Longest drop tube freefall time

The drop tube that allows for the longest freefall time is Fallturm Bremen, a 122-m-high (400-ft) vacuum tube operated by the Center of Applied Space Technology and Microgravity (ZARM) at the University of Bremen in Germany. Although Fallturm Bremen is not the tallest operational drop tube (that is the Zero Gravity Research Facility at NASA's Glenn Research Center, which measures 467 feet [142 m] from top to bottom), it has a unique catapult system that launches payloads up the tower before letting them fall back down. This allows for 9.3 seconds of freefall for each payload. In conventional drop mode, with payloads released from the top of the tower, the freefall time is 4.74 sec (less than the NASA facility's 5.18 sec drop time).