XLR81
Agena D 108.jpg
Standard Agena D 108 delivery to final assembly for Gemini Agena target vehicle 5003.[1]
Country of originUnited States
Date1957
First flight1963-07-12[2]
Last flight1984-04-17[2]
ManufacturerBell Aerosystems Company[3]
ApplicationUpper stage engine[4]
Associated LVThor, Thorad, Atlas and Titan
PredecessorBell 8081
SuccessorBell 8247
StatusRetired
Liquid-fuel engine
PropellantRFNA[3] / UDMH[3]
Mixture ratio2.55[5]
CycleGas generator[3]
Configuration
Chamber1[3]
Nozzle ratio45[2]
Performance
Thrust, vacuum71.2 kN (16,000 lbf)[2]
Chamber pressure3.49 MPa (506 psi)[2]
Specific impulse, vacuum293 s (2.87 km/s)[2]
Burn time265 s[2]
Restarts2[2]
Gimbal range±2.5°[6][7]
Dimensions
Length2.11 m (83.2 in)[7]
Diameter0.90 m (35.5 in)[6]
Dry weight134 kg (296 lb)[7]
Used in
RM-81 Agena[2]
Model 8048
Model 8048

The Bell Aerosystems Company XLR81 (Model 8096) was an American liquid-propellant rocket engine, which was used on the Agena upper stage. It burned UDMH and RFNA fed by a turbopump in a fuel rich gas generator cycle. The turbopump had a single turbine with a gearbox to transmit power to the oxidizer and fuel pumps. The thrust chamber was all-aluminum, and regeneratively cooled by oxidizer flowing through gun-drilled passages in the combustion chamber and throat walls. The nozzle was a titanium radiatively cooled extension. The engine was mounted on a hydraulic actuated gimbal which enabled thrust vectoring to control pitch and yaw. Engine thrust and mixture ratio were controlled by cavitating flow venturis on the gas generator flow circuit. Engine start was achieved by solid propellant start cartridge.[6]

Variants

Starting as an air-launched missile engine and finishing as a multi-mission general propulsion for the space age, the basic design went through a series of iterations and versions that enabled it to have a long and productive career.

See also

References

  1. ^ "Atlas Agena D SLV-3". Encyclopedia Astronautica. Archived from the original on 2013-10-17. Retrieved 2015-06-24.
  2. ^ a b c d e f g h i j k l m Brügge, Norbert. "Propulsion and History of the U.S. Agena upper stage". www.b14643.de. Retrieved 2015-06-17.
  3. ^ a b c d e f "Section II - Agena and Support Systems". Athena Payloads User Handbook (pdf). Lockheed Missile & Space Company. 1971-03-01. pp. 2–4. Retrieved 2015-06-17.
  4. ^ a b "Bell 8096". Encyclopedia Astronautica. Archived from the original on 2016-03-04. Retrieved 2015-06-17.
  5. ^ a b "Section 3.2.3". Reusable Agena Study Final Report (Technical Volume II) (pdf). 1974-03-15. pp. 3–8. Retrieved 2015-06-17.
  6. ^ a b c d e f g h i j Roach, Robert D. The Agena Rocket Engine... Six Generations of Reliability in Space Propulsion (pdf). Retrieved 2015-06-17.
  7. ^ a b c d e "3.3.2 Propulsion Systems". Reusable Agena Study Final Report (Technical Volume II) (pdf). 1974-03-15. pp. 3–37. Retrieved 2015-06-17.
  8. ^ Grassly, Sarah A. "Introduction". Agena Flight History as of 31 December 1967 (pdf). USAF. p. IX. Retrieved 2015-06-18.
  9. ^ a b c d e f "Bell/Texton Space Engines (1935-Present)". www.alternatewars.com/BBOW/. Big Book of Warfare. Retrieved 2015-06-17.
  10. ^ a b "Bell 8048". Encyclopedia Astronautica. Archived from the original on 2016-03-04. Retrieved 2015-06-17.
  11. ^ "Bell 8081". Encyclopedia Astronautica. Archived from the original on 2017-02-04. Retrieved 2015-06-17.
  12. ^ "1.1 General". USAF Propellant Handbook Volume II - Nitric Acid/Nitrogen Tetroxide Oxidiser (pdf). February 1977. pp. 1–3. Archived (PDF) from the original on June 18, 2015. Retrieved 2015-06-17.
  13. ^ "4.5 Alternative Concepts". Reusable Agena Study Final Report (Technical Volume II) (pdf). 1974-03-15. pp. 4–20. Retrieved 2015-06-17.
  14. ^ "2.3 NOMINAL SHUTTLE/AGENA UPPER STAGE CONCEPT". Reusable Agena Study Final Report (Technical Volume II) (pdf). 1974-03-15. pp. 2–4. Retrieved 2015-06-17.
  15. ^ "Bell 8247". Encyclopedia Astronautica. Archived from the original on 2017-02-05. Retrieved 2015-06-17.
  16. ^ "Apendix E". SP-4212 "On Mars: Exploration of the Red Planet. 1958-1978". NASA. pp. 465–469. Retrieved 2015-06-17.