Five-segment Booster
Prior to the destruction of the Space Shuttle Columbia in 2003, NASA investigated the replacement of the current 4-segment SRBs with either a 5-segment SRB design or replacing them altogether with liquid "flyback" boosters using either Atlas V or Delta IV EELV technologies. The 5-segment SRB, which would have required little change to the current shuttle infrastructure, would have allowed the space shuttle to carry an additional 20,000 lb (9,100 kg) of payload in an International Space Station-inclination orbit, eliminate the dangerous "Return-to-Launch Site" (RTLS) and "Trans-Oceanic Abort" (TAL) modes, and, by using a so-called "dog-leg maneuver", fly south-to-north polar orbiting flights from Kennedy Space Center. With the destruction of the Columbia, NASA has shelved the 5-segment SRB for the Shuttle Program, as the three surviving Orbiters, Discovery, Atlantis, and Endeavour were retired in 2011 after the completion of the International Space Station.
A five segment engineering test motor, ETM-03, was fired on October 23, 2003.
On September 10, 2009 a five-segment Space Shuttle SRB was static fired on the ground in ATK's desert testing area in Utah. This was the test of what was to be the first stage for the Ares I rocket.
Read more about this topic: Space Shuttle Solid Rocket Booster