DESIGN AND INTEGRATION OF A SOLAR AMTEC POWER-SYSTEM WITH AN ADVANCEDGLOBAL POSITIONING SATELLITE

A 1,200-W solar AMTEC (alkali metal thermal-to-electric conversion) po wer system concept was developed and integrated with an advanced globa l positioning system (GPS) satellite. The critical integration issues for the SAMTEC with the GPS subsystems included: 1) packaging within t he Delta II launch vehicle envelope; 2) deployment and start-up operat ions for the SAMTEC; 3) SAMTEC operation during all mission phases; 4) satellite field of view restrictions with satellite operations; and 5 ) effect of the SAMTEC requirements on other satellite subsystems. The SAMTEC power system was compared with a conventional planar solar arr ay/battery power system to assess the differences in system weight, si ze, and operations. Features of the design include the use of an advan ced multitube, vapor anode AMTEC cell design with 24% conversion effic iency, and a direct solar insolation receiver design with integral LiF salt canisters for energy storage to generate power during the maximu m solar eclipse cycle. The modular generator design consists of an arr ay of multitube AMTEC cells arranged into a parallel/series electrical network with built-in cell redundancy. Our preliminary assessment ind icates that the solar generator design is scaleable over a 500 to 2,50 0-W range. No battery power is required during the operational phase o f the GPS mission. SAMTEC specific power levels greater than 5 We/kg a nd 160 We/m(2) are anticipated for a mission duration of 10 to 12 year s in orbits with high natural radiation backgrounds.