following modifications were made to improve the performance of
the main landing gear elements:
- The thickness of the main landing gear axle was increased
to provide a stiffer configuration that reduces brake-to-axle
deflections and precludes brake damage experienced in previous
landings. The thicker axle should also minimize tire wear.
- Orifices were added to hydraulic passages in the brake's piston
housing to prevent pressure surges and brake damage caused by
a wobble/pump effect.
- The electronic brake control boxes were modified to balance
hydraulic pressure between adjacent brakes and equalize energy
applications. The anti-skid circuitry previously used to reduce
brake pressure to the opposite wheel if a flat tire was detected
has now been removed.
- The carbon-lined beryllium stator discs in each main landing
gear brake were replaced with thicker discs to increase braking
- A long-term structural carbon brake program is in progress
to replace the carbon-lined beryllium stator discs with a carbon
configuration that provides higher braking capacity by increasing
maximum energy absorption.
- Strain gauges were added to each nose and main landing gear
wheel to monitor tire pressure before launch, deorbit and landing.
Other studies involve arresting barriers at the end of landing
site runways (except lake bed runways), installing a skid on the
landing gear that could preclude the potential for a second blown
tire on the same gear after the first tire has blown, providing
''roll on rim'' for a predictable roll if both tires are lost
on a single or multiple gear and adding a drag chute.
Studies of landing gear tire improvements are being conducted
to determine how best to decrease tire wear observed after previous
Kennedy Space Center landings and how to improve crosswind landing
Modifications were made to the Kennedy Space Center Shuttle Landing
Facility runway. The full 300-foot width of 3,500-foot sections
at both ends of the runway were ground to smooth the runway surface
texture and remove cross grooves. The modified corduroy ridges
are smaller than those they replaced and run the length of the
runway rather than across its width. The existing landing zone
light fixtures were also modified, and the markings of the entire
runway and overruns were repainted. The primary purpose of the
modifications is to enhance safety by reducing tire wear during