Title of Paper: The Design and Implementation of Draperís Earth Phenomena Observing System (EPOS)

Principal Author: Mr. Mark Abramson

Abstract: Current Earth observation systems trade coverage and revisit times against the number and measurement sensitivity of satellites and on-board sensors. Traditionally, high launch and operation costs drive the fielding of large multi-sensor platforms. The coverage and utility of observations these large satellites provide are restricted by their selected orbit, launch time, and bus reliability. In order to lower development and operations costs, a recently proposed alternative is a suite of smaller size satellites that perform single-purpose measurements. Within this concept, however, high visitation rates of specific locations require enormous numbers of platforms since the area of interest for observing short-lived events cannot be predicted. Coverage and utility thus become restricted by the number of satellites one can afford to place into the constellation, and visitation rate is fixed by the constellation design. Earth observation is trending toward adaptive systems of large numbers of multi-parameter or mission specific satellites with the capability to provide continuous point coverage of significant events as well as providing global monitoring to spot significant events.

Draper Laboratory is currently researching methods to address how these constellations or large numbers of platforms with heterogeneous capability and availability can cooperate and be coordinated from the standpoint of measurement utility, temporal concentration and resource allocation. This methodology will enable many, independent systems to be used optimally for a single task and to provide a scalable architecture as the number of available assets grows.

We present initial results from algorithms developed for autonomous reconfiguration of Earth observation satellites. This will reduce requirements on the human operators of satellites, improve system resource utilization, and provide the capability to dynamically respond to temporal terrestrial phenomena. Our initial system model consists of small numbers of satellites, a single point of interest on Earth (e.g., a volcano) with the objective to maximize the total coverage of the target during a fixed time interval. An approach using integer programming, network optimization and astrodynamics jointly was used to calculate integrated observation and burn plans that maximizes the total coverage of the target during the fixed time interval while adhering to fuel constraints.