Relay Planning in the Perseverance Rover's First 600 Solar Days on Mars

Since landing in Jezero Crater on Mars on February 18, 2021, the Mars 2020 mission's Perseverance rover has been performing daily operations on the Martian surface and has been collecting samples that may one day be returned to Earth. The majority of science and engineering data from the Perseverance rover is returned through the Mars orbiters operated by the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA) that make up the Mars Relay Network: Mars Reconnaissance Orbiter (MRO), Mars Odyssey (ODY), Mars Atmosphere and Volatile Evolution (MAVEN), and Trace Gas Orbiter (TGO). Prior to the rover's landing, the Mars 2020 team joined the Mars Relay Network to begin planning relay through the coordinated, multi-mission process that is the cornerstone of relay planning. The Perseverance rover has now been on the Martian surface for more than 600 Martian solar days (“sols”) with several UHF relay sessions planned and executed per sol. The Mars 2020 relay planning team has established and improved upon the recurring process and tool suite to enable both data return and forward link of rover uplink products, and continues to coordinate and negotiate relay asset usages and constraints with the Mars Science Laboratory and Insight relay planning teams. Among many accomplishments, the relay planning team has supported checkouts and commissioning of Low-Density Parity-Check (LDPC) relay link configurations, the mission's first solar conjunction period, and several rover flight software transitions. The Mars 2020 team has also been performing a checkout and commissioning campaign for the use of bitstream, or “unreliable”, relay sessions. Nominal use of bitstream relay is a new operational capability intended for the Perseverance rover that will allow specific science or engineering activities to run in parallel with the relay session, rather than pausing all other activities during relay, enabling additional and more timely data return. Pending the completion of the checkout and commissioning campaign, the operations team plans to approve and begin regular scheduling and use of bitstream UHF relay sessions beginning in 2023. This paper describes the Mars 2020 relay planning processes and tool architecture, key accomplishments (including progress for the bitstream checkout and commissioning campaign), and lessons learned and ongoing challenges during the first 600 sols of the Mars 2020 surface mission.