Encyclopedia Astronautica
IMP



imp8ex50.jpg
IMP-8 / Explorer 50
Credit: NASA
impaimp.jpg
IMP-A
Credit: NASA
American earth magnetosphere satellite. 10 launches, 1963.11.27 (Explorer 18) to 1973.10.26 (Explorer 50).

The IMP series were managed by the Goddard Space Flight Center with the primary objectives of investigation of interplanetary plasma and the interplanetary magnetic field. The orbiting of IMP satellites in a variety of interplanetary and earth orbits allowed study of spatial and temporal relationships of geophysical and interplanetary phenomena simultaneously by several other National Aeronautics and Space Administration satellites. The IMP network provided a crucial 'early warning network' of solar flare activity for Apollo manned missions that ventured beyond the Van Allen Radiation Belts.

AKA: Interplanetary Monitoring Platform.
First Launch: 1963.11.27.
Last Launch: 1973.10.26.
Number: 10 .

More... - Chronology...


Associated Countries
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...
  • Thor Delta C American orbital launch vehicle. Three stage vehicle consisting of 1 x Thor DSV-2A + 1 x Delta D + 1 x Altair 2 More...
  • Delta E American orbital launch vehicle. Thor augmented with 3 x Castor 2 motors with Delta E and Altair 2 upper stage. More...
  • Delta E1 American orbital launch vehicle. Four stage vehicle consisting of 3 x Castor + 1 x Thor DSV-2C + 1 x Delta E + 1 x FW4D More...
  • Delta M American orbital launch vehicle. Long Tank Thor augmented with 3 Castor 2 boosters and Delta E / Burner 2 (Star 37D) upper stages. More...
  • Delta M6 American orbital launch vehicle. Four stage vehicle consisting of 6 x Castor 2 + 1 x LT Thor DSV-2L-1C + 1 x Delta E + 1 x Star 37D More...
  • Delta 1604 American orbital launch vehicle. Four stage vehicle consisting of 6 x Castor 2 + 1 x ELT Thor/MB-3 + 1 x Delta F + 1 x Star 37C More...
  • Delta 1000 American orbital launch vehicle. The Delta 1000 series used Castor 2 strap-ons and the Extended Long Tank core with MB-3 engine. More...
  • Delta C American orbital launch vehicle. Unaugmented Thor with Delta D and solid propellant upper stages. More...

Associated Manufacturers and Agencies
  • NASA American agency overseeing development of rockets and spacecraft. National Aeronautics and Space Administration, USA, USA. More...

Associated Programs
  • Explorer Series of satellites launched by Jet Propulsion Laboratory for the exploration of the space environment (micrometeoroids, charged particles, radiation, etc) from both earth orbital and heliocentric orbital locations. More...

