Alternatives for Ground-Based, Large-Aperture Optical Space Surveillance Systems

The Space Surveillance Telescope (SST), developed by MIT Lincoln Laboratory through sponsorship of the Defense Advanced Research Projects Agency (DARPA), has demonstrated significant capability improvements over legacy ground-based optical space surveillance systems. To fulfill better the current and future space situational awareness (SSA) requirements, the Air Force would benefit from a global network of such telescopes, but the high cost to replicate the SST makes such an acquisition decision difficult, particularly in an era of fiscal austerity. Ideally, the Air Force needs the capabilities provided by the SST, but at a more affordable price. To address this issue, an informal study considered a total of 67 alternative optical designs with each being evaluated for cost, complexity and SSA performance. One promising approach identified uses a single mirror with a small number of corrective lenses at prime focus. This approach results in telescopes that are less complex and estimated to be less expensive than additional SSTs. They should also be acquirable on shorter time scales. Another approach would use a modest network of smaller telescopes for space surveillance. This approach provides significant cost advantages but faces some challenges with very dim objects. In this paper, we examine the cost and SSA utility for each of the 67 designs considered. This paper presents the results of an academic investigation into alternative approaches for ground-based, large-aperture, optical telescopes to conduct space situational awareness. The opinions expressed in this paper do not reflect official positions of the affiliated organizations, the Air Force Space Command, the Air Force, the Department of Defense, or the Department of Energy.