Engine : Ion

[Phenix]

Any information on that technology would be intersting to share.

[Sam Fraser]

Salut, Phenix! Is a "nano-particle field extraction thruster" a bit like an ion drive? I found this recent development quite intriguing:

http://www.msnbc.msn.com/id/31665236/

Measuring no thicker than a half-inch (1 centimeter, including the fuel) and with tens of thousands of accelerators able to fit on an area smaller than a postage stamp, these “stick-on” thrusters could power tiny spacecraft over vast distances.

The focus of this article is crossing colossal interstellar distances, but our use would be much closer to home. Maybe dozens or hundreds of probes with these thrusters could be launched on a small, cheap lifter like a Falcon 1 to target various NEOs in the inner solar system? Of course, the concept of PERMANENT is using off-the-shelf, commercialised technologies to achieve our goals in the short term, not wait for hypothetical or experimental technology to be developed and proven. Still, it's interesting!

[Boxy]

Think millions. A nanometer ("nano size") is a billionth of a meter, and that's the ballpark they seem to be talking about. The individual thrusters may be that size, but we'll need a significant numbers of them for intrasystem transfers, which would in turn require significantly less energy than intersystem ones. We could very easily send up millions of these buggers and send them exploring the entire Near Earth Orbit.

Although the problem arises on how to fit sensors and radio antennae onto the little bastards. And, of course, having the technology to play with.

[Sam Fraser]

Good point, Boxy. To get PERMANENT off the ground (pun intended :) ), I suppose the first step is identifying suitable NEO targets. We seem to have three options:

1. Ground-based surveys
2. Space-based surveys
3. Space probe flybys/orbital missions

I suppose the real issue (and probably suitable for another thread) is which is the most doable and affordable in the short term? All we need is one or two targets with potential, then base a mission profile on that.

[Phenix]

Thanks Boxy, Sam,

I did not realized that such devices would exists. WOW !

[Bluesteel]

More on NanoFETs here, with diagrams...

http://nextbigfuture.com/2009/07/nanofet-nano-particle-field-extraction.html

Edit: There's a good 19 page paper about it in PDF format about 1/3rd the way down the article.

Julian

[Boxy]

Okay, here's my idea: we send in an automated probe for a flyby of the Near Earth Orbit, only we cover the bugger with scads and scads of cameras and a big enough computer to process the data to find NEO's. We identify ones which are likely to be useful -- dormant comets for volatiles and asteroids for platinum group metals. Then we do some spectral analysis to figure out what the hell is in these buggers.

When we find a good source of volatiles and/or metals, we pitch an asteroid mining scenario to a company, tow the asteroid into orbit, and ba-da-bing, we have a dirt farm in orbit.

[Sam Fraser]

Heck, do we even need to tow it into high Earth orbit necessarily? Just periodically launch payloads and commodities on slow Earth-intercept trajectories using ion drives?

[Boxy]

There's a number of problems with repeat-visit asteroid mining (i.e. not towing it into orbit):

A small delta-v to get back to LEO and Earth
As an extension, difficulty cycling human labor in and out and a longer delay for robotic labor
More propellant would have to be exerted to get fuel from the asteroid to a "gas station" in LEO (therefore reducing cost-efficiency)

A number of estimates state that repeat-visits are non-starters, so if we start mining asteroids the best option is to hit up the asteroid, grab the "low-hanging fruit" and move on to the next branch in the asteroid tree. However, lugging an asteroid into orbit (which is pretty cost-effective, since asteroids are pretty much coated in oxygen via oxides and hydrogen via solar winds) is overall the preferred option.

[Sam Fraser]

NASA engineers have finished testing a new ion-propulsion system for earth-orbiting and interplanetary spacecraft. The system is more powerful and fuel-efficient than its predecessors, enabling it to travel farther than ever before.

http://www.technologyreview.com/computing/23120/page1/

[joertexas]

NASA engineers have finished testing a new ion-propulsion system for earth-orbiting and interplanetary spacecraft. The system is more powerful and fuel-efficient than its predecessors, enabling it to travel farther than ever before.

http://www.technologyreview.com/computing/23120/page1/

I just ran some numbers on the Boeing XIPS ion engines they use for stationkeeping on their comsats. They aren't that powerful, but they use very little fuel for the thrust they put out.

In reference to the Dirty Dozen mission, ion thrusters would have to run for the entire travel phase, but we have time for it, and the solar arrays would give us power to burn for radio and video transmissions after we get there. Using two thrusters would require 9kW of power. That should be enough to put out a decent signal home. :D

JR

http://www.boeing.com/defense-space/space/bss/factsheets/xips/xips.html