Artist's impression of Explorer 49 in orbit around the Moon
|Mission type||Radio astronomy|
|Mission duration||2 years|
|Launch mass||328 kilograms (723 lb)|
|Start of mission|
|Launch date||10 June 1973, 14:13:00UTC|
|Launch site||Cape Canaveral LC-17B|
|End of mission|
|Last contact||August 1977|
|Periselene||1,123 kilometres (698 mi)|
|Aposelene||1,334 kilometres (829 mi)|
|Epoch||15 June 1973|
|Orbital insertion||15 June 1973, 07:21 UTC|
Explorer 49 (also called RAE-B) was a 328 kilogram satellite launched on June 10, 1973 for longwave radio astronomy research. It had four 230-meter long X-shaped antenna elements, which made it one of the largest spacecraft ever built.
This mission was the second of a pair of Radio Astronomy Explorer (RAE) satellites, Explorer 38 or RAE-A being the first. Explorer 49 was placed into lunar orbit to provide radio astronomical measurements of the planets, the sun, and the galaxy over the frequency range of 25 kHz to 13.1 MHz. Since the spacecraft's design used gravity gradient booms, the lumpy lunar gravity field made for some interesting problems for the mission scientists.
Explorer 49 was launched after the termination of the Apollo program, and although it did not examine the Moon directly, it became the last American lunar mission until the launch of Clementine spacecraft in 1994.
- Astronautix.com Page on the Radio Astronomy Explorers
- National Space Science Data Center Page on RAE-B (Explorer 49)
- Delta-95, RAE-B Operations Summary
- On Obtaining Lunar Mission Launch Opportunities (Report on Launch/Trajectory planning for the RAE-B mission)
- RAE-B antenna aspect system (Report on the camera system used to verify the antenna deployment of Explorer 49)
- RAE-B antenna aspect processor (Report on the processing hardware for the RAE-B Camera system)
- Proposed gravity-gradient dynamics experiments in lunar orbit using the RAE-B spacecraft