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Clean Nuclear Launches?

michael posted more than 10 years ago | from the lead-lined-underwear dept.

Space 838

AKAImBatman writes "When it comes to launching millions of pounds of material into space, nearly everyone knows about the Orion Project. Blow up a series of nuclear bombs under your dairy-aire and ride the explosion on up. Unfortunately, the Orion spewed out so much radiation that it just wasn't a feasible launch option. If we want commuter trips to space, we're going to have to find another way. Well, it turns out that NASA's been doing quite a bit of research on Gas Core Nuclear Rockets, an ultra-powerful nuclear rocket that puts out almost no radiation. This research has spurred a fascinating new generation of ideas on reaching the cosmos. Could inexpensive cruises to the moon happen within our lifetimes?"

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838 comments

first CLIT! (-1)

News For Turds (580751) | more than 10 years ago | (#7964960)

Fuck yuou all. I hate all of you.

Linux sux.

Love Always,
News For Turds

Re:first CLIT! (0)

Anonymous Coward | more than 10 years ago | (#7965100)

Do you even know what a clit IS? I mean, since you're first-posting on Slashdot, I know you've never actually SEEN one.

Re:first CLIT! (0)

Anonymous Coward | more than 10 years ago | (#7965141)

Easy. Here are several: Check it! [clitoris-information.com]

Nucular Launches (-1, Offtopic)

Anonymous Coward | more than 10 years ago | (#7964963)

Nucular Launches. What is it all about... is it good, or is it whack?

No Nuclear Anything (-1, Offtopic)

Anonymous Coward | more than 10 years ago | (#7964965)

BAN THE BOMB!

Re:No Nuclear Anything (-1, Offtopic)

Anonymous Coward | more than 10 years ago | (#7964998)

No! Bomb the ban!

NASA has been grounded. (-1, Offtopic)

Anonymous Coward | more than 10 years ago | (#7964968)

We'll never get to the moon again.

Re:NASA has been grounded. (-1, Flamebait)

Anonymous Coward | more than 10 years ago | (#7965028)

With all the smart foreigners working for ESA now, you were doomed from the beginning.

I knew it! (-1, Offtopic)

inertia@yahoo.com (156602) | more than 10 years ago | (#7964970)

George: I knew there was a reason to hang on to my old VCR. That's my ticket to the moon, baby!
Craimer: Hey, I still have one too. Giddeup!
Jerry: Hold on, buckos. I'm sure the VCR acronym stands for something very scientific.
Elane: Yeah, you guys are too excitable.
Jerry: "Excitable?" Is that even a word?
Elane: Yep. I used it today in my crossword puzzle.

Re:I knew it! (1)

michaelhood (667393) | more than 10 years ago | (#7965026)

What Seinfeld episode is this supposedly from? I've never seen it. Googled, too- no results.

Re:I knew it! (0)

Anonymous Coward | more than 10 years ago | (#7965029)

Craimer??! Is that a new character?

Re:I knew it! (0)

Anonymous Coward | more than 10 years ago | (#7965096)

Craimer is the charactor who is the actor chosen to play the role of Kramer.

"I'm Kramer!"
"No, I'm Craimer!"

Re:I knew it! (0)

Anonymous Coward | more than 10 years ago | (#7965081)

At the least, give Kramer's "i" to Elaine.

Two Words (5, Insightful)

Hell O'World (88678) | more than 10 years ago | (#7964975)

Space Elevator. Everything else is too dangerous and expensive.

Re:Two Words (0, Insightful)

Anonymous Coward | more than 10 years ago | (#7964999)

Imagine a Nasa disaster with a nuclear payload? no thanks!! Stick to rocket fuel boys!

(Did it say 1 g of plutonium or 1 pound? What's the conversion ANYWAY?!!)

Re:Two Words (5, Insightful)

*weasel (174362) | more than 10 years ago | (#7965075)

Funny, all the old space probes had nuclear powerplants and that all worked out just fine.

This is an education issue mainly.

If people can believe we have designed black boxes that survive being slammed into the Pennsylvania crust at 400 mph or the disintegration of its containing shuttle at 30000 feet - why is it a stretch to believe we can make a containment system for fissile material that would survive even catastrophic launch failure?

Re:Two Words (0)

Anonymous Coward | more than 10 years ago | (#7965118)

I never said there was a nuclear accident before. That's excellent. hopefully there never will be one. What's the only way to ensure that it's safe? Well as Doctor Ruth says "No sex is safe sex".

I wasn't very happy when I read the articles about Nasa using nuclear reactors, and this is a much worse scenerio, on previous missions with a nuclear payload the nuclear reaction wasn't started until the shuttle was well away from Earth's orbit (thereby theoritically reducing the risk), this time they plan on igniting the damn stick of dynamite well the suckers still on the ground! No thanks!!

Re:Two Words (-1, Troll)

Trolling4Dollars (627073) | more than 10 years ago | (#7965140)

If people can believe...

Exactly the point. People can be made to believe anything. Especially when it is financially advantageous to the ruling class. Anyone who believes that a perfectly preserved passport was found outside of the wreckage of the plane that crashed in PA on 9-11-2001 will believe anything.

Re:Two Words (3, Insightful)

MouseR (3264) | more than 10 years ago | (#7965156)

If people can believe we have designed black boxes that survive being slammed into the Pennsylvania crust at 400 mph

An object the size of a shoe box (big shoes) that weight roughtly 30 pounds, slamming at 400mph, is not the same as a truck-size object weighting 30 tons at the same speed.

The lighter object's mass can easily be dealt with, whereas a 30 ton mass requires significantly more energy to bring to a stop.

Re:Two Words (1)

irving47 (73147) | more than 10 years ago | (#7965000)

Slashdot has posted several articles on how close we are to having strong enough material for this... But isn't part of the space elevator a huge-ass asteroid in orbit?

Re:Two Words (5, Interesting)

squiggleslash (241428) | more than 10 years ago | (#7965087)

Not necessarily. The space elevator needs equal pull on both sides of the point where it would be at the same distance from Earth as objects in geosynchronous orbit. You can either do that using a counterwieght such as a large asteroid, or by making the elevator exceedingly long, about the same length on either side of that geosync orbit position.

There's a genuine safety issue with space elevators that ought to mentioned though, which is that if the elevator breaks, the part between Earth and the break point would act as a whip. A few thousand miles probably wouldn't be a big issue, but the closer to the end the cable breaks, the bigger, exponentially, the whiplash. A shockwave that destroys significant amounts of life on Earth isn't impossible.

Re:Two Words (4, Funny)

*weasel (174362) | more than 10 years ago | (#7965111)

now that's fresh fodder for a hollywood disaster film if I've ever heard it.

Re:Two Words (1)

irving47 (73147) | more than 10 years ago | (#7965034)

By whom?
The aliens we encountered on the moon when we never went there?

Re:Two Words (2, Insightful)

nizo (81281) | more than 10 years ago | (#7965035)

Umm, what happens if it breaks somewhere high up? I can't imagine I would want to be anywhere near where the "stalk" came crashing down. Don't get me wrong, I am not real keen on nuclear filled rockets that could explode on or soon after launch either.

Re:Two Words (5, Informative)

Baron_Yam (643147) | more than 10 years ago | (#7965107)

You should read up on the concept;
  • The ribbon would end up fluttering down and wouldn't be dangerous at all
  • The counterweight would fly off into space
  • Any load ON the ribbon would be a different matter, but hey, the space shuttles fell without causing planet-wide destruction.
Also, the base of the ribbon would probably be a floating platform in the middle of an ocean, so any falling load would be extremely unlikely to hit land.

Re:Two Words (5, Insightful)

IWorkForMorons (679120) | more than 10 years ago | (#7965074)

Ok...I'll give you that. To get into space, a space elevator is probably a better idea. Two reason to continue developing nuclear engines:

1) We don't have space elevators. Simple as that. Until the day they are reality, we need something better then conventional rockets.

2) Once in space, either through the use of these rockets or a space elevator, these would be extremely useful for getting around the solar system, or at least roaming our backyard (the moon) or visiting next door (Mars).

IANARS (rocket scientist), but I enjoy learning about developments in space tech. The nuclear engine, while different versions having been developed and tested decades ago, still looks to be the next best thing in space travel.

Re:Two Words (1)

mi (197448) | more than 10 years ago | (#7965077)

What about getting off some other object? Moon? Mars?

Or do you propose, we build a space elevator on anything prior to landing there?

Re:Two Words (1)

Morgon (27979) | more than 10 years ago | (#7965094)

Two more words (in response to the material to be used) ..... Mollusk Snot [slashdot.org]

Re:Two Words (5, Insightful)

Tackhead (54550) | more than 10 years ago | (#7965143)

> Space Elevator. Everything else is too dangerous and expensive.

Two more words for you: Suspension bridge.

When you can build a 40,000-millimeter suspension bridge out of carbon nanotubes and cross the river near the campus materials lab building, then you can start fantasizing about a 40,000-kilometer space elevator.

Until then, NERVA is the only way to go. Everything else is still at the research stage.

Dairy-aire? (-1, Troll)

Anonymous Coward | more than 10 years ago | (#7964978)

It's "derriere" you butt-munch!

Mods, do I get a "5: Informative" for this?

Re:Dairy-aire? (1, Offtopic)

Mantorp (142371) | more than 10 years ago | (#7965025)

Although i agree with you I can't recall ever seeing a post containing the words "butt munch" getting a 5: Informative.

