Today i was reading a article on space.com about rockets powered by nuclear rockets.
http://www.space.com/scienceastronomy/solarsystem/nuclearmars_000521.html
There is aparently a movement against this. I’m all for it but I wondered if there are any objections to using nukes in space.
Not with me. We’ve already sent some ships into space with some small nuclear generators (Yoyager, etc.) If we want to actually get anywhere it will probably take nukes, at least until we figure out something better.
Bruce Gagnon’s organization is described as “Florida-based,” but it looks to me like the homepage is in the U.K. It looks to me like he has the usual “stop the madness!” objections to nuclear power, but I don’t see anything that hasn’t already been said. He also disapproves of the Cassini fly-by, and I’m not sure I follow the reasoning behind that.
FWIW, I don’t think he’s going to be able to stop NASA from sending rockets to Mars powered by whatever kind of engine their little hearts desire, especially if they can make a case to Congress that there’s some kind of economic advantage to be gained.
Here’s a sampling of his websites, and sites where his contributions are featured.
http://www.globenet.free-online.co.uk/
http://www.nonviolence.org/noflyby/global/doe.htm
http://www.nonviolence.org/noflyby/alerts/13n.htm
The only problem is the dangers involved if any of those spacecraft were to accidentally crash on the earth.
I would personally like to see an awful lot more safeguards before they start to use them myself. (Think if Challenger had been carrying warheads…)
What if it had? Creating an actual nuclear explosion takes some mighty careful planning and requires that a lot of specific and delicate stuff happen in a very carefully-timed and ordered fashion. If the Challenger had been carrying warheads, they wouldn’t have detonated during the explosion. Hell, nuclear test-missiles have blown up on the launch pad before; the warhead didn’t detonate just because the fuel tanks did.
What IS of a concern, though, is the nuclear material that can be scattered about by such an explosion. That is indeed a legitimate issue, but I do believe these days that the radioactive material inside a warhead is adequately “sealed” such that it can withstand just about anything except, well, itself, when it goes kaboom.
In short: yay nuclear power!
Duck Duck Goose wrote:
The usual problem some folks have with Cassini is that it gets a gravitational assist by flying past the Earth before it’s going fast enough to get to Saturn. There is a teensy tinsy chance that Cassini’s course will be waaaaaaay off in such a way that it smacks into the Earth, and a teensy tinsy chance that in so doing its nuclear fuel container might bust open.
Cassini carries 72 pounds of plutonium to generate electrical power. (It doesn’t use it in a nuclear reactor set-up; it relies on the plutonium’s normal radioactive decay to generate power.) This is considerably more plutonium than has previously been used in any nuclear-decay powered spacecraft.
Incidentally, spacecraft operating in the inner solar system don’t use nuclear-decay power cells. They’re close enough to the sun that they can rely on good old-fashioned solar panels.
I think nuclear-powered spacecraft have been successful since Voyager and should still be used in some cases for exploring the outer solar system (where solar power is inadequate). NASA does a lot to secure those power sources, even from launchpad accidents. On the other hand, I’d hate to see a nuke weapons build-up in space. The recent talk about starting up the Star Wars defense system again makes me nervous. That was a bad idea I thought had passed in the 80s.
Not to make light of a touchy subject, but you would think that people who are against nuclear power sources for spacecraft (usually due to safety concerns) wouldn’t mind shipping that material millions of miles away. 
Tracer, thanks for explaining that. But I still don’t get why they’re upset–it was my understanding that plutonium isn’t like nitroglycerin, where it explodes if you drop it. Doesn’t it need a trigger mechanism, being inert (albeit radioactive) until it’s triggered? Or is it my not-paying-attention-in-sixth-grade-science-class brain that’s at fault here?
I thought that if the Cassini did impact somewhere on Planet Earth, it would just scatter its 72 pounds of plutonium, making a mess, but not necessarily creating a thermonuclear explosion. Also, 72 pounds isn’t that big an amount, I thought, at least compared to what some nuclear reactors have in them, and compared to the payload of a regular H-bomb. Chernobyl involved a lot more than a suitcase-full, didn’t it?
And also, it was my understanding that the mathematical probabilities of the Cassini getting off course and hitting the Earth were something akin to the mathematical probabilities that a giant asteroid is heading straight towards us, and that the only person who can save us is a balding movie star named Bruce, AND that this “Bruce” person has a daughter with Steven Tyler of Aerosmith.
Duck Duck Goose wrote:
Not only would it not make a thermonuclear explosion, it wouldn’t even make a nuclear one. (“Thermonuclear” is another word for nuclear fusion, which is kinds hard to do without a hefty supply of deuterium and tritium at the ready.)
The problem is that plutonium is highly radioactive and highly toxic. Somewhere I read that a sliver of plutonium the size of a U.S. Nickel, if distributed in just the right way, would be enough to kill every human being in the United States. If Cassini’s 72 pounds of plutonium were scattered over an area 20 miles across, they would basically make that entire area as uninhabitable as Chernobyl is today.
tracer writes:
I haven’t crunched all the numbers, but a quick glance at A Perspective on the Dangers of Plutonium makes it seem most unlikely.
We should perhaps remember that, compared to high-level waste, plutonium is just not very radioactive. Plutonium is also a chemical poison, of course, but then, so is lead.
