|Mission type||Earth science|
|Launch mass||390 kg (860 lb)|
|Start of mission|
|Launch date||23 September 1972, 01:20UTC|
|Rocket||Delta 1604 579/D90|
|Launch site||Cape Canaveral LC-17B|
|Perigee altitude||201,599 km (125,268 mi)|
|Apogee altitude||235,699 km (146,457 mi)|
|Epoch||23 September 1972|
Explorer 47, also known IMP-7 and Interplanetary Monitoring Platform IMP-H, was an American satellite launched as part of Explorers program. Explorer 47 as launched on 23 September 1972 on Cape Canaveral, Florida, U.S., with a Delta rocket. Explorer 47 was the seventh satellite of the Interplanetary Monitoring Platform.
Explorer 47 continued the study begun by earlier IMP spacecraft of the interplanetary and magnetotail regions from a nearly circular orbit, near 37 earth radii. This 16 sided drum-shaped spacecraft was 157 centimetres (62 in) high and 135 centimetres (53 in) in diameter. It was designed to measure energetic particles, plasma and electric and magnetic fields. The spin axis was normal to the ecliptic plane, and the spin period was 1.3 s. The spacecraft was powered by solar cells and a chemical battery. Scientific data were telemetered at 1600 bps (with a secondary 400 bps rate available).
The spacecraft was turned off on October 31, 1978.