Solid rocket boosters (SRBs) are very expensive pieces of kit. In fact, they cost NASA around USD 25 (GBP 15.7) million to manufacture from scratch, so a cost-efficient recovery and refurbishment system was implemented in the Eighties that’s still used today.
Most shuttle flights follow a predictable path across the Atlantic Ocean as they ascend into space. So, once the SRBs have expended 500,000 kilograms (1.1 million pounds) of solid rocket fuel, they separate from the rocket and begin their 72-kilometre (45-mile), parachute-assisted descent back down to Earth.
Seven minutes after liftoff the SRBs will splash down into the ocean, around 260 kilometres (160 miles) from the launch pad and float helplessly in the water. That’s when NASA’s SRB recovery ships are deployed.
The Liberty Star and Freedom Star can recover one SRB each. Nearly everything can be salvaged from these boosters and both vessels have specialist tools for the job.
SRB refurbishing
Each SRB comprises a solid rocket motor, plus thrust vector control, structural, separation, recovery, electrical and instrumentation subsystems. The motor itself is loaded with solid propellant alongside its ignition hardware, which is mixed in three 2,730-litre (600-gallon) bowls and cast in special buildings, before being transported nearly 4,000 kilometres (2,500 miles) to its East Coast destination.
Space ships
NASA building a better solid rocket booster for Space Launch