Encyclopedia Astronautica

American ion engine technology satellite. One launch, 1999.02.23. ARGOS was the USAF Space Test Program P91-1 technology satellite by Boeing/Seal Beach.

It carried an electric propulsion experiment, ionospheric instruments, a space dust experiment, and the NRL's USA hard X-ray astronomy detectors for X-ray binary star timing observations. ARGOS was built by Boeing/Seal Beach.

The ARGOS satellite was built by Space & Missile system Center (SMC), Los Angeles AFB, CA under the program P-91-1. ARGOS carried nine DoD space experiments to orbit, most notably the ESEX Arcjet thruster.

The ESEX (Electric Propulsion Space Experiment) program began in 1989 under the then Air Force Astronautics Lab, Edwards AFB, CA. The prime contractor was TRW, Space Park, Redondo Beach, CA. The Arcjet was build by Rocket Research (now Aerojet), Redmond, WA. The ESEX experiment flew once in 1999 on board the ARGOS satellite.

ESEX was the first High Power Electric Propulsion flight. The system operated on 30 kW with about 26 kW to the thruster. The experiment was powered by 205 kg of silver zinc batteries built by Eagle Pitcher Company of Joplin, Mo. At the time this was the highest power subsystem ever flown in space.

The objective was to verify Arcjet performance in space and determine if any spacecraft compatibility or contamination issues existed. AGROS operated with no detectable impact when the thruster operating. Sensors detected no RF interference, no increase in contamination, and measurements of specific impulse and thrust were within ground measurement uncertainty.

This truly pioneering flight program gave the satellite community great confidence in using High Power Electric propulsion.

AKA: P91-1.
Thrust: 2.00 N (0.40 lbf).
Specific impulse: 800 s.
First Launch: 1999.02.23.
Number: 1 .

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Associated Countries
Associated Engines
  • ESEX Arcjet Redmond electric/ammonia rocket engine. 2 N. In Production. Isp=800s. Electric Propulsion Space Experiment) program begun 1989 under the then Air Force Astronautics Lab. Flew once in 1999 on board the ARGOS satellite. More...

See also
  • Delta The Delta launch vehicle was America's longest-lived, most reliable, and lowest-cost space launch vehicle. Development began in 1955 and it continued in service in the 21st Century despite numerous candidate replacements. More...

Associated Launch Vehicles
  • Delta American orbital launch vehicle. The Delta launch vehicle was America's longest-lived, most reliable, and lowest-cost space launch vehicle. Delta began as Thor, a crash December 1955 program to produce an intermediate range ballistic missile using existing components, which flew thirteen months after go-ahead. Fifteen months after that, a space launch version flew, using an existing upper stage. The addition of solid rocket boosters allowed the Thor core and Able/Delta upper stages to be stretched. Costs were kept down by using first and second-stage rocket engines surplus to the Apollo program in the 1970's. Continuous introduction of new 'existing' technology over the years resulted in an incredible evolution - the payload into a geosynchronous transfer orbit increasing from 68 kg in 1962 to 3810 kg by 2002. Delta survived innumerable attempts to kill the program and replace it with 'more rationale' alternatives. By 2008 nearly 1,000 boosters had flown over a fifty-year career, and cancellation was again announced. More...
  • Delta 2 7000 American orbital launch vehicle. The Delta 7000 series used GEM-40 strap-ons with the Extra Extended Long Tank core, further upgraded with the RS-27A engine. More...
  • Delta 7920-X Three stage vehicle consisting of 9 x GEM-40 + 1 x EELT Thor/RS-27A + 1 x Delta K with 3.05 m (10 foot) diameter fairing More...

Associated Manufacturers and Agencies
  • USAF SM American agency overseeing development of spacecraft. Air Force Space and Missiles Command, USA. More...
  • North American American manufacturer of rockets, spacecraft, and rocket engines. North American, Palmdale, El Segundo. Downey, CA, USA More...

Associated Propellants
  • Electric/Ammonia The many versions of electric engines use electric or magnetic fields to accelerate ionized elements to high velocity, creating thrust. The power source can be a nuclear reactor or thermal-electric generator, or solar panels. Ammonia (NH3) is a colourless gas and liquid with a strong irritating characteristic odour. More...

  • McDowell, Jonathan, Jonathan's Space Home Page (launch records), Harvard University, 1997-present. Web Address when accessed: here.
  • McDowell, Jonathan, Jonathan's Space Report (Internet Newsletter), Harvard University, Weekly, 1989 to Present. Web Address when accessed: here.

Associated Launch Sites
  • Vandenberg Vandenberg Air Force Base is located on the Central Coast of California about 240 km northwest of Los Angeles. It is used for launches of unmanned government and commercial satellites into polar orbit and intercontinental ballistic missile test launches toward the Kwajalein Atoll. More...
  • Vandenberg SLC2W Delta launch complex. Originally a Thor 75 SMS launch pad. Upgraded to a space launch complex in 1966. More...

ARGOS Chronology

1999 February 23 - . 10:29 GMT - . Launch Site: Vandenberg. Launch Complex: Vandenberg SLC2W. LV Family: Delta. Launch Vehicle: Delta 7920-X. LV Configuration: Delta 7920-10 D267.
  • ARGOS - . Payload: P91-1. Nation: USA. Agency: USAF SM. Manufacturer: Seal Beach. Class: Technology. Type: Ion engine technology satellite. Spacecraft: ARGOS. USAF Sat Cat: 25634 . COSPAR: 1999-008A. Apogee: 836 km (519 mi). Perigee: 821 km (510 mi). Inclination: 98.9000 deg. Period: 101.50 min. Summary: ARGOS was a USAF Space Test Program P91-1 technology satellite, equipped with an ion engine, ionosphere, x-ray, and dust detectors. Much delayed, it finally was placed into orbit on the eleventh (!) launch attempt..

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