Atlas II

Atlas II
	Launch of an Atlas II rocket
Function	Medium-lift launch vehicle
Manufacturer	Lockheed Martin
Country of origin	United States
Size
Height	47.54 m (156.0 ft)
Diameter	3.04 m (10.0 ft)
Mass	204,300 kg (450,400 lb)
Stages	2.5 (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);
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);
Associated rockets
Family	Atlas
Launch history
Status	Retired
Launch sites	Cape Canaveral, LC-36; Vandenberg, SLC-3
Total launches	63 (II: 10, IIA: 23, IIAS: 30)
Success(es)	63
First flight	II: December 7, 1991; IIA: June 10, 1992; IIAS: December 16, 1993
Last flight	II: March 16, 1998; IIA: December 5, 2002; IIAS: August 31, 2004
Type of passengers/cargo	SOHO (Atlas IIAS); TDRS (Atlas IIA)
First stage
Powered by	1 × RS-56-OSA
Maximum thrust	386 kN (87,000 lbf)
Specific impulse	316 s (3.10 km/s)
Burn time	283 seconds
Propellant	RP-1 / LOX
Boosters – MA-5A
No. boosters	2
Powered by	1 × RS-56-OBA
Total thrust	2,093.3 kN (470,600 lbf)
Specific impulse	299 s (2.93 km/s)
Burn time	172 seconds
Propellant	RP-1 / LOX
Boosters (Atlas IIAS only) – Castor 4A
No. boosters	4
Maximum thrust	433.7 kN (97,500 lbf)
Total thrust	1,734.8 kN (390,000 lbf)
Specific impulse	237.8 s (2.332 km/s)
Burn time	56 seconds
Propellant	HTPB
Second stage – Centaur II
Powered by	2 × RL-10A
Maximum thrust	147 kN (33,000 lbf)
Specific impulse	449 s (4.40 km/s)
Burn time	392 seconds
Propellant	LH2 / LOX
Third stage (optional) – IABS
Powered by	2 × R-4D
Maximum thrust	980 N (220 lbf)
Specific impulse	312 s (3.06 km/s)
Burn time	60 seconds
Propellant	N2O4 / MMH
	[edit on Wikidata]

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^[update].

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

[astronautixAtlasII-1] Cite error: The named reference astronautixAtlasII was invoked but never defined (see the help page).

[final-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.

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