Centaur top stage

USA

Centaur on Atlas


The Centaur top-stage was the first cryogenic rocket stage. The Pratt & Whitney RL10 engine consuming liquid oxygen and hydrogen had a long and difficult development. Its design started in 1958. It first flew in 1962 but didn't launch a real payload before 1966. The Centaur stage was designed to be used by Atlas. It was 3.05 m in diameter and 9.1 m in length. In its operational version it was equipped with two RL10 A-3-3 engines with a thrust of 66.7 kN each. It carried 13.8 tons propellant and could burn during 450 seconds with several ignitions.

In the late-70ies the Atlas Centaur program was to be abandonned since NASA had decided to transfer all launches to the Shuttle.
In fact STS was less available than expected and the Atlas launch program was resumed (with the help of Intelsat finances) with a simplified motor. On the RL10 A-3-3A (73.4 kN thrust) the turbopump feeding was replaced by a pressurized tank system. This new Centaur was first launched in 1984 with an Atlas-G (streched by 2 meters). The GTO capacity then reached 2.3 tons.

In 1987 the augmented Atlas Centaur was selected by the USAF as the MLV2 standard launcher. This new launcher is refered to as Atlas-2. The first stage was streched by 2.7 m and the second stage by 0.9 m. This new Centaur takes 16.8 tons of propellant and can burn up to 473 seconds. Atlas-2A is different by its second stage RL10 A-4 engines with deployable nozzle. Atlas-2AS is still more powerful. It is made from Atlas-2A to which two pairs of Castor-4A boosters are added. Each pair ignites one after the other. Thus GTO capacity raises to 2.8, 3.1 and 3.7 tons respectively for Atlas 2, 2A and 2AS.

Evolution of Centaur's propulsion system:


Designation First launch Main engine Thrust (kN) Main engineSI (sec.) Applications
RL10 A-1 1962 66.7 425 Tests
RL10 A-3-1 1963 66.7 431 Atlas Centaur
RL10 A-3-3 1966 66.7 444 Atlas Centaur
RL10 A-3-3A 1984 73.4 446 Atlas-1 & -2
RL10 A-4 1991 92.6 449 Atlas-2A & -2AS

Statistics: the RL-10 motor made its 100th flight on the top stage Centaur of AC-114

Centaur on Titan:


Between 1974 and 1977, seven Centaur were used as top stages for Titan 3 rockets, designated as Titan 3E with no major transformation. In this configuration the Centaur was placed into the cap (4.1 m diameter) which provided the thermic protection. Those launchers were devoted to US and German probles and could send 3.6 tons to Mars or Venus.

In 1983 an agreement between NASA and USAF was reached to finance the development of a stage derived from Centaur to launch military satellites and probes from the Shuttle. This new cryogenic stage was a wide body of the Centaur to optimize the volume into the Shuttle's bay. The same motors remained so as the 3.05 m diamater liquid oxygen tank while the hydrogen tank was enhanced to 4.3 m diameter. Two versions of this new stage were developped: Centaur G of 6.1 m long for the USAF and a longer version named Centaur G-prime of 9.1 m long for NASA. After the Challenger accident usage of a cryogenic stage was prohibited for security reasons.

The Centaur G-prime was then adapted to the Titan 4. This version is 4.5 m diameter and about 9 m long. It weighs 26 tons including 23 tons propellant. The motors are RL10-3-3A of 73.4 kN which can operate for up to 617 seconds. The Titan 4 with Centaur top stage is designated Titan 401. It can orbit 4.5 tons in GEO. An enhanced version with Hercules SRMU boosters will enable to place 5.8 tons on such orbits.

Rockets with Centaur top stage:

