Say you want to slip over to Mars and get in on some of that sweet, sweet brine without anyone finding out — NASA has all these rules about not contaminating wet extraterrestrial areas with Earth germs. How do you get to the Red Planet without getting spotted? You use space camouflage, a sci-fi staple that dates all the way back to OG Star Trek.
Could you pull this off outside of the special effects department? People have, at least in theory, tried to solve that question. Results have been, to put it lightly, mixed. But with the weaponization of space feeling inevitable than ever, you better believe people are looking into these options.
Engineers at the University of Michigan unveiled carbon nanotubes in 2011 that, when coating a microscopic object, made it disappear from view. The tubes have a low index of refraction, meaning that light bounces through it roughly that same way through air. The engineers suggested to the BBC that you could seed deep space with the tubes, creating a nanotube forest capable of keeping prying sensors from seeing anything hidden within. But that means you’d need to produce a huge number of nanotubes to blanket wherever you wanted to go. It also means you can’t crash into them. Still, you can consider this the ultimate hidden clubhouse.
Small Blip, Big Field
Painting battleships in black and white stripes like seafaring zebras fell out of favor once we realized that though our eyeballs might be fooled by motion dazzle but radar don’t care. That all-black or day-glo star paint job on your space shuttle might look neat, but it won’t help disguise the fact that you’re something in a vacuum, which is by definition a whole lot of nothing. That said, the expanse of space makes it easy to be sneaky: If someone is looking for you, there’s a whole lotta non-ground for them to cover. NASA has found more than 90 percent of the rocks larger than a kilometer in diameter. But on the hundred-foot scale, of the million or so near-Earth objects, the agency has found about 10,000 of them. In other words, size may matter most. Being little and being invisible may not be that different after all.
Exhaust the Exhaust
Asteroids have a stealthy advantage in that they’re balls of chilled stone. Spacecraft that need to burn thrusters to move run far hotter than the comparative coldness of their surroundings. A heat difference is a huge plus in tracking, and one that’s exploited by homing missiles, for instance, that follow the exhaust of jets. You could conceivably orient your ship so that the sun’s radiation masks some of your signature, though that fails once you have to move away from the star. Say you want to power down, bundle up, and coast on your momentum to avoid thermal sensors — but that won’t quite cut it, either. To keep humans alive and comfy, the inside of the spaceship is warmer (at good old 68 degrees Earth room temperature, nearly 300 times) than the three Kelvin of space.
In space, it’s much better to run than hide.