"butt-munch" is underrated (0)

Anonymous Coward | more than 10 years ago | (#7965084)


I'd like to see a return of that word, along with poppycock, dipstick, and shunt.

last link /.'d already (-1, Redundant)

XaXXon (202882) | more than 10 years ago | (#7964983)

anyone have a copy of what's there?

Re:last link /.'d already (1)

pvt_medic (715692) | more than 10 years ago | (#7965031)

Well since the link is dead we can only speculate about what it would consist of. But basically my theories is that such applications could easily be applied to almost any form of transportation. Clean (renewable?) source of energy that would cuase us to be less dependant on Oil. Of course this is all well and good except for the first time one of these things crashes and spills radioactive waste everywhere.

Just because it a clean propulsion method, the second the rocket goes off course and they decide to abort dump the payload or even selfdestruct the rocket, you have a nice 3 Mile Island.

Full text! (1, Informative)

Anonymous Coward | more than 10 years ago | (#7965036)

A project to explore the feasibility of building a nuclear-pulse rocket powered by nuclear fission. It was carried out by physicist Theodore Taylor and others over a seven-year period, beginning in 1958, with United States Air Force support. The propulsion system advocated for the Orion spacecraft was based on an idea first put forward by Stansilaw Ulam and Cornelius Everett in a classified paper in 1955. Ulam and Everett suggested releasing atomic bombs behind a spacecraft, followed by disks made of solid propellant. The bombs would explode, vaporizing the material of the disks and converting it into hot plasma. As this plasma rushed out in all directions, some of it would catch up with the spacecraft, impinge upon a pusher plate, and so drive the vehicle forward.

Project Orion originated at General Atomics in San Diego, a company (later a subsidiary of General Dynamics) founded by Frederick de Hoffman to develop commercial nuclear reactors. It was de Hoffman who persuaded Freeman Dyson to join Taylor in San Diego to work on Orion during the 1958-59 academic year.

Ulam and Everett's idea was modified so that instead of propellant disks, the propellant and bomb were combined into a single pulse unit. Plastic was chosen as the propellant material, not only because of its effectiveness in absorbing the neutrons emitted by an atomic explosion but also because it breaks down into lightweight atoms such as those of hydrogen and carbon which move at high speed when hot. This approach, in tandem with the pusher plate concept, offered a unique propulsion system that could simultaneously produce high thrust with high exhaust velocity. The effective specific impulse could theoretically be as high as 10,000 to one million seconds. A series of abrupt jolts would be experienced by the pusher plate, so powerful that, if these forces were not spread out in time, they would result in acceleration surges that were intolerable for a manned vehicle. Consequently, a shock absorbing system was devised so that the impulse energy delivered to the plate could be stored and then gradually released to the vehicle as a whole.

Various mission profiles were considered, including an ambitious interstellar version. This called for a 40-million-ton spacecraft to be powered by the sequential release of ten million bombs, each designed to explode roughly 60 m to the vehicle's rear. In the more immediate future, Orion was envisaged as a means of transporting large expeditions to the Moon, Mars, and Saturn.

Taylor and Dyson were convinced that chemical rockets, with their limited payloads and high cost, represented the wrong approach to space travel. Orion, they argued, was simple, capacious, and above all affordable. Taylor originally proposed that the vehicle be launched from the ground, probably from the nuclear test site at Jackass Flats, Nevada. Sixteen stories high, shaped like the tip of a bullet, and with a pusher plate 41 m in diameter, the spacecraft would have utilized a launch pad composed of eight towers, each 76 m high. Remarkably, most of the takeoff mass of about 10,000 tons would have gone into orbit. The bomb units ejected on takeoff at a rate of one per second would have yielded 0.1 kiloton; then, as the vehicle accelerated, the ejection rate would have slowed and the yield increased, until 20-kiloton bombs would have been exploding every 10 seconds.

It was a startling and revolutionary idea. At a time when the United States was struggling to put a single astronaut into orbit using a modified ballistic missile, Taylor and Dyson were hatching plans to send scores of people and enormous payloads on voyages of exploration throughout the solar system. The original Orion design called for 2,000 pulse units, far more than the number needed to reach Earth escape velocity. In scale, Orion more closely resembled the giant spaceships of science fiction than the cramped capsules of Gagarin and Glenn. One hundred and fifty people could have lived aboard in relative comfort in a vehicle built without the need for close attention to weight-saving measures.

One of the major technical issues was the durability of the pusher plate since the expanding bubble of plasma from each explosion would have a temperature of several tens of thousands of degrees, even at distances of 100 m or so from the center of detonation. For this reason, extensive tests were carried out on plate erosion using an explosive-driven helium plasma generator. The results showed that the plate would be exposed to extreme temperatures for only about one thousandth of a second during each explosion, and that the ablation would occur only within a thin surface layer. So brief was the duration of high temperatures that very little heat flowed into the plate, and the researchers concluded that active cooling was unnecessary and that either aluminum or steel would be durable enough to serve as plate material. The situation was similar to that in an automobile engine, in which the peak combustion temperatures far exceed the melting points of the cylinders and pistons. The engine remains intact because the period of peak temperature is short compared to the period of the combustion cycle.

Still, it was evident that some experimentation was needed and so the Orion team built a series of models, called Put-Puts or Hot Rods, to test whether or not pusher plates made of aluminum could survive the momentary intense temperatures and pressures created by chemical explosives. Several models were destroyed, but a 100-m flight in November 1959, propelled by six charges, was successful and demonstrated that impulsive flight could be stable. These experiments also suggested that the plate should be thick in the middle and taper toward its edges for maximum strength with minimum weight.

There was no obvious technical flaw in the Orion scheme, nor any argument to suggest that it could not be implemented economically. Its huge weakness, however, was that it depended upon atomic explosions that would release potentially harmful radiation into the environment -- a fact that would ultimately be its undoing.

Early on, Taylor and his team recognized that they would need substantial government funding. The Advanced Research Projects Agency was approached in April 1958 and, in July, agreed to sponsor the project at an initial level of $1 million per year. However, this funding was short-lived. The newly-formed NASA was beginning to acquire all civil-oriented space projects run by the federal government, while the Air Force was assuming control over space projects with military applications. Orion was initially excluded from both camps because the Air Force felt it had no value as a weapon, and NASA had made a strategic decision in 1959 that the civilian space program would, in the near future at any rate, be non-nuclear. Most of NASA's rocket engineers were specialists in chemical propulsion and either did not understand or were openly opposed to nuclear flight. Moreover, NASA did not want to attract public criticism by being seen to favor atomic devices. Orion was ARPA's only space interest and in 1959 it decided it could no longer support the project on national-security grounds. Taylor then approached the Air Force which, after much persuasion, agreed to support Orion, providing that some military use could be found for it. However, Defense Secretary Robert McNamara was unconvinced that Orion could become a military asset, and his department consistently rejected any increase in funding, effectively limiting it to a feasibility study. For the project to take off literally, it was essential that NASA become involved, so Taylor and James Nance, a General Atomics employee and later director of the Orion project, made representation to Marshall Space Flight Center (MSFC). They put forward a new design that called for the Orion vehicle to be carried into orbit as a Saturn V upper stage, the core of the spacecraft being a 90,000-kg "propulsion module" with a pusher-plate diameter of 10 m (limited by the diameter of the Saturn). This smaller design would restrict the specific impulse to between 1,800-2,500 seconds -- a figure which, though low by nuclear-pulse standards, still far exceeded those of other nuclear rocket designs. The proposed shock absorbing system had two sections: a primary unit made up of toroidal pneumatic bags located directly behind the pusher plate, and a secondary unit of four telescoping shocks (like those on a car) connecting the pusher plate assembly to the rest of the spacecraft. At least two Saturn V launches would have been needed to put the components of the vehicle into orbit. One of the missions suggested for this so-called first-generation Orion was a 125-day round trip to Mars, involving eight astronauts and around 100 tons of equipment and supplies. A great advantage of the nuclear-pulse method is that it offers so much energy that high-speed, low-fuel-economy routes become perfectly feasible.

Wernher von Braun, at MSFC, became a supporter of Orion but his superiors at NASA were not so enthused, and the Office of Manned Spaceflight was prepared only to fund another study. Serious concerns surrounded the safety of carrying hundreds of atomic bombs through Earth's atmosphere. And there was worse news to come for the project. With the signing of the nuclear test-ban treaty by the United States, Britain, and the Soviet Union in August 1963, Orion, as a military-funded program calling for the explosion of nuclear devices, became illegal under international law. The only way it could be saved was to be reborn as a peaceful, scientific endeavor. The problem was that, because Orion was classified, few people in the scientific and engineering community even knew it existed. Nance (now managing the project) therefore lobbied the Air Force to declassify at least the broad outline of the work. Eventually it agreed, and Nance published a brief description of the first generation, Saturn-launched vehicle in October 1964. The Air Force, however, also indicated that it would be unwilling to continue its support unless NASA also contributed significant funds. Cash-strapped by the demands of Apollo, NASA announced publicly in January 1965 that no money would be forthcoming. The Air Force then announced the termination of all funding, and Orion quietly died. Some $11 million had been spent over nearly seven years.

