Explorer 49
Encyclopedia
Explorer 49 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.
Longwave
In radio, longwave refers to parts of radio spectrum with relatively long wavelengths. The term is a historic one dating from the early 20th century, when the radio spectrum was considered to consist of long, medium and short wavelengths...
radio astronomy
Radio astronomy
Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The initial detection of radio waves from an astronomical object was made in the 1930s, when Karl Jansky observed radiation coming from the Milky Way. Subsequent observations have identified a number of...
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
Clementine mission
Clementine was a joint space project between the Ballistic Missile Defense Organization and NASA...
spacecraft in 1994.
External links
- 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)