NASA looking at 'hitchhiking' across solar system on speeding comets

A spacecraft concept under development could shoot diamond harpoons at space rocks to slingshot itself around our corner of the galaxy.

Eric Mack Contributing Editor
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Eric Mack
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Comet Hitchhiker is a cosmic gypsy.

NASA/JPL-Caltech/Cornelius Dammrich

Traveling around space can be hard and require a lot of fuel, which is part of the reason NASA has a spacecraft concept that would hitch a free ride on one of the many comets and asteroids speeding around our solar system at 22,000 miles per hour (on the slow end).

Comet Hitchhiker, developed at NASA's Jet Propulsion Laboratory and presented this week at the American Institute of Aeronautics and Astronautics' Space conference, would be a quirky little spacecraft that reminds me simultaneously of "Moby Dick," "The Hitchhiker's Guide to the Galaxy" and microgravity parkour.

Imagine a little robotic spacecraft that anchors itself to small bodies by firing a harpoon attached to a ridiculously long tether.

But this concept is more clever than just hitching a ride behind a speeding space rock, waterskiing-style. Once Comet Hitchhiker anchors itself to something, it acts like a skilled angler who's just landed the catch of the day. The idea is to let the "fish" swim, letting more fishing line (the tether) out while maintaining just a slight amount of tension in the line. This approach is useful in a couple of key ways, making you think someone as smart as a rocket scientist must have come up with it.

First of all, it allows Comet Hitchhiker to accelerate and slowly match the speed of its ride, and keeping that slight tension on the line harvests energy that is stored on-board for later use, much the same way regenerative braking works in hybrid and electric cars.

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Once Comet Hitchhiker is traveling at the same speed as its "fish," it reels in the tether. But because this is happening in the vacuum of space, the spacecraft actually is reeling itself down to the surface of the comet or asteroid. This means it can then land and take some samples or a selfie to use as a snappy retort when someone in the Diner at the End of the Universe tells it to "go take a ride on a comet."

But Comet Hitchhiker's dismount maneuver is also intriguing. Using its stored energy from "catching" the comet, it propels itself off the rock at a higher velocity, essentially slingshotting itself on to its next target across the solar system.

Just like in a Prius with regenerative braking, this approach is very beneficial for gas mileage. According to early estimates by project leader Masahiro Ono, Comet Hitchhiker could use this technique to slingshot itself to Pluto in the relatively quick period of under six years. Even better, it could get to the far edge of the solar system and probably still have energy stored up, at which point it could essentially be transformed into a distant fuel station for other spacecraft.

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Maybe a Diner at the Edge of the Solar System isn't just a concept for science fiction after all.

Getting to the point where this whole idea is practical is going to require a little bit of technical innovation first, however. It may require advanced technologies like a carbon nanotube tether anywhere between 62 and 620 miles long attached to a diamond-tipped harpoon.

Fortunately, Comet Hitchhiker might just be able to pick up some diamonds along the way to the edge of the solar system by simply plucking some out of Saturn's atmosphere.

Problem solved, NASA. You're welcome. Now stick those thumbs out and get us a ride to the edge of the universe!