fluctuations during a test were used to estimate the temperature related position sensor error in the test  data analysis.  It is well known that composite materials expand and contract in response to humidity due to moisture  absorption in the fiber and the matrix materials.18 This phenomenon is known as moisture expansion.  Therefore, changes in humidity may affect the deployment precision of the specimens in these tests. As  mentioned previously, the humidity is passively stabilized within the test chamber to ±1 percent over 24  hours. While the level of moisture expansion for the specimens is not known, the humidity is measured to  within 1 percent using an Omega HX92Bv0 humidity sensor so that any correlation between position  change and humidity change could be identified during post processing.   During the initial testing, the vibration environment was monitored at normal structural frequency levels with  two accelerometers during many of the early deployment precision tests, but no significant vibration levels  were observed. Therefore, acceleration measurements were not continued beyond the first few specimen  tests in order to decrease the data storage requirements for these long duration tests.  The position, acceleration and humidity measurements were all acquired using National Instruments  LabView software. The Keyence LK-H027 sensors were connected to a Keyence LK-G5001V controller  with a LK-HA100 controller expansion unit. Data was acquired digitally from the controller via an Ethernet  connection using Keyence supplied LabView libraries at a rate of 1 Hz. The humidity measurement was  acquired from the Omega HX92Bv0 using a National Instruments USB-6009 unit and sampled at 1 Hz. The  data from each test was stored in a binary file which is then stored for later post-processing in MATLAB.  With all of the environmental and position measurements defined, the response of the overall test apparatus  to temperature and humidity changes could be characterized. To do this, an Invar reference specimen that  was a form and fit replacement for the hinge specimens was fabricated then installed and measured in the  test apparatus. More details about these measurements are described in Silver et al.17 The results showed  that the changes in the position measurement of the test apparatus to the range of temperature and humidity  changes expected during the tests were approximately 50 nm or less.   Test Procedure  The test flow for a single specimen is shown in Figure 5. It begins with the specimen setup in the test fixture.  However, before a specimen is setup in the test fixture, it is folded and unfolded at least ten times to force  the majority of micro-cracking that may happen when the specimen is folded to occur before the testing  begins. After the specimen is installed, the test chamber is closed out and data is recorded for at least 48  hours. The test chamber door is left closed at all times during the testing except when the specimen needs  to be stowed or deployed. The measurement at the end of that initial settling period is considered the initial  position that serves as the zero reference for all subsequent stow and deploy cycles. As indicated in  Figure 5, a total of 10 creep recovery measurements were made for each specimen made up of three  different stow durations, six tests with 360 minutes (6 hours), two tests with 36 minutes (0.6 hour), and two  tests with 3600 minutes (60 hours) of stow time. The creep response after each stow cycle was measured  for at least 15 hours. Including all of the stow time, recovery and any down time between tests, the full test  sequence for a single specimen takes approximately 17 days.  NASA/CP—2018-219887 423