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History of the PSA:


Concept model• Concept model/handheld mockup built.
• Critical analysis performed on problems, risks, available technologies, and needed technologies.
• Main issues studied: positioning the PSA in its environment, control systems, safety, wireless network, and size.

1999 Model 1• Model 1 developed. This is a functional testing model, and does not conform to the look of the concept model. Model 1 is controlled from a remote server and floats on a cushion of air enabling it to travel on a polished granite table. This allows 3-DOF (degrees of freedom) to be tested: X, Y, and yaw.
2000 Model 2• Testing of Model 1 continued.
• Development of Model 2: 12" diameter sphere built from CAD drawings using stereo-lithography process. Model 2 allows for 6-DOF.
• Development of micro-gravity test facility.
2001 Micro-gravity test facility• Model 2 operational.
• Micro-gravity test facility operational to support 6-DOF. This test facility is similar in shape and size to an ISS module. Inside the test facility there is a crane that attaches to a gimbal, and the gimbal holds the PSA. The crane allows for 3-DOF (X, Y, Z) and the gimbal allows for the other 3-DOF (yaw, pitch, roll).
2002 • Model 2 testing continued.

Model 3• Model 3 nearing completion. This model contains all capabilities planned for the final flight model, yet it is still too large in size (12" diameter).
• Possible test on KC-135 aircraft to simulate microgravity as used by astronauts for trainings.


• Model 4: primary goal is to miniturize the current hardware and reduce the PSA's size to 8-9" diameter.
• Model 5: targeted to be the first PSA flight-tested on a spacecraft. Possible 6" diameter.

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