From space.com
October 24
CAPE CANAVERAL, Fla. -- A five-segment version of the space shuttle's solid rocket motor was successfully test fired Thursday in Utah.
The 128-second test saw the larger motor burn with 3.6 million pounds of thrust, compared to the normal four-segment motor that develops 3.3 million pounds of thrust. The difference in lifting power could add
23,000 pounds of extra cargo capability to the shuttle, officials said.If ever flown, the larger motor could also help a shuttle achieve orbit even if one of the main engines were to shut down during the first two minutes of flight. Right now if that happens the shuttle would have to risk an emergency return to launch site abort or possibly ditch in the ocean.
A quick look at the motor after the test showed it handled the extra power and longer burn time without incident, but officials said they will need several weeks to break apart the motor for extensive inspections before they'll know for sure.
There are no plans right now to test another five-segment motor or to actually fly a set on a shuttle mission. Either option wouldn't happen for another few years, if at all, officials said.