Low gravity provides an outstanding basis for precision measurements in atom optics pursuing multi-disciplines in fundamental physics. On the other hand it leads to an utilization of ultracold quantum matter techniques in unique practical applications. We report on the first establishments of atom optical experiments in the gravitation-free conditions at the Drop Tower Bremen in Germany, a facility of the Center of Applied Space Technology and Microgravity (ZARM). The chosen drop tower has an easy access to low gravity on earth with a daily usage, a more than sufficient time of free fall for experiments in quantum regimes (about 4s in drop mode and about 9s in catapult mode) and a well quality of weightlessness of 10-6g. Our report demonstrates the results of the precursor pilot project ATKAT ("atom catapult") and the current pilot project QUANTUS ("quantum systems under weightlesness") . The pure technological experiment ATKAT could successfully realize a compact and robust setup for trapping and cooling neutral rubidium atoms ( 87Rb) in microgravity conditions. After ATKAT's test accomplishment we have started the parallel developed QUANTUS main pilot projekt to investigate quantum degenerated gases in free fall. The first Bose-Einstein condensate (BEC) in a weightless environment world wide and longest evolution times of the 87Rb BEC up to 1s could be achieved within the science experiment QUANTUS. In respect thereof our collaboration opens further opportunities in atom optics. At least we will give an outlook of the new QUANTUS II project and its supporting project PRIMUS ("precision interferometry with matter waves under weightlessness") aiming on a precise inertial sensor by using an atom interferometer under weightlessness.