Failure Simulation Testing of the Z-1 Spacesuit Titanium Bearing Assemblies



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46th International Conference on Environmental Systems


The Z-1 is NASA's next generation spacesuit, designed for a range of possible missions with enhanced mobility for spacewalks both on planetary surfaces and in microgravity. Increased mobility was accomplished through innovations in shoulder and hip joints, using a number of new bearings to allow spacesuit wearers to dip, walk, and bend with ease; all important tasks for a planetary explorer collecting samples or traveling over rough terrain. The Advanced Spacesuit Development Team of NASA Johnson Space Center requested that NASA White Sands Test Facility (WSTF) perform a simulation test on three titanium bearing assemblies, an elemental part of the joint construction used in the Z-1 spacesuit. This testing simulated two undetected failures within the bearings. The first failure was an inner seal leak sufficient to pressurize the race with +99 percent oxygen. The second failure was an improperly installed or mismatched ball port that created a protrusion in the ball bearing race, partially obstructing the nominal rolling path of each ball bearing. When the spacesuit bearings are assembled, bearing balls are loaded into the assembly via a ball port. The ball port is specific and unique to each bearing assembly (matched pair). The simulated mismatched ball port is a significant source of friction, which would be caused by an assembly error.

The objective of this test program was to evaluate whether a failed or failing bearing can result in ignition of the titanium race material due to friction. To evaluate this risk, the bearings were cycled in a simulated worst case scenario environment, operational loads, and potential flaw conditions. During test the amount of actuation torque required and heat generated through continuous operation were measured and the bearings were observed for sparks or burning events. This paper provides details descriptions of the test hardware, methodology, and results.


United States
ICES400: Extravehicular Activity: Space Suits
Vienna, Austria
Richard C de Baca, NASA Johnson Space Center White Sands Test Facility, USA
Alfredo Juarez, NASA Johnson Space Center White Sands Test Facility, USA
Stephen Peralta, NASA Johnson Space Center White Sands Test Facility, USA
Jonathan Tylka, NASA Johnson Space Center White Sands Test Facility, USA
Richard Rhodes, NASA Johnson Space Center, USA
The 46th International Conference on Environmental Systems was held in Vienna, Austria, USA on 10 July 2016 through 14 July 2016.


Spacesuit, Z-1, Titanium, Bearing