Rocket Engine Classes

  The Space Shuttle's SRBs, at 2.6 million lbs thrust for 123.6 seconds each, manufactured by ATK Thiokol Propulsion Company, are the largest solid rocket motor to date. Visit the ATK Thiokol website. These designations are the same regardless of engine type, ie., solid, liquid, or hybrid.

Impulse Class
Designation		 Total Impulse Range
Minimum
Newton Seconds		 Maximum
Newton Seconds		 Minimum
Pound Seconds		 Maximum
Pound Seconds
1/8 A 0.15 0.29 .035 .069
1/4 A 0.30 0.61 .07 .13
1/2 A 0.62 1.24 .14 .27
A 1.25 2.5 .28 .55
B 2.51 5 .55 1.10
C 5.01 10 1.10 2.2
D 10.01 20 2.2 4.41
E 20.01 40 4.41 8.81
F 40.01 80 8.81 17.62
G 80.01 160 17.62 35.24
H 160.01 320 35.24 70.48
I 320.01 640 70.48 140.97
J 640.01 1280 140.97 281.94
K 1280.01 2560 281.94 563.88
L 2560.01 5120 563.88 1127.75
M 5120.01 10240 1127.75 2255.51
N 10240.01 20480 2255.51 4511.01
O 20480.01 40960 4511.01 9022.03
P 40960.01 81920 9022.03 18044.05
Q 81920.01 163840 18044.05 36088.11
R 163840.01 327680 36088.11 72176.21
S 327680.01 655360 72176.21 144352.42
T 655360.01 1310720 144352.42 288704.85
U 1,310,720.01 2,621,440 288704.85 577409.69
V 2,621,440.01 5,242,880 577409.69 1,154,819.38
W 5,242,880.01 10,485,760 1,154,819.38 2,309,638.77
X 10,485,760.01 20,971,520 2,309,638.77 4,619,277.53
Y 20,971,520.01 41,943,040 4,619,277.54 9,238,555.08
Z 41,943,040.01 83,886,080 9,238,555.09 18,477,110.18
AA 83,886,080.01 167,772,160 18,477,110.19 36,954,220.38
BB 167,772,160.01 335,544,320 36,954,220.39 73,908,440.78
CC 335,544,320.01 671,088,640 73,908,440.79 147,816,881.58
DD 671,088,640.01 1,342,177,280 147,816,881.59 295,633,763.18
EE 1,342,177,280.01 2,684,354,560 295,633,763.19 591,267,526.38
FF 2,684,354,560.01 5,368,709,120 591,267,526.39 1,182,535,053.76
GG 5,368,709,120.01 10,737,418,240 1,182,535,053.77 2,365,070,107.54
HH 10,737,418,240.01 21,474,836,480 2,365,070,107.55 4,730,140,215.10