Launch of the Transit 1A satellite
on a Thor-Able II
|Function|| Expendable launch system |
|Country of origin||United States|
|Height||26.9 metres (88 ft) – 27.8 metres (91 ft)|
|Diameter||2.44 metres (8 ft 0 in)|
|Mass||51,608 kilograms (113,776 lb)|
|Payload to 640km LEO|
|Mass||120 kilograms (260 lb)|
|Derivatives|| Thor-Ablestar |
|Launch sites||LC-17A, Canaveral|
|First flight||24 April 1958|
|Last flight||1 April 1960|
|Notable payloads|| Pioneer |
|First stage – Thor|
|Thrust||758.71 kilonewtons (170,560 lbf)|
|Specific impulse||282 seconds (2.77 km/s)|
|Burn time||165 seconds|
|Second stage – Able|
|Thrust||34.69 kilonewtons (7,800 lbf)|
|Specific impulse||270 seconds (2.6 km/s)|
|Burn time||115 seconds|
|Third stage (optional) – Altair|
|Thrust||12.45 kilonewtons (2,800 lbf)|
|Specific impulse||256 seconds (2.51 km/s)|
|Burn time||38 seconds|
The Thor-Able was an American expendable launch system and sounding rocket used for a series of re-entry vehicle tests and satellite launches between 1958 and 1960. It was a two-stage rocket, consisting of a Thor IRBM as a first stage and a Vanguard-derived Able second stage. On some flights, an Altair solid rocket motor was added as a third stage. It was a member of the Thor family and an early predecessor of the Delta.
Sixteen Thor-Able were launched, nine on sub-orbital re-entry vehicle test flights and seven on orbital satellite launch attempts. Six launches resulted in failures, in which three of those failures were the result of an Altair upper stage added to the rocket to allow it to launch the spacecraft onto a trans-lunar trajectory. All sixteen launches occurred from Cape Canaveral Air Force Station Launch Complex 17A.
The Thor-Able vehicle had a stronger airframe than the standard Thor IRBM and had the inertial guidance system replaced by a radio guidance package mounted on the Able stages. It saw its first test on 23 April 1958 when Vehicle 116 was launched from LC-17A with a biological nose cone containing a mouse named MIA (Mouse In Able). At 19:10 EST, the Thor's engine roared to life and drove the Able stage and its tiny passenger into the evening sky. Two minutes and fifteen seconds after launch, at an altitude of 50 miles (80 km), the Thor exploded and sent the hapless rodent into the Atlantic Ocean instead of space. The cause of the failure was traced to a turbopump bearing coming loose and resulting in pump shutdown and instant loss of thrust. With no attitude control, the Thor pitched down and its LOX tank ruptured from aerodynamic loads. On 9 July, Thor 118 lifted off for a second attempt with a mouse named MIA II. The booster, including the unproven Able stage, performed successfully and the biological nose cone was driven back into the atmosphere for a splashdown in the South Atlantic, but recovery crews failed to locate the capsule and it sank into the ocean. A third attempt was made on 23 July. The press refused to call the mouse by the name of MIA III, so she was instead christened "Wickie", after a local female news reporter who had covered the space program at Cape Canaveral. Unfortunately, Wickie was no luckier than her predecessors when recovery crews once again failed to locate the capsule after splashdown, but telemetry data confirmed the mouse's survival from liftoff through reentry and proved comprehensively that living organisms could survive space travel. Attention now turned to Thor-Able 127 and Pioneer 0, the world's first lunar probe. This flight took place on 17 August, but ended embarrassingly when the Thor exploded 77 seconds into the launch due to another turbopump malfunction. After an Atlas missile test a month later also failed due to the turbopumps, the Air Force Ballistic Missile Division quickly replaced the pumps in all of their missiles and this problem did not repeat itself again.
On 10 October, Pioneer 1 was launched on Thor 130. The second stage shut down too early and the probe did not have sufficient velocity to escape Earth's gravity. It re-entered the atmosphere and burned up 43 hours after launch.
Pioneer 2 was launched on 8 November and reentered the atmosphere less than an hour after launch when the third stage failed to ignite.
The next six Thor-Able flights were suborbital tests for the Air Force (23 January, 28 February, 21 March, 8 April, 20 May, and 11 June 1959). All of these were successful except the first one, which failed to stage due to an electrical problem and fell into the Atlantic Ocean.
On 7 August, Explorer 6 (a scientific satellite) was launched on Vehicle 134 and successfully orbited.
On 17 September, Transit 1A failed to orbit due to the third stage again failing to ignite.
On 3 November, Pioneer 5 was successfully launched. Intended originally as a Venus probe, technical delays caused it to be launched after the 1959 Venus window had closed so that it was instead sent into a heliocentric orbit.
The final Thor-Able launch orbited Tiros-1 on 1 April 1960.
The Able upper stage name represents its place as the first in the series, from the Joint Army/Navy Phonetic Alphabet.
Pioneer 1 was an American space probe, the first under the auspices of NASA, which was launched by a Thor-Able rocket on 11 October 1958. It was intended to orbit the Moon and make scientific measurements, but due to a guidance error failed to achieve lunar orbit and was ultimately destroyed upon reentering Earth's atmosphere. The flight, which lasted 43 hours and reached an apogee of 113,800 km, was the second and most successful of the three Thor-Able space probes.
