The revolutionary breakthrough will come with rockets that are fully and rapidly reusable. We will never conquer Mars unless we do that. It'll be too expensive. The American colonies would never have been pioneered if the ships that crossed the ocean hadn't been reusable.

The space shuttle was often used as an example of why you shouldn't even attempt to make something reusable. But one failed experiment does not invalidate the greater goal. If that was the case, we'd never have had the light bulb.

The fact that most of the time human beings put the truth about the nature and risks of the nuclear war out of their minds because it is too painful and therefore not "acceptable", does not alter the nature and risks of such war.

The nuclear approach I'm involved in is called a traveling-wave reactor, which uses waste uranium for fuel. There's a lot of things that have to go right for that dream to come true - many decades of building demo plants, proving the economics are right. But if it does, you could have cheaper energy with no CO2 emissions.

The alternative to disarmament, the alternative to suspension of nuclear tests, the alternative to strengthening the United Nations and disarming the whole world may well be a civilization plunged into the abyss of annihilation.

The United States strongly seeks a lasting agreement for the discontinuance of nuclear weapons tests. We believe that this would be an important step toward reduction of international tensions and would open the way to further agreement on substantial measures of disarmament.