An unmanned cargo freighter carrying nearly four tons of supplies and science, launched and operated commercially for NASA, blasted off from Cape Canaveral on Tuesday atop an Atlas 5 rocket bound for the International Space Station.

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.

A replay of the United Launch Alliance Atlas 5 rocket launching the Global Positioning System 2F-12 satellite from Cape Canaveral, Florida, completing 27 years and 61 flights of the GPS 2 generation.