History

Track Shoe -- History

The original 1000+ track shoes for the two crawler transporters were produced for NASA in 1965 for the Apollo moon missions.

The first failure of CT shoes was noted in 1986 when long cracks were found along the roller path on one shoe. In 1990, two shoes suffered catastrophic failure during a Shuttle move, with cracks extended across the roller path to the pin lugs; the lugs broke off and the track belt separated.

In 2003, multiple inspections and tests revealed a growing fracture problem with almost 100 cracked track shoes that had to be replaced.
In a follow-up test in March 2004, CT-1 traveled approximately 1.5 miles with its shoes instrumented to record fatigue data. Inspection of the shoes showed that another ten shoes had cracked and had to be replaced.

Close Up of Track Shoes

A detailed failure analysis by the NASA/KSC Materials Failure Analysis Laboratory showed that the track shoe failures were due to fatigue. The fatigue failure initiated at internal casting defects and propagated to the outer surface through a segregated, non-uniform microstructure.
	Back	Next	5