Pointing and tracking subsystem design for optical communications link between the International Space Station and ground

We present a preliminary design for a tracking and pointing subsystem for the optical communication link between the International Space Station and a ground receiver at Table Mountain Facility. The link is intended to demonstrate high rate downlink capability of rates up to 2.5 Gbps. The design objective of tracking and pointing subsystem is to limit the pointing loss to within 4 dB to ensure the maximum downlink capability with 3 dB link margin. We will show the underlying tracking and pointing subsystem design and present analysis that shows the allocated error budget can be met.