Bruce D. Williams

Radiation Belt Storm Probe spacecraft and impact of environment on spacecraft design

NASAs Radiation Belt Storm Probe (RBSP) is an Earth-orbiting mission scheduled to launch in September 2012 and is the next science mission in NASAs Living with a Star Program. The RBSP mission will investigate, characterize and understand the physical dynamics of the radiation belts, and the influence of the sun on the earths environment, by measuring particles, electric and magnetic fields and waves that comprise the geospace. The mission is composed of two identically instrumented spinning spacecraft in an elliptical orbit around earth from 600 km perigee to 30,000 km apogee at 10 degree inclination to provide full sampling of the Van Allen radiation belts. The twin spacecraft will follow slightly different orbits and will lap each other 4 times per year; this offers simultaneous measurements over a range of spacecraft separation distances. A description of the spacecraft environment is provided along with spacecraft and subsystem key characteristics and accommodations that protect sensitive spacecraft electronics and support operations in the harsh radiation belt environment.

Asteroid in situ exploration using planetary object geophysical observer (POGO)

Missions to small bodies greatly benefit from landed measurements of surface composition such as from Rosetta Philae and Hayabusa-2 MASCOT. For future rendezvous or sample return missions, a lander could enhance investigation the small body origin by characterizing its geophysical state, mineralogical composition, and abundances of major and key minor elements. The lander can also characterize the mechanical and thermal properties of the regolith, addressing Decadal goals of investigating processes that alter surfaces of solar system bodies. Key challenges in design of such a lander include lack of knowledge of the regolith before arrival, the landing process, power availability, mass constraints, and large diurnal thermal variations. Communication with either the orbiter or direct-to-Earth also requires great flexibility.

Advanced Solar Probe Experiment Module (AD SOLEM)

A small, low-power suite of fields and particles and imaging experiments is required for fulfilling the critical science objectives for a near-sun flyby mission. We discuss how an integrated instrument suite using novel sensors and advanced detector/microelectronics/packaging techniques can be implemented for such a payload. Critical tradeoffs between science requirements, measurement strategies and these resource limits are discussed, and critical enabling components are identified. The instrument site consists of 6 major investigations, some with multiple sensors, power conditioners for both high and low voltages and a common DPU. The concept design is essentially a dress-rehearsal of how a payload could realistically make the measurements needed to answer the critical science questions while operating within a real-world physics, engineering and technology context.