Apart from the flesh-eating nanobots the government is spraying out of commercial airplanes, one of the cool things about science is its predictability. You can fire a cannonball at a cluster of objects of any size, from dust grains to distant galaxies, and (in theory) predict the exact path of the cannonball for the next 10 trillion years. Then you can fire another 10 trillion cannonballs, and they’ll all obey the same rules and give the same results.
Science news can be a little like that. Back when people were stupid, gentleman-scientists were forever stumbling into major, world-shaking discoveries in their spare time. Today, however, all of the easy science has been used up, so while world-shaking discoveries still happen, they’re really only made by PhDs with multimillion-dollar laboratories and solid publication histories. Since nothing on that scale happens quickly, it’s sometimes possible to predict a major event in science months or years in advance.
As this article is being written, for example, a 230-foot-long (-wide?) asteroid is swinging past the Earth at a distance “only” about three times farther than the Moon.
Scientists have apparently been watching it for some time, though it took me totally by surprise when I read about it this morning, and they have its path charted down to the kilometer. It isn’t pleasant to be surprised by gigantic asteroids like that, so perhaps it would be good to get a head start on some of the sciencey things that will probably be happening in 2015, so we can at least look deeply wise as events unfold.
The Next Step in Rocket Science: Lose the Rockets
You know what’s cool? Rocket science. You know what rocket scientists think is lame? Rockets. It isn’t that rockets aren’t loud and scary and awesome—of course they are, and you’ve wasted your life if you aren’t outside firing one off right now—but they are a bit quaint by rocket scientist standards, which tells you everything you need to know about rocket scientists and the kind of standards they set for themselves.
The problem with chemical rockets is that they’re hilariously inefficient. Nobody in his right mind would use them for boosting payloads if there was any feasible alternative. Think about the last time you lifted something heavy. Did it weigh 100 pounds or so? Maybe 300 pounds if you’re a bodybuilder in the prime of your life? Think about how hard it was to lift that heavy thing and how much energy you put into it. Now, imagine trying to throw it six feet. Imagine how hard you’d have to shove to toss it 100 feet, or 1,000 feet. Now—imagine that heavy thing weighed six tons and you were throwing it hard enough to hit the Moon. How much energy would that take?
That image is of the Saturn V rocket, which was able to lift about 6.5 tons of spaceship and astronaut to the Moon by lifting another 3,000 tons of support structures and fuel with the same energy density as TNT. Every single second of the Stage I burn consumed 15 tons of kerosene, which took 100 megawatts—a whole city’s worth—of energy to pump. Building one of the world’s tallest skyscrapers, filling it with the world’s biggest conventional bomb, and then setting fire to it isn’t cheap, and everybody who’s seen the expense reports wishes there was a better way to do cool stuff in space.
That’s where LightSail comes in. According to the Planetary Society, which raised around $4 million to support the project, the LightSail spacecraft will be launching the first in a series of test flights this May. The payload is the size of a loaf of bread and moves by deploying 344 square feet of thin Mylar sails to catch the Sun’s photons in exactly the same way an old-timey galleon used to catch the wind.
The satellite that’s launching in May is going up on a SpaceX booster for a four-week test cycle and system validation before the sails deploy. It won’t really be traveling anywhere, since it isn’t going high enough to escape the Earth’s atmosphere, but later flights can potentially cross the solar system without any of the high-explosive rocket fuel conventional craft would need. Since sunlight is abundant and free, a small craft with a large sail can accelerate continuously until it’s going way faster than any rocket ever has. Ironically, this accomplishment is worthy of a celebratory fireworks display.