NASA is reportedly working on a new spacecraft that borrows a page from Spider-Man’s book, using a harpoon and a long tether to swing from one asteroid or comet to another and using the kinetic energy of those objects to enter orbit and complete landing maneuvers.
The project, known as Comet Hitchhiker, is being funded through the US space agency’s NIAC (NASA Innovative Advanced Concepts) program and would use its harpoon to secure a foothold on a comet or asteroid. Once it is attached, it would release some of its tether while applying the brake in order to capture kinetic energy from its target, according to Space.com.
Next, the Comet Hitchhiker would land by reeling in the line, which would be approximately 62 miles to 620 miles (100 to 1,000 kilometers) long. Using the harvested kinetic energy to quickly collect the tether would propel the probe away from the object and towards its next target. Most importantly, this would enable the spacecraft to travel without using propellant.
In a statement, Masahiro Ono, principal investigator of the project from NASA’s Jet Propulsion Laboratory in Pasadena, California, explained that, “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.”
Comet-catching concept similar to reeling in a fish
The technique, the agency explained, is similar to fishing: Once you get a bite from a big fish, you initially release some of the fishing line with moderate tension instead of keeping it tight. Provided you have enough line, the boat you are on will ultimately catch up with the fish.
Similarly, once the Comet Hitchhiker hooks its “fish” and matches velocity to that asteroid or comet, it lands by reeling in its tether and descending gently. Once its ready to move on, it uses its harvested energy to quickly retrieve its tether, which accelerates it away from the object it is currently on. This technique could help it reach distant objects fairly quickly, Ono said.
In fact, the research team calculated that using zylon and kevlar, the spacecraft would be capable of executing a velocity change of nearly one mile per hour (1.5 kilometers per hour), which Ono explained is “like going from Los Angeles to San Francisco in under seven minutes.” A 6.2 mile per second (10 km per second) speed is possible, but would require advanced materials such as a carbon nanotube tether and a diamond harpoon, the Comet Hitchhiker team noted.
Of course, as Space.com pointed out, this is all merely speculation at this point. The project is in Phase I NIAC study at this point, having received a grant of about $100,000 to begin initial work over a nine-month period. The next steps for the Comet Hitchhiker team, NASA said, are to run additional simulations and attempt to cast a mini-harpoon at a simulated comet or asteroid.
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