Overshadowed by the Moon race, Orion was forgotten by almost everybody except Dyson and Taylor.1 Dyson reflected that "this is the first time in modern history that a major expansion of human technology has been suppressed for political reasons." In 1968 he wrote a paper2 about nuclear pulse drives and even large starships that might be propelled in this way. But ultimately, the radiation hazard associated with the early ground-launch idea led him to become disillusioned with the idea. Even so, he argued that the most extensive flight program envisaged by Taylor and himself would have added no more than 1% to the atmospheric contamination then (c. 1960) being created by the weapons-testing of the major powers.

Being based on fission fuel, the Orion concept is inherently "dirty" and probably no longer socially acceptable even if used only well away from planetary environments. A much better basis for a nuclear-pulse rocket is nuclear fusion -- a possibility first explored in detail by the British Interplanetary Society in the Daedalus project. See also nuclear propulsion and Project Prometheus.

Re:last link /.'d already (2, Informative)

AKAImBatman (238306) | more than 10 years ago | (#7965079)

Google Cache to the rescue!

Page 1 of the article [216.239.41.104]
Page 2 of the article [216.239.41.104]
Page 3 of the article [216.239.41.104]
Page 4 of the article [216.239.41.104]
Page 5 of the article [216.239.41.104]
Page 6 of the article [216.239.41.104]
Page 7 of the article [216.239.41.104]

more coming...

Why no Orion? (2, Funny)

magarity (164372) | more than 10 years ago | (#7964984)

We should still build a secret Orion and keep it handy in case of alien invasion.

Footfall! (2, Interesting)

DoorFrame (22108) | more than 10 years ago | (#7965121)

Just like Footfall [amazon.com] ! What a great book. I don't think anybody's read it though.

Re:Footfall! (1)

embeesh (560485) | more than 10 years ago | (#7965158)

I've read it. So have many of my friends. We probably don't count though!

Re:Footfall! (0)

Anonymous Coward | more than 10 years ago | (#7965161)

Way to go, spoiling it for everybody. (See the other AC reply for how to do it right)

Re:Footfall! (0)

Anonymous Coward | more than 10 years ago | (#7965170)

I have read almost everything Larry Niven and Jerry Pournelle have put out. Other than the aliens coming from Alpha Centauri (which seemed like a throwback to the age of pulp SF), I really enjoyed this book.

They've already invaded... (0)

Anonymous Coward | more than 10 years ago | (#7965124)

Haven't you seen that guy Michael Jackson on TV yet??!!

Re:Why no Orion? (0)

Anonymous Coward | more than 10 years ago | (#7965138)

There's already an SF novel with that idea! (Sorry, no spoilers.)

All well and good, but... (1)

The Angry Mick (632931) | more than 10 years ago | (#7964985)

It's the landings that have always seemed a little too "dirty" for my taste.

Cant we just (4, Funny)

CompWerks (684874) | more than 10 years ago | (#7964986)

Run a wire to the International Space Station and use straws glued to the sides of the rocket to guide them.

Now, I'm no rocket scientist, but I think you get the idea..

Uh (0, Offtopic)

Medieval (41719) | more than 10 years ago | (#7964991)

Is derriere REALLY that f'ing difficult to spell? If you can't even come CLOSE to spelling the word properly, DON'T USE IT.

Jesus christ, use m-w.com or something if you're not sure.

Re:Uh (3, Funny)

AKAImBatman (238306) | more than 10 years ago | (#7965010)

I've always seen it spelled "dairy-aire". But maybe that's just because I grew up in the Midwest. I'll take note of the spelling in the future. :-)

Re:Uh (1)

Medieval (41719) | more than 10 years ago | (#7965039)

No problem.

Mods: Why did you mod my post as offtopic? The poster misspelled a word by a mile and a half, and the brilliant editor failed to catch it. This is offtopic how, exactly?

Re:Uh (1)

Anonvmous Coward (589068) | more than 10 years ago | (#7965072)

"Mods: Why did you mod my post as offtopic? The poster misspelled a word by a mile and a half, and the brilliant editor failed to catch it. This is offtopic how, exactly?"

Did the mispelling cause confusion? No? What's your case?

Hint: You might not have gotten the mod if not for how hot-headed you were over it.

Re:Uh (5, Funny)

NanoGator (522640) | more than 10 years ago | (#7965030)

"Is derriere REALLY that f'ing difficult to spell?"

Is fucking really that fucking difficult to spell?

Re:Uh (0)

Anonymous Coward | more than 10 years ago | (#7965139)

nahh just most people are not as stupid as you.

some people have tact and class... why dont you get some?

idiot.

Re:Uh (1)

NanoGator (522640) | more than 10 years ago | (#7965171)

"some people have tact and class... why dont you get some?"

Said the guy posting anonymously to avoid retribution. (Yeah we don't know who you are.)

Belarus is ujndre attak!! (-1, Offtopic)

Anonymous Coward | more than 10 years ago | (#7964996)

Komrade, give me teh launche code, immeditaley! kekekekekke ^_^

Space Elevator (2, Redundant)

cflorio (604840) | more than 10 years ago | (#7964997)

I still think the Space Elevator [www.isr.us] will be the ticket for inexpensive space launches.

Re:Space Elevator (1)

ackthpt (218170) | more than 10 years ago | (#7965090)

I still think the Space Elevator will be the ticket for inexpensive space launches.

Fine for you, you probably don't get vertigo.

Re:Space Elevator (4, Insightful)

mark-t (151149) | more than 10 years ago | (#7965117)

You'd like to think so...

But unfortunately, the space elevator will be so obscenely expensive in terms of resources and labour to get going in the first place that though amortized over a large number of launches, the cost would indeed be low... they probably won't be willing to wait that long to recover their costs, so launches that way would be even more expensive than the methods we use currently.

Dairy-aire??? (0, Offtopic)

dchamp (89216) | more than 10 years ago | (#7965003)

Pardon your french... It's "derriere", french for "behind".

Re:Dairy-aire??? (1)

the_consumer (547060) | more than 10 years ago | (#7965085)

You've never been behind me when I've had too much cheese. I don't think I can generate significant lift, unfortunately.

My favorite part... (3, Funny)

Deltan (217782) | more than 10 years ago | (#7965008)

..."almost no radiation"...

Call me back when there is none.

Re:My favorite part... (5, Insightful)

Anonymous Coward | more than 10 years ago | (#7965059)

Call me back when there is none.

Quick, someone ban the sun.

And stop people from living in Denver or flying on planes or going skiing in the mountains.

And let's not forget xray machines, cathode ray tubes (TVs and computer monitors to you non-engineers).

And what about that deadly substance known as "granite" that releases radioactive radon?

Re:My favorite part... (0)

Anonymous Coward | more than 10 years ago | (#7965062)

I don't know where you're going to go to find a place where there's "no radiation." Do you live in a salt mine at the moment?

(Yay, as usual, for American science education.)

Re:My favorite part... (0)

Anonymous Coward | more than 10 years ago | (#7965082)

That depends on what "almost no radiation" means. I don't mind if it shoots out cell phone radiation at the rate of a modern tower or CRT radiation.

If it means alomost no alpha radiation (and that's it) then I have no problem. I'll just walk around in my paper suit.

Or maybe it means almost no gamma radiation. I wouldn't be too happy about that. My lead suit is really heavy.

Warning! Flee your home! (5, Funny)

Chris Burke (6130) | more than 10 years ago | (#7965083)

You are being bombared with deadly radiation right now! Coming from the ground, objects in your home, and worst, from mankind's eternal nemesis, the Sun itself. Please flee your home screaming and head for your nearest all-lead fallout shelter!

We'll call you out when it's safe.

Re:My favorite part... (1)

tonyr60 (32153) | more than 10 years ago | (#7965086)

Is "almost no radiation" low enough to pass vehicle emmision testing? And is it small enough to fit in the back of my Landcruiser? I just have this idea....

The pieces are starting to fall together... (1)

Thud457 (234763) | more than 10 years ago | (#7965163)

Could this be the DOD's "justification" for research into Stimulated Gamma Decay Weapons [slashdot.org] ?

Re:My favorite part... (1)

mi (197448) | more than 10 years ago | (#7965168)

I'd be satisfied not when pollution reaches zero, but simply when it becomes less than that of the currently used method(s).

Public Perception (5, Insightful)

Anonymous Coward | more than 10 years ago | (#7965016)

One of the biggest problems with anything Nulcear, be it power, subs, or rockets, there is a very negative public perception. You can tell people that it is safe all you want but there will always be that paranoia. It doesn't help that people don't neccesarily trust the government.

Re:Public Perception (0)

Anonymous Coward | more than 10 years ago | (#7965127)

You have a point there. Why would they call MRIs that when the origonal name is NMR. Apparently patients didn't like getting into anything called nulcear-anything.

Even if it is just nucleus releated.

Re:Public Perception (0)

Anonymous Coward | more than 10 years ago | (#7965131)

I bet there is a strong correlation between being anti-nuclear and supporting Howard Dean....

Hmm, should I post this now or wait until the parent gets modded +5, Interesting/Insightful? Because the /sheep will mod this as a troll instinctively....

Re:Public Perception (3, Interesting)

AKAImBatman (238306) | more than 10 years ago | (#7965160)

Ah, but that's the point of stories like this. Trying to explain to the public that *managed* dangers can bring tremendous benefits.

Heh (1)

smoondog (85133) | more than 10 years ago | (#7965020)

I'm not worried about the clean launches. What I'm worried about is the very dirty explosions (UF4 all over the place). I agree with the previous poster on spending money on the space elevator. Lets skip the flying dirty bombs.

