The ZARM drop tower in Bremen

The Bremen drop tower, on the site of the University of Bremen, is one of the tallest and best-known drop tower facilities in Europe. At the heart of the facility is the 146 m high tower surrounded by support facilities that include control rooms, laboratories and hardware workshops. The tower itself houses a steel tube from which air can be evacuated and accommodates all the technical components to accelerate, guide and decelerate the capsule.

The capsule is a specially designed bus that is designed to be shockproof, in order to withstand the acceleration / deceleration forces, and pressurised to normal atmospheric pressure and temperature. Three capsule types are available: short, long and catapult. 

In the drop mode the capsule is released from a height of 120 m giving 4.74 s of microgravity experiment time. The capsule experiences a deceleration of up to 50 g after the experiment is completed.

Since 2007, the Bremen facility has also offered a catapult mode in which the capsule is catapulted vertically to the top of the tower and then drops back down the deceleration chamber. Using this mode, the microgravity experiment time can be extended from 4.74 to 9.3 s. Unlike the drop mode, the capsule and its enclosed experiment experience an upward acceleration of up to 35 g before the experiment begins. 

More information about ZARM drop tower can be found on their website.