Solid rocket booster
Encyclopedia
Solid rocket boosters or Solid Rocket Motors, SRM, are used to provide thrust
in spacecraft launches from the launchpad
up to burnout of the SRBs. Many launch vehicles include SRBs, including the Ariane 5
, Atlas V
(optional for extra thrust), and the NASA
Space Shuttle
. The NASA Space Shuttle used two Space Shuttle SRBs
, which were the largest of their type in production service.
The solid-fuel
SRBs are advantageous for the purpose of boosting launches compared to liquid-fueled rockets, because they provide greater thrust and do not have the refrigeration and insulation requirements of liquid-fueled rockets. Adding detachable SRBs to a vehicle also powered by liquid-fueled rockets (known as staging) reduces the amount of liquid-fuel needed and lowers the launch vehicle mass.
One example of the increased performance from SRBs is the Ariane 4
rocket. The basic 40 model with no boosters could lift 2175 kilogram payload to Geostationary transfer orbit
. The 44P model with 4 solid boosters has a payload of 3465 kg to the same orbit. The propellant for each rocket motor on the Space Shuttle weighs approximately .
Solid boosters are usually cheaper to design, test, and produce compared to equivalent thrust liquid boosters. However, the costs on a per-flight basis tend to be equivalent.
It is difficult to stop a solid rocket motor before normal burnout. This can be done by explosively separating the nozzle and/or splitting the case lengthwise with a linear shaped charge
. The latter method is common in range safety
destruct systems. Either method terminates thrust by reducing combustion chamber pressure and propellant burn rate, though the propellant (usually in many pieces at this point) will continue to burn vigorously.
SRB failure rates are about 1%. They usually fail in sudden, catastrophic explosions due to case overpressurization.
(The SRB failure mode on Challenger
was an exception.)
These are all serious risk factors for manned spacecraft.
Solid rocket motors also present a significant handling risk on the ground. Once their propellant is poured into place and cured, they could catch fire or explode in an accident. Such an accident on August 22, 2003 killed 21 technicians
at the Brazil
ian VLS rocket launch pad.
The manned and unmanned Shuttle Derived Launch Vehicles currently planned as part of NASA
's Vision for Space Exploration
both rely heavily on modified versions of the current Space Shuttle solid rocket boosters.
Thrust
Thrust is a reaction force described quantitatively by Newton's second and third laws. When a system expels or accelerates mass in one direction the accelerated mass will cause a force of equal magnitude but opposite direction on that system....
in spacecraft launches from the launchpad
Launch pad
A launch pad is the area and facilities where rockets or spacecraft lift off. A spaceport can contain one or many launch pads. A typical launch pad consists of the service and umbilical structures. The service structure provides an access platform to inspect the launch vehicle prior to launch....
up to burnout of the SRBs. Many launch vehicles include SRBs, including the Ariane 5
Ariane 5
Ariane 5 is, as a part of Ariane rocket family, an expendable launch system used to deliver payloads into geostationary transfer orbit or low Earth orbit . Ariane 5 rockets are manufactured under the authority of the European Space Agency and the Centre National d'Etudes Spatiales...
, Atlas V
Atlas V
Atlas V is an active expendable launch system in the Atlas rocket family. Atlas V was formerly operated by Lockheed Martin, and is now operated by the Lockheed Martin-Boeing joint venture United Launch Alliance...
(optional for extra thrust), and the NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
Space Shuttle
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...
. The NASA Space Shuttle used two Space Shuttle SRBs
Space Shuttle Solid Rocket Booster
The Space Shuttle Solid Rocket Boosters were the pair of large solid rockets used by the United States' NASA Space Shuttle during the first two minutes of powered flight. Together they provided about 83% of liftoff thrust for the Space Shuttle. They were located on either side of the rusty or...
, which were the largest of their type in production service.
The solid-fuel
Solid rocket
A solid rocket or a solid-fuel rocket is a rocket engine that uses solid propellants . The earliest rockets were solid-fuel rockets powered by gunpowder; they were used by the Chinese in warfare as early as the 13th century and later by the Mongols, Arabs, and Indians.All rockets used some form of...
