Function | Medium expendable 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 |
|
Payload to GTO | |
Mass |
|
Associated rockets | |
Family | Atlas |
Launch history | |
Status | Retired |
Launch sites | SLC-36,Cape Canaveral SLC-3 Vandenberg AFB |
Total launches | 63 (II: 10,IIA: 23,IIAS: 30) |
Success(es) | 63 (II: 10,IIA: 23,IIAS: 30) [2] |
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 [2] |
Type of passengers/cargo | SOHO (Atlas IIAS) TDRS (Atlas IIA) |
Boosters (Atlas IIAS) –Castor 4A | |
No. boosters | 4 |
Powered by | 1 Solid |
Maximum thrust | 478.3 kN (107,500 lbf) |
Specific impulse | 266 s (2.61 km/s) |
Burn time | 56 seconds |
Propellant | HTPB [3] |
Boosters (all) –MA-5A | |
No. boosters | 1 |
Powered by | 2 RS-56-OBA |
Maximum thrust | 2,093.3 kN (470,600 lbf) |
Specific impulse | 299 s (2.93 km/s) |
Burn time | 172 seconds |
Propellant | RP-1 / LOX |
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 |
Second stage –Centaur | |
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 –Integrated Apogee Boost Stage (Only on DSCS III launches) | |
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 |
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.
In May 1988,the US Air Force chose General Dynamics (now Lockheed Martin) to develop the Atlas II vehicle,primarily to launch Defense Satellite Communications System payloads under the Medium Launch Vehicle II (MLV-II) program. [4] Additional commercial and U.S. Government sales resulted in production increases leading to greater than 60 vehicles being produced and launched.
Atlas II was developed from the Atlas I and featured numerous upgrades over that vehicle. [5]
Atlas II was launched from Launch Complex 36 at Cape Canaveral Space Force Station in Florida as well as Space Launch Complex 3E at Vandenberg Space Force Base in California. All launches were successful.
Atlas II provided higher performance than the earlier Atlas I by using engines with greater thrust and longer propellant tanks for both stages. The increased thrust,engine efficiency,and propellant capacity enabled the vehicle to lift payloads of 6,100 pounds (2,767 kg) into geostationary transfer orbit (GTO),or more on later Atlas II variants. [5]
Atlas II also featured lower-cost electronics,an improved flight computer,and longer propellant tanks than its predecessor,Atlas I. [6]
The Atlas II first stage was 3.05 m (10.0 ft) in diameter and 24.90 m (81.7 ft) long. The stage was powered by 3 RS-56 rocket engines (derived from the RS-27 main engine of the Delta II rocket) burning 156 t (344,000 lb) of RP-1 and liquid oxygen. The two booster engines were the RS-56-OBA variants (the complete assembly of both engines and the aft skirt was referred to as the MA-5A),with high thrust but moderate efficiency. The sustainer (center) engine was the RS-56-OSA variant,featuring much less thrust but higher efficiency at high altitudes than the booster engines.
