Encyclopedia Astronautica
Able


Nitric acid/UDMH propellant rocket stage. Loaded/empty mass 1,884/429 kg. Thrust 34.69 kN. Vacuum specific impulse 270 seconds. Engine for Vanguard was AJ10-37; for later Able models AJ10-41 and AJ10-42. Total of 21 stages built and delivered by Aerojet.

The minor modification of the Vanguard aluminum tube thrust chamber to meet the Able requirements was accomplished in the record time of only three months. The major effort during this time was the testing of six aluminum tube thrust chambers for durations longer than the full burn time. This was done to develop confidence that the expected burn-through failure in the throat would occur at least 30% beyond the nominal duration, that it would be repeatable, and that the total impulse would be within specification limits. This was accomplished, and it provided the first opportunity for Aerojet's aluminum tube bundle engine to perform successfully in space.<

Status: Retired 1960.
Gross mass: 1,884 kg (4,153 lb).
Unfuelled mass: 429 kg (945 lb).
Height: 5.67 m (18.60 ft).
Diameter: 0.81 m (2.65 ft).
Span: 0.84 m (2.75 ft).
Thrust: 34.69 kN (7,799 lbf).
Specific impulse: 270 s.
Burn time: 115 s.
Number: 35 .

More... - Chronology...


Associated Countries
Associated Engines
  • AJ10-101 Aerojet Nitric acid/UDMH rocket engine. 34.3 kN. Isp=270s. Derivative of Vanguard second stage for use with Thor IRBM to produce satellite launch vehicle. First tests February 21, 1958. Flown through 1960. More...
  • AJ10-40 Aerojet Nitric acid/UDMH rocket engine. 34.690 kN. Isp=270s. Minor modification of the Vanguard aluminum tube thrust chamber to meet the Able requirements. accomplished in the record time of only three months. More...

Associated Launch Vehicles
  • Vanguard American orbital launch vehicle. Vanguard was the 'civilian' vehicle developed by the US Navy to launch America's first satellite as part of the International Geophysical Year. The Army / von Braun Jupiter-C instead launched the first US satellite after Sputnik and Vanguard's public launch failure. The second stage design led to the Able upper stage for Thor/Atlas, and then to the Delta upper stage still in use in the 21st Century. The original version of Vanguard used a Grand Central final stage. More...
  • Thor Able American orbital launch vehicle. Thor with Able stage derived from Vanguard second stage. More...
  • Thor Able I American orbital launch vehicle. Three stage vehicle consisting of 1 x Thor DM-18A + 1 x Able 1/AJ10-41 + 1 x Altair More...
  • Thor Able II American orbital launch vehicle. Two stage vehicle consisting of 1 x Thor DM-18A + 1 x Able 2/AJ10-42 More...
  • Thor Able III American orbital launch vehicle. Three stage vehicle consisting of 1 x Thor DM-18A + 1 x Able 3/AJ10 + 1 x Altair More...
  • Atlas C Able American orbital launch vehicle. Version with Atlas C first stage, Able AJ10-101A second stage, Altair solid third stage. More...
  • Atlas Able American orbital launch vehicle. Atlas with upper stage based on Vanguard second stage. More...
  • Atlas D Able American orbital launch vehicle. Version with Atlas D first stage, Able AJ10-101A second stage, Altair solid third stage. More...
  • Thor Able II M1 American orbital launch vehicle. Three stage vehicle consisting of 1 x Thor DM-18A + 1 x Able 2/AJ10-42 + 1 x Altair More...
  • Thor Able IV American orbital launch vehicle. Three stage vehicle consisting of 1 x Thor DM-18A + 1 x AJ10 + 1 x Altair More...

Associated Manufacturers and Agencies
  • Aerojet American manufacturer of rockets, spacecraft, and rocket engines. Aerojet, Sacramento, CA, USA. More...

Associated Propellants
  • Nitric acid/UDMH Drawing on the German World War II Wasserfall rocket, nitric acid (HNO3) became the early storable oxidiser of choice for missiles and upper stages of the 1950's. To overcome various problems with its use, it was necessary to combine the nitric acid with N2O4 and passivation compounds. These formulae were considered extremely secret at the time. By the late 1950's it was apparent that N2O4 by itself was a better oxidiser. Therefore nitric acid was almost entirely replaced by pure N2O4 in storable liquid fuel rocket engines developed after 1960. Unsymmetrical Dimethylhydrazine ((CH3)2NNH2) became the storable liquid fuel of choice by the mid-1950's. Development of UDMH in the Soviet Union began in 1949. It is used in virtually all storable liquid rocket engines except for some orbital manoeuvring engines in the United States, where MMH has been preferred due to a slightly higher density and performance. More...

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