At the time suggestions included microwave or laser power beamed up from the Earth's surface. Now, thanks to a group named LaserMotive, the dream is closer to becoming reality.An AP article noted that a robot powered by a ground-based laser beam climbed a long cable dangling from a helicopter on Wednesday to
qualify for prize money in a $2 million competition to test the potential reality of the science fiction concept of space elevators.
The contest requires their machines to climb 2,953 feet (nearly 1 kilometer) up a cable slung beneath a helicopter hovering nearly a mile high.
LaserMotive's vehicle zipped up to the top in just over four minutes and immediately repeated the feat, qualifying for at least a $900,000 second-place prize.
The device, a square of photo voltaic panels about 2 feet by 2 feet and topped by a motor structure and thin triangle frame, had failed to respond to the laser three times before it was lowered, inspected and then hoisted back up by the helicopter for the successful tries.
LaserMotive's system used a high-power laser array to shine ultra-intense infrared light onto high-efficiency solar cells, converting the light into electric power which then drives a motor, according to Slashdot. The second place prize level required the platform to travel up the tether faster than 2 m/s; their top speed was 4.13 m/s. For the top prize, the group needs to hit faster than 5 m/s.
Space elevators are envisioned as a way to reach space without the risk and expense of rockets.
Instead, electrically powered vehicles would run up and down a cable anchored to a ground structure and extending thousands of miles up to a mass in geosynchronous orbit—the kind of orbit communications satellites are placed in to stay over a fixed spot on the Earth.
Electricity would be supplied through a concept known as "power beaming," ground-based lasers pointing up to photo voltaic cells on the bottom of the climbing vehicle—something like an upside-down solar power system.
The idea is neat, but is it even practical? Surprisingly, doubting Thomases are running LaserMotive. The two principals, Jordin Kare and Thomas Nugent (no known relation to Ted), say their real goal is "to develop a business based on the idea of beaming power, not the futuristic idea of accessing space via an elevator climbing a cable. 'We both are pretty skeptical of its near-term prospects,' Kare said of an elevator."
All 4000 orbits shift across the longitudes on each cycle, eventually bringing each of the 4000 objects into high speed collision with the elevator.
So the story works better as a way to knock junk out of space, than a way to put more junk into space.
Geosynchronous orbit is around 42,000 km or 26,000 miles. Your example has 100,000 km of elevator shaft. That's how the center of gravity gets located at the geo-sync.
The top 48,000 km of the shaft isn't useful for anything unless we develop it for residential property.
Unfortunately the shaft has to built very strong because of secondary twisting moments, so it is also very heavy, like a medium sized asteroid. Maybe it could withstand the impacts of other hardware.
Now for the good news.
With a mass of that size there is gravitational interference with other geosynchronous orbits, making all but two of them unstable.
So your options are 4000 objects in space, or one elevator and two communication satellites.
Now it goes up for vote in the security council.
Does any one trust these people with beaming power?