-Sean

You don't say (1)

Highrollr (625006) | more than 10 years ago | (#7965021)

"Serious concerns surrounded the safety of carrying hundreds of atomic bombs through Earth's atmosphere."

Technological innovation (3, Interesting)

Anonymous Coward | more than 10 years ago | (#7965023)

I think it's great that the we are still seeing innovation in regards to propulsion for space-bound vehicles. I'm especially excited about the new concepts used in the Vostok [videocosmos.com] booster-like series that the Russian space agency is evaluating.

We're definately a long way from the V2 when some simple hydrogen would be ignited, and then Bob would be your uncle.

Radiation can be beneficial and should not be feared. Of course there will be some potential for accidents and some minor radiactive pollution, but it's all worth it in the case of scientific progress. We don't have clean water or clean air, and you don't city inhabitants rioting, or do you?

hrm.... (4, Funny)

xao gypsie (641755) | more than 10 years ago | (#7965037)

on Gas Core Nuclear Rockets
those have been around for years, and i have been fortunate enough to work with them for much of my life. they are called bean burritos. there is more explosive energy in one of those bad boys than most realize, especially when the chemistry behind the force is just right...granted, the fallout is pretty terrible too...

A joke, yes? (0)

Anonymous Coward | more than 10 years ago | (#7965092)

they are called bean burritos

This is what people in the USofA, call "humour", is it not? I do find it very amusing, sir. May we have another?

I can imagine the protests now... (5, Insightful)

DaRat (678130) | more than 10 years ago | (#7965040)

A few years back, I remember there being some amazingly loud protests from some anti-nuclear power folks about the dangers of a deep space probe going up with a nuclear power source. Those folks were worried about the danger if the rocket blew up on the pad or the 1 in 100,000 or so chance the probe would hit the earth on one of its acceleration orbits.

Just imagine how happy these folks will be with a nuclear powered rocket, even if the scientific community claims that they are safe. After all, it's nuclear related, so it's gotta be bad!! (tongue firmly in cheek)

Re:I can imagine the protests now... (1)

hondo77 (324058) | more than 10 years ago | (#7965099)

A few years back, I remember there being some amazingly loud protests from some anti-nuclear power folks about the dangers of a deep space probe going up with a nuclear power source. Those folks were worried about the danger...

Why? We all know space travel has been perfected and is 100% safe. Cough-Challenger-cough...COUGH-Columbia-cough.

Re:I can imagine the protests now... (0, Troll)

Darth23 (720385) | more than 10 years ago | (#7965113)

You mean the way the TWO Space shuttles came crashing to Earth? Launches blow up ALL THE TIME. When they're not manned, it's no big deal and barely gets covered. Now a rocket with a little URANIUM or worse, PLUTONIUM..... THAT woudl get news overage.

Within our lifetime? (4, Interesting)

addie (470476) | more than 10 years ago | (#7965042)

Could inexpensive cruises to the moon happen within our lifetimes?

I highly doubt it. As the last twenty years have shown, it's not the level of technology that determines how easily we get into space, it's the cost. And concepts such as these, while interesting to think about and develop, are ultimately going to take that many more decades to become proven.

Add to all this that the public would need a near-100% safety record in order to buy into a space tourism industry, and we're looking at more decades added onto the R&D and testing.

However, this kind of engine if developed properly COULD lower costs for putting satellites in orbit. So what's our benefit in the end? Lower satellite TV, telephone, and internet costs perhaps... But that's being optomistic.

But the design itself? Neat.

Hmmm (3, Funny)

odano (735445) | more than 10 years ago | (#7965046)

How many years are we talking about? The lease on my land on the moon is running out, and I need to know how soon I should renew.

I Don't Know About This... (-1, Interesting)

Trolling4Dollars (627073) | more than 10 years ago | (#7965048)

All I can imagine is some future generation of rich folks taking off in one of these things for a base on Mars. While their ship rains down nuclear radiation on the poor left behind on Earth, the last bits of whatever life support the ecosystem had left are destroyed. Oh well... I suppose that the rise of the working class against the rich might be more interesting if it was a war between two worlds.

in case/when the IIS server gets /.ed.... (5, Informative)

Anonymous Coward | more than 10 years ago | (#7965050)

(article text, minus pictures)

Opening the Next Frontier
by Anthony Tate

Part 1: The Frontier Spirit

America loves its legends. George Washington in Valley Forge. The Wild West. World War II. The Man on the Moon.

But lately, it seems the legends have stopped.

Sure, we have the Internet to play with now, and computers are changing the world in ways we can scarcely grasp as of yet. The Soviet Union is no more, and despite our current travails with terrorism, a certain comfortable familiarity has us in its grip.

Where is the next legend? Where is the next frontier? Or are we just going to go comfortably off into retirement?

If the 'entertainments' of the kids these days are any indication, no way.

Extreme sports, fun little things like 'base jumping' and other diversions indicate that the next generation of Americans are harkening back to their roots in a big way. America is ready for the next challenge, refreshed, revitalized, and shaking off old fears and inhibitions.

But what could have caused our recent doldrums?

Why have we not gone back to deep space, that logical 'Final Frontier,' for so many years after Apollo? I believe it was a confluence of several factors, most of which have now passed, that caused us to huddle close to the bosom of Mother Earth for these past decades.

Part 2: What went wrong.

To be blunt, it was the 70's.

After the turbulent change of the 60's, the 70's were just a hard time for America. The Cold War dragged on and on, no end in sight. Vietnam was a horrible, bloody mess, deeply misunderstood to this day, and bitterly divisive even in the aftermath. Watergate destroyed the faith of millions in their own government. The Oil Embargo shocked the economy as well, causing the nightmarish condition of 'stagflation.' Cultural upheaval became the norm as gains in civil rights were cemented into place.

With that litany of bad news, there is little wonder that the public lost interest in space. When you are scared for your job, your children, and whether or not your paycheck next year will still cover the rent, idealism and exploration goes out the window.

Also, lets be honest, landing on the Moon in the 1960's was an incredible feat. That entire rocket, the whole plan, was designed, built, and flown using less computing power than you have in your PC. Genius level effort was used to make that program possible, and the chance of disaster was perilously high, even by the comparatively relaxed standards of the day. In other words, Saturn was ahead of its time, by many years.

If it wasn't for the Cold War imperative to beat the Soviets, we'd probably be looking to go to the Moon right about now, all things considered.

Add in the fact that science itself was throwing up massive roadblocks, and there is little surprise to be had from the seeming 'retreat from space.' The rocket fuel used in the Saturn V moon rocket at launch was BETTER than the rocket fuel used to launch the Space Shuttle today. Why is that? Well, it's simple: The chemical fuels used in the Saturn V are among the best fuels that chemistry allows. Science is remarkably inflexible: unlike in the movies we can't just 'whip up' better rocket fuels. Chemistry is pretty stubborn that way.

So, exploring further in space was not important to the country while we had other problems to deal with, and making rockets better than the SaturnV was pretty much impossible.

So, NASA went sideways for a while. The Space Shuttle is a remarkable system, but it is at its core a compromise. So while it is good at many things, it is great at nothing. But nonetheless, the Space Shuttle kept America in space, and slowly we were building momentum to move forward once again away from the Earth.

Then Challenger blew up (and now we've lost Columbia and her crew as well).

Now, to the doughty folks who made Apollo fly, that disaster would have been a learning experience, and development would have continued. To the folks in the 80's it was a stunning, shocking, stomach-churning event. See, the counterculture of the 60's had grown up by the 80's, and was wielding considerable political and social clout. Why spend money on dangerous rockets when that same money could be put to better use performing good deeds?

But as always, American restlessness asserted itself, slowly and surely. The Shuttle flies again. A new Space Station, terribly crippled for now but THERE, flies.

And a new generation, who think slamming themselves into cement looks like fun, are looking around and saying, 'So, like, where do we go next?'

I find this very promising.

Part 3: Where do we go next?

Oh, there are MANY places to go and things to do. Lets take a quick look at a few.

Mars: The obvious place is Mars. NASA is exploring Mars in great detail, and has found literal oceans of water. Water is like treasure undreamed of in space, finding oceans of the stuff so close by is a tremendous draw. Mars has never been touched, who knows what wonders and riches lie on the ground there, waiting to be gathered up. And think of the ROOM! Mars is a small world, but without those huge oceans to cover it, the land area on Mars is as big as all the land on Earth. What a land rush, just waiting to happen!

Luna: Yes, we've already been to the Moon, but there is treasure there, as we have recently realized. Nuclear fusion is the dream of many for clean energy here on Earth, but the best fusion fuel that we can imagine is called Helium 3. Earth doesn't have any Helium 3 to speak of, but there is lots of it on the Moon. Once we get fusion mature enough to burn Helium 3, treasure lies on the Moon. At today's energy prices, Helium 3 is worth billions of dollars per ton. The Moon has lots more than a ton. Oh, and you remember what I said about water? Well, the Moon has water, too. Not a lot, but its there.

Lagrange points: The Earth-Moon system L4 and L5 points are two stable points in space in the same orbit as the Moon, but a sixth of the way before and behind it in its orbit. They have been looked at for decades as great places to build stuff in space, such as huge solar power satellites. The power could be sent to Earth, or the Moon, or used right there. Plus, there are the L1 and L2 points. The Earth-Sun system has a different L2 point which would be perfect for deep space astronomy. As a matter of fact, we are already planning to put the replacement for the Hubble Space telescope there. Imagine how much more reliable that replacement would be if we could actually go out there and do work on it. As it currently stands, if something goes wrong, that new instrument is useless. Imagine if the same fate had befallen the Hubble, as it so nearly did!

