NASA Unveils Centennial Challenges

wonderfesten writes "NASA has finally got its Centennial Challenges program off the ground. Like the X Prize, the Challenges award cash prizes to private inventors who come up with solutions to problems. The first challenges are to design a light-weight, ultra-strength tether and a means of transmitting power wirelessly. But with a prize of just $50,000, will anyone give it a shot?" Details also available on MSNBC and Space.com.

Comments

Transmitting power wirelessly...

[slavemowgli]

Transmitting power wirelessly is easy. Every signal, be it from a radio station, wifi, a cell phone or whatever, is a transmission of power.

Space elevator?

[ag0ny]

The first challenges are to design a light-weight, ultra-strength tether and a means of transmitting power wirelessly.

This has "space elevator" all written over. :)

A good idea for wireless power would be lasers

[imsabbel]

Today, good ir lasers can get 60% wallplug efficiency (>99% quantum efficency and little outcoupling losses, plus little additional resistances adding to the bandgap).
The main reason why solar cells are unefficient is that you have to gamble with the bandgap: set it too high, and you will lose to many low energy photons. set it too low, and all those high energy photons will lose all energy >E_gap as phonons/heat. So even an absolutely ideal Solar cell could only get a little over 25% or so efficiency with a backbody spectrum.

But now take a laser and create a optimally tuned solar cell with a bandgap just a bit lower than the laser wavelenght. You should be able to get 20-30% total transmission efficiency at least, imho, after a little optimisation.
That doesnt sound too good, but its not so bad compared to other ways to store and carry energy (batteries, ect).

But of course, having solar power stations in orbit that beam down their power with lasers would make a lot of people very nervous, for very good reasons ...