SWF Releases New Compilation of Robotic Rendezvous and Proximity Operations in Space

Tuesday, July 14, 2020

SWF has released a new compilation of the history of robotic rendezvous and proximity operations (RPO) in space as a public Google Spreadsheet. The spreadsheet was put together by SWF summer intern Kaila Pfrang, working with SWF Director of Program Planning Dr. Brian Weeden. 

Proximity operations are a series of orbital maneuvers executed to place and maintain a spacecraft in the vicinity of another space object on a relative planned path for a specific time duration to accomplish mission objectives. Rendezvous is a process wherein two space objects (artificial or natural body) are intentionally brought close together through a series of orbital maneuvers at a planned time and place. Taken together, RPO technologies enable a wide range of capabilities to support civil and commercial space activities such as on-orbit inspections, repairs, refueling, assembly, and life extension. RPO capabilities can also be used for military and intelligence space activities such as intelligence, surveillance, and offensive weapons such as co-orbital anti-satellites.

The goal of the spreadsheet is to document all robotic RPO in space for both military/intelligence and commercial/civil purposes. Criteria for inclusion in this sheet are: known RPO conducted via commercial, civil, or military entities for non-aggressive purposes or autonomous & robotic interaction between two or more satellites with low relative velocity. RPO activities involving human spaceflight, such as docking to the International Space Station, were not included in this database.

The sheet currently lists more than 20 robotic RPO conducted by three countries (the United States, Russia, and China) for military or intelligence purposes and five RPO conducted by civil space agencies or commercial companies for satellite servicing purposes. While most occurred without incident, several involved unplanned physical contact or "bumping" between the two objects and three resulted in the release of a few dozen pieces of orbital debris. A third tab lists known upcoming RPO activities, mainly for 

SWF welcomes feedback on the sheet, including comments, questions, corrections, and additions. Contact details can be found in the spreadsheet.