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Herakles and the other elements of a Prometheus craft are scheduled for advanced flight development in 2006.
The craft would be powered by an onboard nuclear reactor.
The ion beam produced from xenon gas to propel the craft to speeds of 200,000 mph, 10 times faster than the top speed of the space shuttle.
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From the article:
The new system would make the moon, which is about 239,000 miles away from Earth, a short trip.
I doubt an ion engine would produce enough thrust to significantly shorten the flight time between Earth and Moon, especially if it is used to spiral out from LEO instead of a chemical sling shot. But for Earth->Mars or even further it could make a big difference.
Assumed the 200 000 Mph is delta v, that's about 80km/sec. Hmm interesting, it would have to work at tremendeous ISP to make the dry-weight/propellant ratio big enough (which also means very low thrust, even with a nuclear reactor).
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Yup 200,000 mph seems fast but what it does not say is how long it took to get to that speed and whether that speed was after some initial chemical boost from LEO towards its destination target.
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And if you tried to crank up your reactor power, it would in turn get heavier too, canceling out much of that bennefit.
Nuclear fission/electric propulsion doesn't make a great deal of sense with current reactor technology for manned applications. A vapor core reactor or something else exotic like that would be needed.
Of course, there is always the engine of my namesake, the Gas Core Nuclear (fission) Rocket.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Yep, GCN reactors are an interesting way to reach high ISP also with the fuel cooling the chamber wands and allowing some 50000K for the reactor core. One thing I don't know about is how the reactor fuel is replenished. Or was it designed to run until the gas core is "spent" and then exchange the whole thing?
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As far as the Uranium goes, quenching the chain reaction and then sucking up the Hydrogen-cooled Uranium vapor is the only practical way to recover the fuel.
But, since Uranium isn't that expensive, and you don't need that much of it, and it weighs very little compared to the mass of Hydrogen you need for the thing... why bother? Just flush the Uranium out the back to turn the engine off.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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