Scotty beaming photons up, not people
The idea was cooked up by a now-dead astrophysicist (Steven Hawking) and a Russian billionaire (Yuri Milner). What go wrong?
The idea was to build a lightweight spaceship attached to a lightweight light sail. The ship and sail would weigh maybe ~5 grams (~ 0.17637 oz), maybe less. The light sail attached to the tiny ship would be about one square meter in size and weigh almost nothing, being a couple hundred atoms in thickness. One or a flock of these pipsqueak ships would be launched into space by a regular rocket and released once in space. After they are released in space, each pipsqueak would by powered by blasting it with a 100 gigawatt laser light beam from hundreds or thousands of lasers on the ground that can all be precisely aimed at a single point in Earth orbit. The point they will aim at is the little sail.
100 Gigawatts is enough juice to power about 70,000,000 homes or a pile of small countries. That's a lot of power.
The force of the laser light hitting the sail would power the light sail on its way to the nearest star Alpha Centauri, about 4.37 light years away from Earth. The ship would be looking for alien civilizations in that neighborhood. The video below shows the array of lasers doing their blasting thing. The idea is to accelerate the tiny sail ship to about 100 million miles/hour. At that speed, it would take only about 20 years to reach Alpha Centauri.
The little spaceship would carry about 150 mg (0.00529109 oz) of Plutonium or Americium as its electrical power source to run the tiny ship's guidance system, communications gear, cameras, cafeteria and other needed items. OK, no cafeteria.
There are still a couple of technical hurdles to work through. One is how to hit the sail with 100 gigawatts and not instantly vaporize the ship and its sail. Actually, that's a really big hurdle.
Another is the light sail material itself. It will be made of an ultra-thin "metamaterial." A metamaterial is stuff, mainly experimental stuff, designed to "pick up" photons from a light source. That picking up thingie acts as a pressure force on the sail, which gently pushes it away from the light source. Stuff sounds a bit vague so some more work on that detail is probably needed. The push on the sail has to be gentle because it will be just a couple of hundred atoms thick. For context, a human hair is about 100,000 atoms thick. The sail will be reeeeeally thin.
Other ongoing projects include design of a coating that will resist space dust particle damage, means to aim the onboard cameras at things of interest at Alpha Centauri and figuring a way to get the contraption to survive the forces on it during launch from Earth into space. Just launching the little bugger from Earth could tear the sail to pieces. Heck, the puff of air from someone just sneezing toward the sail would rip it apart.
For anyone with ideas of how to solve some of the development problems, you can go to this link and pick a problem you want to fix. Once you have figured out how to fix the problem, just let them know and they will be grateful and happy to implement your clever solution. I'm working on the diode laser photon thruster problem right now and am close to a solution.
Other information about this wonderful project can be found here.
No comments:
Post a Comment