Civil Space Technology Initiative Research Articles

The need for high power space systems in anticipated within the next 10 to 20 years. Examples are the Space Station, co-orbiting platforms, geostationary orbit (GEO) platforms, and space-based radar satellites and some classified high power missions. Sodium-sulfur (NaS) batteries have been identified as the most likely successor to nickel-hydrogen (NiH 2) batteries for space applications. One advantage of the NaS battery system is that the useable specific energy is two to three times that of NiH 2 batteries. This represents significant launch cost savings or increased payload mass capabilities. NaS batteries support NASA OAST's proposed Civil Space Technology Initiative goal of a factor of two improvement in spacecraft power system performance, as well as the proposed Spacecraft 2000 initiative. The NaS battery operates at between 300 and 400 °C, using liquid sodium and sulfur/polysulfide electrodes and solid ceramic electrolyte [1 – 3]. The transport of the electrode materials to the surface of the electrolyte is through wicking/capillary forces. These critical transport functions must be demonstrated under actual microgravity conditions before NaS batteries can be confidently utilized in space. For Aerospace Corporation, under contract to NASA Lewis Research Center, is currently working on the NaS battery space flight experiment definition study. The objective is to design the experiment that will demonstrate operation of the NaS battery/cell in the space environment, with particular emphasis on evaluation of microgravity effects. Experimental payload definitions have been completed and preliminary designs of the experiment have been defined.