Category Archives: Space Tethers

Someone is Wrong on the Internet!

And ironically, it’s XKCD What-if that is wrong. Well, not wrong by commission, but wrong by omission. First off, I’m a huge fan of both XKCD (well the 98% of their comic strips that are SFJ) and XKCD-What If. If … Continue reading

Posted in Humor, Propellant Depots, Space Tethers, Space Transportation | 5 Comments

Steve Canfield and his marvellous mechanical joint

In previous posts I’ve mentioned that when I first got to NASA I worked in the Propulsion Research Center, which was a fun place to work because you got to think about and try just about anything you wanted to … Continue reading

Posted in Space Tethers | 17 Comments

Recursive Algorithm for Moravec’s Mass Ratio

Computing the mass ratio for a tapered tether (tether mass/tip mass) was first done (to the best of my knowledge) by Hans Moravec in an appendix to his unpublished 1978 paper, “Non-Synchronous Orbital Skyhooks for the Moon and Mars with … Continue reading

Posted in Space Tethers, Space Transportation, Technology | 9 Comments

Momentum Exchange Tethers — Early History

The history of momentum-exchange tethers goes back many, many years but is bound by a common thread that, until recently, limited the realization of this technology. That common thread is the need for high specific tensile strength. The first idea … Continue reading

Posted in Space Tethers, Space Transportation, Technology | 5 Comments

A Tether Technology Anniversary

Rotating momentum-exchange tethers are a very exciting technology, but one of my first thoughts after being exposed to the technology was the tricky rendezvous. The space industry has spent all kinds of money and time on satellite rendezvous, and these … Continue reading

Posted in Space Tethers, Space Transportation, Technology | 8 Comments

MXER Tether Intro #1: Simple Untapered Tethers

So I’ve started out telling you that momentum-exchange tethers are great. Why? you might ask. Well, because a spinning momentum-exchange tether is capable of transferring a fair fraction of the orbital energy and angular momentum in its orbit to a … Continue reading

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Momentum Exchange Tethers — An Introduction

Anyone who’s interested in going to the Moon ought to take a serious look at the technology of momentum-exchange tethers. My own interest began back in 1998, when as a summer intern on the X-33 program at Lockheed Martin Skunk … Continue reading

Posted in Space Tethers, Space Transportation, Technology | 10 Comments