Asteroid 1982DB: I bet you've never heard of this one. This little lump of rock and metal has the distinction of being an asteroid that is one of the easiest to get to from Earth. I pick it because we've known about it for 20 years, but it is far from alone, there are a hundred other known asteroids almost as close, or even closer. Even one small asteroid is enormously large. 1982DB has more mass than every car in the United States, and it's already in orbit above our heads, and very close by indeed. Enterprising souls have worked out how to 'nudge' 1982DB and use the Moon to capture it and bring it into an orbit around Earth. Suddenly, those astronauts on the Space Station would have plenty of stuff to work with. The dollar value of such a second moon is almost impossible to overstate. Steel, carbon, oxygen, silica, nickel, rare earths, all in huge abundance, all in space already. Plus, the few looks at asteroids we have gotten so far show us that more precious metals are there in abundance. Gold, platinum, silver, copper, all are in asteroids in huge amounts, close by, waiting for us to go and get it. Plus, mining in orbit means no pollution on Earth! Also, note that not one of the hundred asteroids I mention above is in the Asteroid Belt. We have no need to look that far afield for incredible amounts of stuff.

Jupiter: Talk about your SIGHTSEEING! The moons of Jupiter are like a whole other Solar System. There is so much to do and see at Jupiter, I can't imagine why we aren't trying to get there NOW. Plus, the resources available in the Jovian system of moons hugely exceeds everything I have described so far.

There are many other places to go and things to do, if only we can get there.

Part 4: So, why aren't we going?

The mood of the country has changed, at last. The mass swell of the 60's counterculture is passing through its lifecycle, and slowly clearing the way for new, younger, more aggressive leaders and thinkers. Slowly but steadily America is looking for those new frontiers. We are tired of resting on the laurels won for us by our grandfathers.

But one huge hurdle remains. While America's mood is looking for adventure, and our technology has emphatically progressed to the point that we can tackle hurdles of this size with less than a Herculean effort, science has not altered its rules one little bit.

And that is why the Space Shuttle uses fuels that are not even as good as the ones the moon Rocket used. We are stuck.

Sure, there is research into high energy metastable fuels. Liquid Ozone has been investigated as a possibly better oxidizer, but even with our better technology we can't make it stable enough to use.

Metallic hydrogen also has great potential, but we can't even make it last a few seconds, never mind make rocket fuel out of it. Spin-stabilized triplet helium also has huge potential, but it's even harder to make than metallic hydrogen. Sadly, it looks like chemistry is just not going to be amenable to our desires, at least not anytime soon. By anytime soon, I mean 'this century.' Metastable fuels are HARD.

So, it looks like we are stuck, despite our newly adventurous mood.

Well, not quite, but getting past the stubbornness of chemistry requires that we cheat. Or maybe make a little deal with the Devil.

Part 5: Dealing with the Devil

What is the Devil? Well, it's everybody's favorite villain, nuclear power.

Oooh, scary, isn't it?

Nuclear power has gotten a terribly bad reputation. According to the press you read, it is dangerous, poisonous, pollutes the Earth, kills bunnies, and generally is Bad. Why, oh why, would anyone even consider using such a terrible thing?

Because it is very, very powerful, like any terrible thing should be.

Remember, chemistry is failing us here. Chemical rockets are just about as powerful right now as they are ever going to get. We have two options for going out into the rich bounty of space. We wait a very, very long time for metastable propellants to finally be developed. Or we use our shiny new technology to tame that nuclear Devil and put it to work. Kind of like fire.

A few words about nuclear power and radiation. Despite all the bad press, nuclear power has killed almost no one compared to risks that we take without thought every day.

Yes, Chernobyl was a very bad accident. But bad accidents happen all the time, and are often much, much worse than Chernobyl was.

For example, Bhopal, India, makes Chernobyl pale in comparison, but we don't stop using all chemicals. According to the UN, burning coal kills 2 million people a year in India. For that matter, burning coal in the United States belches thousands of pounds of Uranium into the air you are breathing right now, millions of times more radiation than nuclear power plants do.

As for nuclear power plants: Every nuclear power plant in the United States was designed decades ago. We have put more effort into building better cars than we have into building better nuclear power plants. Compare the safety, comfort, and efficiency of a car today to a car in the 1960's. Air bags? Seat belts? Anti-lock brakes? Traction-control? Engine control computers? Air conditioning? Remember when cars had manual chokes? How about dieseling? Kids today don't even know what 'pre-detonation' means, much less why its bad for a car. In other words, we could do much better with nuclear today if we wanted to.

I think the Cold War scares about nuclear bombs were the worst, though. Don't get me wrong, nuclear bombs are very scary things, but they are not the only use of nuclear power. We have been throwing out the baby with the bathwater for many, many years. It's time to be sensible about nuclear power. Given that the young people in America these days seem much less timid than their 'counterculture' parents were, I think we can finally look at nuclear power with honest eyes, not ones clouded with irrational fears.

Now, as it turns out, the smart and brave folks who built the Saturn V also knew that they were using the best chemical fuels we were likely to see for a very long time, so they experimented with nuclear powered rockets. They made tests of solid cored nuclear rockets using pure hydrogen as fuel. The NERVA and ROVER programs were only two that experimented with this sort of concept, and even using the primitive means available 40 years ago, the rockets they built were twice as efficient as the best chemical fuels we use today.

That sturdy foundation is what will take us to space for real this time.

Part 6: A brief technical interlude

This should be quick, so hang with me. If you are already comfortable with rocket jargon, feel free to skip ahead to section 7.

Rockets are measured using totally different units and measurements than more familiar machines, like cars. Cars use horsepower and miles per gallon. Rockets use Specific Impulse, DeltaV and Thrust.

Everybody knows what MPG means, but a quick explanation of rocket terms is needed.

First is Thrust. Thrust is how hard a rocket pushes itself along. It is usually measured in pounds force(pounds) or kilograms force or newtons. If one rocket produces a million pounds of thrust, and a second rocket produces three million pounds of thrust, the second one is three times as 'strong' as the first one. So, thrust is sort of like horsepower.

Second is acceleration. Acceleration is measured in meters per second squared, or more crudely in 'gravities.' A gravity is roughly 10 meters per second squared. For simplicity, I will use gravities. If a rocket has exactly as much thrust in pounds as it weighs in pounds, then it accelerates at exactly one gravity, or 'g.' Using the two rockets from above, if the one that makes a million pounds of thrust weighs a million pounds, then it can accelerate at one g. If the second one weighs 2 million pounds and makes three million pounds of thrust, then it accelerates at 1.5 g's. Simple! Now, as the smaller rocket example shows, if you have equal or less thrust than your rocket weighs, you can't get of the ground. Bigger thrust is usually good. Acceleration is sort of like power to weight in cars. If a tiny motorcycle has 100 horsepower, and a big car also has 100 horsepower, obviously the motorcycle will accelerate faster than the car will.

Third is Specific Impulse. Specific Impulse is often abbreviated as Isp. Isp is a little more complicated, but it is very important. Isp is sort of like the fuel efficiency of a rocket. It is easiest to explain with an example. The two giant rockets we use to launch the Space Shuttle have an Isp of about 250 at takeoff. What this means is that for every pound of fuel they fire out the back in a second, 250 pounds of thrust is generated. Simple! Another way of looking at it is if you have an Isp of 250, you can make one pound of thrust for 250 seconds. High Isp is very important for efficient rockets. Isp is very like fuel economy for a car. If one car has a very old motor that makes 100 horsepower but gets 5 miles per gallon, and a second car has a new motor that makes the same 100 horsepower but gets 50 miles per gallon, which one would you rather have?

Fourth is DeltaV. Very cryptic sounding, isn't it? Measuring distance in space is very different than measuring distance on Earth. Since there is no air or anything else, once you have built up some velocity, you just keep going. So, the only limit on how far you can go (assuming you are patient) is your ability to speed up at the beginning of the trip and then slow down at the end of the trip. This change of velocity is how you measure the ability to get from one place to another in space and is called deltaV. DeltaV is measured in kilometers per second(kps), or meters per second for small amounts. An example is that it takes about 8.5 kps to go from the surface of the Earth to a low Earth orbit. (As our further talks will show, getting that 8.5 kps is pretty tough.) DeltaV is sort of like the fuel tank of a car. If you have a car with a fuel tank that will take you 100 miles, and a second car with a fuel tank that will take you 200 miles, the second car will take you twice as far on one tank of gas. Simple, isn't it!

Part 7: So how good is Nuclear, anyway?

VERY good. Fission and fusion and antimatter have the ability, once we build them, to get us anywhere in the Solar System with ease. Chemicals on the other hand can barely get us into orbit.

For this discussion, I will stick to nuclear fission. Fusion/antimatter is more complicated, and I like simple.

As I mentioned above, way back in the 60's NERVA and ROVER made nuclear powered rockets. These rockets were thoroughly tested and were able to generate as much as 250,000 pounds of thrust, with an Isp of 900 seconds or better. The best chemical fuels in use today are liquid hydrogen and liquid oxygen, the stuff burned by the three Main Engines on the Space Shuttle (SSME's). The SSME's produce a maximum of about 450 Isp.

NERVA did this using technology that still used vacuum tubes. And not because they 'sound better' than transistors.