Cape Canaveral Air Force Station (CCAFS) is an installation of the United States Space Force's 45th Space Wing, located on Cape Canaveral in Brevard County, Florida.
The PGM-17A Thor was the first operational ballistic missile of the U.S. Air Force (USAF). Named after the Norse god of thunder, it was deployed in the United Kingdom between 1959 and September 1963 as an intermediate-range ballistic missile (IRBM) with thermonuclear warheads. Thor was 65 feet (20 m) in height and 8 feet (2.4 m) in diameter. It was later augmented in the U.S. IRBM arsenal by the Jupiter.
Delta is an American versatile family of expendable launch systems that has provided space launch capability in the United States since 1960. More than 300 Delta rockets have been launched with a 95% success rate. Only the Delta IV Heavy rocket remains in use as of September 2020. Delta rockets are currently manufactured and launched by the United Launch Alliance.
The PGM-19 Jupiter was the first nuclear tipped, medium-range ballistic missile (MRBM) of the United States Air Force (USAF). It was a liquid-propellant rocket using RP-1 fuel and LOX oxidizer, with a single Rocketdyne LR79-NA rocket engine producing 667 kilonewtons (150,000 lbf) of thrust. It was armed with the 1.44 megatons of TNT (6.0 PJ) W49 nuclear warhead. The prime contractor was the Chrysler Corporation.
Space Launch Complex 17 (SLC-17), previously designated Launch Complex 17 (LC-17), was a launch site at Cape Canaveral Air Force Station, Florida used for Thor and Delta rocket launches between 1958 and 2011.
The Atlas-Agena was an American expendable launch system derived from the SM-65 Atlas missile. It was a member of the Atlas family of rockets, and was launched 109 times between 1960 and 1978. It was used to launch the first five Mariner uncrewed probes to the planets Venus and Mars, and the Ranger and Lunar Orbiter uncrewed probes to the Moon. The upper stage was also used as an uncrewed orbital target vehicle for the Gemini crewed spacecraft to practice rendezvous and docking. However, the launch vehicle family was originally developed for the Air Force and most of its launches were classified DoD payloads.
Thor was a US space launch vehicle derived from the PGM-17 Thor intermediate-range ballistic missile. The Thor rocket was the first member of the Delta rocket family of space launch vehicles. The last launch of a direct derivative of the Thor missile occurred in 2018 as the first stage of the final Delta II.
The Thor-Burner was an American expendable launch system, a member of the Thor rocket family. It consisted of a Thor missile, with one or two Burner upper stages. It was used between 1965 and 1976 to orbit a number of satellites, most commonly Defense Meteorological Satellite Program weather satellites. Twenty-four were launched, of which two failed. It weighed 51,810 kg and was 24 metres tall.
Juno II was an American space launch vehicle used during the late 1950s and early 1960s. It was derived from the Jupiter missile, which was used as the first stage.
The Thor-Ablestar, or Thor-Able-Star, also known as Thor-Epsilon was an early American expendable launch system consisting of a PGM-17 Thor missile, with an Ablestar upper stage. It was a member of the Thor family of rockets, and was derived from the Thor-Able.
The Burner and Burner 2 rocket stages have been used as upper stages of launch vehicles such as the Thor-Burner and Delta since 1965. The currently available Burner 2 is powered by a Star 37 solid rocket motor. Thor Altair and Thor Burner were mainly used for US military meteorological programs (DMSP), although they also launched technological satellites.
The Thor DSV-2 was a series of sounding rockets, test vehicles, and anti-satellite weapons derived from the Thor Intermediate-range ballistic missile. It was also used as the first stage of several Thor-derived expendable launch systems
The Thor-Delta, also known as Delta DM-19 or just Delta was an early American expendable launch system used for 12 orbital launches in the early 1960s. A derivative of the Thor-Able, it was a member of the Thor family of rockets, and the first member of the Delta family.
The Delta B, or Thor-Delta B was an American expendable launch system used for nine orbital launches between 1962 and 1964. A derivative of the Thor-Delta, it was a member of the Delta family of rockets.
The Delta C, or Thor-Delta C was an American expendable launch system used for thirteen orbital launches between 1963 and 1969. It was a member of the Delta family of rockets.
The Delta D, Thrust Augmented Delta or Thor-Delta D was an American expendable launch system used to launch two communications satellites in 1964 and 1965. It was derived from the Delta C, and was a member of the Delta family of rockets.
The Delta L, Thor-Delta L, or Thrust-Augmented Long Tank Thor-Delta was a US expendable launch system used to launch the Pioneer E and TETR satellites in 1969 (failed) and HEOS satellite in 1972. It was a member of the Delta family of rockets.
The Delta N or Thor-Delta N was an American expendable launch system used for nine orbital launches between 1968 and 1972. It was a member of the Delta family of rockets, and the last Delta to be given an alphabetical designation - subsequent rockets were designated using a four digit numerical code.
The 6555th Aerospace Test Group is an inactive United States Air Force unit. It was last assigned to the Eastern Space and Missile Center and stationed at Patrick AFB, Florida. It was inactivated on 1 October 1990.