The starboard fin/rudder was removed from the vehicle after static testing and installed on an engineering  unit that had a representative lowe r fin structure housing the fin ac tuation mechanism. This unit was  successfully vibration-tested in the X, Y, and Z axes. Reference “X-38 V-201 Fin Engineering  Development Unit (EDU) Vibration Test Plan”.  Functional Testing   The port and starboard fins have been actuated several dozen times. Before and after each static test  and vibration test, the fin mechanism was actuated.  The majority of the functional tests have been  performed using the EVA interface either with a socket wrench or the PGT. The starboard fin was  actuated multiple times using one of the COTS motors. 

Conclusions   X-38 Status   The X-38 project was officially shut down in  May 2003. NASA Headquarters decided that NASA needed  to pursue a multi-use vehicle. The two B-52 drop test vehicles, V-131R and V-132, and the space flight  prototype vehicle V-201 have been mothballed and are mu seum pieces at JSC. V-201 is approximately  80% c omplete. 

Remaining work for Fin before Flight   Due to the cancellation of the X-38 project, the mechanism flight performance may never be known.  However, the testing completed thus far indicates the mechanism would function in the thermal/vacuum  environment after withstanding the vibro-acoustic launch loads and could also lock the fin deployed  against the aerodynamic flight loads. Remaining testi ng would include a vehicle level acoustic test with  the fins stowed and a vehicle level thermal/vacuum te st where the fins would be functionally tested. The  mechanism is currently in a ground test configurati on with nonfunctioning motors installed. The fin can be  actuated via the EVA interface. The 1-G counterbalance is also installed in the upper fin. The primary  outstanding issue is the procurement of  flight motors. A specification control drawing for the motors has  been released. There are also several minor iss ues that have been documented in Discrepancy Reports  that would have to be resolved in order to fly.  The keys to success on this project included building  prototypes early and performing sub-assembly level testing leading up to system level testing.   

References 

1. Robertson, Brandan “X-38 V-201 Fin Linkage Ca libration Report” JSC-49740 – JSC Scientific  and Technical Information Center  2. Lupo, Christian P. “Procedure, Fin Fold ing Drivetrain” SKK51356551 – NASA/JSC Engineering  Drawing Control Center  3. Lupo, Christian P. “X38 V-201 Fin Mid Hinge/Lat ch Qualification Test Plan” JSC-28409 – JSC  Scientific and Technical Information Center  4. Smith, James P. “X38 V-201 Fin Hinge/Latch  Qualification Test Report” JSC-29294 – JSC  Scientific and Technical Information Center  5. Robertson, Brandan “X-38 V-201 Fin Drivetrain Thermal/Vacuum Test Report” JSC 29911 – JSC  Scientific and Technical Information Center  6. Edelstein, Karen S. “X 38 V 201 Integrated Static Structural Test Plan – Shuttle Launch &  Landing Tests” JSC 29182 – JSC Scientific  and Technical Information Center  7. Edelstein, Karen S. “X-38 V-201 Integrated St ructural Test Plan – Aerosurfaces Tests” JSC  29184 – JSC Scientific and Technical Information Center  8. Lupo, Christian, “X-38 V 201 Fin Deployed Test Report” (Draft available upon request)  9. Lupo, Christian, “X-38 V-201 Static Test  Report – Shuttle Launch & Landing Tests” (Draft  available upon request)  10. Edelstein, Karen S. “X-38 V-201 Fin Engineering Development Unit (EDU) Vibration Test Plan”  (Available upon request).   376