"Star Wars"â€"as the Strategic Defense Initiative (SDI) is dubbedâ€"will require reliable sources of immense amounts of energy to power such advanced weapons as lasers and particle beams. Are such power sources available? This study says no, not yetâ€"and points the way toward the kind of energy research and development that is needed to power SDI. Advanced Power Sources for Space Missions presents a comprehensive and objective view of SDI's unprecedented power requirements and the opportunities we have to meet them in a cost-effective manner.

th th Mars, the Red Planet, fourth planet from the Sun, forever linked with 19 and 20 Century fantasy of a bellicose, intelligent Martian civilization. The romance and excitement of that fiction remains today, even as technologically sophisticated - botic orbiters, landers, and rovers seek to unveil Mars’ secrets; but so far, they have yet to find evidence of life. The aura of excitement, though, is justified for another reason: Mars is a very special place. It is the only planetary surface in the Solar System where humans, once free from the bounds of Earth, might hope to establish habitable, self-sufficient colonies. Endowed with an insatiable drive, focused motivation, and a keen sense of - ploration and adventure, humans will undergo the extremes of physical hardship and danger to push the envelope, to do what has not yet been done. Because of their very nature, there is little doubt that humans will in fact conquer Mars. But even earth-bound extremes, such those experienced by the early polar explorers, may seem like a walk in the park compared to future experiences on Mars.

This report evaluates the Defense Threat Reduction Agency prior and present sponsored efforts; assess the present state of the art in thermionic energy conversion systems; assess the technical challenges to the development of viable thermionic energy conversion systems for both space and terrestrial applications; and recommend a prioritized set of objectives for a future research and development program for advanced thermionic systems for space and terrestrial applications.