Encyclopedia Astronautica
Astrobee



wastrobf.jpg
Astrobee F
Credit: via Andreas Parsch
American sounding rocket. Aerojet-designed family of sounding rockets conceived as a lower-cost replacement of the liquid-propellant Aerobee.

From Aerojet - The Creative Company, 1995:

…by 1969 it appeared that there was a substantial need for small and extremely low cost sounding rockets, and enough experience had been gained that a dual thrust motor would be attractive. As a result the NASA Office of Aeronautics and Space Technology (NASA-OAST) funded the development of such a motor and vehicle. The resulting Astrobee D motor (and complete vehicle of the same name) was 6" in diameter and had a thrust in the boost phase of about 3600 lbf, and 2000 lbf in the sustainer mode. Sixty five were produced, and 49 were flown, with one failure.

While this program was in process, NASA Goddard Space Flight Center authorized a much larger version (15" diameter) having thrust levels of 38,000 lbf boost and 8,000 lbf sustain, which was designated the Astrobee F. The first firing test in December 1970 resulted in meeting the desired propulsion parameters, including a duration of 50 seconds. However the nozzle suffered asymmetric erosion that removed one quadrant of the insulation. The second test resulted in chamber burnout close to this same location, and it took two more iterations to achieve a successful design. The Astrobee F was designed specifically to approximate the very mild flight environment of the Aerobee in terms of wind sensitivity, dynamic pressure, aerodynamic heating and stability margin - and it met these goals. Flight tests were successful, and 48 units were flown, but again suffered one failure of the rocket motor.

Although Space General Corporation fielded several other vehicles designated as Astrobees, none of these used any dual thrust Aerojet solid propellant motors. These included Astrobee 200, 250, and 1500.

Astrobee is a family of sounding rockets that is in the tradition of the Aerobee family. The Astrobee rocket uses a solid propellant second stage where the Aerobee has a liquid one. Astrobees are a family of four, ranging from the tiny 10 ft long Astrobee D to the 48 ft high Astrobee Super Chief II and III. The name Chief was selected by the Navy in the same tradition as the Army Corporal and Sergeant rockets. The middle range Astrobee F is comparable in performance to Aerobee 170. But the Astrobee 1500 has about three to four times the altitude capability of the largest Aerobee - the 350. The Super Chief III Astrobee has up to 60% more payload than the Aerobee 350. The largest Astrobees are 31 in. diameter compared to the 15 in. and 22 in. diameters of the Aerobees. This 31 in. diameter is quite large for a sounding rocket and quite respectable for any rocket when considering that the small ICBM is 46 in. diameter and Minuteman III is 52 inches. The largest Astrobee is also nearly 10% longer than the Trident II SLBM

The D, F and 1500 models use an aerodynamic fin-stabilized first stage and a spin-stabilized second stage. Both stages of the Super Chief are fm-stabilized. Most motors are built by Aerojet and include Aerojet Jr., ALCOR, and Astrobee motors. They mostly use Hydroxyl Terminated Polybutadiene (HTPB) for the required environmental characteristics and the ability to produce the slender designs peculiar to sounding rocket sustainer motors. It also gives high Isp at the very low propellant burning rates needed for these motors. Dual thrust was designed into the motors to limit the wind dispersion by use of high initial acceleration without auxiliary boosters. The sustainer thrust is about one-fourth the booster thrust to limit aerodynamic loading to Aerobee levels. The Astrobee Super Chief used a Talos booster motor with over 115,000 lbf average thrust on the first stage. Either a Sergeant or Castor motor were used on the second stage with burn durations of up to 40 seconds. The Astrobees would sometimes compete with the more expensive but longer duration and earth-circling satellites. The Astrobee 1500 could generally go higher than most satellites and certainly cost less. Practical size payloads could be lifted to 700 to 1,600 miles altitude.

Astrobee design stressed reliability and low cost. Reed Jenkins remembers, "They had elegant simplicity. The motor was only four parts, including a one-piece nozzle. We had to keep the cost down and it was a constant battle." Launch configurations were oriented to low cost and also quick turnaround. The limit of two stages allowed units to be readily trailered. Assembly was made at ground level like the Aerobees and the launcher would erect the vehicle to the vertical launch position. The Super Chief needed very substantial launchers, yet there were several to choose from, including one adapted from a ship's 5 inch gun turret mount, the Athena launcher and the AML-20K launcher.

The flight logs maintained by Al Olson show there were 309 successful Astrobee flights of 314 post-development flights yielding a reliability of 98.4%. This is an enviable record for any multi-stage rocket launch vehicle.

Failures: 11. Success Rate: 90.68%. First Fail Date: 1960-03-22. Last Fail Date: 1979-01-28. Launch data is: complete.

Status: Retired 1983.
First Launch: 1960.03.22.
Last Launch: 1983.03.02.
Number: 118 .

More... - Chronology...


Associated Countries
See also
  • Astrobee Aerojet-designed family of sounding rockets conceived as a lower-cost replacement of the liquid-propellant Aerobee. More...

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

Bibliography
  • McDowell, Jonathan, Jonathan's Space Home Page (launch records), Harvard University, 1997-present. Web Address when accessed: here.

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