Total Nr Type Nr Launch Vehicle Serial Nr Launch Date Launch Site ID Year Payload Comment
128 1 Atlas-LV3C Centaur-A AC 18/05/1962 CC, LC-36A 1962-A74 Centaur AC-1Failure
197 1 Atlas-LV3C Centaur-B AC-227/11/1963 CC, LC-36A 1963-047 Centaur-AC 2  
212 1 Atlas-LV3C Centaur-C AC-330/06/1964 CC, LC-36A 1964-F09 Centaur-AC 3 Failure
232 2 Atlas-LV3C Centaur-C AC-411/12/1964 CC, LC-36A 1964-082 Surveyor-Model 1  
241 1 Atlas-LV3C Centaur-D AC-52/03/1965 CC, LC-36A 1965-F04 Surveyor-SD 1 Failure
262 2 Atlas-LV3C Centaur-D AC-611/08/1965 CC, LC-36B 1965-064 Surveyor-SD 2  
281 3 Atlas-LV3C Centaur-DAC-88/04/1966 CC, LC-36B 1966-030 Surveyor-SD 3  
289 4 Atlas-LV3C Centaur-D AC-1030/05/1966 CC, LC-36A 1966-045 Surveyor 1  
306 5 Atlas-LV3C Centaur-D AC-720/09/1966 CC, LC-36A 1966-084 Surveyor 2  
310 6 Atlas-LV3C Centaur-DAC-926/10/1966 CC, LC-36B 1966-095 Surveyor-SD 4  
327 7 Atlas-LV3C Centaur-DAC-1217/04/1967 CC, LC-36B 1967-035 Surveyor 3  
336 8 Atlas-LV3C Centaur-D AC-1114/07/1967 CC, LC-36A 1967-068 Surveyor 4  
341 1 Atlas-SLV3C Centaur-D AC-138/09/1967 CC, LC-36B 1967-084 Surveyor 5  
346 2 Atlas-SLV3C Centaur-D AC-147/11/1967 CC, LC-36B 1967-112 Surveyor 6  
350 3 Atlas-SLV3C Centaur-DAC-157/01/1968 CC, LC-36A 1968-001 Surveyor 7  
364 4 Atlas-SLV3C Centaur-D AC-1710/08/1968 CC, LC-36A 1968-068 ATS 4 Partial Failure
370 5 Atlas-SLV3C Centaur-DAC-167/12/1968 CC, LC-36B 1968-110 OAO 2  
372 6 Atlas-SLV3C Centaur-D AC-2025/02/1969 CC, LC-36B 1969-014 Mariner 6 Marsprobe
374 7 Atlas-SLV3C Centaur-D AC-1927/03/1969 CC, LC-36A 1969-030 Mariner 7  
376 8 Atlas-SLV3C Centaur-DAC-1812/08/1969 CC, LC-36A 1969-069 ATS 5  
388 9 Atlas-SLV3C Centaur-D AC-2130/11/1970 CC, LC-36B 1970-U03 OAO B Failure
390 10 Atlas-SLV3C Centaur-D AC-2526/01/1971 CC, LC-36A 1971-006 Intelsat-4 2  
392 11 Atlas-SLV3C Centaur-D AC-249/05/1971 CC, LC-36A 1971-F04 Mariner 8 Failure
393 12 Atlas-SLV3C Centaur-D AC-2330/05/1971 CC, LC-36B 1971-051 Mariner 9  
398 13 Atlas-SLV3C Centaur-DAC-2620/12/1971 CC, LC-36A 1971-116 Intelsat-4 3  
399 14 Atlas-SLV3C Centaur-DAC-2823/01/1972 CC, LC-36B 1972-003 Intelsat-4 4  
400 1 Atlas-SLV3C Centaur-D Star-37E AC-273/03/1972 CC, LC-36A 1972-012 Pioneer 10  
401 15 Atlas-SLV3C Centaur-DAC-2913/06/1972 CC, LC-36B 1972-041 Intelsat-4 5  
402 16 Atlas-SLV3C Centaur-D AC-2221/08/1972 CC, LC-36B 1972-065 OAO 3  
406 1 Atlas-SLV3D Centaur-D1A Star-37E AC-306/04/1973 CC, LC-36B 1973-019 Pioneer 11  
407 1 Atlas-SLV3D Centaur-D1AAC-3123/08/1973 CC, LC-36A 1973-058 Intelsat-4 7  
410 2 Atlas-SLV3D Centaur-D1A AC-343/11/1973 CC, LC-36B 1973-085 Mariner 10 Mercuryprobe
