THE 21ST CENTURY SPACE SHUTTLE
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Tomorrow’s Shuttle:Cutting Risks in Half by 2005

Enhancements now under development could double the Shuttle's
safety by 2005: New sensors and computer power in the main engines
will "see" trouble coming a split second before it can do harm, allowing
a safe engine shut down. A new engine nozzle will eliminate the need
for hundreds of welds and potential leaks

Solid Rockets and External Tank Upgrades

Future improvements for the solid rocket boosters
include a redesign of several valves, filters and seals in
the steering system to enhance their reliability as well
as studies of the potential for an electrical system to
power the booster hydraulics. Also, changes to the
solid rocket propellant manufacturing process will
make the workplace safer for Shuttle technicians

Better Main Engines

The Space Shuttle's main engines operate at greater
extremes of temperature and pressure than any other
machine. Since 1981, three overhauls to the original
design have more than tripled estimates of their safety.
Now, a fourth major overhaul is planned that will make
them even safer by 2005. The planned improvements
include a high-tech optical and vibration sensor system and
computing power in the engines that will "see" trouble coming a
fraction of a second before it can do harm


A Lighter Fuel Tank

A redesigned Lightweight External Tank — 10,000
pounds lighter than the original design — flew on
STS-6 in 1983, increasing the Shuttle’s cargo capacity
by the same amount. In 1998, a Super Lightweight
External Tank flew on STS-91, further reducing the
tank’s weight by 7,500 pounds and again increasing
the Shuttle’s cargo capacity by the same amount