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posted by LaminatorX on Thursday September 03 2015, @05:05PM   Printer-friendly
from the freight-train-hopping-IN-SPAAAAAACE! dept.

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, would feature a reusable tether system to replace the need for propellant for entering orbit and landing on objects.

The spacecraft would first cast an extendable tether toward the object and attach itself using a harpoon attached to the tether. Next, it would reel out the tether while applying a brake that harvests energy while the spacecraft accelerates. This 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, reeling itself down to the surface of the comet or asteroid. A comet hitchhiker spacecraft can obtain up to ~10 km/s of delta-V by using a carbon nanotube (CNT) tether, reaching the current orbital distance of Pluto (32.6 AU) in just 5.6 years.

Unfortunately rocket scientists apparently don't read SN, or they'd know from discussions last year that it simply won't work. It seems that the idea defies "basic orbital mechanics" and "makes no sense".

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  • (Score: 1) by Absolutely.Geek on Friday September 04 2015, @12:22AM

    by Absolutely.Geek (5328) on Friday September 04 2015, @12:22AM (#232049)

    Replying to myself to clarify; the 40g that I stated above is the MINIMUM acceleration achievable. It is quite likely that the actual acceleration would be much higher then 40g; if there was a failure of the unspooling mechanism half way along the craft would need to gain 4km/s is a very short amount of time....most likely outcome would be the unspooling mechanism tearing away from the craft or the teather snapping at a weak point somewhere along its length.

    Don't trust the police or the government - Shihad: My mind's sedate.
  • (Score: 2) by mhajicek on Friday September 04 2015, @02:32AM

    by mhajicek (51) on Friday September 04 2015, @02:32AM (#232095)

    Yeah, Mythbusters tried it with a car. It didn't work very well.

    The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
  • (Score: 2) by Adamsjas on Friday September 04 2015, @04:19AM

    by Adamsjas (4507) on Friday September 04 2015, @04:19AM (#232123)

    Stretchy tether?

    Not necessarily a bungie cord, just a weave that could stretch slowly, (no rebound, its stays lengthened).
    You could soak up a lot of Gs in the cable itself.