SIM-II

SIM-II (Satellite Inspector Mission-II)

SIM-II, or Satellite Inspector Mission-II, was a proposed United States Air Force (USAF) satellite inspection and servicing program. It was intended as a follow-on to the earlier SIM program and aimed to further develop technologies for in-orbit rendezvous, proximity operations, inspection, and potentially repair or refueling of other satellites. The overall objective was to enhance space situational awareness (SSA) and enable the U.S. to better understand and potentially interact with satellites in geosynchronous orbit (GEO).

The SIM-II concept involved a spacecraft capable of autonomously approaching and observing other satellites. It would carry sensors and instruments to assess the condition and functionality of target satellites, relaying data back to ground controllers. Potential capabilities explored under SIM-II included determining the operational status of a satellite, identifying anomalies, and potentially providing emergency assistance, such as extending a satellite's lifespan through refueling or component replacement.

While the specific details of SIM-II's proposed architecture and capabilities remain somewhat limited in publicly available information, it represented a significant step toward realizing advanced on-orbit servicing technologies and bolstering the United States' ability to operate effectively in a complex and contested space environment. The program contributed to research and development efforts that ultimately influenced subsequent endeavors in space situational awareness and on-orbit servicing. The program's status is generally considered to be concluded, with its technological advancements informing other related initiatives.