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Dr.
Leik Myrabo hopes to revolutionize space launches with his
"Laser Lightcraft." |
EAA
member Dr. Leik Myrabo is one of a few dozen forward-thinking scientists
who are working on a better, cheaper, safer way to hurl payloads from
way down here to way up there.
"The
trouble with rockets," he says, "is that they are very, very
thirsty. Launching even a small payload into orbit requires huge amounts
of fuel and it’s a vicious circle. The bigger the payload, the more
thrust you need. The more thrust you need, the more fuel you need to
carry along. And the more fuel you carry, the less weight you have left
over for payload. Getting the right ratio of fuel, thrust, and payload
is always a delicate balancing act."
Back in
the 1990s, Myrabo borrowed ideas and technology from the Strategic
Defense Initiative ("Star Wars") and launched a tiny
"laser lightcraft" straight up, using beamed energy propulsion
(BEP), at the White Sands Missile Range in New Mexico. The craft’s
thrust came from a ground-based 10-kilowatt CO2 pulsed laser.
His
softball-sized, 50-gram aluminum "vehicles" have since made
150 flights reaching a maximum altitude of 230 feet. While that is far
short of orbital altitude, it is enough, says Myrabo, to prove the
concept. With a 1-megawatt laser (100 times 10 kilowatts), he says he
could launch a vehicle up to 1kg (2.2 lbs) into orbit. Since most of the
vehicle’s "engine" and "fuel" remain on the
ground, its size and weight, he says, is limited only by the frequency
of the laser and the amount of beam power it can produce.
Myrabo’s
Laser Lightcraft looks like a highly polished child’s top. For each
launch it is spun at 13,000 rpm to stabilize it during flight. "It’s
really a flying gyroscope," he says. Pulsing 25 times per second,
the ground-based laser beam hits the vehicle’s parabolic underside.
Reflected out to the rim of the vehicle, the beam superheats the air at
the vehicle’s edge, the air expands explosively, and the vehicle is
pushed upward on a pulsejet of superheated air. That’s the atmospheric
version.
For space
flight, the vehicle’s rim—its "engine"—is lined with
some kind of inert propellant for the laser to vaporize. Myrabo has used
Delrin—a kind of plastic—as propellant, but he says any substance
that expands explosively would work—even water. Future air-breathing
laser- or microwave-powered lightcraft could scavenge water from clouds
on their way up, and then use that water to leave the atmosphere at
hypersonic speeds.
Myrabo’s
lightcraft could also be powered from above by a laser or microwave
acting as a kind of "tractor beam." The beam would be
re-directed by mirrors to the vehicle’s underside, where it would be
converted to thrust.
Myrabo’s
immediate goal is to develop a practical way of delivering payloads up
to 100kg (220 lbs.) into space at a very low cost. "It will take 1
million watts (1 megawatt) of power to put 1 kilogram in orbit,"
says Myrabo." Today we have terrestrial electric plants that put
out a gigawatt all day. We could send thousands of small satellites into
orbit for the cost of just a few hundred dollars per kilogram of
payload."
"Beam
me up, Scotty," might be closer to reality than we once thought.
Ultimately,
the vision shared by Myrabo and his colleagues goes way beyond launching
nano-satellites. They foresee a global transportation grid to power
freight trains, suborbital passenger and cargo flights, orbital
insertions, and interplanetary flights. It would be powered by huge
ground-based and orbiting solar panel arrays—a "solar grid"—that
could eventually provide up to 70 or 80 percent of the world’s
electrical energy.
The
revolutionary lightcraft is a totally "green" transportation
solution, says Myrabo. It burns no fossil fuels and releases no CO2 or
other emissions. A solar grid infrastructure for the planet would
promote the development of electric and hybrid cars, trucks, trains, and
light planes, he says and would reduce our dependence on foreign oil.
Myrabo’s lightcraft technology will be featured in a television
documentary, "Flying on the Grid," to be aired this fall.
A
professor at Renssellaer Polytechnic Institute (RPI) in Troy, New York,
Myrabo is an aerospace engineer with a Ph.D. in engineering physics. He
spent seven years working on the Star Wars program—"the only
place to learn about microwave and laser power beaming technology"—before
beginning work "in earnest" on his laser lightcraft about 25
years ago.
His company, Lightcraft
Technologies Inc., continues to push the frontiers of flight propulsion.
You can learn more at www.lightcrafttechnologies.com.
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