The vernier engines used on the first stage of the Atlas I (and all previous Atlas models) were replaced by a hydrazine-fueled roll control system on Atlas II. This system,mounted on the interstage between the first and second stages,utilized small thrusters to control the vehicle's roll. [1] [7] [8] Compared to Atlas I,the Atlas II first stage was 2.7 m (8 ft 10 in) taller. [9]
The Atlas II was the last Atlas rocket to use the "stage-and-a-half" technique,where it ignited all 3 RS-56 engines at liftoff and then jettisoned the 2 RS-56-OBA side engines and their support structure during ascent. The two RS-56-OBA engines were integrated into a single unit called the MA-5A and shared a common gas generator. They burned for approximately 164 seconds before being jettisoned,when acceleration reached approximately 5.0-5.5 g. The central sustainer engine on the first stage,an RS-56-OSA,would burn for an additional 125 seconds after their jettison. It featured better efficiency at high altitudes than the RS-56-OBAs. [10] [7]
The first stage also had the option to be fitted with 4 Castor 4A solid rocket boosters as part of the IIAS version,each providing an additional 478.3 kN (107,500 lbf) of thrust for 56 seconds. The first two boosters were ignited at liftoff,and the other two were ignited after the first two burnt out. Both pairs of boosters were jettisoned shortly after their respective burns. [11]
The second stage of Atlas II, the Centaur II, was the result of over 3 decades of flights and enhancements of the Centaur upper stage. Centaur II featured 2 RL-10A-3-3A engines, burning liquid hydrogen and liquid oxygen. It featured propellant tanks 0.9 meters longer than its predecessor, Centaur I, giving the stage more propellant and therefore higher performance. Due to the super cold propellants inside Centaur, foam insulation was installed onto the outer metal skin on the stage to help mitigate propellant boiloff inside the tank. Centaur II's foam insulation was permanently attached to the side of the stage, whereas previous versions of the stage (including Centaur I) jettisoned their insulation panels during flight. [1]
The Centaur II upper stage (along with all other Centaur variants) used a pressure-stabilized propellant tank design and cryogenic propellants. The two stainless steel propellant tanks were separated by a common bulkhead, which helped keep mass down. Centaur II was 10.1 m (33 ft) long, carrying almost 17 t (37,000 lb) of fuel. The stage also featured 12 27 N (6.1 lbf) hydrazine thrusters to orient the stage and settle the propellants prior to engine ignition. [7]
For the IIA and IIAS versions, Atlas used the Centaur IIA variant which featured 2 RL-10A-4 engines, providing higher thrust and efficiency over the RL-10A-3-3A. The two engines could be fitted with extendable nozzles, which would provide an increase in efficiency and therefore performance. [12]
Centaur II was further refined to create the Centaur III, which flew on the Atlas III and continues to fly today on the Atlas V. Atlas II was the final Atlas rocket that only had a dual-engine Centaur available, future rockets had the option for one or two RL-10 engines on Centaur. [13] However, the Centaur V flying on the Vulcan rocket will only utilize two RL-10 engines. [14]
The Integrated Apogee Boost Stage was an optional upper stage, used only as an apogee kick stage when launching Defense Satellite Communications System III satellites (which were designed to be delivered directly to geostationary orbit using the Transtage or Inertial Upper Stage, and so were not capable of performing their own circularization burn at the apogee of their geostationary transfer orbit) on board the Atlas II and, later, the Delta IV. It was powered by two R-4D engines, and could operate on-orbit for up to twelve days before deploying its payload, allowing additional flexibility in mission planning. The IABS measured 2.9 m in diameter, and 0.68 m in length, carrying 1303 kg of propellant with a dry mass of 275 kg.
Three fairing models were available for the Atlas II: [7]
The Medium variant was not commonly used for Atlas II but was often used in earlier Atlas rockets. The Large and Extended fairing options were also later used on the Atlas III and Atlas V rockets. For the Atlas V, these fairings were part of the 400-series of that rocket, and a further extended option ("Extra Extended") was available. [15] The 4-meter Atlas fairing last flew in 2022. [16]
Atlas II rockets flying with a Medium fairing could move the most payload to orbit, as that fairing was the lightest. Similarly, rockets with Large or Extended fairings suffered slight hits to their payload capacity.
Atlas II was developed from the Atlas I and was available in 3 versions.
The original Atlas II was based on the Atlas I and its predecessors. Its lengthened propellant tanks and improved electronics over the Atlas I offered better performance. It was designed to work as part of the US Air Force's Medium Launch Vehicle II program. This version flew between 1991 and 1998. [1]
Atlas IIA was a derivative of the Atlas II designed to service the commercial launch market. The main improvement was the switch from the RL10A-3-3A to RL10A-4 engine on the Centaur upper stage, increasing the stage's performance and the vehicle's payload capability. [7] The IIA version flew between 1992 and 2002. [12]
Atlas IIAS was largely identical to IIA, but added four Castor 4A solid rocket boosters to increase performance. These boosters were ignited in pairs, with one pair igniting on the ground, and the second igniting in the air shortly after the first pair separated. The half-stage booster section would then drop off as usual. [7] IIAS was used between 1993 and 2004, concurrently with IIA. [11]
Titan was a family of United States expendable rockets used between 1959 and 2005. The Titan I and Titan II were part of the US Air Force's intercontinental ballistic missile (ICBM) fleet until 1987. The space launch vehicle versions contributed the majority of the 368 Titan launches, including all the Project Gemini crewed flights of the mid-1960s. Titan vehicles were also used to lift US military payloads as well as civilian agency reconnaissance satellites and to send interplanetary scientific probes throughout the Solar System.
