Explorer 49

Infobox Spacecraft
Name = "Explorer 49"


Caption =
Organization = NASA
Major_Contractors =
Mission_Type = Radio Astronomy Research
Satellite_Of = Moon
Decay =
Launch = June 10 1973
Launch_Vehicle = Delta 95
Mission_Duration =
NSSDC_ID = 1973-039A
Webpage =
Mass = 328 kg
Power =

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 to 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.

External links

* [http://www.astronautix.com/craft/rae.htm Astronautix.com Page on the Radio Astronomy Explorers]
* [http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=1973-039A National Space Science Data Center Page on RAE-B (Explorer 49)]
* [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19730021146_1973021146.pdf Delta-95, RAE-B Operations Summary]
* [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720013184_1972013184.pdf On Obtaining Lunar Mission Launch Opportunities] (Report on Launch/Trajectory planning for the RAE-B mission)