Video: Orion flight highlights

Gearing up for a predawn blastoff July 31, launch crews have positioned a Delta 4-Heavy rocket in the starting blocks on a seaside launch complex at Cape Canaveral as engineers inside a tightly-controlled clean room a few miles away put the final touches on a NASA probe that will travel closer to the sun than any mission before.

Vice President Mike Pence said Tuesday that NASA should land astronauts near the south pole of the moon within five years “by any means necessary,” calling for “new urgency” in the U.S. space program and sounding a warning for entrenched aerospace contractors to better meet schedule and cost commitments, or else lose work to other companies.

The most powerful variants of the Atlas 5 and Delta 4 rockets have been purchased by the Air Force to launch intelligence-gathering spacecraft for the U.S. government, and NASA has bought an Atlas 5 to deploy a critical polar-orbiting weather satellite.