Masahiro Ono of NASA’s Jet Propulsion Laboratory had a “aha” moment – design a spacecraft capable of landing on multiple comets and asteroids. Equip a craft with harpoons and tethers for landing, then cast off for the next destination using kinetic energy.
This week Ono submitted his Hitchhikers Guide to the Galaxy based research at the American Institute of Aeronautics and Astronautics SPACE conference. Included were solutions to initial concerns over harpoon and tether strength. Exhaustive analysis and computer simulation arrived at a solution dubbed the Space Hitchhike Equation. The equation led to Ono’s conclusion – materials exist (Zylon and Kelvar) capable of withstanding changes in velocity necessary for safe landing. (velocity change of 1.5 Km/second – imagine Los Angeles to San Fransisco in under 7 minutes). The next phase will include harpoon tests at targets mimicking asteroids and comets.
You go Masahiro – imaginations like yours are the future of cosmic exploration and discovery.
While closely flying by the target, a spacecraft would first cast an extendable tether toward the asteroid or comet and attach itself using a harpoon attached to the tether. Next, the spacecraft would reel out the tether while applying a brake that harvests energy while the spacecraft accelerates.
This technique is analogous to fishing on Earth. Imagine you’re on a boat on a lake with a fishing pole, and want to catch a big fish. Once the fish bites, you would release more of the line with a moderate tension, rather than holding it tightly. With a long enough line, the boat will eventually catch up with the fish.
Once the spacecraft matches its velocity to the ‘fish’ – the comet or asteroid, in this case – it is ready to land by simply reeling in the tether and descending gently.
When it’s time to move on to another celestial target, the spacecraft would use the harvested energy to quickly retrieve the tether, which accelerates the spacecraft away from the body.
This artist concept shows Comet Hitchhiker, an idea for traveling between asteroids and comets using a harpoon and tether system. Image via NASA/JPL-Caltech/Cornelius Dammrich
A description of Comet Hitchhiker by Masahiro Ono –