SRBs are advantageous for the purpose of boosting launches compared to liquid-fueled rockets, because they provide greater thrust and do not have the refrigeration and insulation requirements of liquid-fueled rockets. Adding detachable SRBs to a vehicle also powered by liquid-fueled rockets (known as staging) reduces the amount of liquid-fuel needed and lowers the launch vehicle mass.
One example of the increased performance from SRBs is the Ariane 4
Ariane 4
Ariane 4 was an expendable launch system, designed by the Centre National d'Etudes Spatiales and manufactured and marketed by its subsidiary Arianespace. Ariane 4 was justly known as the ‘workhorse’ of the Ariane family. Since its first flight on 15 June 1988 until the last, on 15 February 2003, it...
rocket. The basic 40 model with no boosters could lift 2175 kilogram payload to Geostationary transfer orbit
Geostationary transfer orbit
A geosynchronous transfer orbit or geostationary transfer orbit is a Hohmann transfer orbit used to reach geosynchronous or geostationary orbit....
. The 44P model with 4 solid boosters has a payload of 3465 kg to the same orbit. The propellant for each rocket motor on the Space Shuttle weighs approximately .
Solid boosters are usually cheaper to design, test, and produce compared to equivalent thrust liquid boosters. However, the costs on a per-flight basis tend to be equivalent.
It is difficult to stop a solid rocket motor before normal burnout. This can be done by explosively separating the nozzle and/or splitting the case lengthwise with a linear shaped charge
Shaped charge
A shaped charge is an explosive charge shaped to focus the effect of the explosive's energy. Various types are used to cut and form metal, to initiate nuclear weapons, to penetrate armor, and in the oil and gas industry...
. The latter method is common in range safety
Range safety
In rocketry, range safety is assured by the systems which protect people and assets on the rocket range in cases when a launch vehicle might endanger them. Range safety is usually the responsibility of a Range Safety Officer...
destruct systems. Either method terminates thrust by reducing combustion chamber pressure and propellant burn rate, though the propellant (usually in many pieces at this point) will continue to burn vigorously.
SRB failure rates are about 1%. They usually fail in sudden, catastrophic explosions due to case overpressurization.
(The SRB failure mode on Challenger
Space Shuttle Challenger
Space Shuttle Challenger was NASA's second Space Shuttle orbiter to be put into service, Columbia having been the first. The shuttle was built by Rockwell International's Space Transportation Systems Division in Downey, California...
was an exception.)
These are all serious risk factors for manned spacecraft.
Solid rocket motors also present a significant handling risk on the ground. Once their propellant is poured into place and cured, they could catch fire or explode in an accident. Such an accident on August 22, 2003 killed 21 technicians
Brazilian rocket explosion
VLS-1 V03 was a Brazilian Space Agency VLS-1 rocket, which was intended to have launched two satellites into orbit. On August 22, 2003, at 13:30 an explosion destroyed the rocket as it stood on its launch pad at the Alcântara Launching Center in the state of Maranhão in northern Brazil...
at the Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
ian VLS rocket launch pad.
The manned and unmanned Shuttle Derived Launch Vehicles currently planned as part of NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
's Vision for Space Exploration
Vision for Space Exploration
The Vision for Space Exploration is the United States space policy which was announced on January 14, 2004 by President George W. Bush. It is seen as a response to the Space Shuttle Columbia disaster, the state of human spaceflight at NASA, and a way to regain public enthusiasm for space...
both rely heavily on modified versions of the current Space Shuttle solid rocket boosters.
See also
- Liquid Rocket BoosterLiquid Rocket BoosterA Liquid Rocket Booster is similar to a solid rocket booster attached to the side of a rocket to give it extra lift at takeoff. A Liquid Rocket Booster has fuel and oxidiser in liquid form, as opposed to a solid rocket or hybrid rocket....
- Solid-fuel rocket
- Space Shuttle Solid Rocket BoosterSpace Shuttle Solid Rocket BoosterThe Space Shuttle Solid Rocket Boosters were the pair of large solid rockets used by the United States' NASA Space Shuttle during the first two minutes of powered flight. Together they provided about 83% of liftoff thrust for the Space Shuttle. They were located on either side of the rusty or...