I watched this interview with Elon Musk of SpaceX a few weeks ago and have found myself thinking about it now and again:
(Fast forward to 24’30″)
His claim is that, by creating a truly reusable spacecraft, they’ll be able to reduce the cost of getting to space dramatically (by 90+%, or perhaps 99%). The space shuttle was an attempt to do this, but it fell well short.
He makes an analogy that’s been sticking with me: imagine that planes were disposable. To fly from San Francisco to London, you’d buy a new jet, fuel it up, fly it, and then throw it away. Repeat for the return trip. Total cost: at least $500 million. Nobody flies this way. It would be insane. But to a large extent, this is what we do for space travel. I’m not sure what the marginal cost of one flight in a jet is, but Musk says that the cost of fuel for a rocket is typically around 0.3% of the cost of the rocket. So there are huge potential savings here.