Hitchhiking has just been elevated from simply sticking your thumb out to reeling in comets and asteroids. NASA’s newly unveiled Comet Hitchhiker concept can offer a tour of bodies scattered across the solar system without the need to gas up.
Comet Hitchhiker idea is inspired from Hitchhiker’s Guide to the Galaxy
The Comet Hitchhiker idea is simple: A spacecraft lands on small celestial bodies like comets and asteroids by harnessing their own energy, and then takes off to another body by comet-hopping its way through the solar system. This idea of hitching rides from cosmic bodies was developed by NASA’s jet propulsion laboratory in Pasadena, California. Masahiro Ono, the principal investigator of this project, presented the results at the American Institute of Aeronautics and Astronautics SPACE conference.
Though it is easy to imagine jumping from one comet to another, practical limitations such as their astronomical speed and low gravitational pull throw a wrench into things.
Comet Hitchhiker uses a tether and a harpoon to reel in comets
The spacecraft will attach itself to a comet or asteroid by means of a harpoon attached to an extendable tether. Once secured, the tether will be reeled out to maintain moderate tension, while harnessing the kinetic energy of the comet. This is analogous to reeling in fish using a fishing pole: once the fish takes a bite, the line is reeled out to keep the tension low, so as to use the length of the fishing line for the boat to catch up to the fish. Similarly, once the speed of the spacecraft matches that of the comet, simply reeling in the tether will be enough to safely land on the comet. When it’s time to fly again, the energy harvested from the comet is used to catapult the spacecraft away onto other celestial bodies.
The physics of the Comet Hitchhiker
The comet hitchhiker idea is brilliant because it doesn’t require fuel for landing. The spacecraft, however, needs sufficient deceleration to land safely on a comet. The researchers of this project, therefore, needed tether and harpoon materials that could withstand the heat and enormous tension generated during such a deceleration. They anticipate using carbon nanotube tethers and diamond harpoons to sustain the huge velocity fluctuations that occur while entering the orbit of a comet. Though this concept is still under its Phase I study (and requires multiple simulations to deem it functional), it is believed that this method of travel might spur interest in finding practical solutions to space exploration.
