fixture is used to simulate undocking. Functional testing was completed using both the A and B string  motor/controller. During vibration testing, the capture latch was mounted on a fixture on a vibration table  and subjected to the Qualification vibration spectrum in each of the three axes (X, Y, and Z). Between each  axis and after the final axis, the Latch was functionally tested. During TVAC testing, the unit is placed in a  thermal vacuum chamber and functionally tested at both the hot and cold vacuum conditions. The Primary  Release test demonstrates that the capture latch can release while loaded up to the maximum expect load  for undocking at both ambient and vacuum conditions.  The Secondary (NEA) release test demonstrates that the secondary release mechanism can release the  latch when subjected to the maximum expected load during a contingency release. This test was conducted  only at ambient conditions. Finally, the Static (Ultimate) load test demonstrates that the Capture Latch  remains contained after being subjected to the ultimate design load.   All development tests were completed successfully except the Secondary Release test, which failed. This  test will be discussed later.    Qualification Testing  Qualification testing was the same as development testing, with the following exceptions. Thermal Cycle  testing was included, with 24 cycles to the same temperature extremes as the development test. Three  thermal vacuum cycles were conducted. Finally, a Life Cycle test was performed.  All tests were completed successfully, with two exceptions. (1) During the Thermal Vacuum test, one  channel of the motor failed as described in the next section of this paper. However, since one string of the  motor was still operational, the test was allowed to continue with the remaining string. (2) The Secondary  Release Mechanism failed to release the latch during the Secondary Release Test. This test failure is also  discussed in subsequent sections of this paper.  Acceptance Testing  The Acceptance Test consists of the following tests: 1. Run-In, 2. Functional, 3. Random Vibration  (acceptance levels/durations), 4. Thermal Vacuum (TVAC), and 5. Primary Release. In general, the levels  and durations of exposure are lower during Acceptance Testing, as compared to qualification testing. NEA  functionality cannot be checked since the NEA is a single use item.   The Acceptance Test was successful in screening a number of minor defects in some of the capture latches.  Minor defects detected included limit switch rigging issues, worm gear alignment problems, and motor-tocontroller splicing deficiencies. The test also uncovered a major defect in the motor assemblies, which will  be discussed later.  Motor Failures During Acceptance Testing  Description of Failures  Failures occurred in four separate motors during Capture Latch Assembly Acceptance Test at Boeing and  at the supplier of the motor/controller. A timeline of events is shown in Table 1. The initial failure (Failure 1)  occurred during Acceptance Test of the Capture Latch motor at the supplier. During the ninth hot cycle of  the Thermal Cycle test, the motor ceased operating on the A string. The second failure (Failure 2) occurred  during Thermal Cycle testing of the Capture Latch Assembly at Boeing. During the eighth hot cycle of the  thermal cycle test, the motor failed to operate on the B string. The third and fourth failures (Failure 3 and  Failure 4) occurred during Hot Thermal Vacuum testing of the Capture Latch Assembly at Boeing. During  this test, high current spikes were observed, and the units operated intermittently on both the A and B  strings.  NASA/CP—2018-219887 489