Reconstructed Performance of the Mars 2020 Parachute Decelerator System

Abstract

On February 18, 2021 the Mars 2020 mission's Perseverance rover successfully landed on Jezero crater. The space-craft's Entry, Descent, and Landing (EDL) sequence included a 21.53-m supersonically deployed Disk-Gap-Band parachute that was a strengthened version of the parachute used by the Mars Science Laboratory mission to land the Curiosity rover in 2012. This paper will provide an overview of the Mars 2020 parachute decelerator system, summarize the methodology and data sources used to reconstruct the spacecraft's trajectory, and describe the parachute system's performance in flight. System performance was reconstructed using measurements from the onboard inertial measurement unit and Mars Entry, Descent and Landing 2 instrumentation suite, along with pre-launch measurements of the parachute system and spacecraft, assumptions about the vehicle's aerodynamics, and models for the Martian atmosphere. In addition, images of the parachute's deployment and inflation acquired by the EDL camera system were used to assess the parachute's deployment, extraction, and inflation. The parachute system was found to have performed nominally throughout. The parachute was mortar-deployed at a Mach number of 1.81 and a dynamic pressure of 520 Pa. The deployment, canopy extraction, and inflation were observed to be orderly with no significant causes for concern identified. The peak inflation force was 152 kN (34.2 klbf), which was well below the parachute's flight limit load of 222 kN (50 klbf). Following inflation, the supersonic and subsonic aerodynamics of the parachute and the dynamics of the system were nominal.