To the left is shown the ATMOSPHERIC TEMPERATURE PROFILE (as a function of altitude) and the +/-- 1 σ uncertainties derived from the acceleration measurements obtained during the SPIRIT Lander's Entry, Descent, and Landing on January 04, 2004. To the right is the profile for the OPPORTUNITY Lander on January 25, 2004.
Atmospheric Density and Pressure profiles were also derived from the EDL accelerometer measurements. In fact, Density is the primary derived quantity. Pressure is derived via vertical integration of the Density, and Temperature is then derived via application of the Ideal Gas Law to the derived Density and Pressure values.

   The data presented above and other relevant measurements and derived quantities are provided in the MER1PROFILES.TAB ASCII data file (Spirit data) and MER2PROFILES.TAB ASCII data file (Opportunity data) which are located within the data directory within the Mars Exploration Rover RDR data archive merimu_2001. The contents of these two data files are described in the MER2PROFILES.LBL and MER1PROFILES.LBL files which are also located within the data directory.

   The 'raw' IMU data consisting of measured accelerations, rotation rates, etc., are available in the merimu_1001 data archive.