231 1 Titan-3E Centaur-D1T 3E-1/ TC-111/02/1974 CC, LC-41 1974-F01 SPHINX Failure
418 3 Atlas-SLV3D Centaur-D1AAC-3221/11/1974 CC, LC-36B 1974-093 Intelsat-408  
239 1 Titan-3E Centaur-D1T Star-37E 3E-2/ TC-210/12/1974 CC, LC-41 1974-097 Helios 1  
419 4 Atlas-SLV3D Centaur-D1AAC-3320/02/1975 CC, LC-36A 1975-F01 Intelsat-4 6 Failure
421 5 Atlas-SLV3D Centaur-D1AAC-3522/05/1975 CC, LC-36A 1975-042 Intelsat-4 1  
246 2 Titan-3E Centaur-D1T 3E-4/ TC-420/08/1975 CC, LC-41 1975-075 Viking 1  
247 3 Titan-3E Centaur-D1T3E-3/ TC-39/09/1975 CC, LC-41 1975-083 Viking 2  
423 1 Atlas-SLV3D Centaur-D1ARAC-3626/09/1975 CC, LC-36B 1975-091 Intelsat-4A 1  
252 2 Titan-3E Centaur-D1T Star-37E 3E-5/ TC-515/01/1976 CC, LC-41 1976-003 Helios 2  
424 2 Atlas-SLV3D Centaur-D1AR AC-3729/01/1976 CC, LC-36B 1976-010 Intelsat-4A 2  
426 3 Atlas-SLV3D Centaur-D1ARAC-3813/05/1976 CC, LC-36A 1976-042 Comstar 1A  
427 4 Atlas-SLV3D Centaur-D1AR AC-4022/07/1976 CC, LC-36B 1976-073 Comstar 1B  
429 5 Atlas-SLV3D Centaur-D1AR AC-3926/05/1977 CC, LC-36A 1977-041 Intelsat-4A 4  
431 6 Atlas-SLV3D Centaur-D1AR AC-4512/08/1977 CC, LC-36B 1977-075 HEAO 1  
266 4 Titan-3E Centaur-D1T 3E-7/ TC-720/08/1977 CC, LC-41 1977-076 Voyager 2  
267 5 Titan-3E Centaur-D1T 3E-6/ TC-65/09/1977 CC, LC-41 1977-084 Voyager 1  
432 7 Atlas-SLV3D Centaur-D1AR AC-4330/09/1977 CC, LC-36A 1977-F05 Intelsat-4A 5 Failure
435 8 Atlas-SLV3D Centaur-D1ARAC-467/01/1978 CC, LC-36B 1978-002 Intelsat-4A 3  
436 9 Atlas-SLV3D Centaur-D1AR AC-449/02/1978 CC, LC-36A 1978-016 Fleetsatcom 1  
438 10 Atlas-SLV3D Centaur-D1AR AC-4831/03/1978 CC, LC-36B 1978-035 Intelsat-4A 6  
441 11 Atlas-SLV3D Centaur-D1AR AC-5020/05/1978 CC, LC-36A 1978-051 Pioneer 12 Venusprobe
443 12 Atlas-SLV3D Centaur-D1AR AC-4129/06/1978 CC, LC-36B 1978-068 Comstar 3  
444 13 Atlas-SLV3D Centaur-D1AR AC-518/08/1978 CC, LC-36A 1978-078 Pioneer 13 Venusprobe
447 14 Atlas-SLV3D Centaur-D1AR AC-5213/11/1978 CC, LC-36B 1978-103 HEAO 2  
450 15 Atlas-SLV3D Centaur-D1AR AC-474/05/1979 CC, LC-36A 1979-038 Fleetsatcom 2  
452 16 Atlas-SLV3D Centaur-D1AR AC-5320/09/1979 CC, LC-36B 1979-082 HEAO 3  
453 17 Atlas-SLV3D Centaur-D1AR AC-4918/01/1980 CC, LC-36A 1980-004 Fleetsatcom 3  
458 18 Atlas-SLV3D Centaur-D1AR AC-5731/10/1980 CC, LC-36A 1980-087 Fleetsatcom 4  
459 19 Atlas-SLV3D Centaur-D1ARAC-546/12/1980 CC, LC-36B 1980-098 Intelsat-5 2  
461 20 Atlas-SLV3D Centaur-D1AR AC-4221/02/1981 CC, LC-36A 1981-018 Comstar 1D  
462 21 Atlas-SLV3D Centaur-D1AR AC-5623/05/1981 CC, LC-36B 1981-050 Intelsat-5 1  
