Debris in the Orbiter crew compartment of early Shuttle missions created crew health concerns and physiological discomfort, and was the cause of some equipment malfunctions. Debris from Orbiters during flight and processing was analyzed, quantized, and evaluated to determine its source. Records were kept on the amount of debris vacuumed by the crew during on-orbit cleaning and the amount found on air-cooled avionics boxes during ground turnaround. After ground turnaround operations at Kennedy Space Center and Palmdale were reviewed from a facility, materials use, and materials control standpoint, the following remedial steps were taken. Selected ground support equipment and some Orbiter hardware was redesigned to preclude or reduce particularization/debris generation, and new access ports were added for cleaning; new detachable filters were developed and added to most air-cooled avionics boxes; tape-on screens were added in several locations to filter debris; new Orbiter maintenance and turnaround procedures were implemented to clean filters and the crew compartment, and for stricter materials control; Kennedy Space Center and Palmdale management and technicians were briefed on debris-related concerns and the importance of adequate cleaning; as part of preflight cleaning, steps were taken to delint flight crew clothing; and an inflight cabin air cleaner was developed and flown to verify its operation and effectiveness in enhancing the quality of cabin air. Most of these steps were implemented before the return-to-flight of STS-26 in September 1988. Since that time, the crew compartment has been considerably cleaner, and the amount of debris found during in-flight and postflight cleaning of filters has been significantly reduced. The results are improved crew compartment habitability and less potential for equipment malfunction.