The Mars Science Laboratory Entry, Descent, and Landing Instrument (MEDLI) Suite is a set of engineering sensors designed to measure the atmospheric conditions and performance of the MSL heatshield during entry and descent at Mars. While not part of the core MSL scientific payload, it will provide important information for the design of entry systems for future planetary missions. The MEDLI suite consists of seven MEDLI Integrated Sensor Plugs (MISP) and seven Mars Entry Atmospheric Data System (MEADS) pressure sensors, located on the heatshield of the spacecraft.

The picture shows a sensor MEADS

• MEADS measures the atmospheric pressure on the heat shield at the seven MEADS locations during entry and descent through Mars' atmosphere. The MEADS pressure sensors are arranged in a special cross pattern. This cross pattern will allow engineers to determine the spacecraft's orientation (its position and how that changes) as a function of time. Engineers will use this information to see how well their models predicted the spacecraft's real trajectory (its path) and its aerodynamics (how it acts when moving through the atmosphere). That information will allow them to plan future missions that will have even better performance during critical stages of entry, descent, and landing.