Understanding fluid behavior in microgravity is essential to further development of cryogenic storage in space environments. The Reduced Gravity Cryogenic Transfer project is designed to investigate tank chilldown in a microgravity environment onboard a parabolic flight. This work focused on examining the feasibility of chilling down different tank sizes using liquid nitrogen within the time constraints of the flight. Thermal models of four different tank geometries were made using Thermal Desktop and SINDA/FLUINT. The tank wall was modeled as a series of solid finite elements while the fluid inside the tank was represented by twinned liquid and vapor lumps. Fluid was injected into the bottom of the tank to simulate a dip tube and vented out of the top of the tank. The tank wall temperature as well as the state of the fluid inside the tank was tracked throughout the simulation. Several different cases were run with different chilldown operations for each tank model using a combination of charge, hold, and vent cycles. The average wall temperature, propellant mass savings and thermal efficiency of each of the four tanks were compared under seven different chilldown operations. A recommendation was made for the receiver tank size based on these parameters.