The theoretically high efficiency and possible low temperature operation of hydrogen-oxygen fuel cells caused them to be the subject of much study upon invention ca. 1900, but their relatively high life cycle costs kept them as a "solution in search of a problem" for their first half century. The first problem for which fuel cells presented a cost effective solution was that of providing a power source for NASA's human spaceflight vehicles. NASA thus invested, and continues to invest, in the development of fuel cell power plants for this application. This development program continues to place its highest priorities on requirements for minimum system mass and maximum durability and reliability. These priorities drive fuel cell power plant design decisions at all levels, even that of catalyst support. However, starting in the mid-1990's, prospective environmental regulations have driven increased governmental and industrial interest in "green power" and the "Hydrogen Economy." This has in turn stimulated greatly increased investment in fuel cell development for a variety of commercial applications. This investment is bringing about notable advances in fuel cell technology, but, as these development efforts place their highest priority on requirements for minimum life cycle cost and field safety, these advances are yielding design solutions quite different at almost every level from those needed for spacecraft applications. This environment thus presents both opportunities and challenges for NASA's Human Spaceflight Program.

John H. Scott serves as Chief of the Energy Conversion Branch at NASA’s Lyndon B. Johnson Space Center, managing the team of engineers that constitute the Human Spaceflight Program’s core technical expertise in fuel cells, gas turbines, hydraulics, pyrotechnics, and the mining of lunar resources. Originally from Memphis, TN, he holds a Bachelor of Science in Mechanical Engineering from Rice University as well as a Master of Science in Mechanical Engineering and a Master of Business Administration, both from the University of California at Los Angeles (UCLA).

Mr. Scott began his career at TRW Space & Technology’s (now Northrup Grumman’s) Applied Technology Division at Redondo Beach, CA in 1986. He subsequently joined NASA’s Lyndon B. Johnson Space Center at Houston, TX. At Johnson Space Center he held increasingly responsible engineering and project management positions in support of the Space Shuttle and International Space Station Programs prior to taking up his current position in functional engineering management.

Mr. Scott is a speaker and published author on the development of fuel cell technology for aerospace applications. His current technical interests are focused on the development of fuel cell, battery, and other energy conversion technologies in support of NASA’s Human Spaceflight Program. He is a member of the American Society of Mechanical Engineers.