A second runway was added crossing the original north-south landing strip, and in 1979 both lakebed runways were lengthened to 35,000 ft (10,668 m), which includes 15,000 ft (4,572 m) usable runway with 10,000 ft (3048 m) extensions on either end, to allow White Sands Space Harbor to serve as shuttle backup landing facility.
An additional runway was added crossing the original east-west landing strip, and in 1979 both lakebed runways were extended to 35,000 ft (10,668 m), which includes 15,000 ft (4,572 m) usable runway with 10,000 ft (3048 m) additions on either side, to enable White Sands Space Harbor to function as a backup landing site for shuttles.