MicroGravity Test Facility
The MicroGravity Test Facility has been developed to test and validate autonomous
vehicle navigation and control in a simulated microgravity environment. The Facility
counteracts Earth’s gravitational influence allowing a subject vehicle to test
propulsion and navigation systems.
Background
The MicroGravity Test Facility (MGTF) was originally developed for testing and
validating propulsion, autonomous navigation, and control of the Personal Satellite
Assistant (PSA). The MGTF is designed to simulate the microgravity environment
on board the International Space Stations (ISS) US Lab Module. Six Degrees of
Freedom (DOF) are achieved with a 3 DOF gimbal system, suspended from a 3 DOF
translation crane, allowing vehicle motion in all directions. Precision sensors
in the x-y-z axes measure vehicle thrust down to a fraction of an ounce. These
measurements are then used to actuate external motor controllers in the suspension
system, which simulate the vehicle’s motion in a microgravity environment.

Currently the MGTF is being used to test and validate the PSA’s ability to navigate
using a fiducial-based vision system. In addition, the MGTF can simulate disturbances
likely to occur on ISS, such as an overheated rack or experiment, or unusual noise
from faulty equipment. The PSA then seeks out and identifies these anomalies.
Image right: The Personal Satellite Assistant (PSA) in the MicroGravity Test Facility (MGTF).
In addition to simulating the US Lab Module, the MGTF could also be configured
for external spacecraft simulation, such as autonomous vehicle inspection and
autonomous rendezvous.
Relevance to Exploration Systems
The MGTF facility is a state-of-the-art test facility allowing for microgravity
simulation of small spacecraft. The technology developed for the MGTF could be
scaled to support even larger and more complex simulations such as rendezvous
and docking maneuvers for two independently operated vehicles, as well as terrestrial
lander studies for various microgravity environments.