Now, technically speaking all rockets that use a reactor to heat up a gas to make thrust are called Nuclear Thermal Rockets (NTR's). An NTR like NERVA is what is called a solid core NTR, since the reactor core was a heavy solid mass of ceramics.

The efficiency of any NTR is limited by the difference in temperature between the core and the gas. The bigger the difference, the more efficient the rocket is. I'll repeat that, because it is an important principal: A nuclear rocket is more efficient when the reactor runs hotter.

NERVA was pretty hot, basically running just barely under the temperature that would start the core ceramics melting. The smart guys who came up with this concept way back then were not satisfied with that however. They came up with an even more efficient system, in which the core of the rocket was not a huge solid mass of ceramic, but it was a cloud of Uranium HexaFluoride gas. Since the core started out as a cloud of gas, it couldn't melt! Therefore it could get much hotter than a solid core rocket, and would thus be much more efficient.

This idea was dubbed the Gas Core Nuclear Rocket, or GCNR for short. The way a GCNR kept the gaseous core in a single mass was the height of simplicity:

Imagine a pot of hot water. You stick in a spoon and begin stirring it in a circle, as fast as you can. Soon, a deep funnel shaped hole appears in the center of the water. If you then crack an egg into the pot, it settles quickly into the bottom of the funnel, which is called a vortex, and cooks all the way through without ever touching the pot itself. Now imagine the water is a buffer gas, and the egg is the Uranium Hexafluoride fissile mass. Simple, isn't it.

They built test models of the GCNR many years ago, and discovered a little problem. Since the core was a hot gas, when you pumped the fuel gas through it to get it hot, the radioactive core gas would leak out through the exhaust. This is a real problem. Luckily, they were able to figure out a way to get around this issue. To fully understand this concept will take a little explaining, but bear with me.

Part 8: Heat, temperature, and cooling.

Now, in a Nuclear Thermal Rocket (NTR) we have to get the heat out of the nuclear reactor part of the engine and into the gas we plan to shoot out the back. In a solid core reactor this is done using conduction. IE, you drill hundreds of holes right through your reactor core and pump the gas through them. The gas picks up heat by rubbing along the inside of the reactor, and then blasts out the back. This worked great, but as I said above, you can't run the reactor very hot, since it melts.

With a gas core reactor, you can use a combination of conduction, where the hot reactor gas rubs against the cold fuel gas, and convection, where small amounts of the hot core gas mixes with the cold fuel gas. This is more efficient than conduction alone, with the huge problem that now you are leaking radioactive core gas out of your rocket. This is bad for a lot of reasons.

Luckily for us, there is a third way of moving heat around, and that is radiative. Under most conditions, radiative heating is very small compared to conduction or convection, and can be ignored. However, the inside of a GCNR is not 'most conditions.'

The way this works is simple. If you turn on an electric stove element, and put your hand off to one side of it but not touching, you still feel the heat. That is radiative heat transfer working.

In a GCNR, the core is run SO hot, it lights up like a lightbulb, and then gets much, much, much hotter. The energy being given off goes above red hot, even goes above white hot, until the core is blazing away in the deep ultraviolet. Yes, it gets so hot you can't see it any more.

At those huge temperatures, the normally small radiative heat transfer mechanism grows until it is easily big enough to get the energy from the core into the reaction gas all by itself. You no longer need to mix the two gases together, and you can keep them separate. But how can we do that, if the core is so super hot?

The answer is fused silica.

Silica is very transparent to ultraviolet light. If we treat the core like a real lightbulb and put a dome of fused silica glass around it, the glass lets basically all of the ultraviolet energy shine right through. Even though it seems impossible, the smart fellows back in the 70's actually built test models of this type of system and made it work. Given the technology we have today, we can make fused silica of such perfect transparency that this works great.

A GCNR with one of these bulbs in it is called a nuclear lightbulb. With today's technology we can build these pretty easily.

Part 9: But isn't this dangerous?

Of course it is! Cars are dangerous. Planes are dangerous. Storms are dangerous. Anything powerful is dangerous.

The Space Shuttle is dangerous, for example. The Space Shuttle generates about 100 gigawatts of power when it is launched, or as much as 50 big nuclear power plants. Plus, the exhaust gases left behind by those huge rockets are not very safe to breathe, either. Not to mention the number of workers who have died in accidents while getting it ready to fly.

Power is dangerous. But the way to stop dangerous from becoming deadly is to be aware of the danger, and take steps to avoid that danger. This is also called risk mitigation. Since the Space Shuttle has flown well over a hundred times so far, we have had a LOT of practice in risk mitigation in this kind of a system.

I can already imagine folks reading this saying, 'Yeah, but the Space Shuttle isn't nuclear!' This is true. But nuclear radiation isn't some magical, evil thing. Radiation is part of nature. The Sun is radioactive, but we aren't all dead from it. The Sun is dangerous too, as anybody with a sunburn will tell you, and many people die of sunstroke and sun poisoning every year. Yet nobody advocates living in caves because of the dangerous Sun. In other words, we know how to handle radiation, we just have to be careful.

Let's examine exactly how much risk we have from using a nuclear rocket to get to space.

Suppose we have a nuclear rocket. Suppose it has 10 pounds of radioactive nuclides in it.

'Radioactive nuclides' is not the fissile fuel, it is the waste generated after that fissile fuel has done its thing and the atoms have split. Surprisingly enough, fissile fuel before you use it is not terribly nasty stuff. You wouldn't ask it home for dinner, but it is not 'kill you in your tracks' stuff either. No, the nuclides left after you use it is the mean stuff, which is why we want to discuss it now. Ten pounds of radioactive nuclides doesn't seem like much, does it? You could hold it in one hand, easily.

Well, it is a lot, trust me. To put it into perspective, all of the radioactive nuclides that were released by Chernobyl were also about 10 pounds worth. That's all. Just ten pounds was enough to kill nearly 40 people and generate a terrible panic among hundreds of thousands of others.

Sounds pretty bad, doesn't it?

Well, let's compare our ten pounds of radioactive nuclides to something else, like the Ivy Mike nuclear bomb test which took place on November 1st, 1952. This is a real test, you can go look it up. Now, when Ivy Mike happened, it obviously released radioactive nuclides into the air. How much?

1023 pounds worth, that's how much.

Holy Cow! That old nuclear test back in 1951 was 100 times worse than Chernobyl! There must have been terrible casualties because of it! How did anybody survive such a huge release of radiation? Thousands of people must have died!

Well, no, as a matter of fact, not a single person died, or was even hurt, by that huge release of radiation. Why not?

Because we knew it was going to happen, and we planned for it. In other words, the risk was mitigated.

Now, given the many, many years of experience we have with launching rockets like the Space Shuttle, I can confidently say that we treat rockets much more like a nuclear bomb than we do a quiet power plant. The only reason Chernobyl was a disaster was because it was a surprise. If we had had even a day to get ready, nobody would have been hurt, and nobody would have died.

A nuclear powered rocket, even a HUGE one like I am about to describe in the next section, is not very dangerous on a global scale because we can launch it from a safe place (like the middle of the Pacific Ocean), and we can be prepared for any problems that occur because we know exactly when we are going to launch it. We can tame this Devil.

We have tamed much bigger ones in the past, and the world did not end 50 years ago, did it?

Part 10: Prometheus would be proud of us.

In this section I describe a huge nuclear powered rocket launcher. I will repeat and expand upon many of the points I made above, because I don't want to throw cryptic acronyms around. I want people to understand just how powerful we can make this rocket if we decide to do it.

The effective use of nuclear power in space transportation allows a paradigm shift in our thinking. All boosters which have been built to date have been shackled by the low efficiency of chemical fuels. Using chemicals it is possible to get off earth, but only barely. Every gram of structure must be trimmed, exotic materials and cutting-edge techniques are a necessity, and safety margins must be as slim as we dare if success is to be achieved.

Nuclear power changes all that. Nuclear is VASTLY more energetic than chemical. We no longer must guard every gram of mass. Much more "margin" can be included. Much more safety can be designed into the machine.

Let's examine a large heavy lift booster. There are other kinds of nuclear rockets we could build, but we desperately need a heavy lift booster if we are to excite people, catch their dreams, and actually do big stuff in space.

The most powerful booster America has built to date was the Saturn V. The size and weight of the Saturn V are easily accommodated by existing infrastructure.

Lets use the Saturn V as a "template" for a nuclear powered heavy lift booster. We will make the launcher roughly the same size, weight and power as the Saturn V, and let's see how the performance compares.

The most important difference between our new booster and the Saturn V is in the engines. The Saturn V used five massively powerful F1 engines in the first stage, burning kerosene and liquid oxygen. The mighty F1 produced 1.5 million pounds of thrust. Despite its large size and power, the F1 was a very "relaxed" design. It ran well inside the possible performance envelope. The reason it did so was to increase reliability. This is a sound design principle, so I will apply it to the new launcher wherever possible.

For an engine, I will designate a Gaseous Core Nuclear Reactor design, of the Nuclear Lightbulb subvariant. I like the gas core design for a number of reasons, and the nuclear lightbulb variant for several more.

To recap, the efficiency and power of the thruster is based on the difference in temperature between the fissioning mass and the reaction mass. If you run a solid core NTR much above 3000 C, it melts. This provides a firm "ceiling" on how efficient a solid core reactor can be. A gas core design STARTS melted. In addition, since all of the structure of the fuel mass is dynamic, a gas cored reactor is inherently safer than a solid core device. If a "hot spot" develops in a solid core, disaster ensues. If a hot spot develops in a gas core, the hot spot superheats and "puffs" itself out of existence. A gas core reactor is expected to operate at temperatures of 25,000C. The much higher temperature gradient makes the thruster inherently more efficient.

