Six days were scheduled for vehicle modifications before beginning final systems tests.

Unexpected difficulties in incorporating filters in the command controller, which required considerable redesign, and alignment problems with the forward auxiliary rack, which required extensive machining, imposed a lengthy delay. These problems added 29 days of slippage to the GATV 5001 schedule, leaving the vehicle 66 calendar days behind schedule by the end of March. Machining of the forward auxiliary rack was completed April 5, and vehicle systems testing finally began April 9.