Bibliography
  • McDowell, Jonathan, Jonathan's Space Home Page (launch records), Harvard University, 1997-present. Web Address when accessed: here.
  • JPL Mission and Spacecraft Library, Jet Propulsion Laboratory, 1997. Web Address when accessed: here.
  • Ertel , Ivan D; Morse , Mary Louise; et al, The Apollo Spacecraft Chronology Vol I - IV NASA SP-4009, NASA, 1966-1974. Web Address when accessed: here.
  • McDowell, Jonathan, Launch Log, October 1998. Web Address when accessed: here.
  • Aerospace Yearbook, 1966,
  • NASA Report, Experiments on Explorer XV, Project SERB, Study on the Enhanced Radiation Belts Final Report, Web Address when accessed: here.
  • NASA Report, Interplanetary Monitoring Platform, IMP I- Explorer XVIII Second Interim Status Report, Web Address when accessed: here.
  • NASA Report, Interplanetary Monitoring Platform IMP II- Explorer XXI Flight Report, Web Address when accessed: here.
  • NASA Report, Observations of The Solar Wind During The Flight of Imp-I (Explorer Xviii), Web Address when accessed: here.
  • NASA Report, Instrumentation of the Ionosphere Direct- Measurements Satellite Explorer VIII, Web Address when accessed: here.
  • NASA Report, Flight report - Interplanetary Monitoring Platform IMP-II /Explorer XXI/, Web Address when accessed: here.
  • NASA Report, Explorer 35 Attitude Control System, Web Address when accessed: here.
  • NASA Report, Flight report - Interplanetary Monitoring Platform - IMP-I - Explorer XVIII, Web Address when accessed: here.
  • NASA Report, Clean-Room Facilities for Explorer 35 Spacecraft, Web Address when accessed: here.
  • NASA Report, Some results from the IMP-1 GM cosmic ray detector, Web Address when accessed: here.
  • NASA Report, Interplanetary monitoring platform IMP III - Explorer XXVIII Interim flight report no. 2, Web Address when accessed: here.
  • NASA Report, Performance Parameter Measurements on the Interplanetary Monitoring Platform IMP I, Web Address when accessed: here.
  • NASA Report, AIMP /IMP-D/ technical summary description, Web Address when accessed: here.
  • NASA Report, Interim flight report, Anchored Interplanetary Monitoring Platform AIMP I - Explorer XXXIII, Web Address when accessed: here.
  • NASA Report, The decline and fall of IMP 3 Preliminary report, Web Address when accessed: here.

Associated Launch Sites
  • Cape Canaveral America's largest launch center, used for all manned launches. Today only six of the 40 launch complexes built here remain in use. Located at or near Cape Canaveral are the Kennedy Space Center on Merritt Island, used by NASA for Saturn V and Space Shuttle launches; Patrick AFB on Cape Canaveral itself, operated the US Department of Defense and handling most other launches; the commercial Spaceport Florida; the air-launched launch vehicle and missile Drop Zone off Mayport, Florida, located at 29.00 N 79.00 W, and an offshore submarine-launched ballistic missile launch area. All of these take advantage of the extensive down-range tracking facilities that once extended from the Cape, through the Caribbean, South Atlantic, and to South Africa and the Indian Ocean. More...
  • 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 SLC2E Delta launch complex. Originally a Thor 75 SMS launch pad. Upgraded to a space launch complex in 1966. More...
  • Cape Canaveral LC17B Delta launch complex. Part of a dual launch pad complex built for the Thor ballistic missile program in 1956. Upgraded over the decades for use with Thor, Delta, Delta II, and Delta III launch vehicles, it remained in use for over half a century. More...
  • Vandenberg SLC2W Delta launch complex. Originally a Thor 75 SMS launch pad. Upgraded to a space launch complex in 1966. More...
  • Cape Canaveral LC17A Delta launch complex. Part of a dual launch pad complex built for the Thor ballistic missile program in 1956. Pad 17A supported Thor, Delta, and Delta II launches into the 21st Century. More...

IMP Chronology


1963 November 27 - . 02:30 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC17B. LV Family: Delta. Launch Vehicle: Thor Delta C. LV Configuration: Thor Delta C 387/D21.
  • Explorer 18 - . Payload: IMP A. Mass: 62 kg (136 lb). Nation: USA. Agency: NASA Greenbelt. Program: Explorer. Class: Earth. Type: Magnetosphere satellite. Spacecraft: IMP. Decay Date: 1965-11-30 . USAF Sat Cat: 693 . COSPAR: 1963-046A. Apogee: 197,616 km (122,792 mi). Perigee: 192 km (119 mi). Inclination: 33.3000 deg. Period: 5,666.20 min. Summary: Radiation data; Interplanetary Monitoring Program. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B). .

1964 October 4 - . 03:45 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC17A. LV Family: Delta. Launch Vehicle: Thor Delta C. LV Configuration: Thor Delta C 392/D26.
  • Explorer 21 - . Payload: IMP B. Mass: 62 kg (136 lb). Nation: USA. Agency: NASA Greenbelt. Program: Explorer. Class: Earth. Type: Magnetosphere satellite. Spacecraft: IMP. Decay Date: 1965-12-31 . USAF Sat Cat: 889 . COSPAR: 1964-060A. Apogee: 95,590 km (59,390 mi). Perigee: 191 km (118 mi). Inclination: 33.5000 deg. Period: 2,097.00 min. Summary: Lower than planned orbit. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B). .

