NASA Power Beaming Challenge is On For November 2nd

carstene writes "The NASA Centennial Challenge Powered Beaming competition, to develop technology for uses such as a space elevator, or to power a rover in a shadowed crater on the moon, was delayed indefinitely due to trouble setting up the kilometer-high race track. It has now had the kinks worked out and is rescheduled for the week of November 2nd. The competition involves using a high-power laser to beam power to a robot that climbs a kilometer-high cable attached to a helicopter. The competition was previously covered on Slashdot."

Comments

Why not just use wires?

[slifox]

Why must we beam the power to a space elevator?

Wouldn't it be reasonable to use wire conductors? If we will be able to build the support lines that can span from the earth to orbit, why couldn't we also make a couple of smaller ones inside the main one for carrying power? Or why not just use the support lines themselves to provide power (assuming there are multiple support lines for redundancy)?

Can anyone provide some more insight into this? I haven't been able to find a decent explanation

Re:Why not just use wires?

[fred fleenblat]

aside from the weight issue, shouldn't the cable specifically be designed to be an insulator anyway? Shorting out the fair weather return current and/or tapping into particle storms in the upper atmosphere seems like it could lead to some nasty little electrical issues.

Re:Why not just use wires?

[Anonymous Coward]

There are limitations to the length of power lines for other than mechanical reasons. It is 36000km (22000miles) to Geosynchronous orbit, which is where we ultimately want to go with this thing. Using cables for anything near that is highly problematic. (longest power line on earth is about 1700 km)

http://en.wikipedia.org/wiki/Electric_power_transmission

Re:Why not just use wires?

[mcrbids]

Carbon nanotubes in the "armchair configuration" AKA 5,5 configuration, are excellent conductors of electricity along with having fantastic tensile strength properties.

To see this at work:

1) Get a metal, NON-magnetic tube (eg aluminum)

2) Get a magnet.

3) drop the magnet down the tube. The magnet will go VERY SLOWLY down the tube because of the magnetic field it generates. It never touches the tube. That's because of the electricty inducted by the magnet creates its own magnetic field. Since there's nowhere for the electricity to go, the magnet drops very slowly.

If we make the space elevator a loop, where there are two points touching the earth (perhaps a few hundred miles apart) then we could use the flow of electricity and a magnetic field to provide both power and propulsion, and "get it back" when an elevator goes back down to Earth, without ever touching the nano cable. And we can control the rate of ascent/descent just by adjusting how much resistance we put on the loop circuit.

Re:Why not just use wires?

[gurps_npc]

It is totally correct that we can't make a space elevator right now.

But we could make a space elevator.

1. Take a particle accelerator, preferably one built at a high altitude. You should be able to start at least 4000 meters above sea level (China's Qinghai-Tibet Plateau averages 4,500 meters.

2. Put a bend in the output - straight up.

3. Detach the final u turn that bends the particle stream down again.

4. Add some magnets to recover power from the particle stream. Use it to power the magnets in the final U bend, that is now detached.

5. Focus the energy so that the it is self-centers the now detached final U.

6. Up the power. The detached U bend now floats.

7. Keep raising the power. U bend keeps going up.

8. At low altitudes, the atmosphere will drain massive energy. So build an air-tight 2000 meter tower around the particle stream. At the very least this should take you 6000 meters above sea level. Air pressure is now 50% sea level. This will reduce power consumption

Problems: 1. Power requirements will be HIGH. We will need to build a Nuclear power plant (probably a 2nd on as a backup). 2. We will building the tallest man made structure on Earth, at one of the highest points on Earth. 3. A lot of untested engineering, although the physics is known.

Why a helicopter?

[AJWM]

Wouldn't it make a lot more sense and be a lot easier to hold the cable up with a balloon? (Or rather, hold the balloon down with the cable.)