Chapter 6 - Aerospace applications. II. Planetary Exploration Missions (Orbiters, Landers, Rovers and Probes)

Abstract

Batteries are essential components of spacecraft and provide their heartbeat either alone or in conjunction with an energy source. Solar arrays are usually preferred for inner and near planets or planetary objects, where sufficient solar intensity is available for many missions. The choice of power generation source influences the requirements for energy storage, which in turn dictates the selection of the battery system. For solar-powered missions, rechargeable battery systems with adequate life cycle are desirable for providing power during eclipse periods. For some radioisotope-powered missions, battery systems with high power and long calendar life are essential. This chapter deals with batteries used in planetary exploration missions. Three different types of batteries are used in such missions: primary, secondary, and thermal batteries. Primary batteries are expected to be rechargeable batteries in one-shot applications, owing to their higher specific energies, especially where there is no provision for recharge or when there is no energy source available. Rechargeable batteries are used in a spacecraft to provide power during launch and post-launch until the deployment of solar panels for firing pyros and rockets for attitude control, during cruise anomalies, for night time, for communication and data transmission, for keeping electronics warm, and for clocks. Thermal batteries are used to support a series of short-duration high-power pulses for firing pyros. These batteries have characteristically high power capability owing to the use of molten salt electrolytes, albeit with low specific energies.