Weather permitting, the SCA will depart Houston early Thursday for a refueling stop at Biggs Army Airfield in El Paso, Texas. A low pass over White Sands, N.M., host to a shuttle runway, is planned as the carrier aircraft makes its way to Edwards AFB, Calif., for an overnight stay at Dryden Flight Research Center.

Early Friday, Endeavour is scheduled to take flight for a final time atop the SCA, circling low over the San Francisco and Sacramento, Calif., areas before touching down at LAX at about 11 a.m. PDT. Endeavour will be trucked through the streets of Los Angeles to its final home, the California Science Center, arriving on Oct. 13. It is scheduled to go on public display Oct. 30.

Endeavour, manufactured by Rockwell International (now Boeing), rolled off the assembly line at Palmdale, Calif., in 1991. The fifth and final orbiter replaced Challenger, which was lost in a fatal 1986 launch explosion.

Atlantis will complete NASA orbiter retirement deliveries as it rolls to the Kennedy Visitor Center Complex in October.

The SCA will move on as well after 227 flights transporting orbiters over more than three decades. The highly modified 747 will be transferred to NASA’s Sofia (Stratospheric Observatory for Infrared Astronomy) flying observatory program.