6h 15min, jan 3, 1999 y - Mars Polar Lander
Failed Mars lander & 2 penetrators (NASA)
When Mars Polar Lander arrived at Mars, it turned its antenna away from Earth to prepare for its entry into the Martian atmosphere. This was the last time controllers heard from the spacecraft. A review board determined the most likely cause for the loss of mission was a faulty software system that may have triggered the retrorockets to turn off early, causing the lander to crash. The spacecraft had carried The Planetary Society’s Mars Microphone to Mars, the first privately funded hardware provided to a planetary mission. Two microprobes, Amundsen and Scott, were piggy-backed on the lander and expected to separate just before the lander entered the atmosphere. However, no signal was ever received from the probes.
Added to timeline:
the videos are in the parts of Mars Exploration Rover Spirit...