SRB-A

SRB-Ais a series ofJapanese solid-fueledrocket booster manufactured byIHI Corporationfor use on theH-IIA,H-IIB,andEpsilonrockets.

Design

SRB-A is 2.5 meters in diameter, and 15.1 meters in length. Its casing is acarbon-fiber-reinforced polymerfilament-wound composite. Two-axis attitude control is provided by electrically-actuated thrust vectoring.^[1]

IHI led the development and production of the SRB-A, and various companies also participated in its development and production. For example, the composite fuel is BP-208, developed and manufactured by NOF Corporation (ja), and the carbon fiber, one of the components of the motor case, is T1000GB, developed and manufactured byToray.^[2]

On the other hand, in order to shorten the development time of the SRB-A, foreign technology was used for the molding process of the motor case.^[3]The composite motor case design is based on technology used on theCastor 120motor byAlliant Techsystems,itself based on the first stage motor for theLGM-118 Peacekeeper MIRV-capableintercontinental ballistic missile(ICBM).^[4]

Versions

SRB-A

The original SRB-A was developed for theH-IIArocket, and was used on its first 6 flights. It was derived from the SRB used onH-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.^[1]^[5]

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^[1]

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.^[1]It has been used on all H-IIA flights past the thirteenth mission, as well as the H-IIB and as the first stage of Epsilon.^[1]^[6]^[7]

Successor

SRB-3

Unlike the SRB-A, the composite motor case of the SRB-3 is manufactured using Japan's own technology, without using ATK's technology.^[3]

The SRB-3 used in theH3andEpsilon Srockets has one ton more propellant than the SRB-A series to increase its launch capability. To improve reliability and reduce cost, the separation mechanism of the SRB-3 has been greatly simplified compared to the SRB-A series, and the nozzle has been changed from a variable type to a fixed type. In the SRB-A series, the burn pattern was different when two or four boosters were used in the H-IIA/B and when used as the first stage of the Epsilon, but in the SRB-3, the burn pattern is the same when two or four boosters are used in the H3 and when the SRB-3 is used as the first stage of the Epsilon S.^[8]^[3]

References

^^a ^b ^c ^d ^e"SRB-A Engine Overview".JAXA.Retrieved14 February2016.^{[permanent dead link]}
^"JAXA, H-IIB ロケットで vũ trụ ステーション tiếp viện cơ ７ hào cơ (HTV7 “こうのとり” )を đánh thượng げ ".Tokyo Express. 28 September 2018. Archived fromthe originalon 2 October 2022.Retrieved18 February2023.
^^a ^b ^c"Vũ trụ に rống えろ! Kiểu mới thể rắn ロケットブースター “SRB-3” châm thiêu thí nghiệm lấy tài liệu đệ 2 hồi カギは quốc sản hóa と giản tố hóa - trước đại から đại きく tiến hóa を toại げた “SRB-3” ".マイナビニュース. 7 September 2018. Archived fromthe originalon 17 February 2023.Retrieved17 February2023.
^"ATK Composite Technology Supports Maiden Flight of Japan's H-IIA Space Launch Vehicle".ATK. August 29, 2001. Archived fromthe originalon 2013-12-26.
^Stephen Clark; Justin Ray (29 November 2003)."Japanese launch fails".Spaceflight Now.Retrieved14 February2016.
^"H-IIB Launch Vehicle"(PDF).JAXA. Archived fromthe original(PDF)on March 26, 2014.Retrieved14 February2016.
^"Epsilon Launch Vehicle"(PDF).JAXA.Retrieved14 February2016.
^"H3プロジェクト đi tới へ"(PDF).Vũ trụ hàng không の mới nhất tình báo マガジン JAXA's.74.JAXA: 10. 1 October 2018. Archived fromthe original(PDF)on 18 March 2022.Retrieved17 February2023.

[SRBAOverview-1] "SRB-A Engine Overview".JAXA.Retrieved14 February2016.^{[permanent dead link]}

[tokyoex-2] "JAXA, H-IIB ロケットで vũ trụ ステーション tiếp viện cơ ７ hào cơ (HTV7 “こうのとり” )を đánh thượng げ ".Tokyo Express. 28 September 2018. Archived fromthe originalon 2 October 2022.Retrieved18 February2023.

[mynavi_srb3-3] "Vũ trụ に rống えろ! Kiểu mới thể rắn ロケットブースター “SRB-3” châm thiêu thí nghiệm lấy tài liệu đệ 2 hồi カギは quốc sản hóa と giản tố hóa - trước đại から đại きく tiến hóa を toại げた “SRB-3” ".マイナビニュース. 7 September 2018. Archived fromthe originalon 17 February 2023.Retrieved17 February2023.

[4] "ATK Composite Technology Supports Maiden Flight of Japan's H-IIA Space Launch Vehicle".ATK. August 29, 2001. Archived fromthe originalon 2013-12-26.

[5] Stephen Clark; Justin Ray (29 November 2003)."Japanese launch fails".Spaceflight Now.Retrieved14 February2016.

[6] "H-IIB Launch Vehicle"(PDF).JAXA. Archived fromthe original(PDF)on March 26, 2014.Retrieved14 February2016.

[7] "Epsilon Launch Vehicle"(PDF).JAXA.Retrieved14 February2016.

[jaxas_no74-8] "H3プロジェクト đi tới へ"(PDF).Vũ trụ hàng không の mới nhất tình báo マガジン JAXA's.74.JAXA: 10. 1 October 2018. Archived fromthe original(PDF)on 18 March 2022.Retrieved17 February2023.

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