Some information to JAXA's Solid Rocket Booster (SRB-A and SRB-3)
 

Norbert Brügge, Germany
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30.06.22020
 


SRB-A is a series of Japanese solid-fueled rocket booster manufactured by IHI Corporation for use on the H-IIA, H-IIB, and Epsilon rockets.
SRB-A is 2.5 meters in diameter, and 15.17 or 15.10 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
SRB-3 with the same diameter is 14.60 m long due to the shortened tip and will developed for the H-3 rocket (and Epsilon-S).



SRB-A


SRB-3 nozzle

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 lengthed, 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. 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 ASR-Epsilon.

Source:
Wikipedia

However, according to a table published by JAXA, there are obviously further modifications in which thrust and burn time are varied. According to my calculations, the following overview is obtained:

Type

 Vehicle Propellant Max thrust (kN) Aver. Thrust (kN) Isp (sec) Pressure

Duration

 Total vac Imp.

Used on vehicle

t s.l. vac s.l. vac s.l. /vac  MPa  sec

MN*sec

SRB-A

J-1 (2) 65 2,098.6 2,260.0 1,657.4 1,784.9 260 / 280   100 178.48

not realized

H-IIA 65 2,098.6 2,260.0 1,657.4 1,784.9 260 / 280 11.8 100 178.48

F01 to F06

SRB-A2

H-IIA 65 1,959.2 2,110.0 1,453.9 1,565.8 260 / 280   114 178.48

not used

SRB-A
 improved

 H-IIA 66 2,084.7 2,245.0 1,314.7 1,415.9 260 / 280   128 181.23

F07

66 2,122.3 2,285.0 1,407.7 1,515.5 261 / 281   120 183.56

 ?

SRB-A3

H-IIA  65 2,271.5 2,445.0 1,670.1 1,797.5 262 / 282   100 179.76

F14

66 2,102.9 2,262.5 1,421.7 1,529.8 263.6 / 283.6 11.1 120 183.56

F15, F17

64.9 2,324.2 2,500.5 1,711.7 1,841.6 263.6 / 283.6 11.8 98 180.50

F18

66 2,142.5 2,305.0 1,421.7 1,529.8 263.6 / 283.6   120 183.56

F21

H-IIB

66 2,142,5 2,305.0 1.496.4 1,610.1 263.6 / 283.6 11.1 116 183.56

3040: F01 to F09

Epsilon 66 2,142.5 2,305.0 1,523.3 1,639.0 263.6 / 283.6   112 183.56

F01

Epsilon-2 66 2,184.3 2,350.0 1,579.6 1,699.7 263.6 / 283.6   108 183.56

F02 to F04

SRB-3

H-3 66.8 2,233.5 2,402.6 1,647.0 1,771.7 264 / 284   105 186.04  

                      Red colored =official source; Average thrust calculation on base duration



SRB-A full thrust sequences in tests (PM, EM, QM)



SRB-A QM3



First SRB-A nozzle



The following SRB nozzles (SRB-A.imp./-A3 and -3)
are slightly bell-shaped and shorter.



SRB3-OM2