燃料なしのロケット飛行
Researchers have just launched a rocket that flies without carrying fuel using laser propulsion.
Welcome to SCIEN-SPOT and SCIEN-SPOT is a podcast that helps you spot the latest in science.
Your host is REN from SCIEN-TALK. Today's topic sounds like something from a sci-fi movie.
Unusually, rockets carry tons of fuels. They burn it and push themselves into space.
But fuel is heavy and expensive. That's why only a few missions can afford to go.
Now imagine a rocket that gets its push from the ground by a powerful laser beam.
That's laser propulsion. And that's what researchers at Tohoku University have been testing.
And here's how it works. At the bottom of the rocket is a parabolic mirror
curved surface that focuses the laser beam. And when laser hits, it heats the air so much
that it becomes a plasma and super hot charged gas. And this plasma creates a shock wave,
kind of like a mini explosion, pushing the rocket upward. No fuel tanks, just laser energy from
below. And this could change space travel completely. Some estimates say it could cut
launch costs to a quarter of what they are now. That would open the door to more missions,
more satellites, and even space tourism. But laser propulsion isn't easy. One big challenge is
keeping the rocket stable. Imagine trying to keep a pencil balanced on your finger. Now replace the
pencil with a rocket and your finger with a laser beam. This kind of stable flight is called
beam riding. If the rocket drifts off the laser beam, it loses power and falls.
Tohoku University's team tackled this with two strategies, passive control and active control.
And let's start with passive control. They built a tiny rocket just 50 millimeters long
and 2 grams in weight. It's shaped a bit like a UFO, with spatial mirrors and a ring-like
structure underneath. They call it a multi-parabolar laser propulsion vehicle.
レーザーによる無燃料飛行の実験
When the laser hits this shape, the beam focuses into a ring. If the rocket drifts
sideways, the force becomes unbalanced, automatically pushing it back to the center of
the beam. It's like a self-correction system. And they tested it in the lab. Shooting laser pulses
at 50 times per second, the rocket flew 110 millimeters high, which is about seven times
its own length. And it stayed on track. No wires, no fuel, just light. The researchers said it took
like a tiny UFO taking off. But passive control alone may not be enough for longer flights,
so they developed a laser tracking system, a more active approach. This system uses stereo cameras
to watch the rocket's position in real time. If the rocket moves, motors and mirrors shift
the laser beam to follow it. That's active control. Instead of flying freely, they attach the rocket
to a robot arm to stimulate flight. Then they tested how well the laser could track it.
The system worked, and it followed the rocket's movement accurately, delivering continuous
laser pulses that kept generating thrust without interruption. This is the first time in the world
that such continuous laser driving propulsion has been demonstrated in this way. These experiments
are still on a small scale. Each flight lasted just 0.26 seconds. But the next step is to test
longer stable flights using this tracking system. And the ultimate goal is to launch rockets beyond
100 kilometers into space using just lasers from the ground. And there's more. This technology
isn't limited to rockets. The team believes it could be used for aircraft, too. In the future,
we might see drones or flying vehicles powered not by propellers or jet engines,
but by laser beams from the ground. And laser propulsion could cost cost and reduce pollution
and change the way we think about flying. Tokyo University's work is a powerful step forward,
レーザー推進の探求
a real-world breakthrough that brings us closer to a new space age.
That's it for today's episode. SciencePod is broadcast every weekday in both Japanese and
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SciencePod. Thanks for listening and see you next time.
