Engineering topics
Kim, David
Publications and source records attributed to Kim, David.
Functional Autonomy Challenges in Sampling for an Europa Lander Mission
We present a baseline approach to Functional Autonomyfor the purpose of conducting excavation and samplingbehaviors in a proposed Europa Lander mission. Aspects ofthe problems of site selection, excavation progress tracking,and fault identification are related; with particular emphasison parameters peculiar to an icy moon environment. Firstpass approaches to addressing these challenges are presentedin isolation, while motivating the current development goal ofproducing a general Functional Autonomy architecture thatallows state estimation, fault diagnosis, isolation, & recovery(FDIR), and adaptive behaviors to be formulated in concert.
CITADEL: an icy worlds simulation testbed
Icy Worlds present an exciting target for in-situ sample acquisition and analysis of surface samples for their potential to contain conditions necessary to support life. The unknown surface composition and topography of icy worlds present a challenging environment for which to develop effective sampling systems. Testing such sampling systems in a relevant environment is a critical part of validating and refining their design. We have developed the Cryogenic Ice Testing, Acquisition Development, and Excavation Laboratory (CITADEL) to enable sample acquisition and handling operations in an icy world or primitive body representative environment of <70K and 10-5 Pa.
The Global Precipitation Measurement (GPM) Spacecraft Power System Design and Orbital Performance
The Global Precipitation Measurement (GPM) spacecraft was jointly developed by National Aeronautics and Space Administration (NASA) and Japan Aerospace Exploration Agency (JAXA). It is a Low Earth Orbit (LEO) spacecraft launched on February 27, 2014. The spacecraft is in a circular 400 Km altitude, 65 degrees inclination nadir pointing orbit with a three year basic mission life. The solar array consists of two sun tracking wings with cable wraps. The panels are populated with triple junction cells of nominal 29.5% efficiency. One axis is canted by 52 degrees to provide power to the spacecraft at high beta angles. The power system is a Direct Energy Transfer (DET) system designed to support 1950 Watts orbit average power. The batteries use SONY 18650HC cells and consist of three 8s x 84p batteries operated in parallel as a single battery. The paper describes the power system design details, its performance to date and the lithium ion battery model that was developed for use in the energy balance analysis and is being used to predict the on-orbit health of the battery.