Space Shuttle Solid Rocket Booster - Future and Proposed Uses

Future and Proposed Uses

NASA plans to reuse the SRB designs and infrastructure in several Ares rockets. In 2005, NASA announced the Shuttle-Derived Launch Vehicle slated to carry the Orion Crew Exploration Vehicle into low-Earth orbit and later to the Moon. The SRB-derived Crew Launch Vehicle (CLV), named Ares I, originally featured a modified standard 4-segment SRB for its first stage, while a liquid-fueled second stage, powered by a single, modified Space Shuttle Main Engine, would have propelled the Orion into orbit.

The current design, initially introduced in 2006, and since revised, will feature the originally planned, but scrapped 5-segment SRB for its first-stage, with a second stage powered by an uprated J-2X rocket engine derived from the J-2 engine used in Project Apollo on the Saturn IB, Saturn V, and Saturn INT-20 rockets. In place of the standard SRB nosecone, the Ares I would have a tapered interstage assembly connecting the booster proper with the second stage, an altitude control system derived from the Regulus missile system, and larger, heavier parachutes to lower the stage into the Atlantic Ocean for recovery.

Also introduced in 2005, was a heavy-lift Cargo Launch Vehicle (CaLV) named Ares V. Early designs of the Ares V utilized five standard-production SSMEs and a pair of 5-segment boosters identical to those proposed for the Shuttle, but since then NASA had redesigned the boosters around the RS-68 rocket engine used on the Delta IV EELV system. Initially, NASA switched over to a system using the 5-segment boosters and a cluster of five RS-68s (which resulted in a widening of the Ares V core unit), but since then, NASA has further reconfigured the vehicle with six RS-68B engines (which would operate like the current SSMEs, but at half the price), with the boosters themselves becoming "5.5-Segment Boosters," with an additional half-segment to provide additional thrust at liftoff.

The current redesign will make the Ares V booster taller and more powerful than the now-retired Saturn V/INT-20, N-1, and Energia rockets, and will allow the Ares V to place both the Earth Departure Stage and Altair spacecraft into Low-Earth orbit for later on-orbit assembly. Unlike the 5-segment SRB for the Ares I, the 5.5-segment boosters for the Ares V are to be identical in design, construction, and function to the current SRBs except for the extra segments. Although there is no final decision on the recovery or reuse of this system, it is most likely that the standard recovery process like that employed on the shuttle will be used. Like the current shuttle boosters, the Ares V boosters would fly an almost-identical flight trajectory from launch to splashdown.

The Constellation program, including Ares I and Ares V, was canceled in October 2010 by the passage of the 2010 NASA authorization bill. Existing Constellation contracts remain in place until Congress passes a new funding bill for 2012.

The DIRECT proposal for a new, Shuttle-Derived Launch Vehicle, unlike the Ares I and Ares V boosters, uses a pair of classic 4-segment SRBs with the SSMEs used on the Shuttle.