Traveling at approximately 6.9 kilometers/second and 125 kilometers above the surface, the spacecraft entered the atmosphere and was initially decelerated by using a 2.4 meter ablation heat shield, located on the bottom of the entry body, to aerobrake through 116 kilometers of the atmosphere. Three minutes after entry, the spacecraft had slowed to 496 meters per second signaling an 8.4-meter, polyester parachute to deploy from a mortar followed immediately by heat shield separation and MARDI powering on, while 8.8 kilometers above the surface. The parachute further slowed the speed of the spacecraft to 85 meters per second when the ground radar began tracking surface features to detect the best possible landing location.
When the spacecraft had slowed to 80 meters per second, one minute after parachute deployment, the lander separated from the backshell and began a powered descent while 1.3 kilometers aloft. The powered descent was expected to have lasted approximately one minute, bringing the spacecraft 12 meters above the surface.
]]>Premature engine shutdown caused by a software error related to the landing leg touchdown sensors has been found to be the most likely cause for the loss of the Mars Polar Lander.
The findings from the Beagle 2 investigation were more general because there was no data from the spacecraft after separation from MEX. ESA/UK inquiry here - it concluded that bad project management and funding problems contributed to the failure.
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