Difficulties of the Nuclear Powered Prometheus Project

brandido writes "Space.com is reporting on some of the technological difficulties facing the nuclear powered Prometheus Project. In particular, it is focusing on the fact that the Prometheus project promises to represent a paradigm shift in the capabilities of interplanetary probes. Such a large shift in capabilities entails the development of new technologies and designs, a process that is often full of mishaps and setbacks."

Comments

Just one problem...

[JScarpace]

What happens when something like the Challenger disaster occurs to a launch vehicle carrying a nuclear reactor?

Re:Just one problem...

[Kiriwas]

As far as I know, there are protective measures you can take surrounding the actually nuclear material. There's no doubt it will come tumbling out of the sky, but it won't be radioactive dust, it will be more like a giant, heavy metal box that goes BANG..still fully encased. We've been building enclosures to keep explosions INSIDE for years, I see no reason we can't build enclosures to keep explosions OUTSIDE.

Re:Just one problem...

[BigBir3d]

Just like last time...

1965

This is why we need manned missions...

[RobertB-DC]

Unless you buy into the notion that all the Mars probe failures were due to xenophobic Martians, we've recently witnessed several examples of unmanned, robotic craft turning into expensive piles of junk for reasons ranging from the sublime (legs bounced harder than expected) to the ridiculous (meters? feet? what's the difference?).

Contrast those catastrophic failures with events on human-occupied craft. Fires and collisions on Mir, and of course Apollo 13 for those who get their science from the local multiplex -- yet the craft kept flying, due to human involvement and ingenuity. The conclusion is clear: the more complex the system, the more likely you need a non-silicon-based intelligence to keep it from self-destructing.

To address the issue at hand: NASA wants to send a nuclear-powered spaceship to Jupiter? Cool, but you'd darned well better include a crew compartment, unless you *want* to see what happens during a space-based meltdown.

The bottom line is that there is no way to predict everything that can go wrong with any complex system. That's why we need more manned missions. Spend less money on absolutely "perfect" systems, and more on systems to support a human presence to fix it when it breaks.

After all, Captain Cook explored the south Pacific with nothing more than boats of wood, and men of iron. He also had a whip, and generous quantities of very strong beer...

Re:This is why we need manned missions...

[RobertB-DC]

And did the presence of humans help with Columbia or Challenger?

As cool as the shuttle program is, I'm afraid it's turned out to be another example of overengineering: so heavily dependent on supposedly failsafe systems that a single failure (O-ring, foam strike) destroys the entire system.

Contrast with the comparatively simple Soyuz launch system. It may seem primitive, but by golly, the thing usually works. And when it doesn't, you can still survive (though "15-17 Gs" doesn't sound like a picnic in the Russian countryside).

And the reference to Cook's terrestrial explorations has another parallel with space exploration: sailors on his ships (or any ship of the time) had no guarantee that they'd make it back home. They don't call it a "widow's walk" for nothing. I'm not sure we can get anywhere on the "new frontier" until we're able to accept the sort of losses that were common on the "old frontier".

Of course, this is easy to say, sitting in a comfy chair in an air-conditioned office, listening for the boss' footsteps so I can minimize my browser when she walks by...

Not A Lot

[turgid]

Firstly, unused nuclear fuel is not very radioactive relatively speaking and is not very toxic.
Secondly, the fuel can (and is) built into very strong and resilliant "cans" and can be further protected to the point that even a fall from a great height such as earth-orbit will not result in any radioactive release.
Thirdly, any engineer woth their salt will design the darned thing such that it will not start its nuclear reactor (when the nasty fission products start to be produced) until the craft is either a significant distance away from earth already, or has achieved escape velocity and can not fall back to earth.
I am a qualified nuclear engineer with several years reactor physics experience at a nuclear power station.

How about the damn name?

[JUSTONEMORELATTE]

IIRC, Prometheus' story didn't exactly have a happy ending. (obSlashjoke: This project will surely open a Pandora's Box)
Maybe we could call it Magellan Mark IV or something a bit more optimistic?

--

Re:fuel?

[jwdg]

See, for example: this ESA article: Solar-electric propulsion is ESA's new spacecraft engine. It does not burn fuel as chemical rockets do; instead the technique converts sunlight into electricity via solar panels and uses it to electrically charge heavy gas atoms, which accelerate from the spacecraft at high velocity. This drives the spacecraft forwards. In a chemical rocket, burning the fuel creates gas that is expelled relatively slowly compared to electric thrusters. However, in an ion engine, the gas is ejected at large velocities, which makes it generally much more efficient, so less fuel is required.

Because propulasion works by conservation of momentum, if you can fire the ions out the back fast enough you don't need too many of them. The problem with normal jet propulsion is that the jets aren't very high velocity.

Interesting topic...

[Unknown Kadath]

...and just in time for me to go home, too.

Here's a NASA page on Project Prometheus.

Have a good weekend, all.

-Carolyn

Nice idea, no chance it'll fly.

[phrackwulf]

Prometheus has been on the drawing boards at the Jet Propulsion Lab since the early eighties. The reason it didn't get anywhere then is the same reason it won't get off the ground now. It's nuclear. Let's give an example. Recently, there was a major press blow-up (no pun intended) in Michigan about allowing the transport of used fissile material across the state. Never mind that said material was cast in the center of rain barrel or bigger sized pieces of concrete. Never mind that you could drop the damn containment vessels off a five story building and they wouldn't break. Everyone was screaming about the possibility of radiation getting into the water and air. The poor NRC guys had a public relations nightmare. And all because Ralph Nader and his merry bunch of marauders has made "nuclear" anything the scariest thing in the public imagination since Anthrax. You can't build new nuclear reactors and there is no chance you can get a nuclear powered craft whether propelled or simply powered by radiation off the ground. Too many people are too dumb to understand how infitesimal the possibility of disaster is, because all they remember is Chernobyl and Three Mile Island. Sad but true my friends. And now we get treated to the same feast of ignorance about cloning or genetically modified foods by people who let ignorance and fear rule their imaginations. [-)