A estimate the cost of an array of aperture reflector antennas to be used instead or in conjunction with current large reflector antennas of Deep Network for servicing present NASA missions which smaller spacecraft with power and smaller, gain antennas. The advantages of the array configuration in of cost and reliability are studied A probabilistic determination of the reliability and availability of the array as a of the number of array elements and the availability of individual elements is made. impact of marginal elements on the operational availability of array is studied. Parametric cost and reliability plots are presented and directions for investigation are outlined I. INTRODUCTION The Jet Propulsion Laboratory is currently engaged in a study to develop a quantitative understanding of the performance, cost, and technical risks associated with using a large array of aperture reflector antennas for Deep Space Network applications [l- 2]. The array be a receive-oniy system, o..