1965 May 4 - .
  • Three-station Apollo Solar Particle Alert Network ordered - . Nation: USA. Program: Apollo. Spacecraft: IMP. NASA Associate Administrator for Manned Space Flight George E. Mueller concurred with a plan of MSC Director Robert R. Gilruth to implement a three-station developmental Solar Particle Alert Network. Mueller said he understood that Gilruth would "review the necessity for the Guaymas station, and that you will examine having all data reduction related to this network carried out under contract," and adding that he felt the program would be enhanced if arrangement could be made to involve one or more academic institutions in the analysis of data.

1965 May 29 - . 12:00 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC17B. LV Family: Delta. Launch Vehicle: Thor Delta C. LV Configuration: Thor Delta C 441/D31.
  • Explorer 28 - . Payload: IMP C. Mass: 58 kg (127 lb). Nation: USA. Agency: NASA Greenbelt. Program: Explorer. Class: Earth. Type: Magnetosphere satellite. Spacecraft: IMP. Decay Date: 1968-07-04 . USAF Sat Cat: 1388 . COSPAR: 1965-042A. Apogee: 261,206 km (162,305 mi). Perigee: 229 km (142 mi). Inclination: 30.5000 deg. Period: 8,419.70 min. Summary: Magnetic field, radiation data. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B). .

1966 July 1 - . 16:02 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC17A. LV Family: Delta. Launch Vehicle: Delta E1. LV Configuration: Thor Delta E1 467/D39.
  • Explorer 33 - . Payload: AIMP D. Mass: 93 kg (205 lb). Nation: USA. Agency: NASA Greenbelt. Program: Explorer. Class: Earth. Type: Magnetosphere satellite. Spacecraft: IMP. USAF Sat Cat: 2258 . COSPAR: 1966-058A. Apogee: 480,762 km (298,731 mi). Perigee: 265,679 km (165,084 mi). Inclination: 24.1000 deg. Period: 38,792.40 min. Summary: Intended to enter lunar orbit. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B). .

1967 May 24 - . 14:05 GMT - . Launch Site: Vandenberg. Launch Complex: Vandenberg SLC2E. LV Family: Delta. Launch Vehicle: Delta E1. LV Configuration: Thor Delta E1 486/D49.
  • Explorer 34 - . Payload: IMP F. Mass: 75 kg (165 lb). Nation: USA. Agency: NASA Greenbelt. Program: Explorer. Class: Earth. Type: Magnetosphere satellite. Spacecraft: IMP. Decay Date: 1969-05-03 . USAF Sat Cat: 2817 . COSPAR: 1967-051A. Apogee: 214,379 km (133,208 mi). Perigee: 242 km (150 mi). Inclination: 67.1000 deg. Period: 6,358.20 min. Summary: Radiation, magnetic field data. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B). .

