Launch day begins with a weather update. If the conditions are right, the launch team lays out the flight train on the ground.
This generally consists of the gondola and science instruments, as well as a radar reflector, parachutes for the balloon landing, and a small auxiliary balloon to lift the gondola off the ground until the main balloon is airborne.
They must find a landing site where the balloon and its precious scientific payload can be brought safely and securely back to Earth.
During these tricky final 30 minutes of the descent, the balloon is braked by parachutes also opened by remote control from the ground.