scope:

Description of Driving Event:

During recent Multi-Purpose Logistics Module (MPLM, S/N FM1) operations, loose debris generated by rivets from the Personnel Access Floor (PAF, S/N 002) was discovered. The suspect Foreign Object Debris (FOD) material are rivet collars that are metallic and approximately 0.3 mm - 5 mm in diameter and weigh approximately .04 grams.

Root cause: It was determined that when the Personnel Access Floor was installed into the MPLM, foot traffic (clean room boots) were snagging the rivet collars and dislodging them. The rivet collars were carefully inspected, it was determined that the rivet collars were not thoroughly ground down flush during manufacturing and the remaining raised material was snagging the clean room garments.

An extensive search was conducted in MPLM (FM1) by three technicians using hand held lights; one rivet collar was found. The following day, the MPLM was rotated 180 degrees, a post rotation inspection was performed on the interior of the MPLM and no rivet collars were found. The MPLM is currently in the passive configuration with no racks installed, the Y and Z panels are accessible, the interior of the MPLM has been thoroughly inspected and no rivet collars have been found. This MPLM configuration is the optimum configuration for cleaning and performing inspections. MPLM (FM1) current schedule indicates over a year of ground processing in which interior cleanings and inspections are scheduled, furthermore this anomaly was detected within very short time of GSE installation into the MPLM and it is highly unlikely that any rivet collars remain in the module. The following MPLM engineering groups were notified: Electrical Power Distribution (EPD), Command & Data Handling(C&DH), Environmental Control and Life Support (ECLS), Alenia KSC representative, Huntsville PAF design group, Boeing and NASA quality organizations.