1967 July 19 - . 14:19 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC17B. LV Family: Delta. Launch Vehicle: Delta E1. LV Configuration: Thor Delta E1 488/D50.
  • Explorer 35 - . Payload: AIMP E. Mass: 104 kg (229 lb). Nation: USA. Agency: NASA Greenbelt. Program: Explorer. Class: Earth. Type: Magnetosphere satellite. Spacecraft: IMP. USAF Sat Cat: 2884 . COSPAR: 1967-070A. Apogee: 675 km (419 mi). Perigee: 484 km (300 mi). Inclination: 32.4000 deg. Period: 96.26 min. Earth magnetic tail measurements. Lunar Orbit (Selenocentric). The Westinghouse Aerospace Division, under contract to National Aeronautics and Space Administration's Goddard Space Flight Center, engaged in the system design, integration, assembly and launch support for Anchored Interplanetary Monitoring Platform Satellite, officially designated Explorer 35 by the National Aeronautics and Space Administration. It was launched on July 19, 1967, with the primary objectives of investigation of interplanetary plasma and the interplanetary magnetic field out to and at the lunar distance, in either a captured lunar orbit or a geocentric orbit of the earth. In the geocentric orbit, the apogee was near or beyond the lunar distance. In a lunar orbit, additional objectives included obtaining data on dust distribution, lunar gravitational field, ionosphere, magnetic field, and radiation environment around the moon. AIMP-E also studied spatial and temporal relationships of geophysical and interplanetary phenomena simultaneously being studied by several other National Aeronautics and Space Administration satellites. The investigation in the vicinity of the moon provided for measurements of the characteristics of the interplanetary dust distribution, solar and galactic cosmic rays, as well as a study of the magnetohydrodynamic wake of the earth in the interplanetary medium at the lunar distances.

1969 June 21 - . 08:47 GMT - . Launch Site: Vandenberg. Launch Complex: Vandenberg SLC2W. LV Family: Delta. Launch Vehicle: Delta E1. LV Configuration: Thor Delta E1 482/D69.
  • Explorer 41 - . Payload: IMP G. Mass: 174 kg (383 lb). Nation: USA. Agency: NASA Greenbelt. Program: Explorer. Class: Earth. Type: Magnetosphere satellite. Spacecraft: IMP. Decay Date: 1972-12-23 . USAF Sat Cat: 3990 . COSPAR: 1969-053A. Apogee: 98,159 km (60,993 mi). Perigee: 80,374 km (49,941 mi). Inclination: 86.0000 deg. Period: 4,906.30 min. Summary: Cislunar radiation data. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B). .

1971 March 13 - . 16:15 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC17A. LV Family: Delta. Launch Vehicle: Delta M6. LV Configuration: Thor Delta M6 562/D83.
  • Explorer 43 - . Payload: IMP I. Mass: 288 kg (634 lb). Nation: USA. Agency: NASA Greenbelt. Program: Explorer. Class: Earth. Type: Magnetosphere satellite. Spacecraft: IMP. Decay Date: 1974-10-02 . USAF Sat Cat: 5043 . COSPAR: 1971-019A. Apogee: 203,130 km (126,210 mi). Perigee: 1,845 km (1,146 mi). Inclination: 31.2000 deg. Period: 5,957.90 min. Summary: Earth magnetosphere research. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B). .

1972 September 23 - . 01:20 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC17B. LV Family: Delta. Launch Vehicle: Delta 1604. LV Configuration: Delta 1604 579/D90.
  • Explorer 47 - . Payload: IMP H. Mass: 376 kg (828 lb). Nation: USA. Agency: NASA Greenbelt. Program: Explorer. Class: Earth. Type: Magnetosphere satellite. Spacecraft: IMP. USAF Sat Cat: 6197 . COSPAR: 1972-073A. Apogee: 235,600 km (146,300 mi). Perigee: 201,100 km (124,900 mi). Inclination: 17.2000 deg. Period: 17,670.00 min. Summary: Investigated cislunar radiation, Earth's magnetosphere, interplantary magnetic field. Spacecraft engaged in practical applications and uses of space technology such as weather or communication (US Cat C). .

1973 October 26 - . 02:26 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC17B. LV Family: Delta. Launch Vehicle: Delta 1604. LV Configuration: Delta 1604 582/D97.
  • Explorer 50 - . Payload: IMP J. Mass: 371 kg (817 lb). Nation: USA. Agency: NASA Greenbelt. Program: Explorer. Class: Earth. Type: Magnetosphere satellite. Spacecraft: IMP. USAF Sat Cat: 6893 . COSPAR: 1973-078A. Apogee: 244,361 km (151,838 mi). Perigee: 190,749 km (118,525 mi). Inclination: 31.6000 deg. Period: 17,576.70 min. Summary: Solar flare and radiation monitor. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B). .

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