Cold Case Model Hot Case Model GPS LMC GPS LMC Launch 4.7 QCL LO Cryocooler OFF Ascent 4.7 QCL LO Cryocooler ON Predictions of the Cooling fluid temperature at the inlet of the radiator for two environmental model cases. The parameters for the two cases are in the next slide This model assumes that the cryocooler used to cool the 4.7THz QCL is turned ON for ONLY 2 hours during the second day at about 2 hours prior to changing attitude to look at the LMC. It is turned OFF when moving to the LMC Cooling system input power assumptions: 260 W when 4.7 THz is NOT in use, 500W when it is in use.

Hot and Cold cases simulations Hot Case Float altitude 120 kft Latitude 70° S Date Jan 31st Dec 21st Solar Flux 1392 W/m2 1397 W/m2 Albedo 63% 95% Earth Flux of 156 W/m2 250 W/m2 For both Cold and Hot cases runs the model simulates dynamically prelaunch, ascent, and first 48 hours of flight with predicted gondola attitude and telescope elevation