16

I seem to recall reading of a design by Robert Heinlein (but maybe Sheffield, Clarke or another scientific writer), where the energy cost of a space elevator was virtually nil, as descending loads were used to recoup the energy cost of the lift.

Looking for the story,author and if possible the quote where it is described.

9
  • 1
    The only Heinlein on this page is Friday.
    – Micah
    Commented Aug 19, 2013 at 15:08
  • 2
    You probably mean Robert Forward.
    – Kyle Jones
    Commented Aug 19, 2013 at 17:18
  • @Micah Edited question; I don't have a copy of Friday handy, but I don't think that was it. I have surfed around a bit and not find a good list of attributes of each authors elevators. Commented Aug 20, 2013 at 0:26
  • @KyleJones in my memory it was described in SciFi story or book. Commented Aug 20, 2013 at 0:29
  • 3
    Possible duplicate of Trying to find a book about an extraordinary elevator
    – SQB
    Commented Feb 14, 2017 at 5:52

2 Answers 2

15

If you think it might have been Clarke, I would try The Fountains of Paradise. I don't remember the specific passage you're talking about, but it predates (and in fact probably caused) the era of science fiction in which space elevators are a common trope, so as I recall it spends more time describing them than most.

Edit

Chapter 10 "The Ultimate Bridge"

Quote delivered by the hologram of Vannevar Morgan, Chief Engineer of Terran Construction's Land Division.

"Capsules for passengers, freight, fuel would ride up and down the tubes, at several thousand kilometers an hour. Fusion power stations at intervals would provide all the energy needed: since ninety percent of it would be recovered, the net cost per passenger would be only a few dollars. As the capsules fall earthward again, their motors will act as magnetic brakes, generating electricity. Unlike re-entering spacecraft, they won't waste all their energy heating up the atmosphere and making sonic booms, it will be pumped back into the system. You could say that the down trains will power the up ones. So even at the most conservative estimate, the Space Elevator will be a hundred times more efficient than any rocket."

2
  • 1
    Charles Sheffield's The Web Between the Worlds came out at about the same time as The Fountains of Paradise, so is also worth a look.
    – Mike Scott
    Commented Aug 20, 2013 at 5:24
  • Could not find a "DRM free" copy to buy. I finally figured out how down load as a library loan (it was much easier then I though). Reading now;and here it is, just as I remembered. Commented Oct 5, 2013 at 21:55
13

As Mike Scott mentions, Sheffields book The Web Between the Worlds fits the bill. Here is the relevant passages, as gleaned from amazon's "look inside" feature:

..if we send a mass all the way to the end of the beanstalk, far beyond geostationary orbit, the we will also have a free launch system. A mass released from 100,000 kilometers out can be thrown to any part of the solar system. The energy for this is, incidentally, free. It is provided by the rotational energy of the Earth itself [...] since any energy used in the drive train to take mass up the beanstalk can be recovered by making the same mass do work as it comes down, a remarkably efficient system is possible. And by using the beanstalk as a slingshot, we have the energy-free launch system for payloads going to destinations anywhere in the solar system

But note that this is from the book's second appendix, "space elevators in fact and fiction" where the author goes into technical detail. I'm not sure if it's elaborated on in-story or if the appendix was present in the first edition. In any case, and with apologies to Heinlein, there is no such thing as a free launch.

1
  • 5
    +10 "In any case, and with apologies to Heinlein, there is no such thing as free launch." :) Commented Aug 20, 2013 at 11:13

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.