Booster (rocketry)

AGEM-40strap-onbooster for aDelta IIlaunch vehicle.

Aboosteris arocket(orrocket engine) used either in the first stage of amultistagelaunch vehicleor in parallel with longer-burningsustainer rocketsto augment thespace vehicle's takeoff thrust and payload capability.Boosters are traditionally necessary to launchspacecraftintolow Earth orbit(absent asingle-stage-to-orbitdesign), and are especially important for a space vehicle to go beyond Earth orbit.The booster is dropped to fall back to Earth once its fuel is expended, a point known asbooster engine cut-off(BECO).

Followingbooster separation,the rest of the launch vehicle continues flight with its core or upper-stage engines. The booster may be recovered, refurbished and reused, as was the case of the steel casings used for theSpace ShuttleSolid Rocket Boosters.

Drop-away engines

TheSM-65 Atlasrocket used three engines, one of which was fixed to the fuel tank, and two of which were mounted on a skirt which dropped away at BECO. This was used as anIntercontinental ballistic missile(ICBM); to launch the crewedProject Mercurycapsule into orbit; and as the first stage of theAtlas-AgenaandAtlas-Centaurlaunch vehicles.

Strap-on

See also:Modular rocket

Several launch vehicles, includingGSLV Mark IIIandTitan IV,employ strap-on boosters.NASA'sSpace Shuttlewas the first crewed vehicle to use strap-on boosters. Launch vehicles likeDelta IV HeavyandFalcon Heavyemploy strap-onliquid rocket boosters.

Recoverable

Thebooster casingsfor theSpace Shuttle Solid Rocket Boosterswere recovered and refurbished for reuse from 1981 to 2011 as part of theSpace Shuttle program.

In a new development program initiated in 2011,SpaceXdevelopedreusable first stagesof theirFalcon 9 rocket.After launching the second stage and the payload, the boosterreturns to launch siteor flies to adrone shipandlands vertically.After landing multiple boosters both on land and on drone ships in 2015–2016, a landed stage was first reflown in March 2017:Rocket core B1021that had been used to launch a re-supply mission to theISSwhen new in April 2016 was subsequently used to launch the satelliteSES-10in March 2017.The program was intended to reduce launch prices significantly, and by 2018, SpaceX had reduced launch prices on a flight-proven boosters toUS$50 million,thelowest price in the industryformedium-liftlaunch services.

By August 2019, therecovery and reuse of Falcon 9 boostershad become routine, with booster landings/recovery being attempted on more than 90 percent of all SpaceX flights, and successful landings and recoveries occurring 65 times out of 75 attempts. In total 25 recovered boosters have been refurbished and subsequently flown a second time by late 2020, with several having been flown a third time as well.

In late 2020,Rocket Labguided the booster of theirElectronrocket for a splashdown in the Pacific Ocean with aparafoilafter launching theReturn to Sender mission,as part of a program to catch the booster with a helicopter and reuse it on later missions.

Use in aviation

Rocket boosters used on aircraft are known asjet-assisted take-off (JATO)rockets.

Variousmissilesalso use solid rocket boosters. Examples are:

• 2K11 (SA-4)which uses SRBs as a first stage, and then aramjet.
• S-200 (SA-5)which uses SRBs as the first stage, followed by a liquid fuel rocket.
• Surface and submarine launched versions of theturbojet-poweredBoeing Harpoonand many othercruise missilesuse an SRB.

See also

• Liquid rocket booster
• Booster Systems Engineer- a support position at NASA's mission control, referred to by call signBOOSTER
• Falcon 9 B1060