Title of Presentation: Family Systems Of Advanced Charring Ablators for Planetary Aerocapture and Entry Missions

Primary (Corresponding) Author: William M. Congdon

Organization of Primary Author: ARA Ablatives Laboratory, Applied Research Associates, Inc.

Abstract: During the past four years, the ARA Ablatives Laboratory has been conducting performance characterization testing and production scale-up testing of new family systems of advanced charring ablators. The primary application is future aerocapture missions to the planets and to the moon Titan. This effort has been sponsored by the In-Space Propulsion Technology Project and managed by the NASA Marshall Space Flight Center. With a development history that started more than ten years back, these advanced family systems consist of phenolic-carbon ablators with densities ranging from 0.32 g/cm3 to 0.58 g/cm3 (20.0 lb/ft3 to 36.0 lb/ft3) and silicone ablators with densities from 0.22 g/cm3 to 0.38 g/cm3 (14.0 lb/ft3 to 24.0 lb/ft3). The higher density phenolic ablators are suitable for heating environments to more than 1000 w/cm2, whereas the silicone materials, which are better insulators, are recommended for heating up to about 300 to 400 w/cm2. The ablators are reinforced with internal fibers and also with large-cell honeycomb (2.5-cm cell size) into which the mixed ablator compound is pressure packed and then cured. Alternate manufacturing methods besides the honeycomb packing approach (HCPA) are the strip-collar bonding approach (SCBA) and monolithic production and application. The proposed paper discusses the results of extensive ablator arc-jet testing and thermal radiation testing performed under the ISPT project since 2003. Much of this discussion centers on the Ablatives Laboratory’s silicone ablator, SRAM-20, that was selected in 2006 by NASA for a possible Earth-return demonstration flight of aerocapture technology.