Consider the following idea for inserting a human on the surface of the earth into orbit:

In orbit, attach a long (~80km) rigid shaft to a large weight (presumably an asteroid) and set it spinning. Alter its trajectory and angular velocity on a collision course with the surface, such that the shaft will briefly touch the person's harness on the surface with zero instantaneous relative velocity, and become attached.

As the apparatus continues spinning and falling, further rotation of the shaft carries our human up and out of the atmosphere. By detaching at apogee, our traveler achieves orbit, leaving the the apparatus to destroy itself in a collision with the planet.

Do plausible future materials allow it, and do the angular momenta work out?

  • 2
    $\begingroup$ It sounds like you're describing a rotating skyhook: en.wikipedia.org/wiki/Skyhook_%28structure%29 $\endgroup$
    – 1337joe
    Jul 23, 2015 at 15:53
  • $\begingroup$ Three differences from the skyhook Wikipedia entry: (1) this is single-use, (2) it goes all the way through the atmosphere to the surface of the earth, and (3) a rigid shaft replaces a flexible tether. $\endgroup$
    – Brian B
    Jul 23, 2015 at 16:14
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    $\begingroup$ A rigid 80km shaft isn't technically feasible. Right now. Or in the next 30 years. $\endgroup$ Jul 23, 2015 at 16:17
  • $\begingroup$ I'd thing trying to use that for a person on the surface of the Earth would essentially amount to a giant flyswatter :-) The similar proposals I've seen - bolas, with a cable rather than rigid beam - all use an aerial rendevous. $\endgroup$
    – jamesqf
    Jul 23, 2015 at 20:01
  • 1
    $\begingroup$ 80km is way too short! You'll die. $\endgroup$ Jul 25, 2015 at 5:02

1 Answer 1


In the reading that I have done, it was indicated that, for the person to survive, they would need an initial velocity of Mach 10 or better and an altitude of well over 100k feet. Otherwise, the only thing that would reach orbit would be well cooked protoplasm. For many reasons beyond the marginal physical capabilities of materials, an Earth elevator or tether is highly unlikely in this century. However, the Moon is a candidate for an elevator with existing materials, but requires an unreasonably length for anything but cargo. Mars is a perfect candidate for both tethers and elevators, with the top of Olympus Mons being the perfect site for both. The atmosphere there is effectively zero, and the Areosychronous orbit is quite low, restricting the length of both the elevator and the counterbalance.


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