[vannrox]

A good read.

[techcor]

Bumped. And a ping.

[Mr. Thorne]

kewl.

[freefly]

cool tech bump

[DETAILER]

Neat - yet one more step towards machines that have no need for humans? They decide we should be removed? Lets all go home and watch good old "Terminator"......

[isthisnickcool]

That's very interesting! Thanks for the post.

[No Truce With Kings]

Brings back memories. I led the pre-flight navigation analysis of TSS-1, the first tethered satellite mission.

[MeekOneGOP]

Bump for later read. . .

[Scully]

Thanks for the post! For those of us (like myself) who need a bit more information about how the danged thing works, here's another article:

Science Daily

[FreedomPoster]

The root problem we've got is that NASA has become a welfare program for space scientists and engineers, and doesn't do enough missions that advance getting hardware in orbit cheaply. There have been any number of concepts deserving study / development money killed for the sake of bureaucratic inertia.

If this can do that, let's hope it doesn't become another one.

[callisto]

Good find! A very interesting mode of propulsion. I'll have to look forward to updates on its performance.

[r9etb]

It is indeed cool. The concept was demonstrated during the Shuttle tether experiment. I left the Shuttle program just before that mission, but as I recall, we expected a force on the order of 2 lbs -- which is actually quite a lot for a spacecraft.

What they're talking about here is the use of electricity and the Earth's magnetic field.

However, tethers potentially provide another form of "propulsion," in the sense that the top or bottom ends of the tether are going the "wrong speed" for their altitude -- the system moves at the velocity of the center of mass. You can use the position on the tether to raise or lower an orbit.

If you raise something to the top of the tether and let it go, it's going faster than orbital velocity for that altitude. Letting it go raises the orbit. (Which is what happened to the Tethered Satellite piece after the line broke.)

Likewise for downward -- it's going too slow for the altitude, so letting it go lowers the orbit. (Which is what happened to the Shuttle when the line broke.)

This approach probably works best when you have a massive center structure with tethers extending up and/or down, and relatively light deployables.

[boris]

Yawn. Good only in near-earth space; develops a mouse-fart of thrust.

Same with tethers. They are only "momentum transfer" devices, providing modest increases in velocity which is given to the payload at the tether's expense...ultimately paid by a small dimunition of the Earth's momentum.

Neither technology will work for boosters or deep-space propulsion. In this sense they are just stupid stunts.

--Boris

[Physicist]

Recommended reading: "Tank Farm Dynamo" by David Brin (short story).

[Scott from the Left Coast]

Bump for a fantastic read.

[Blood of Tyrants]

Interesting. I wonder what the principle is behind the thrust.

[doug from upland]

You don't have to be a rocket scientist to appreciate this. This is good stuff. Go USA!

[Brett66]

Space bump.

[vannrox]

Going through some of my old bookmarks. I thought that you would enjoy this.

[SunkenCiv]

Thanks, vannrox, for the ping.

Kevin, a ping list candidate?

[KevinDavis]