BTW, if you’re interested in how far you are from a horrible, lingering, cancerous death you are, here’s Cassini’s Home Page.
Without reading the Cassini home page, I seem to recall that the nuclear fuel was designed to be contained even in the event of a collision with Earth.
If you did get a Plutonium spill, you’d basically just have to clean it up. Plutonium is very toxic if ingested, but it’s not all that radioactive. It’s not about to turn the area around it radioactive like some of the high level wastes can. So if you spill a bunch, get your gieger counters out and go cleaning.
SDI: Could someone outline the big objections they have to this? I’ve been a big proponent of missile defense since Reagan first announced SDI in the early 80’s. I believe it played a big part in the collapse of the Soviet Union (read the history of the Nuclear Arms reduction talks between Reagan and Gorbachev, and you’ll see just how frightened the Soviets were of SDI). The spinoffs from SDI research have also had a lot of benefits in commercial fields. And it seems really hard to me to come up with rational, moral arguments against building a system to stop weapons from killing people.
In the cold war, SDI had the benefit of moving the arms race away from the raw buildup of deadly weapons (which the Soviets could do better than we could), to an arms race in high technology (which the Soviets sucked at). This had the double benefit of being more cost-effective for the U.S., and also diverting dollars away from mere inventory buildup and into R&D, which pays off in many ways in the civilian sector.
Threll asked:
**
Wee shud sertenlee knot uze nukclear paur een spaice - Eet wuld bee phar to dangeroos doo too guallowt thet kuld cawze unsaiphe raydeeaishun levulz har an Urth.
As I remember, there was a plan for a Soviet rocket that used liquid hydrogen and a nuclear reacter to lanch stuff into orbit. It was never built for cost and enviromental resons.
Sdimbert take it to the pit. We all make mistakes.
Yeesh, threll… I apologized in advance. :rolleyes:
BTW, it would be a lot easier to swallow your scorn for my joke if you knew how to spell “nuckclear reacter.”
I’m done now…
The main reason for not using nuclear weapons is fear of nuclear retaliation. If you have a defensive system that removes your enemy’s ability to retaliate, or reduces that ability to an “acceptable” level, you also remove a strong argument against engaging in a war. It could also push your enemy to make a first strike before their entire arsenal is rendered useless.
The main reason for US-Soviet treaties against Ballistic Missile Defense Systems was to stop the nuclear arms race. If an enemy BMDS destroys half the incoming missiles, the easiest way to overcome it is to send twice as many missiles. A ban on BMDSs = No escalated arms race.
Another example of a defensive system:
If I recall correctly ( otherwise consider this a hypothetical situation ), in the late 80’s Iraq wanted to import gas masks (a defensive system) for its army. They were not allowed to import them since these masks could, and most likely would, be used to protect Iraqi troops when they themselves used gas against their enemies.
Just one question, sdimbert:
What in heaven’s name is “guallowt”? 
In addition to that, Soap Box, SDI was(is) pretty much considered unworkable, either for straight scientific reasons or simple economic ones (if it costs more to shoot down one ICMB then to make one ICBM then you’ve got a small problem).
Bear in mind when discussing SDI that this was a project explained to the general public through a child’s drawing…it’s just a politically useful pipe dream.
Crud - It should have been “ghallowt.”
Gee, threll, you were right; everyone make spelling mistakes.
Actually, when I first saw the Topic: line of this thread, I thought it was asking if we should use knucklehead power in space.
I’d think even Moe, Larry, and Curly would get tired out if you used them for spacecraft propulsion. Nyuk nyuk nyuk!
The arguments you’ve put forward against SDI are based on the layman’s misunderstanding of the whole concept, which goes something like this: “SDI is unworkable, because no shield is 100% reliable. And if even 5% of the missiles get through, you still have massive destruction.” The corollary is, “If it IS 100% effective, then it’s a first strike weapon because you can attack without fear of retaliation. So it escalates the cold war.”
Now here’s the straight dope: SDI was never designed to be 100% effective. It doesn’t even have to be 50% effective against a massive strike. Here’s why: Let’s say you have a 50% effective missile defense. Now if the enemy launches missiles against your 10,000 missiles, you still have 5,000 left to retaliate. So they build 20,000 missiles and launch them. But that doesn’t solve the problem. If they aim TWO missiles at each silo, and the silo has a 50% chance of shooting down each one, then there’s a 25% chance that the silo will survive two attempts. So they build 10,000 more missiles, and only take out 2500 more of ours. If they build 30,000 missiles and fire 3 at each silo, we still have 1250 left. And after they triple their missile supply, if we make the system 75% effective we still have 4200 missiles.
The end result is that they can NEVER overwhelm the defense with missiles and insure enough missile kills to make a first strike feasible. And yet, they don’t have to worry about us first-striking them, because even if we shoot down 90% of the 10,000 missiles coming back at our cities we still get obliterated.
SDI was the perfect concept, and a great way to move the battlefield onto the intellectual and moral high ground. And it CAN be 100% effective against the new missile threat - a minor rogue country firing a dozen or so missiles at us.
BTW, SDI did not use nukes in space (there was a couple of early proposal for nuclear pumped beam weapons, but that died). SDI was typically envisioned as a multi-stage defense, with orbital beam or kinetic energy weapons (shotgun pellets fired at missiles, basically), coupled with point-defense weapons around missile silos (rockets, and 20mm gatling guns).