A Control-system for a Skylark Earth-observation Platform

Résumé du livre

A simple 3-axis control-system for a Skylark sounding rocket is described; the system was developed for an Anglo-Argentinian Geoscopy experiment which entailed the photography of a large region of Argentina. The head of the rocket carrying the photographic payload is stabilised with its roll-axis horizontal by the use of Earth-albedo horizon sensors in the pitch and roll axes, the yaw axis having rate control only; control torques are provided by a compressed nitrogen gas jet system; a series of manoeuvers of the head in the yaw-axis is necessary to build up complete photographic coverage The limit-cycle amplitudes in the pitch and roll axes is 0.25° with a maximum rate of 0.25°/sec and the drift-rate in the yaw-axis is less than 0.1°/sec; these rates enable photography with a ground-resolution of 15m to be obtained from a height of 250km over an area of 3 x 106km2. The prototype was lanuched successfully and further launchings are planned.