IRCOMM: spacecraft free-space optical bus development

This paper summarizes the on-going work at the Johns Hopkins University Applied Physics Laboratory (JHU/APL) towards implementation of a free-space optical bus for small spacecraft applications. After reviewing the current state of the art as well as previous work at JHU/APL, a comparison of several protocols, including USB, RS232, 10Mbit Ethernet (IEEE 802.3) is summarized, with Ethernet being the chosen protocol. Component selection is discussed in the context of radiation environments. Finally, a prototype point-to-point link that was assembled using COTS hardware and several different transmitting elements is described. It was found that the key technical challenge that remains is the receiver sensitivity. Plans for follow on work to complete the link are also summarized