April 2010

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April's Newsletter

This month's presentation is on Rocketry.

You will find the following links useful for getting background knowledge and ideas for teaching:

http://www.nar.org/teacher.html (The National Association of Rocketry...be sure to look at the "Safety Code"!!

http://www.nasa.gov/audience/foreducators/topnav/materials/listbytype/Rockets.html (Rockets Educator Guide)

Dorothy Diehl's Monthly Article: If you would like to respond, send comments to dnwbrwn@gmail.com

Why Isn’t Nuclear Power Green?

By Dorothy Diehl

The U.S. public suffers from anti-nuclear power hysteria for two reasons: they believe it isn’t safe and no one wants radioactive waste, that harmfully irradiates its environment for up to fifty thousand years, stored in their backyard. Even though five point four million cubic yards of coal ash spilled across three hundred acres of land into the Emory River in Tennessee in 2008—creating a toxic and carcinogenic mess that is still not cleaned up—the public has not reacted with anti-coal hysteria. Why is there a double standard? Anti-nuclear hysteria over the safety issue is irrational. The U.S. Navy has safely propelled much of its fleet with nuclear power for decades by stringently following safety rules.

The radwaste storage issue is more difficult to solve. Obviously, there is no place inside the biosphere to store it safely. It needs to go outside the biosphere into space, which is already an environment naturally filled with hazardous radiation. And no, we do not leave it with all the other orbital debris in LEO.

Here are the five steps for storing radwaste in an out-of-the way, but still retrievable location, in space: If the radwaste is not solid, we glassify it before shipping it, wrapped in lead insulation, by truck to a New Mexico spaceport from which unmanned SSTO spacecraft—like the Graham Delta Clipper almost built by McDonnell Douglas two decades ago—launch into space. Robots load the radwaste as cargo on an unmanned Clipper, which is tele-piloted to LEO.

The Clipper approaches an orbital depot in LEO, which consists of a command module centrally attached to a transverse cylinder to which a docking port module is attached at one end, a habitation module is attached in the middle, and an OMV hangar module with a satellite repair room is attached to the other end. This complex is shaped like a short-handled trident—a spear with three prongs. Flying separately in formation with the complex are a propellant storage module and an unmanned hangar module with two robotic arms for arriving tele-piloted Clipper spacecraft to dock.

Space workers in the depot’s command module tele-operate the robotic arms on the unmanned hangar module to unload the radwaste cargo from the Clipper, and attach to the cargo an internal guidance system and enough PAMs to launch it to escape velocity towards the planet Venus. The Clipper returns to New Mexico for another cargo. The radwaste cargo swings by Venus for a gravity assist and repeats this maneuver around Earth and Venus as often as necessary to acquire adequate energy to coast out to Jupiter.

Approaching Jupiter, it receives a gravity assist that inclines its velocity vector ninety degrees to the plane of the Solar System and puts it into Solar Polar Orbital Storage. (Yes, NASA has already flown this trajectory with the Ulysses spacecraft, which launched from Earth on October 6, 1990.) Putting the radwaste into SPOS virtually keeps it out of future commercial interplanetary space lanes. However, if at some future time, there arises a need to retrieve it, the radwaste can be tele-piloted towards Jupiter for a reverse gravity assist and returned to the plane of the Solar System. * * * Do we now have operational SSTO spacecraft like the Clipper or an orbital depot in LEO? No, but if there were a market for delivering radwaste to SPOS, the private rocket companies could get the venture capital to build them.

Meanings of the acronyms above: LEO, Low Earth Orbit; SSTO, Single Stage to Orbit; OMV, Orbital Maneuvering Vehicle (a space tug); PAMs, Payload Assist Modules

Note: Mrs. Diehl's comments do not represent NASA or JPL.