scope:

Description of Driving Event:

The initial runs of an On-Orbit Constraint Test (OOCT) at KSC ran into a number of anomalies. These initial runs were the first attempts (or "pathfinder" event) in a series of OOCT from which lessons learned would result in smoother, more efficient OOCTs prior to future flights. The OOCT are a series of tests that emulate one side of an element to element interface using test aids. These Test Aids are set up in a test configuration with the flight element to be tested. The flight crew actually comes to KSC to conduct the test on the flight hardware. The OOCT is considered training for the crew as well as a checkout of the on-orbit procedure with the actual flight hardware.

Both Extra-vehicular Activities (EVA) and the Inter-vehicular Activities (IVA) are subject to the OOCT discipline. In an OOCT, connect cables, fluid ducts and umbilicals on the flight are run in a test configuration so that routing, mating/de-mating of the flight hardware, clocking, length of lines, stress/strain or twisting of cables and potential obstructions to be encountered can be evaluated.

This pathfinder OOCT occurred for Flight 3A where Node 1 was emulated (Node 1 is on-orbit) and with PMA3 (Flight 3A) which had been delivered (DD250) to NASA. The PMA3 configuration actually encountered during the test set-up was different than envisioned from review of the drawing package from which the test aid alignment data and test procedure had been generated. The test procedures are generated from the on-orbit operational sequences being built by mission planners (in this case, in JSC's Missions Operations Directorate, or MOD).

Because of the misunderstandings documented in the root causes below, the test alignments, setup of the test aids and the actual conduct of the tests exceeded the planned test timeline. While the test was completed successfully, a regression test will have to be conducted to repeat parts of the test because of insufficient / incorrect data available for the test procedure.

Root causes:

1. Setup and Alignment Data for the Test Aid was insufficient, incorrect and misunderstood by the KSC support teams responsible for the test aid setup and alignment of the test configuration. There was no tabletop review of this data with KSC prior to these pre-test activities nor was the data formally released prior to pretest activities.

2. The On-Orbit Constraints Meeting was not utilized as a requirements gate review. Since this was the initial test, this meeting was process oriented and lacked specific implementation requirements to be agreed to and baselined.

3. Hardware fit interference - overhanging of PMA3 by EVA test aid - was not anticipated. It was a surprise to the test team. With appropriate configuration control processes, this would not have occurred. Scaffolding and protective padding was applied to the element.

4. Undocumented mating targets were applied to mating / sealing surfaces because target locations identified were not on same planar surface as expected. Because the test technicians had done similar exercises before, the targets were applied successfully prior to test.

5. N2 and O2 lines were incorrectly called out in the test procedure. Test Procedure was written to the PMA3 to Node3 ICD that is the correct data source. This was questioned prior to TRR and PMA3 Flight Element team provides a sketch of the lines which was also incorrect. The running of the test identified several errors including this one.