Weight is an important factor in ballooning. It determines the size of the balloon that must be used, the altitude that can be achieved and how long we can fly. It also influences the amount of ballast that can be carried on the gondola. Ballast is dropped during flight to control the balloon altitude.
Today, technicians from Columbia Scientific Balloon Facility (CSBF) picked up our payload in its final flight configuration with a crane in order weigh it. Before we did this we removed all non-flight equipment, such as external power supplies. The wheels you can see in the picture will not fly, but their weight was measured independently and subtracted. The gondola itself weighs just under 3400 lbs, in very good agreement with our engineering prediction.