Video: Tower rollback prior to launch of Mars Pathfinder atop a Delta 2

NASA’s Kepler planet-finder began its mission to discover Earth-like worlds orbiting other stars in the galaxy today in 2009, successfully launching aboard a Delta 2 rocket from Cape Canaveral.

NASA’s Mars Pathfinder probe dropped to the surface of Mars for an airbag-cushioned landing 20 years ago Tuesday, bouncing 15 times across an ancient flood plain before deploying a mobile robot to usher in two decades of uninterrupted Martian exploration.

A team of United Launch Alliance and NASA engineers worked through Delta 2 launch day fueling procedures during a simulated countdown Wednesday for what should be the second-to-last time before the venerable rocket’s final liftoff next month from California’s Central Coast.