464 22 Atlas-SLV3D Centaur-D1AR AC-596/08/1981 CC, LC-36A 1981-073 Fleetsatcom 5  
465 23 Atlas-SLV3D Centaur-D1AR AC-5515/12/1981 CC, LC-36B 1981-119 Intelsat-503  
467 24 Atlas-SLV3D Centaur-D1ARAC-585/03/1982 CC, LC-36B 1982-017 Intelsat-5 4  
468 25 Atlas-SLV3D Centaur-D1AR AC-6028/09/1982 CC, LC-36B 1982-097 Intelsat-5 5  
472 26 Atlas-SLV3D Centaur-D1AR AC-6119/05/1983 CC, LC-36A 1983-047 Intelsat-506  
477 1 Atlas-G Centaur D-1ARAC-62/5042G9/06/1984 CC, LC-36B 1984-057 Intelsat-509  
482 2 Atlas-G Centaur D-1AR AC-63/5043G22/03/1985 CC, LC-36B 1985-025 Intelsat-5A 10  
483 3 Atlas-G Centaur D-1AR AC-64/5044G30/06/1985 CC, LC-36B 1985-055 Intelsat-5A 11  
484 4 Atlas-G Centaur D-1AR AC-65/5045G28/09/1985 CC, LC-36B 1985-087 Intelsat-5A 12  
488 5 Atlas-G Centaur D-1AR AC-66/5046G5/12/1986 CC, LC-36B 1986-096 FLTSATCOM 7  
489 6 Atlas-G Centaur D-1AR AC-67/5048G26/03/1987 CC, LC-36B 1987-F02 Fleetsatcom 6 Failure
494 7 Atlas-G Centaur D-1AR AC-6825/09/1989 CC, LC-36B 1989-077 FLTSATCOM 8  
330 1 Titan-4(01)A Centaur-T K-10/TC-127/02/1994 CC, LC-40 1994-009 Milstar-1 1  
331 2 Titan-4(01)A Centaur-T K-7/TC-103/05/1994 CC, LC-41 1994-026 Trumpet 1  
332 3 Titan-4(01)A Centaur-T K-9/TC-1127/08/1994 CC, LC-41 1994-054 Mercury 1  
334 4 Titan-4(01)A Centaur-TK-23/TC-1714/05/1995 CC, LC-40 1995-022 Mentor 1  
335 5 Titan-4(01)A Centaur-TK-19/TC-810/07/1995 CC, LC-41 1995-034 Trumpet 2  
336 6 Titan-4(01)A Centaur-T K-21/TC-136/11/1995 CC, LC-40 1995-060 Milstar-1 2  
338 7 Titan-4(01)A Centaur-T K-16/TC-1524/04/1996 CC, LC-41 1996-026 Mercury 2  
344 1 Titan-4(01)B Centaur-T B-33/TC-2115/10/1997 CC, LC-40 1997-061 Cassini, Huygens  
346 8 Titan-4(01)A Centaur-T A-17/TC-168/11/1997 CC, LC-41 1997-068 Trumpet 3  
347 2 Titan-4(01)B Centaur-T B-25/TC-189/05/1998 CC, LC-40 1998-029 Mentor 2  
349 9 Titan-4(01)A Centaur-T A-20/TC-912/08/1998 CC, LC-41 1998-F02 Mercury 3 Failure
351 3 Titan-4(01)B Centaur-T B-32/TC-1430/04/1999 CC, LC-40 1999-023 Milstar-2 1  
358 4 Titan-4(01)B Centaur-TB-41/TC-2227/02/2001 CC, SLC-40 2001-009 Milstar-2 2  
361 5 Titan-4(01)B Centaur-T B-38/TC-1916/01/2002 CC, SLC-40 2002-001 Milstar-2 3  
364 6 Titan-4(01)B Centaur-T B-35/TC-238/04/2003 CC, SLC-40 2003-012 Milstar-2 4  
365 7 Titan-4(01)B Centaur-TB-36/TC-209/09/2003 CC, SLC-40 2003-041 Mentor 3  
    Vulcan Centaur VC2S V-0018/01/2024 CC, SLC-41 2024-006 Peregrine 1 
    Vulcan Centaur VC2S V-0024/10/2024 CC, SLC-41 2024-179 Cert 2 

Note:

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Ref.: #0 - update: 13.07.2025 Home