Second, a solid core reactor has a "fixed" core, since it is solid. A gas core reactor does not, and the radioactive fuel is easily "sucked" out of the core and stored in a highly non-critical state completely out of the engine! The fuel storage system I propose is a mass of thick walled boron-aluminum alloy tubing. As I said above, the fuel proper is uranium hexaflouride gas. UF6 is mean stuff, but we have decades of experience handling it in gaseous diffusion plants, and common aluminum and standard seals are available which resist attack from it. It is stoichiometric, fluorine is low activation, and UF6 changes phase at moderate temperatures, allowing it to be converted from high pressure gas to a solid and back again using nothing fancier than gas cooling and electrical heaters. This naturally makes dealing with the engine easier.

In addition, the design of the gas core allows the addition and removal of fuel "on the fly." The core can also have its density varied by control of the vortex, which directly affects criticality. Both of these elements allow very potent control inputs to be applied to a gas core reactor which are very stable and unaffected by the isotopic condition of the fuel mass.

Also, to repeat, due to the extremely high temperature gradient in the motor, the main cooling of the fissioning mass is not conductive but radiative, a mode which is inherently less susceptible to perturbations. (Having no working fluid for cooling means no material characteristics for the working fluid must be considered.) This radiative cooling mechanism is what allows the "lightbulb" system to work. The silica bulb just has to be transparent enough to let the gigantic power output of the fissioning core flow through, while keeping the radioactive material of the core safely contained inside the thruster. No radioactive materials leak out of the exhaust, it is completely "clean."

Third, a gas cored reactor has several potential "scram" modes, both fast and slow, and the speed of the reaction is easily "throttled" by adding and removing fuel or by manipulating the vortex. A 'scram' is an emergency shutdown, usually done in a very fast way. For example: a gas cored reactor can be fast scrammed by using a pressurized "shotgun" behind a weak window. If the core exceeds the design parameters of the window, which are to be slightly weaker than the silica "lightbulb," then the "shotgun" blasts 150 or so kilos of boron/cadmium pellets into the uranium gas, quenching the reaction immediately. A slightly slower scram which is implemented totally differently is to vary the gas jets in the core to instill a massive disturbance into the fuel vortex. This disturbance would drastically reduce criticality in the fission gas. A third scram mode, slightly slower still, is to implement a high-speed vacuum removal of the fuel mass into the storage system. Having three separate scram modes, one of which is passively triggered, should instill plenty of safety margin in the nuclear core of each thruster.
Extensive work was done on gas core reactors, and 25 years ago several experimental designs were built and run successfully. There were technical challenges, but nothing that seems insurmountable or even especially difficult given our current computer and material skills.

The engine I propose is this:

A Gas cored NTR using a silica lightbulb. The silica bulb is cooled and pressure-balanced against the thrust chamber by high pressure hydrogen gas. The cooling gas from the silica bulb is used to power three turbopumps "borrowed" from the Space Shuttle Main Engine. These pumps are run at a very relaxed 88 percent of rated power at their maximum setting. The three pumps move 178 kilos of liquid hydrogen per second combined. Most of this is sprayed into the thrust chamber. A portion of the liquid hydrogen is forced into cooling channels for the thrust chamber and expansion nozzle, where a portion of it is bled from micropores to form a cooling gas layer. The gaseous hydrogen that is not bled then flows down the silica lightbulb to cool it, and the cycle finally goes into powering the turbopumps.

This engine produces 1,200,000 pounds of thrust, with an exhaust velocity of 30,000 meters per second, from a thermal output of approximately 80 gigawatts. This equates to an Isp of 3060 seconds. Several sources state that a gas core NTR can exceed 5000 seconds Isp, so 3060 is well inside the overall performance envelope. The three turbopumps from the SSME are run at low power levels, and even losing a pump allows the engine to continue running as long as there is no damage to the nuclear core. Lets assume this design is able to achieve a thrust to weight ratio of ten to one, so the engine and all of its safety systems, off-line fuel storage, etc, weighs 120,000 pounds. I think we can build this engine easily for 60 tons.

We have the engine. Now to design the entire vehicle.

Since we are using the Saturn V as our template, we will make the new machine about the same weight, or six million pounds launch weight. With our engines giving 1.2 million pounds of thrust, we need at least five to get off the ground. But, since we have the power of nuclear on our side, we will use seven engines instead of five. Why seven? The most vulnerable moments of a rocket launch are the first fifteen seconds after launch. If we have to scram a motor in those fifteen seconds, having two extras is very comforting. Engine failures further along the flight profile are much easier to recover from, and having two spare engines allows us to be very "chicken" on our criteria for scramming a motor. We can shut one down even at one second after launch if we need to with no risk of crashing the entire vehicle. This further lowers the risk of nuclear power as a means of getting off the earth.
With seven engines, we have a thrust of 8.4 million pounds available. In addition, the turbopumps can "overthrottle" the engines easily in dire straits. This gets more thrust at the expense of less Isp.

Let's design the vehicle for a total DeltaV of 15 km per second. This is very high for a LEO booster, but the reason for it is to allow enough reaction mass to perform a powered descent. In other words, this is a true spaceship, that flies up and then can fly back down again.

The formula to calculate DeltaV from a rockets mass is:
DeltaV = c * ln(M0/M1).

'c' is exhaust velocity of the engines and equals 30,000 m/s.
'ln' is the natural log.
'M0' is the initial mass of the vehicle, and we have set this to be 6 million pounds.
'M1' is the mass of the vehicle when it runs dry of reaction mass.

The value of M1 is what we need to find, since we know we want a total DeltaV of 15,000 m/s.

Doing a little simple math, we find we need 2,400,000 pounds of reaction mass. Since we are using liquid hydrogen, we can now calculate the size of the hydrogen tank needed, which is 15,200 cubic meters. This works out to be a whopping 20 meters in diameter and 55 meters long!

We look at the Saturn V and find our new booster is going to be quite plump compared to the sleek Saturn V, but we have no choice if we want to use liquid hydrogen as reaction mass. Since hydrogen is the best reaction mass physics allows, and is cheap, plentiful, and we have decades of experience handling it, we will use it.

A design height of 105 meters seems reasonable. We assign 15 meters to the engines, 55 meters for the hydrogen tank, 5 meters for shielding and crew space, and a modular cargo area which is 30 meters high and 20 meters in diameter. This is enough cargo space for a good sized office building!

How heavy is the rest of the vehicle? Well, we already decided that the engines are going to weigh 120,000 pounds each, for a total of 840,000 pounds. (To make a comparison, the entire Saturn V, all three stages, engines and all, weighed a mere 414,000 pounds dry.)

Let's splurge here. With nuclear power, we have the power to splurge. Let's use 760,000 pounds to build all of the structure of the new booster. We use thicker and stronger metal, we use extra layers of redundancy, we make it strong and safe and reliable.

We have now used 2,400,000 pounds for reaction mass, 840,000 pounds for the engines, and 760,000 pounds for the rest of the ship's dry structure. This adds up to 4,000,000 pounds, fully built, fully fueled, ready to launch.

But we said at the beginning, the booster has a design launch weight of 6,000,000 pounds! If it only weighs 4 million pounds ready to launch, the rest must be cargo capacity.

This machine has a Low Earth Orbit cargo capacity of TWO MILLION POUNDS.

It is fully reusable. We gave it enough fuel to fly back safely from orbit.

It has MASSIVE redundancy and multiple levels of safety mechanisms.

Its exhaust is completely clean: It is very difficult to make hydrogen radioactive in a fission reactor. It basically can't happen.

It flies to space with a thousand tons of cargo, and flies back using some gentle aero-braking and its thrusters with another thousand tons of cargo.

This means it has eight times the cargo capacity of the Saturn V, which was not reusable at all. No longer will the Saturn V be the mightiest American rocket. No more resting on our laurels.

With this sort of performance potential, can anyone argue that NTR's are NOT the only sensible course for heavy lift boosters?

There are risks, of course, but careful design and the proper launch site can easily mitigate those risks so that the huge advantages of nuclear propulsion can be realized.

Part 11: Ok, that all sounds nice, but this is just fantasy, right?

Well, no.

The sort of huge nuclear powered booster described above is pretty far out, but it is based on technology and ideas that are decades old. Modern technology just makes it possible to make the design more powerful while keeping it safe, but the concepts and design principals are all well established.

Indeed, NASA has been bringing up the scary 'nuclear' word more and more in the last few years, dipping a cautious toe to see what the mood of the country is. They seem to find that mood agreeable, as more and more nuclear projects get looked at.

As well, the government recently approved funds to construct a new facility in the US deserts to test nuclear rockets, the SAFE facility. In the 60's we could just test them out in the open. Enough of the unjustified nuclear paranoia of the last three decades has infected the government that they desire to be insanely cautious. But the important thing is, progress has begun.

Nuclear power is really the only viable option to open space to our use. Fortunately, the government finally realizes that fact and is slowly moving to capitalize on it.

Part 12: But isn't this just too big?

Well, a one thousand ton capable booster is certainly much too large to perform the sorts of commercial missions of today. Heck, a one hundred ton capable booster is probably too large.

But that is assuming the commercial missions won't change. I believe there is a huge pent-up demand for resources in space, and if we could put huge payloads into orbit, uses for those payloads would appear quickly.

