Facility

[Print-friendly version]

In the QUT microgravity facility, reduced-gravity conditions are generated by allowing experiments to free-fall down a vertical corridor, called a drop tower.  The experiment is protected from air resistance by enclosing it inside a drag shield.  As the experiment free-falls down the drop tower, it experiences reduced gravity for approximately two seconds.  It is then safely decelerated in an airbag at the bottom of the tower, ready for retrieval and re-use.  The QUT facility is capable of up to twenty tests per day, depending on the experiment.

Drop tower specifications and performance data are presented in the following sections:

Drop Tower

Experiment Platform and Drag Shield

Performance

Drop Tower

The following images show the views looking up and down the drop tower.  The drop tower is more than six storeys high and allows for a free-fall height of 20 m.

Enlarge Image

Experiment Platform and Drag Shield

The following image shows the experiment platform and drag shield.  The experiment platform provides a housing for all experimental equipment to be used in the drop tower.  All objects mounted on the experiment platform experience reduced gravity.  The experiment platform is not attached to the drag shield, but instead falls independently within the enclosed space.  Since the drag shield experiences air resistance, the experiment platform falls slightly faster and 'catches up' to it during a drop.  Thus the experiment platform must be permitted to move relative to the drag shield, which means a large clearance gap below the experiment platform, as shown, is required at the beginning of each drop test.

Enlarge Image

Some important payload specifications are presented in the table below.  For more specific information, please contact us.

Additional equipment available includes:

• 24 V power supply
• Data acquisition equipment, including accelerometer
• Switches for signalling the onset of reduced gravity

Performance

The following graph presents the gravity level measured before, during and after a typical test.  The small spike at the end of the reduced-gravity period occurs when the experiment platform contacts the drag shield, and the large spike represents impact with the airbag and deceleration.  The duration of the reduced-gravity period, measured from the moment of release to the point when the experiment platform contacts the inside of the drag shield, is 1.95 s.  The maximum loading expected during deceleration is less than 20 g, which lasts for a duration of approximately 0.25 s.

Enlarge Image