American earth ionosphere satellite. One launch, 1965.11.29, Explorer 31. Explorer 31, the Direct Measurement Explorer, was launched with a Canadian Alouette II on November 28, 1965, on a Thor-Agena rocket from Vandenberg Air Force Base, California.
The double-launch project, known as ISIS-X was the first in a new co-operative NASA-Canadian Defense Research Board program for International Satellites for Ionospheric Studies. Explorer 31 was in orbit with an apogee just over a kilometer more than Alouette's and with a perigee of just more than a kilometer lower. The orbits were some 3000 km at apogee and 500 km at perigee.
Explorer 31 was built for the NASA Goddard Space Flight Center, Greenbelt, Maryland, by the Applied Physics Laboratory of The Johns Hopkins University. Eight ionospheric measurement experiments sampled the environment both forward and after the satellite's path. Explorer 31 was 0.76 m across the top and was 25 inches high. A spherical mass spectrometer protruded 0.58 m above the top surface, making the total height 0.64 m. The satellite was powered by solar cells which covered about 15 percent of the spacecraft's surface.
AKA: Direct Measurement Explorer.
More... - Chronology...
Gross mass: 99 kg (218 lb).
First Launch: 1965.11.29.
Number: 1 .
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...
Associated Manufacturers and Agencies
NASA American agency overseeing development of rockets and spacecraft. National Aeronautics and Space Administration, USA, USA. More...
APL American manufacturer of rockets and spacecraft. Applied Physics Laboratory, Johns Hopkins University, Laurel, MD, Laurel, Maryland, USA. More...
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...
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.
Aerospace Yearbook, 1966,
NASA Report, Results from Alouette 1, Explorer 20, Alouette 2, and Explorer 31, 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 SLC2E Delta launch complex. Originally a Thor 75 SMS launch pad. Upgraded to a space launch complex in 1966. More...
1965 November 29 -
04:48 GMT - .
. Launch Complex
: Vandenberg SLC2E
. LV Family
. Launch Vehicle
: Thor Agena B SLV-2
. LV Configuration
: Thor SLV-2A Agena B 453 (TA5) / Agena B S-01 6102 .
- Explorer 31 - .
Payload: DME A. Mass: 99 kg (218 lb). Nation: USA. Agency: NASA Greenbelt. Program: Explorer. Class: Earth. Type: Ionosphere satellite. Spacecraft: DME. USAF Sat Cat: 1806 . COSPAR: 1965-098B. Apogee: 2,833 km (1,760 mi). Perigee: 505 km (313 mi). Inclination: 79.8000 deg. Period: 119.70 min. Ionospheric research; data correlated with Alouette 2. The Explorer 31, Direct Measurement Explorer, was launched with a Canadian Alouette II on November 28, 1965, on a Thor-Agena rocket from Vandenberg Air Force Base, California. The double-launch project, known as ISIS-X was the first in a new co-operative NASA-Canadian Defense Research Board program for International Satellites for Ionospheric Studies. Explorer 31 was in orbit with an apogee just over a kilometre more than Alouette's and with a perigee of just more than a kilometre lower. The orbits were some 3000 km at apogee and 500 km at perigee. Eight ionospheric measurement experiments sampled the environment both forward and after the satellite's path.
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