English: Left: The Kuiper Airborne Observatory flies with its telescope door open in 1980. The converted C-141 aircraft had a 36-inch telescope just in front of the wing. Right: Inside the KAO, where the mission crew sat during flight. These consoles were positioned along the side of the aircraft’s cabin. The portion of the telescope system that was inside the cabin can be seen at the back of the image. The open telescope cavity was separate from the pressurized cabin.