Orbiting hotels could be made in thousand ton chunks and orbited high enough to provide truly spectacular views. Those hotels could be shielded by enormous masses of material from a captured asteroid. L5 would also be a useful place to place such structures, and with such a powerful booster system, getting to the L5 point would be trivial. When you can designate a few hundred tons to radiation shields, space is suddenly a much safer place for humans. Not to mention recent breakthroughs in radiation resistant clothing.

Or imagine the exploration capabilities. NASA and others have designed many, many deep space exploration missions, all of which have one fatal flaw: They are too heavy. The smallest feasible Mars expedition requires 150 or so tons in Earth orbit, which takes 5 trips on the most powerful rocket flying today, the Space Shuttle.

A large nuclear powered booster could put six times that mass in orbit in one flight! If we have a large capable booster, the Solar System is easy to get to. Others have designed spacecraft to carry men all the way to Jupiter and back, which requires a mere 750 tons in Earth orbit.

We could go to Jupiter in 20 years. We could really explore the asteroid belt. We could have the ability to stop a 'dinosaur-killer' asteroid before it hits us.

Imagine a permanent space station around Saturn. Think of the science we could do there, imagine the pictures, imagine the knowledge, if scientists could go there and look for themselves for years at a time, not simply get pictures trickled back with agonizing slowness.

So, yes, this booster is far too big for what we do in space now. It is just right for what we should be doing in space for the near future.

Part 13: But doesn't this thing make nuclear waste?

Ahhh, this is possibly the best part of the whole system. Yes, it does make nuclear waste, but unlike all Earth-based nuclear power, the disposal of this nuclear waste is built into the system. Indeed, with just a little work, this sort of a nuclear booster could get rid of more waste than it makes.

How does it do this? It shoots it into the Sun!

I can see you all out there rolling your eyes. For how many years have we been wishfully saying, 'why don't we just load it on a rocket and shoot it into the Sun.' Well guess what, when you build a nuclear powered rocket, it is positively easy to use that same rocket to do exactly that.

Here's how: Almost every rocket, as it gets into orbit, shuts off its motors for about 45 minutes, then fires them again one last time, halfway around the Earth. The reason for this is a little complicated, but can be summed up simply. Since the Earth is round, your orbit around the Earth had better be round too. And it's a lot easier to make round orbits if you do that small 'circularization' burn halfway through your first orbit. We will use this standard feature of rocket travel to get rid of our nuclear waste.

In a traditional chemical rocket, the circularization burn is used to add a tiny bit more speed to the spaceship, making the orbit nicely round. In this nuclear system, we have so much power to burn that we deliberately 'overshoot' on the way up, so the circularization burn is a lot larger than normal.

Now, if you will remember, up above I mentioned that the exhaust of this nuclear spaceship shoots out at a whopping fast 30 kilometers per second. If you add this 30 kilometers per second to the 8.5 kilometers per second the whole rocket is moving while in orbit, and you point your rocket in just the right direction, you can literally shoot the exhaust right away from the planet so fast that it never comes back. You can then aim it to drop into the Sun without too much trouble.

Now, the radioactive spent fuel of this rocket is gaseous, remember? So, if we only use one of the seven big rocket engines to perform the circularization burn, it is a trivial chore to pump the gaseous waste from the other six rocket engines into the rocket chamber, heat it super hot, and shoot it into space forever.

If we take a few hundred pounds of the worst waste from the ground up with us on each trip, stored in the fuel vaults for safety, of course, this system can easily get rid of more waste than it generates.

What's not to love?

Part 14: Conclusions

Decades ago, we thought of the way to get into space in a big way, but our technology then was only really able to build chemical rockets. Today, we have much better technology and much more experience with nuclear power and space travel. We can use the experiments and tests of the past to build powerful, safe nuclear rockets today that not only give us incredible access to space, but also gets rid of nuclear waste!

So, when you read about nuclear power in space, be excited by the idea. It is the key to a future so bright we can hardly even imagine it today, no more than the people who sent Columbus on his way could imagine what his three little ships would begin.

Launches? (5, Informative)

znu (31198) | more than 10 years ago | (#7965056)

My understanding is that the clean nuclear propulsion systems presently under serious consideration don't provide a high enough thrust/weight ratio to actually lift a spacecraft off the surface of the Earth. Rather, their primary use would be for entirely space-born craft, which would be assembled in orbit and zip around the solar system without actually ever touching down anywhere.

Only so much juice to make the nukes go (1)

corebreech (469871) | more than 10 years ago | (#7965057)

This is solving the wrong problem. It's like turning to petroleum to make the automobile's internal combustion engine work instead of hemp, as was Henry Ford's original intent.

That said, anything that increases the pace of our exploration of space is a good thing, particularly if said exploration makes settlement a priority.

We'll just need to watch and make sure the ultra-rich and other assorted-powers-that-be don't look upon the program as some sort of life raft that gives them license to fuck up the planet even more than it already is.

Not for launches (1)

fname (199759) | more than 10 years ago | (#7965058)

These nuclear-blast fueled ships are generally not designed for launch into orbit (or into space); rather, they are designed for propulsion once the vehicle has already left earth orbit (or at least earth itself).

Dairy-aire? Derriere. (3, Informative)

sielwolf (246764) | more than 10 years ago | (#7965061)

From dictionary.com:

2 entries found for derriere.
derriere also derriere ( P ) Pronunciation Key (dr-ar)
n.

The buttocks; the rear.


Also:

No entry found for dairy-aire [tripoli.org] .

It's like the difference between a segway and a segue. One is a normal word used in English, the other is an amalgam coined for some other purpose.

Martian Haiku, appropriate now. (1)

ackthpt (218170) | more than 10 years ago | (#7965064)

Martian Haiku:
Red sand between my toes,
Summer vacation in outer space.

--Robin Williams, "Reality, What a Concept"

It will never happen (5, Interesting)

Tassach (137772) | more than 10 years ago | (#7965073)

Most people go batshit whenever they hear the N-word. That's why NUCLEAR Magnetic Resonance Imaging had to lose the N before it could go mainstream. NMRI became MRI for PR purposes, not because the technology changed.

The environmental whackos go nuts (and let slip the lawyers of war) when you launch a totally sealed reactor, can you imagine what they would do if you wanted to launch something that *gasp* released radioactive gasses into the atmosphere?

Re:It will never happen (0)

Anonymous Coward | more than 10 years ago | (#7965147)

And on the other end of the whacko spectrum is people like you.

Orion was not a launcher proposal (1)

fiannaFailMan (702447) | more than 10 years ago | (#7965095)

Correct me if I'm wrong, but I thought that the Orion proposal was for travel in space. I don't remember reading anything about it being used as a launcher from the ground. Excuse me while I RTFA and see if I was mistaken....

Ok, so what is this exactly (0)

Anonymous Coward | more than 10 years ago | (#7965102)

Me very stupid - can someone explain how exactly this works please?

Posting Anon. as I don't want you guys to know exactly how thick I really am.

Where do we bid? (1)

CompWerks (684874) | more than 10 years ago | (#7965116)

One the lucrative space waste management contracts that will be available in the coming years? Millions of pounds of material sounds like $$ in the bank to me when it needs to be hauled to the landfill on the Moon. Hopefully (fingers crossed) we can avoid unions

Safety measure (5, Funny)

j_dot_bomb (560211) | more than 10 years ago | (#7965120)

To prevent any sealed radio active capsule from possibly breaking on impact with the ground a malfunctioning rocket will have a 50Meg hydrogen bomb on it to destroy all the pieces in the air

No radiation == Nuclear war (3, Interesting)

daemous (43293) | more than 10 years ago | (#7965130)

The Project Orion guys believed they could make
the explosions clean and as small as they wanted.
This scared the shit out of them. They
puposefully did not pursue that line of
development for fear of weapons applications.

Another dream dashed (4, Funny)

Kgreene (606578) | more than 10 years ago | (#7965144)

..."almost no radiation"...

Drat, it seems to be getting harder and harder to realize my life long ambition of being exposed to massive quantities of harmful radition that will be the key to unlocking my secret mutant powers.

Disk MHD (0, Offtopic)

Delirium Tremens (214596) | more than 10 years ago | (#7965151)

MHD Disk is the latest in video encoding for Media requiring a High-Definition format. It is superior to the other formats that are being fought over right now, including certain DVD initiatives [slashdot.org] that were discussed here recently. MHD is the only high-definition encoding that supports VCR [ufl.edu] , as the article judiciously illustrates.
The initial prototype comes with a dual-tray system that allows you to load two MHD disks at the same time, and makes a smart use of different color cables to facilitate connections with your Audio/Video receiver.
And it runs BeOS, too.

Dairy-aire? (0)

Anonymous Coward | more than 10 years ago | (#7965154)

WTF is "dairy-aire"? Cow farts?

Who knew (5, Funny)

GoodNicsTken (688415) | more than 10 years ago | (#7965165)

Magnetoplasmadynamic was actually a word? And why didn't Piccard ever use it?

VASIMR (Variable Specific Impulse magnetoplasmadynamic Rocket)- And I though telecom had too many acrynoms.

One of these things is not like the other.... (5, Informative)

DerekLyons (302214) | more than 10 years ago | (#7965175)

A gas core nuclear reactor has a high ISP (meaning it's very efficient), but it does not have a particularly high thrust. That means it's great for cruising and orbital work, but it's not a launch engine like Orion could be.
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