Planetary Radar

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Planetary Radar studies the celestial bodies in our solar system: planets, moons, asteroids and comets. Directed by the 1000 foot reflector, a powerful beam of radio energy is transmitted in the direction of the target object. A very small portion of this energy is reflected by the target, back in the direction of earth. This weak radio echo is collected, focused and detected by the Arecibo Telescope. The signal is processed, then analyzed to yield information about the surface roughness, composition, size, shape, rotation and path of the target object. The Arecibo Radio Telescope has been used to measure the rotation rate of Mercury and to generate surface maps of large areas on Mercury, Venus and the Moon, locating mountain ranges, craters and rift valleys. The first detection of radar echo from a comet was made at Arecibo.

Science Group

The Planetary Radar Science group is a department of the Arecibo Observatory, which is an NSF facility operated under cooperative agreement by SRI International, Universities Space Research Association (USRA), and la Universidad Metropolitana (UMET). The Arecibo Observatory Planetary Radar program is fully funded through grants to USRA from NASA's Near-Earth Object Observations program (Grants NNX12AF24G and NNX13AQ46G). The Planetary Radar Science group is also partnered with the Center for Lunar Science and Exploration node (USRA-Lunar and Planetary Institute/NASA-Johnson Space Center) of the NASA Solar System Exploration Research Virtual Institute program.

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S-Band Spotlight

Arecibo Planetary Radar Returns to Action with Images of Asteroid Phaethon

Phaethon - Figure 1

    December 22, 2017

Columbia, MD and Puerto Rico: After several months of downtime in the aftermath of Hurricane Maria, the Arecibo Observatory Planetary Radar returned to normal operation providing the best images to date of near-Earth asteroid 3200 Phaethon, which is thought to be the parent body for the Geminids meteor shower. Radar images reveal Phaethon to be roughly spherical with a diameter of about 6 km (3.6 mi), roughly 1 km (0.6 mi) larger than previous estimates. Read More


Publications making use of Arecibo Observatory Data


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NOTE: Any opinions, findings, or recommendations expressed here do not necessarily reflect the views of the Arecibo Observatory, the National Science Foundation (NSF), the National Astronomy and Ionosphere Center (NAIC), the Universities Space Reseach Association (USRA), SRI International, Universidad Metropolitana (UMET), or the National Aeronautics and Space Administration (NASA). This website section is maintained by Dr. Edgard G. Rivera-Valentin.