Space Elevator Test Games Explore Bold Technology
|Artist concept of a space elevator viewed from the geostationary transfer station looking down along the length of the elevator toward earth|
Rocketing into space? Some think an elevator might be the way to go. That’s the future goal of the $2 million Space Elevator Games taking place November 4 to 6, 2009, in California’s Mojave Desert. In a major test of the concept, robotic machines powered by laser beams race to climb a cable suspended from a helicopter hovering more than a half-mile (one kilometer) high.
The highly technical contest brought teams from Missouri, Alaska and Seattle to the Mojave Desert for this year’s “Power Beaming Challenge.” KC Space Pirates, LaserMotive and USST qualified to participate on the dry lakebed near NASA’s Dryden Flight Research Center at Edwards Air Force Base.
Funded by a space agency program to explore bold technology, the contest is a step toward bringing the idea of a space elevator out of the realm of science fiction and into reality. Theorized in the 1960s and then popularized by Arthur C. Clarke’s 1979 novel The Fountains of Paradise, space elevators are envisioned as a way to gain access to 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.
This challenge is a practical demonstration of wireless power transmission. Teams build mechanical devices (climbers) that can propel themselves up the vertical cable. Since the power supply for the device is not self-contained, but remains on the ground, the technical challenge is to transmit the power to the climber and transform it into mechanical motion, efficiently and reliably. In past competitions, some teams used power from the sun or ordinary spotlights, but all of the teams competing now use lasers.
The space elevator competition has not produced a winner in its previous three years, but has become increasingly difficult. The vehicles must climb a cable six-tenths of a mile into the sky and move at an average speed of 16.4 feet (five meters) per second to qualify for the top prize. A lesser prize is available for vehicles that climb at 2 meters per second. The rules allow one team to collect all $2 million or for sums to be shared among all three teams depending on their achievements.
A robot powered by a ground-based laser beam climbed a long cable dangling from a helicopter on the first day to qualify. 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 two principals, Jordin Kare and Thomas Nugent, said they were relieved after two years of work. They said 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.
The contest, however, demonstrates that beaming power works, Nugent said.
“Anybody who needs power in one place and can’t run wires to it — we’d be able to deliver power,” Kare said.
Earlier, out on the lakebed, team member Nick Burrows had pointed out how it grips the cable with modified skateboard wheels and how the laser is aimed with an X Box game controller. It had never climbed higher than 80 feet previously, he said.
The day’s competition began late after hours of testing the cable system, refueling the helicopter and waits for specific time windows in which the lasers can be fired without harming satellites passing overhead.
The Kansas City Space Pirates went first with a machine that initially balked but eventually began climbing. Its speed was too slow to qualify for any prizes but it got within about 160 feet of the top before the laser had to be shut down for satellite protection. Ben Shelef, CEO of the contest-sponsoring Spaceward Foundation, said the Pirates had a minor laser tracking problem, but the real problem appeared to be in the mechanical system.
The competition was five years in the making, Shelef said. “A lot of hurdles to cross,” he said. “Now that it’s happening, I’m actually happy already. It doesn’t matter what the outcome is.”
While the concept of an elevator to space may seem too fanciful, Andrew Williams, 26, a mechanical engineer on the Saskatchewan team, said he has no doubts it will come about. “Once we put our minds to something it’s just a matter of time for us to achieve it,” he said.
Practical systems employing power beaming would have a wide range of applications from lunar rovers and space propulsion systems to airships above the Earth.
The competition is sponsored by the nonprofit Spaceward Foundation with support from NASA’s Centennial Challenges program.
Copyright 2009 The Associated Press