SRB-A is a series of
Japan
Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...
ese
solid-fueled
Solid fuel refers to various forms of solid material that can be burnt to release energy, providing heat and light through the process of combustion. Solid fuels can be contrasted with liquid fuels and gaseous fuels. Common examples of solid fuels ...
rocket booster manufactured by
IHI Corporation for use on the
H-IIA,
H-IIB, and
Epsilon
Epsilon (, ; uppercase , lowercase or lunate ; el, έψιλον) is the fifth letter of the Greek alphabet, corresponding phonetically to a mid front unrounded vowel or . In the system of Greek numerals it also has the value five. It was der ...
rockets.
Design
SRB-A is 2.5 meters in diameter, and 15.1 meters in length. Its casing is a
carbon-fiber-reinforced polymer filament-wound composite. Two-axis attitude control is provided by electrically-actuated thrust vectoring.
The composite motor case design is based on technology used on the
Castor 120
The Castor family of solid-fuel rocket stages and boosters built by Thiokol (now Northrop Grumman) and used on a variety of launch vehicles. They were initially developed as the second-stage motor of the Scout rocket. The design was based on the ...
motor by
Alliant Techsystems
Alliant Techsystems Inc. (ATK) was an American aerospace, defense, and sporting goods company with its headquarters in Arlington County, Virginia, in the United States. The company operated in 22 states, Puerto Rico, and other countries. ATK's ...
, itself based on the first stage motor for the
LGM-118 Peacekeeper MIRV-capable
intercontinental ballistic missile
An intercontinental ballistic missile (ICBM) is a ballistic missile with a range greater than , primarily designed for nuclear weapons delivery (delivering one or more thermonuclear warheads). Conventional, chemical, and biological weapons c ...
(ICBM).
Versions
SRB-A
The original SRB-A was developed for the
H-IIA rocket, and was used on its first 6 flights. It was derived from the SRB used on
H-II. During the sixth launch of an H-IIA, one of the boosters failed to separate due to a leak of hot gasses eroding the detachment points, causing the rocket to fail to reach orbit.
[
]
SRB-A2
SRB-A2 was a planned upgrade, intended to replace SRB-A on H-IIA. Following the 2003 failure, it was cancelled and its design improvements were merged into the SRB-A Improved.
SRB-A Improved
An improved version of SRB-A was developed following the 2003 incident. The nozzle was changed from a conical to a bell shape, to reduce thermal loading and erosion. Its thrust was also reduced slightly, and its burn time lengthened, to further decrease heating. This version was flown on the seventh through the thirteenth H-IIA. However, the nozzle erosion problem was still not fully solved, leading to the development of the SRB-A3[
]
SRB-A3
SRB-A3 is the current version, redesigned to provide higher performance and improve reliability. It is available in two variants, one producing high thrust at a short duration burn, and the other with a longer duration lower thrust burn.
References
{{Rocket engines
Solid-fuel rockets
Rocket engines of Japan