Triggering those sensors cuts the lander's Retrorockets and send two signals-
one to indicate that the robot has landed, and a second, seven minutes later, to communicate that the robot is functional.
During the short span of time, InSight had to autonomously perform thousands of operations such as separate the heat shield, deploy the legs, activate the radar,
fire the Retrorockets and orient for landing and it had to them flawlessly and by all the indications,
it was able to do just that.