Science Forums 2

[BlameTheEx]

Ghad. The asteroid belt is well within the region where solar power is plausible.

Freethinker.

You have a point. Beyond jupiter nuclear power becomes the obvious choice for powering the instruments. However it still does not become essential for powering the acceleration for the following reasons:

1) There will be budgets for very few missions beyond jupiter. These can be arranged to use gravity assisted acceleration, in the same way that previous missions did. They needed no more that chemical rockets could provide.

2) We can still use solar powered drives. The boost required can be delivered at the beginning of the mission, before the craft gets too far from the sun.

Nuclear generators powerful enough to power communications and instruments have already been developed. I have shown that developing a high powered nuclear generator for thrust is not essential. It's also unlikely to be the cheap solution. Safety concerns are bound to result in expensive precautions during development and launch. Don't minimise these costs. This is why nuclear generated electricity is so expensive on earth.

Nasa has latched on to nuclear powered drives with the same woolly accounting that prompted the development of the shuttle. The vast majority of electricity demand in space is, and will continue to be, served by solar power. This is for good commercial reasons. Solar power will continue to develop with or without Nasa's help. Even if it isn't the aesthetic solution to boosting to the outer planets it IS the budget solution.

I personally think there is a deception going on here. Nasa can't possibly expect sufficient missions to the outer planets to justify the cost. I think they are hoping to use nuclear powered boosts for manned missions to mars. If so, they are making a bad error. For the inner planets, and for both nuclear and solar collector power, the big problem will be dissipating the waste heat. Solar collectors will prove easier to cool.