If the Latin phrase ad astra per aspera—“to the stars through difficulty”—applies to anyone, it’s Jim Bridenstine, the newly confirmed administrator of the National Aeronautics and Space Administration. After a lengthy and bitterly partisan confirmation fight, the 42-year-old former naval aviator takes charge of an agency that has been whipsawed by the policy reversals of recent presidential administrations.

The George W. Bush-era Constellation Program would have sent American astronauts to the moon for the first time since...