Sensors Collect Crucial NASA Data on Mars Environment With Perseverance Landing MEDLI2 was one of the crucial technologies onboard the rover’s protective aeroshell that helped document the entry, descent, and landing (EDL) of the spacecraft. MEDLI2’s role was to collect critical data about the harsh environment during Perseverance’s entry through the planet’s atmosphere. It included three types of sensors – thermocouples, heat flux sensors, and pressure transducers – that measured extreme heat and pressure during entry. It also contained electronics and hardware for recording the thermal and pressure loads experienced during entry and through the parachute deployment. MEDLI2 used its pressure, temperature, and heat flux measurements to determine the heating that occurred on the heat shield and back shell. Together, these two components make up the aeroshell, which housed the Perseverance rover.