3.1.1: Centaur for Atlas

The Centaur stage was build by GD/Convair in San Diego. It was the first LH2/LOX stage to fly. Planned for the later cancelled US Army Advent comsat program, its development was taken over for the Surveyor program by NASA MSFC and later by NASA-Lewis. Following test flights of Centaur A,B,C models the standard Centaur D supported the Surveyor launches. The initial single-burn variant flew a direct ascent lunar trajectory; following tests of the two-burn parking orbit technique with AC-6, AC-8 and AC-9 this became the standard type. The D-1A/D-1T had improved avionics and structure. The D-1AR had reliability improvements. The Centaur I had modernized avionics. The Centaur II was stretched and swapped jettisonable foam panels for fixed. The Centaur IIIA was the first SEC (Single Engine Centaur); Centaur IIIB also came in DEC (Dual Engine) variant.

Stage   Engines   Size   mass f   Flts 
Centaur A   2 x RL-10A-1?       AC-1 
Centaur B   2 x RL-10A-3   3.05 9.1     AC-2 
Centaur C   2 x RL-10A-3   3.05 9.1     AC-3,4,5 
Centaur D   2 x RL-10A-3-1   3.05 9.1   16780f   AC-6,7,10,11 
Centaur D   2 x RL-10A-3-3   3.05 9.1   16780f   AC-8,9,12 
Centaur D-1A   2 x RL-10A-3-3   3.05 9.1   13950p   AC-13 to 29 
Centaur D-1T   2 x RL-10A-3-3   3.05 9.1   13950p   TC-1 to TC-7 
Centaur D-1AR   2 x RL-10A-3-3   3.05 9.1    AC-30 to AC-61 
Centaur D-1AR   2 x RL-10A-3-3   3.05 9.1    AC-62 to AC-68 
Centaur I   2 x RL-10A-3-3A   3.05 9.1    AC-69 to AC-79 
Centaur II   2 x RL-10A-3-3A   3.05 10.1     
Centaur IIA   2 x RL-10A-4   3.05 10.1 1840+16810   AC-109,118,122,129,138,140 
Centaur IIA   2 x RL-10A-4(N)   3.05 10.1 1840+16810   AC-105,107,108,110,111, 
Centaur IIA   2 x RL-10A-4-1   3.05 10.1 1840+16810   AC-130,136,137,139,142-144 
Centaur IIA   2 x RL-10A-4-1(N)  3.05 10.1    AC-113,115,117,121,123 
Centaur G   2 x RL-10A-3-3A?  4.32 6.0    SC-3 
Centaur G'   2 x RL-10A-3-3A?  4.32 9.0    SC-1,SC-2 
Centaur "T"   2 x RL-10A-3-3A   4.32 9.0    TC-8 to TC-22 
Centaur "T"   2 x RL-10A-4-1A   4.32 9.0    TC-23 
Centaur IIIA   1 x RL-10A-4-1   3.05 10.1 1720+16930   AC-201 
Centaur IIIB DEC 2 x RL-10A-4-2   3.05 11.7 2110+20830    
Centaur IIIB SEC 1 x RL-10A-4-2   3.05 11.7 2026+20830    

Centaur IIIA is the IIAS stage with one engine and modified TVC. Centaur IIIB is 12.7m with the extended nozzle.

The ISA (interstage adapter) on Centaur IIA is 3.05m dia, 4.0m length, mass 545 kg, with the Atlas Roll Control Module (ARCM). The IIIA/B adapter is 4.5m long, mass 465 kg. The V/400 short adapter is 3.05 x 3.13m, 374 kg above the Booster Interstage Adapter (3.05-3.83m dia x 1.65m l, 420 kg). The V/500 ISA (V/HLV-Upper ISA) is 3.83 x 3.81m, 1297 kg. The V/500 (V/HLV-Lower) BIA is 3.83 x 0.32m, 272 kg.