Wednesday, April 29, 2009
If you want really cheap orbital launching & we can't yet hang a 36,000 km cable without expecting it to break we have laser launching. A laser launcher beams power, usually suggested in a pulsed beam at the back of the "rocket" which vapourises propellant (water/ice( to provide push. We probably only want this for transporting cargo because of high acceleration & the large amounts of power needed for craft carrying people.
To achieve the sort of accelerations needed for Earth-to-orbit, you need about a megawatt per kilogram. So long as you restrain yourself to small cargo launches, say 50kg and under, that kind of laser power is no big deal. (Note that a laser launcher does not use photon thrust -- it uses beamed power to heat rocket propellant.)...the whole point of the
exercise is that the heavy hardware gets to stay on the ground where power
is cheap and weight is unimportant
Theoretically, once the lasers & launch vehicles are built we could be getting stuff to orbit for little more than electricity costs - cheaper than we get fruit air transported from Africa (where investment in airfields & much of the cost of planes has also long since been repaid).
A large X-Prize for getting something up this way or a government guarantee to purchase a set amount of flight time, or a mixture of the 2 should do it.
Thanks to Next Big Future for the illustration & more ideas.
American Institute of Beamed Energy site
NASA could simply contract out much of its routine missions to the ISS to whoever was cheapest.
During the 1930's the US used air mail contracts to develop the US airplane and airline system.