Adjustments are made as needed in thermal blanketing, and thermal-vacuum tests may be repeated. Then the spacecraft is transported to the launch site. The spacecraft is sealed inside an environmentally controlled carrier for the trip, and internal conditions are carefully monitored throughout the journey whether it is by truck or airplane. Once at the launch site, additional testing takes place. Propellants are loaded aboard.
Any pyrotechnic devices are armed.
Then the spacecraft is mated to its upper stage, and the stack is hoisted and mated atop the launch vehicle. Clean-room conditions are maintained atop the launch vehicle while the payload shroud is put in place. Command sequences must be loaded aboard the spacecraft, verified, and initiated at the proper time prior to launch. Spacecraft health must be monitored, and the launch process interrupted if any critical tolerances are exceeded. Once the spacecraft is launched, the DSN begins tracking, acquiring the task from the launch-site tracking station, and the cruise phase is set to begin.