Publisher's Synopsis
On August 6, 2012 (1:31 AM EDT), the Mars Science Laboratory (MSL) successfully traversedthe atmosphere to land on Mars. But by the time the sky crane lowered the Curiosity rover to thesurface, one experiment (the MSL Entry Descent and Landing (EDL) Instrumentation (MEDLI)suite) had already collected all of its data. For the entire atmospheric entry phase, from justbefore atmospheric interface until it was powered off approximately 10 seconds after theparachute was deployed, MEDLI monitored the entry vehicle's surface pressures and heatshieldtemperatures.MEDLI delivered the first in-depth understanding of the Mars entry environments and theresponse of the entry vehicle to those environments. Previous Mars entry missions assessed theirentry performance (vehicle drag and stability) via the observed initial states coupled with the onboardinertial measurement unit (IMU) data. This approach is devoid of environmentalmeasurements, so total drag force cannot be decomposed into aerodynamics and atmosphericconditions. In addition, no through-thickness measurements to ascertain heatshield thermalprotection system (TPS) performance were taken on previous entry missions.MEDLI culminated decades of advocacy by the EDL community for entry vehicleinstrumentation. The fate of the Genesis and Stardust sample return missions served as animpetus for this advocacy. On September 8, 2004, an incorrectly installed g-trigger did notcommand deployment of its drogue chute, and the Genesis capsule tumbled through theatmosphere. The plan had called for a mid-air retrieval via its slow-descent parafoil to avoidlanding impact loads, but instead the parafoil did not deploy and the Genesis capsule crashed intothe ground. The minimal EDL data available from Genesis also slowed the mishap investigation.Sixteen months later, on January 15, 2006, a successful Stardust return prompted the NASAAdministrator to request an assessment of how the vehicle performed. Since the capsule was notinstrumented, the ability to quantify vehicle stability and drag performance, as well as theheating environment and the response of the TPS to that environment, was limited. As a result, the Administrator mandated that NASA should instrument all future atmospheric entry systems