Atlas II

Atlas II
Launch of an Atlas II rocket
FunctionMedium-lift launch vehicle
ManufacturerLockheed Martin
Country of originUnited States
Size
Height47.54 m (156.0 ft)
Diameter3.04 m (10.0 ft)
Mass204,300 kg (450,400 lb)
Stages2.5 (3.5 with IABS)
Capacity
Payload to LEO
Mass
  • Atlas II: 6,580 kg (14,510 lb)
  • Atlas IIA: 7,280 kg (16,050 lb)
  • Atlas IIAS: 8,610 kg (18,980 lb)[1]
Payload to GTO
Mass
  • Atlas II: 2,810 kg (6,190 lb)
  • Atlas IIA: 3,039 kg (6,700 lb)
  • Atlas IIAS: 3,630 kg (8,000 lb)[1]
Associated rockets
FamilyAtlas
Launch history
StatusRetired
Launch sitesCape Canaveral, LC-36
Vandenberg, SLC-3
Total launches63 (II: 10, IIA: 23, IIAS: 30)
Success(es)63
First flightII: December 7, 1991
IIA: June 10, 1992
IIAS: December 16, 1993
Last flightII: March 16, 1998
IIA: December 5, 2002
IIAS: August 31, 2004[2]
Type of passengers/cargoSOHO (Atlas IIAS)
TDRS (Atlas IIA)
First stage
Powered by1 × RS-56-OSA
Maximum thrust386 kN (87,000 lbf)
Specific impulse316 s (3.10 km/s)
Burn time283 seconds
PropellantRP-1 / LOX
Boosters – MA-5A
No. boosters2
Powered by1 × RS-56-OBA
Total thrust2,093.3 kN (470,600 lbf)
Specific impulse299 s (2.93 km/s)
Burn time172 seconds
PropellantRP-1 / LOX
Boosters (Atlas IIAS only) – Castor 4A
No. boosters4
Maximum thrust433.7 kN (97,500 lbf)
Total thrust1,734.8 kN (390,000 lbf)
Specific impulse237.8 s (2.332 km/s)
Burn time56 seconds
PropellantHTPB[3]
Second stage – Centaur II
Powered by2 × RL-10A
Maximum thrust147 kN (33,000 lbf)
Specific impulse449 s (4.40 km/s)
Burn time392 seconds
PropellantLH2 / LOX
Third stage (optional) – IABS
Powered by2 × R-4D
Maximum thrust980 N (220 lbf)
Specific impulse312 s (3.06 km/s)
Burn time60 seconds
PropellantN2O4 / MMH

Atlas II was a member of the Atlas family of launch vehicles, which evolved from the successful Atlas missile program of the 1950s. The Atlas II was a direct evolution of the Atlas I, featuring longer first-stage tanks, higher-performing engines, and the option for strap-on solid rocket boosters. It was designed to launch payloads into low Earth orbit, geosynchronous transfer orbit or geosynchronous orbit. Sixty-three launches of the Atlas II, IIA and IIAS models were carried out between 1991 and 2004; all sixty-three launches were successes, making the Atlas II a highly reliable space launch system. The Atlas line was continued by the Atlas III, used between 2000 and 2005, and the Atlas V, which is still in use as of 2024.

  1. ^ a b Cite error: The named reference astronautixAtlasII was invoked but never defined (see the help page).
  2. ^ Tariq Malik "Final Atlas 2 Rocket Orbits Classified U.S. Satellite", Space News, August 31, 2004 (Accessed September 24, 2014)
  3. ^ Wade, Mark. "Castor 4A engine". astronautix.com. Archived from the original on December 28, 2016.