Largest solid rocket booster

The largest solid-fuel rocket is the Five-Segment Solid Rocket Booster, developed by NASA and Northrop Grumman (both USA) and successfully test-fired for the first time on 10 September 2009. Each one of these boosters measures 177 ft (53.94 m) in length, 12 ft (3.65 m) in diameter and weighs approximately 1.6 million pounds (725,747 kg). The solid rocket motor itself accounts for 153 ft (46.63 m) of the booster’s total length (the rest is the upper fairing and nozzle) and holds 1,385,000 lb (628,225 kg) of fuel. At ignition, each booster generates 3,600,000 lbf (16,013 kN) of thrust, making the boosters around 25% more powerful than the Space Shuttle’s Solid Rocket Boosters.

This booster is a modernised and extended version of the four-segment boosters that were used to launch the Space Shuttle for more than 30 years. Its development began in the early 2000s, as part of a program to update the Space Shuttle, but the destruction of the shuttle Columbia in 2003 caused this project to be cancelled. Its development resumed in 2005 when it was selected to form the first stage of the planned Ares I rocket. However, this project was also cancelled in 2010 without the five-segment booster being flown. Development continues today as part of the Space Launch System (SLS) program. SLS rockets will use two of the five-segment boosters to augment the power of the rocket’s first stage.

As of April 2018 the five segment rocket booster has not been flown, but it has had three successful static-fire tests (in 2009, 2010 and 2011). Current schedules suggest it will fly for the first time in late 2019 or early 2020.