Jeremy Hsu reports that until recently, NASA faced a severe plutonium shortage that jeopardized future deep-space missions. In 2013 the U.S. DoE announced, after a 25-year pause, that it would restart production of plutonium 238, the backbone of long-lasting nuclear batteries that have powered numerous missions since 1969. Yet the damage from the hiatus was already done. By 2021 the new effort will yield only enough of the radioactive fuel to make about two and a half nuclear battery modules a year. (The Mars rover Curiosity alone needed eight modules.) This paucity, plus the small existing stockpile, is barely adequate for the next decade of planned planetary missions to destinations such as the icy moons of Jupiter and Saturn. So NASA has been investigating alternatives. It recently become interested in a seafaring candidate - a military technology that has propelled U.S. Navy torpedoes.
The navy first experimented with Stored Chemical Energy Power Systems (SCEPS) in the 1920s, but it was not until the 1980s that engineers at Pennsylvania State University adapted the technology for warheads that could go fast enough and deep enough in their hunt for Soviet submarines. SCEPS harnesses the chemical reaction of two energy-dense reactants that remain stored and separated until needed. In torpedoes, the system commonly holds its energy in reserve as a solid block of lithium and a tank of the inert gas sulfur hexafluoride. When triggered, the combustion reaction of the two materials creates heat that turns the weapon steam turbine to produce thousands of kilowatts of power.
The NASA version would tweak that chemical recipe. Michael Paul, a space systems engineer at Penn State, has proposed a demonstration mission to Venus, where a SCEPS-enabled robotic lander would draw on the atmospheric carbon dioxide of the planet to burn the lithium. The resulting heat could drive an electrical generator to produce about three lightbulbs-worth of power.
Resource Portal for I2M Clients, Associates, and Geoscientists
Managed & Built by I2M Consulting, LLC | © 2010-
Managed & Built by I2M Consulting, LLC | © 2010-