NASA Wants to Tether Spacecraft to Comets to Hitch ‘Free Rides’ to Deep Space

The development would halve the amount of time it'd take to get to Pluto.

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Jan 27 2015, 2:45pm

Image: ​Museum of Science Fiction

​NASA has floated a couple fanciful ideas in the last year—​submarines on Titan, ​drones on Mars—and here's one more: comet-powered spacecraft.

It's just a concept for the time being, but Masahiro Ono, an engineer at the Jet Propulsion Laboratory, believes that spacecraft could one day latch themselves onto a passing comet and use the comet's energy to propel it into deep space at speeds nearly twice as fast as those we have today.

It's really not that complicated of a concept, Ono suggests.

"The comet hitchhiker concept is literally to hitch rides on comets to tour around the Solar System," he wrote in a proposal for the agency's Innovative Advanced Concepts Program, which encourages scientists to put forward seemingly crazy ideas about the future of space travel.

"This idea can be intuitively understood by the analogy of fishing. Imagine a fisherman on a small boat tries to catch a big fish that runs at a high relative speed," he added. "Once the fish is on a hook, the experienced fisherman would let the line go while applying a moderate tension on it, instead of holding it tightly. If the line has a sufficient length, the boat can eventually catch up with the fish with moderate acceleration."​

And it'd work much the same way. The spacecraft would "harpoon" a comet with a carbon nanotube tether, using it as a completely fuel-less way to travel. For this to work, NASA scientists would have to project the trajectory of a comet and would have to find one suitable for traveling on.

Image: NASA

Ono suggests that we could get to Pluto in roughly five-and-a-half years, and that it would take just under nine years to get to Haumea, an elliptically-shaped dwarf planet nearly twice as far away from the Sun as Pluto. That's almost twice as fast as it's taking New Horizons, a NASA probe that was launched in 2006, to get to the former planet.

This is, of course, only a concept. There's no specific funding for it, and there has been no suggestion that the agency is moving forward with it. But here you see an extremely detailed depiction of what it might look like. That's because, in partnership with the Museum of Science Fiction, Ono worked with German designer Cornelius Dammrich to envision the thing. The ​concept art was released on Monday.

That may be the first step toward actually getting a spacecraft like this built.

"It's a great opportunity to help the space agency. It's now able to take this art and go to the legislators for funding. It's a pilot program to see how the museum can help NASA," Greg Viggiano, the museum's director, told me. "If you take a technical and sophisticated program and put some really compelling concept art behind it, it makes the story easier to tell."

Viggiano says that Ono was involved with the entire thing, and that Dammrich designed the spacecraft specifically according to his vision.

Image: Museum of Science Fiction

Comet hitchhiking is different from other deep space propulsion methods in several important ways. Besides requiring no fuel, he suggests that it can be used to actually enter the orbit of large bodies in the solar system, and that it might even be possible to land on them with the help of the tether. The tether can also be used to "brake," which may make it possible for the spacecraft to actually harvest energy from the comet, allowing it to power instruments onboard.

The comet wouldn't necessarily have to be very large, so we likely wouldn't have to wait for years before a suitable comet passed by, he suggests.

Finally, the system could create thrust that's "impractical or extremely costly using currently available technologies," he wrote. "We strongly believe that the comet hitchhiker concept will advance the frontier of space exploration to the most exotic worlds in the Solar System."

And if it happens, the spacecraft might look like this.