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

The nation’s existing Atlas and Delta launch sites are vying for a future when United Launch Alliance completes its modernization with a new rocket system and downsizing to one pad on each coast.

The 60 satellites SpaceX is set to launch Wednesday night, beginning the build-out of a broadband network of orbiting spacecraft that could eventually number thousands, are based on a new flat-panel design, with krypton-fueled plasma thrusters, high-power antennas, and a capability to autonomously steer away from other objects in space.

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.