アポロ司令・機械船
Lind served as backup Pilot alongside backup Commander Vance D. Brand and backup Science Pilot Lenoir for Skylab 3 and Skylab 4, the second and third manned Skylab missions; was on standby for a rescue mission planned when malfunctions developed in Skylab 3's Apollo Command/Service Module (ultimately thwarted due to Brand and Lind's resourcefulness in devising a solution in the simulators) and the proposed 20-day Skylab 5 mission (scrapped in favor of the more economical extension of Skylab 4 from 56 to 84 days); and may have flown as a Pilot or Science Pilot on Skylab B.