The Centaur is a family of rocket propelled upper stages that has been in use since 1962. It is currently produced by U.S. launch service provider United Launch Alliance, with one main active version and one version under development. The 3.05 m (10.0 ft) diameter Common Centaur/Centaur III flies as the upper stage of the Atlas V launch vehicle, and the 5.4 m (18 ft) diameter Centaur V is being developed as the upper stage of ULA's new Vulcan rocket. Centaur was the first rocket stage to use liquid hydrogen (LH2) and liquid oxygen (LOX) propellants, a high-energy combination that is ideal for upper stages but has significant handling difficulties.
A multistage rocket or step rocket is a launch vehicle that uses two or more rocket stages, each of which contains its own engines and propellant. A tandem or serial stage is mounted on top of another stage; a parallel stage is attached alongside another stage. The result is effectively two or more rockets stacked on top of or attached next to each other. Two-stage rockets are quite common, but rockets with as many as five separate stages have been successfully launched.
Delta II was an expendable launch system, originally designed and built by McDonnell Douglas, and sometimes known as the Thorad Delta 1. Delta II was part of the Delta rocket family and entered service in 1989. Delta II vehicles included the Delta 6000, and the two later Delta 7000 variants. The rocket flew its final mission ICESat-2 on 15 September 2018, earning the launch vehicle a streak of 100 successful missions in a row, with the last failure being GPS IIR-1 in 1997.
The Delta rocket family is a versatile range of American rocket-powered expendable launch systems that has provided space launch capability in the United States since 1960. Japan also launched license-built derivatives from 1975 to 1992. More than 300 Delta rockets have been launched with a 95% success rate. The series has been phased-out in favor of the Vulcan Centaur, with only the Delta IV Heavy rocket remaining in use as of June 2023.
Delta IV was a group of five expendable launch systems in the Delta rocket family introduced in the early 2000s. Originally designed by Boeing's Defense, Space and Security division for the Evolved Expendable Launch Vehicle (EELV) program, the Delta IV became a United Launch Alliance (ULA) product in 2006. The Delta IV was primarily a launch vehicle for United States Air Force (USAF) military payloads, but was also used to launch a number of United States government non-military payloads and a single commercial satellite.
Titan IV was a family of heavy-lift space launch vehicles developed by Martin Marietta and operated by the United States Air Force from 1989 to 2005. Launches were conducted from Cape Canaveral Air Force Station, Florida and Vandenberg Air Force Base, California.
Titan IIIB was the collective name for a number of derivatives of the Titan II ICBM and Titan III launch vehicle, modified by the addition of an Agena upper stage. It consisted of four separate rockets. The Titan 23B was a basic Titan II with an Agena upper stage, and the Titan 24B was the same concept, but using the slightly enlarged Titan IIIM rocket as the base. The Titan 33B was a Titan 23B with the Agena enclosed in an enlarged fairing, in order to allow larger payloads to be launched. The final member of the Titan IIIB family was the Titan 34B which was a Titan 24B with the larger fairing used on the Titan 33B.
The Titan IIIC was an expendable launch system used by the United States Air Force from 1965 until 1982. It was the first Titan booster to feature large solid rocket motors and was planned to be used as a launcher for the Dyna-Soar, though the spaceplane was cancelled before it could fly. The majority of the launcher's payloads were DoD satellites, for military communications and early warning, though one flight (ATS-6) was performed by NASA. The Titan IIIC was launched exclusively from Cape Canaveral while its sibling, the Titan IIID, was launched only from Vandenberg AFB.
Delta III was an expendable launch vehicle made by McDonnell Douglas. The vehicle was developed from the highly-successful Delta II to help meet the launch demand of larger satellites. The first Delta III launch was on August 26, 1998. Of its three flights, the first two were failures, and the third, though declared successful, reached the low end of its targeted orbit range and carried only a dummy (inert) payload. The Delta III could deliver up to 3,810 kg (8,400 lb) to geostationary transfer orbit, twice the payload of its predecessor, the Delta II. Under the four-digit designation system from earlier Delta rockets, the Delta III is classified as the Delta 8930.
