https://medium.com/@telluric/nasa-mars-insight-and-its-legacy-to-mars-polar-lander-and-mars-surveyor-2001-426f7cc6ea4d

A NASA spacecraft — InSight is less than a day away from landing on Mars! For the sake of landing and basic operations — supplying power, thermal control, communications, the InSight lander is an identical twin to its predecessors — Mars Polar Lander and Mars Phoenix. I had the pleasure of being a software analyst on the Mars Phoenix project and as a final task, completed an independent walkthrough of the Entry-Descent-Landing command sequence.

In 1999, Mars Polar Lander took 11 months to reach Mars and was one of the two Mars mission mishaps that year. Polar Lander’s failure was attributed to the flight software lacking the ability to discern the difference between the landing leg deployment and the vehicles touchdown. Consequently, nearly as soon as the landing rockets fired, they were shut down and the lander crashed landed on the surface. Mars Phoenix was a second identical lander which was originally intended to be the Mars Surveyor 2001 Lander.