Solar-electric Advancing For Deep-space Propulsion

[bananas]

http://www.aviationweek.com/Article.aspx?id=/article-xml/AW_08_13_2012_p21-483700.xml

Solar-electric Advancing For Deep-space Propulsion
By Frank Morring
Source: Aviation Week & Space Technology
August 13, 2012

Working in the background, a relatively small group of U.S. spaceflight engineers has been figuring out just what it will take to get humans out of low Earth orbit to Mars, with stops along the way in cislunar space and perhaps on near-Earth asteroids. Spearheaded by William Gerstenmaier, associate NASA administrator for human exploration and operations, and managed in part by John Shannon, the last space shuttle program manager, the team is developing mission architectures that will guide the elected and appointed politicians who must fund and manage mankind's next steps into the Solar System. With budgets tight for the foreseeable future, a lot of attention is going into affordable technology.

One promising technology finding a big role in future exploration architectures is solar-electric propulsion (SEP). Work is underway at advancing the readiness levels of technologies that covert energy from the Sun into propulsion by using solar-generated electricity to force ions out of an engine at high speeds to produce thrust. It isn't a lot of thrust, but it can go a long way on relatively little fuel. A SEP system weighs a lot less than chemical propulsion. Given enough time it can move a lot of mass through space. That in-space advantage makes it particularly attractive for pre-positioning cargo—supplies, habitats and the like—to keep human explorers alive after they arrive on a faster vehicle to explore a distant location.

“Folks in the human exploration mission directorate have identified all of this need,” says Amy Lo, lead system engineer on a SEP project Northrop Grumman has run for NASA's Glenn Research Center. “We would like to send humans to asteroids. In order to do that we need a big tug. Others have identified the fact that in order to, for example, send humans to Mars, we need a lot of cargo in space, so how do we send those things out with existing launch vehicles?”

Lo's project—one of several funded by Glenn—proposes using a “high-heritage” lightweight deployable concentrator to focus solar energy on a receiver containing a working fluid that, when heated, would drive a Brayton-cycle engine to generate electricity. The electricity would power a Hall thruster (photo) to move the spacecraft. Northrop Grumman and its partners—Sandia National Laboratory and the University of Michigan—believe the approach would support a 300-kw SEP system, and are refining a concept to demonstrate the technology by using it to move a spacecraft from low Earth orbit to geostationary orbit.

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[a geek named Bob]

1. Sounds like a variation on the older Solarmoth concept

[bongbong]

2. Exploration of the Solar System is a nice goal

But it is a pipe dream, since the various tipping points of Climate Change (like the methane from melting permafrost) will drastically lower the level of civilization to a simple struggle to stay alive, probably within 50 years.

The Fermi Paradox and all that....