Mars 2020 Entry, Descent, and Landing System Overview

Abstract

Building upon the success of the Mars Science Laboratory (MSL) landing and surface mission, the Mars 2020 project is a flagship-class science mission intended to address key questions about the potential for life on Mars and collect samples for possible Earth return by a future mission. [1] Mars 2020 will also demonstrate technologies needed to enable future human expeditions to Mars. Utilizing the groundbreaking entry, descent, and landing (EDL) architecture pioneered by the MSL, [2] [3] Mars 2020 will launch in July 2020 and land on Mars in February 2021. Like its predecessor, Mars 2020 will deliver its rover payload to the Martian surface through the use of Apollo-derived entry guidance, a 21.45 meter supersonic Disk-Gap-Band parachute, a Descent Stage powered by throttleable Mars lander engines, and the signature Sky Crane maneuver. While Mars 2020 inherits most of its EDL architecture, software, and hardware from the MSL, a number of changes have been made to correct deficiencies, improve performance, and increase the robustness of the system. For example, Mars 2020 will take advantage of the favorable atmospheric conditions of the 2020 launch opportunity to deliver a larger and more capable rover than has landed on Mars to date. A primary focus in developing the Mars 2020 EDL system has been mitigating residual risks identified after the landing of the MSL. The Advanced Supersonic Parachute Inflation Research Experiment (ASPIRE) was performed to address new concerns about the stresses experienced by parachute canopies during inflation. Other risk reduction activities include investigating possible interactions between the parachute deployment system and the inertial measurement unit (IMU) which could lead to IMU saturation, researching the effects of airborne dust on radar ground measurements, and site-specific gravity modeling for improved fuel usage. Several enhancements were added for Mars 2020 to improve performance. The addition of Terrain Relative Navigation (TRN) allows the system to land at sites with more hazardous terrain, enabling scientists to select from locations which have previously been considered inaccessible. Mars 2020 will utilize a Range Trigger for initiating parachute deployment, which reduces landing ellipse sizes by 40% compared to the Velocity Trigger approach used on the MSL. New EDL Camera hardware will capture high resolution and high frame rate images and videos of key events, such as parachute deployment and rover touchdown. Finally, the Mars Entry, Descent, and Landing Instrumentation 2 (MEDLI2) sensor suite will build upon the successful MSL MEDLI experiment with the addition of heatshield pressure sensors tuned for the supersonic flight regime and backshell instrumentation. The team has faced new and unexpected challenges throughout development. Notably, the failure of the flight heatshield during a static load test has prompted the fabrication of a new unit. Also, in accommodating the first ever Mars Helicopter under the rover belly pan, the EDL design has been further constrained by reduced ground clearances. Despite these challenges, much of the EDL-related hardware and software have already been delivered, and the EDL verification and validation program is on track to be completed on schedule prior to launch in July 2020.