As much as Elon Musk is impatient for us to be an interplanetary species and NASA wants to send us beyond the solar system, humans won’t be the first ones to go boldly where no one has gone before. That astronomical milestone belongs to the tardigrade.
Tardigrades, the tiny eight-legged things that (under a microscope) look like they could be the faceless cousins of the hookah-smoking caterpillar of Alice in Wonderland, just won’t die. Freeze them and they will curl up into ice balls and just wait it out until they can melt their internal fluids again. Boil them and they won’t get blistered. Smash these creatures with asteroids, blast gamma radiation at them, throw them into a supernova—they will still come crawling out. This makes them the perfect micro-astronauts for launching into the beyond.
There are too many destructive forces in the universe to risk rocketing humans into interstellar space without seeing the effects of everything that could possibly kill them on an almost indestructible life form. At just a millimeter (0.04 inches) long, tardigrades won’t really add much to a spaceship’s payload, and neither will their extremophile companions, the nematode C.elegans. This worm has only 1,000 cells in its microscopic body, and can actually observe and learn from its environment despite being devoid of a brain. Nematodes also have serious survival powers, which is obvious when you realize that some species can thrive 12,000 feet beneath the surface.
What these creepy-crawlies will tell us is what happens when you shoot through the cosmos on wafer-size spacecraft, riding laser beams at the speed of light. This sci-fi mode of travel is the brainchild of NASA’s Starlight program, which will use photons to propel the microorganisms at extreme fractions of the speed of light. They will jet toward Alpha Centauri and other nearby stars that really aren’t so nearby, especially for a monster rocket carrying its weight in equipment and human bodies. The trip to Alpha Centauri takes 20 years at much less than half the speed of light. There is just no viable way for this to happen with humans, or at least no one has actually dreamed it up yet.
While NASA doesn’t have a launch date, look for the first intrepid and nearly invisible deep-space travelers to be taking off anywhere in the next 20 to 25 years, if you believe the collaborators on Stephen Hawking’s Breakthrough Starshot mission. At least they’ll still be alive by then.