall that my favorite Mars story was Asimov's "The Martian Way."I haven't read it in about a decade, but I remember it being very cool, with people humming around in nuclear ships that use water as reaction mass, everything very casual. I don't remember the exact plot, but I remember it being about, in a Heinlein kind of way, the colonists becoming self-sufficent for water...

(Darn, I was going to watch "The Mummy" and "The Mummy Returns" tonight -- Now I guess I'll have to dig out a copy of TMW and buckle down for some reading instead of four hours of Rachel Weisz watching...)

Mark W.

[MarkWar]

>Opening up Mars should require opening up the minds of the planners. Think a little outside the box.

I agree 100% with this.

Let's hope that some fringe group or some pseudo-crackpot has or is developing a real "reaction-less" drive. Some kind of real space drive like Townsend Brown seems to have had in embryo.

Taking a year to get to Mars is crazy.

Taking a couple of weeks to get to Mars is like bicycling across the US.

A serious opening of space needs some kind of 1G drive. Then you get to Mars in about a day and a half...

Mark W.

[RightWhale]

10 days at 1 gee, best time.

Anyway, what's the hurry? You'll be stuck on line at the terminal forever, and when you get to Mars they'll just put you to work. Take an extra paperback.

[techcor]

Taking a couple of weeks to get to Mars is like bicycling across the US. A serious opening of space needs some kind of 1G drive. Then you get to Mars in about a day and a half...

Dang! You're tough to please. I figure two weeks is the best I could do. BTW have you ever read a book called "The Boot-Strap Effect" (I think). It was sci-fi but very interesting concerning "reaction-less" drives? In which case, who wrote it because I'd like to get a copy?

[chimera]

The cool thing about californium is that it emits neutrons much more profusely than do most radioactive atoms. As a result, its critical-mass requirement is quite small -- a few grams. Herman Kahn's book On Thermonuclear War describes a hypothetical nuclear weapon utilizing californium fuel: an "atomic six-gun" the size of a regular revolver shooting hollow-point californium-tipped bullets. Upon impact, the kinetic energy of the bullet crushes the hollow-point tip into a critical mass and boom -- a nuclear explosion in the sub-kiloton range, one per bullet.

This sounds interesting but I must admit I don't see how it could work. We're talking about spontaneous fission with 252Cf, and a lot of it. The problems with predetonation become quite difficult to manage with this kind of material. Add to that the fact that in any kind of impact the compression will be quite asymmetric and difficult to control, which makes it difficult to attain a supercritical assembly, much less maintain it for the time necessary to achieve a significant fission rate. If Kahn suggested something like this, either he was free-associating ideas or knows a lot more about the physics of the weapons than I do (which is probably true).

[B-Chan]

Californium mini-nukes

[chimera]

Well, that link discusses some elementary stuff but does not address the predetonation issue, and only gives a wave of the hand to the problem of symmetry in the implosion scheme. 252Cf has such a huge rate that the reaction mass would be blown apart by predetonation before much could be attained in the way of yield. It would then be a "mini-fizzle". The thing that makes nuclear artillary shells work is a sophisticated sensor and timing system, that begins the implosion process just before the shell hits and smashes itself and the impact forces significantly deform and scatter the fissile and implosive materials. I doubt that something like that could be made to fit and work in a handgun projectile, there just isn't the space. Nuke warheads are quite compact compared with their conventional counterparts, but reducing the size of the working components to something on the order of a 9mm or .45 slug is really a challenge.

[jackoakwood]

It would have to be an Atomic Nerf pistol.

just saw this old post. You’re right that there were old tales about atomic revolvers. But I believe those were based on somewhat exaggerated numbers and would not actually work, as cool as they sound.

A critical piece of californium (which at current prices would cost either billions or trillions of dollars to produce depending on whom you ask) weighs about 11 pounds. It’s heavy stuff, so a bomb-sized globe of it is only about 2 1/2 inches in diameter. So that is not revolver bullet sized, or even .50 bmg sized. But it sounds Nerf gun sized!