William Atkins
Friday, 30 October 2009 20:02
Science -
Space
Page 2 of 2
As an interesting sideline, the U.S. space agency NASA drew up a report in September 1988, over twenty years ago, entitled
“Megawatt Class Nuclear Space Power Systems (MCNSPS) conceptual design and evaluation report. Volume 2, technologies 1: Reactors, heat transport, integration issues.”
The pdf file is found at the NASA Technical Reports Server (NTRS): “
Megawatt Class Nuclear Space Power Systems (MCNSPS) Conceptual Design and Evaluation Report.”
Or, go straight to the pdf report at: “
NASA Contractor Report 1796 14
SPI-25- 1.”
The 1988 article includes the statement,
“Free Piston Stirling gas engines coupled to linear actuated alternators have an advantage for space application because they can be made to have a high efficiency, and designed to operate between any temperatures for which suitable construction materials can be found."
"However, very high power engines operating at the high temperatures required for megawatt class electric power systems have never been approached in Stirling engine technology.”
A Stirling engine is a heat engine that operates by compressing and expanding air, or another gas, repeatedly in order to produce heat. The heat is then used to power a vehicle, such as a spacecraft.
Heat sources that have been studied in the past include solar, geothermal, waste, biological, and, most importantly in this case, nuclear.
The U.S. space program already use small Stirling engines in some of its spacecraft that explore the outer solar sytem or have extended missions where sunlight is not available in sufficient quantities.
Called the Stirling Radioisotope Generator (SRG), they generate electricity from a dry, solid nuclear fuel for missions in deep space.
Generating hundreds of watts of power, these small SRGs will need to be upgraded and/or modified so they can generate millions of watts of power for spacecraft that use Megawatt-class nuclear space power systems (MCNSPS).
The ability to use MCNSPS spacecraft was not possible in 1988. Of course, that was over twenty years ago....