Comments on: Technology Readiness Levels for Non-rocket Space Launch

By: Tihamer Toth-Fejel

Tihamer Toth-Fejel — Tue, 04 Oct 2011 17:30:44 +0000

One of the lowest cost, and least problematic competitors to the Clarke elevator (other than the momentum exchange tether, which still needs to get the momentum from somewhere) is the Hall Space Pier http://autogeny.org/tower/tower.html
The problem with the Clarke elevator is that it is under so much stress that a nanocrack started by single cosmic ray will propagate faster than the speed of sound (i.e. explosively).

By: ben lipkowitz

ben lipkowitz — Mon, 07 Jun 2010 09:53:57 +0000

since the MAST experiment demonstrated deployment of kilometer-long hoytether on orbit, I’d put the momentum exchange tether concept at TRL 6
http://www.tethers.com/MAST_Blog.html

By: ben lipkowitz

ben lipkowitz — Mon, 07 Jun 2010 09:42:37 +0000

I’m not Dick Taylor, but for an explanation of how to use momentum exchange tethers to reach orbit, read http://www.tethers.com/papers/HASTOLAIAAPaper.pdf
Instead of the massively expensive boeing hypersonic airplane, you could use a suborbital rocket like the SpaceShipOne. Also, note that with a small improvement in the tensile strength of lightweight plastic fiber we could reach zero tip velocity and pick cargo up straight from the ground.

By: Ben

Ben — Thu, 29 Apr 2010 23:00:12 +0000

James,

Thanks for responding. I would imagine that a new technology which created a localized vacuum would not necessarily need to envelope the entire craft, but only the forward-facing area extending outward enough to allow the craft not to be subjected to drag on its sides. I would assume this scheme would reduce the escape velocity requirements, especially when used in conjunction with a mass driver located at high altitude here on Earth.

I am not an engineer, so I don’t even know if physics (as we currently understand it) would even allow for a technology like this, but I still wanted to share my idea with you in the event it had any theoretical merit.

By: James Doehring

James Doehring — Wed, 28 Apr 2010 01:50:00 +0000

Ben, a reduction in drag could be seen with an onboard device that created a local vacuum, so long as the air particles were pushed off in a direction perpendicular to the direction of travel. If the air was pushed forward, rather than sideways, this would still cause drag. I’m not aware of any technology that could move air via force field, but it’s an idea worth investigating.

Dick, how do you see transfer tethers helping get things to orbit?

By: Dick Taylor

Dick Taylor — Thu, 22 Apr 2010 03:52:53 +0000

No mention of dynamic transfer tethers to be used in conjunction with either spacegun or electromagnetic catapult. They are also very useful for transfer to the surface of moon as no atmospheric drag.

By: Ben

Ben — Mon, 19 Apr 2010 15:01:07 +0000

What about creating a portable vacuum that moves with the craft, created by some kind of on-board electromagnetic force field which negates atmospheric drag?

I know it’s a crazy idea, but still…