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Arecibo Planetary Radar
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The Arecibo radio telescope in Puerto Rico is used in radar mode, at a frequency of 2380 MHz, to map out the surface structure and orbits of planets, planetary moons, asteroids, comets, and the Moon. The radar can be used to detect near-Earth asteroids that could pose a threat to our planet.
The planetary radar is the most powerful transmitter on Earth, combining a 1 million watt transmitter with the 76 dBi forward gain of the giant Arecibo 1000' speherical reflector, to provide about 40 trillion watts of effective isotropic radiated power.
The radar transmitter has been used on several occasions to broadcast messages to space, in the hopes that the messages may one day be intercepted by extraterrestrial civilizations.
The Arecibo telescope is also capable of transmitting at 430 and 46 MHz, frequencies which are used for probing the Earth's magnetosphere, ionosphere, and upper atmosphere.
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Frequency Bands |
| Band | Use | Service11 | Table |
| 2370 - 2390 MHz | Arecibo Planetary Radar | Radiolocation | F |
Associated Files:
This Arecibo radar image in delay-Doppler coordinates of the south pole region of the Moon was made at Arecibo in a search for ice in permanently shadowed areas. It is 400 km in each coordinate and the original image has a resolution of 500 m in delay (vertical) and 580 m in Doppler (horizontal). The illumination is from the top (so range increases downward), and increasing Doppler frequency is towards the left. The approximate location of the south pole is indicated by the cross. The search was for the characteristic radar signature of ice, high backscatter cross section and high circular polarization ratio. No clear indication of ice was found, although a small number of areas with anomalous radar properties need further investigation. These lunar investigations were done by N. J. Stacy as part of his Cornell Ph.D. thesis.
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