A small scale CPL (Capillary Pumped Loop) is proposed to be tested under microgravity condition. The CPL consists basically of one solar absorber plate, one radiator plate and one reservoir to control the loop operation system. The heat load required for testing the CPL is supplied by the solar absorber plate. One capillary pump made of sintered nickel is planned to be attached to the absorber plate. Preliminary results regarding the expected performance for the CPL are presented, taking into account the maximum and the minimum solar radiation along an equatorial and elliptic orbit. A solar power up to 33 W is expected to be transferred from the absorber plate to the radiator plate, using ammonia as the working fluid.