NASA hatches hitchhiker’s guide to the galaxy plan using comets

2 Sep 2015

An artist's conception of how the Comet Hitchhiker system would look. Image via NASA/JPL-Caltech/Cornelius Dammrich

NASA plans to hitchhike its way across the galaxy — or at least the solar system — by harpooning on to comets and pulling itself towards them, rather than try to make a landing.

The idea proposed by NASA to further our attempts at landing on comets in our solar system is far removed from the meaning of life and 42, however, with its harpoon concept it will save time and fuel.

Simply called Comet Hitchhiker, the concept developed by NASA’s Jet Propulsion Laboratory would see a spacecraft tether a harpoon line towards a comet or asteroid and attach itself to the celestial body.

Once it has attached, the spacecraft would reel out the tether while applying a brake that harvests energy while the spacecraft accelerates.

Fishing, but in space

Making a comparison with fishing, NASA said it would be the equivalent of releasing a fishing line with a moderate tension after catching a fish, rather than holding it tightly. With a long enough line, the boat will eventually catch up with the fish.

Once it has matched the comet’s velocity, it will reel itself in and land slowly on it and when it wants to leave again it uses the harvested energy to retrieve the tether and push itself away.

Principal investigator on the project, Masahiro Ono, said that the beauty of the concept is that it can be used multiple times on one mission.

“This kind of hitchhiking could be used for multiple targets in the main asteroid belt or the Kuiper Belt, even five to 10 in a single mission,” Ono said.

A 1,000km-long harpoon

To withstand the strains of clinging on to a giant comet at high speeds, the tether would need to be between 100km and 1,000km in length or, in comparable terms, the distance from Dublin to Hamburg.

It would also need to be incredibly strong, with suggestions that it could be made from either Kevlar or Zylon.

The next steps for Ono and the team studying the concept is to run more high-fidelity simulations and try to cast a mini-harpoon at a target that mimics the material found on a comet or asteroid.

Here’s hoping this harpoon concept has better luck than the European Space Agency’s (ESA), which when landing the Philae lander on Comet 67p saw its harpoon system fail, leaving the lander lost for a period of time.

Here is Inspirefest 2015 speaker Ariel Waldman giving her thoughts on the concept.

Colm Gorey was a senior journalist with Silicon Republic