The Atlas-Centaur was a United States expendable launch vehicle derived from the SM-65 Atlas D missile. The vehicle featured a Centaur upper stage, the first such stage to use high-performance liquid hydrogen as fuel. Launches were conducted from Launch Complex 36 at the Cape Canaveral Air Force Station (CCAFS) in Florida. After a strenuous flight test program, Atlas-Centaur went on to launch several crucial spaceflight missions for the United States, including Surveyor 1, Mariner 4, and Pioneer 10/11. The vehicle would be continuously developed and improved into the 1990s, with the last direct descendant being the highly successful Atlas II.
Atlas V is an expendable launch system and the fifth major version in the Atlas launch vehicle family. It was originally designed by Lockheed Martin, now being operated by United Launch Alliance (ULA), a joint venture between Lockheed Martin and Boeing. It is used for DoD, NASA, and Commercial payloads. It is America's longest-serving active rocket. After 87 launches, in August 2021 ULA announced that Atlas V would be retired, and all 29 remaining launches had been sold. As of 6 October 2023, 17 launches remain.
The Atlas III was an American orbital launch vehicle, used in the years between 2000 and 2005. It was developed from the highly successful Atlas II rocket and shared many components. It was the first member of the Atlas family since the Atlas A to feature a "normal" staging method, compared to the previous Atlas family members, which were equipped with two jettisonable outboard engines on the first (booster) stage. The Atlas III was developed further to create the Atlas V, which still flies to this day.
Atlas is a family of US missiles and space launch vehicles that originated with the SM-65 Atlas. The Atlas intercontinental ballistic missile (ICBM) program was initiated in the late 1950s under the Convair Division of General Dynamics. Atlas was a liquid propellant rocket burning RP-1 kerosene fuel with liquid oxygen in three engines configured in an unusual "stage-and-a-half" or "parallel staging" design: two outboard booster engines were jettisoned along with supporting structures during ascent, while the center sustainer engine, propellant tanks and other structural elements remained connected through propellant depletion and engine shutdown.
The Atlas I was a US expendable launch system manufactured by General Dynamics in the 1990s to launch a variety of satellites. It was largely a commercial rebrand of the Atlas G, but did feature several electrical and guidance improvements. Atlas I did not feature any major payload capacity improvements over its predecessor but did offer a larger payload fairing option. Eleven launches took place, with three failures.
The Atlas G, also known as Atlas G Centaur-D1AR was an American expendable launch system derived from the Atlas-Centaur. It was a member of the Atlas family of rockets and was used to launch seven communication satellites during the mid to late 1980s. Atlas G consisted of an improved Atlas core with modernized avionics and stretched propellant tanks. The Centaur stage also had several updated components and other technical improvements. Atlas G flew 7 times, with all missions aiming to go to a geostationary transfer orbit. It was replaced by the near-identical Atlas I, which had an improved guidance system and offered a larger payload fairing.
The Atlas SLV-3, or SLV-3 Atlas was an American expendable launch system derived from the SM-65 Atlas / SM-65D Atlas missile. It was a member of the Atlas family of rockets.
The Delta 3000 series was an American expendable launch system which was used to conduct 38 orbital launches between 1975 and 1989. It was a member of the Delta family of rockets. Several variants existed, which were differentiated by a four digit numerical code.
Vulcan Centaur is a two-stage-to-orbit, heavy-lift launch vehicle under development by United Launch Alliance (ULA) since 2014. It is principally designed to meet launch demands for the U.S. government's National Security Space Launch (NSSL) program for use by the United States Space Force and U.S. intelligence agencies for national security satellite launches. It will replace both of ULA's existing launchers in this role, as these launchers are retiring. Vulcan Centaur will also be used for commercial launches, including an order for 38 launches from Kuiper Systems.
MA-5A was an American liquid fueled rocket stage. It was manufactured by Lockheed Martin for use on the Atlas II rocket, derived from the MA-5 used on the Atlas I.