Variable emittance materials based on conducting polymers for spacecraft thermal control

Ashwin-Ushas has developed a unique, patented Variable Emittance technology based on the infrared (IR) electrochromism of unique Conducting Polymers. This has features of: very thin ( < 0.5 mm), flexible, light weight (1.6 kg/sq m) variable area (1 sq cm to 1 sq m), entirely solid-state, extremely physically durable construction; switching times < 5 s at room temperature, < 3 min at -35 deg C; cyclabilities > 10 exp 4 cycles; low power consumption ( < 40 microW/sq cm); and, most importantly, space environment durability (space vacuum and -40 C to + 75 C, solar wind, gamma radiation to 7.6 Mrad). A demonstrator spaceflight is tentatively planned on NASA-Goddard's ST5 mission. This paper describes the features and current status of the technology, including results from the most recent tests. It is shown that the technology is the most promising among proposed new Variable Emittance technologies, and possibly one of the only technologies applicable to microspacecraft, besides also being applicable to large spacecraft, space based radars, and future interplanetary missions.