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This series of radar images obtained by the Deep Space Network's Goldstone Solar System Radar near Barstow, California, on Sept. 16, 2024, shows the near-Earth asteroid 2024 ON a day before its close approach with our planet. The asteroid passed Earth at a distance of 620,000 miles (1 million kilometers) – about 2.6 times the distance between the Moon and Earth.

Discovered by the NASA-funded Asteroid Terrestrial-impact Last Alert System (ATLAS) on Mauna Loa in Hawaii on July 27, the near-Earth asteroid's shape resembles that of a peanut. Like the asteroid 2024 JV33 that made close approach with Earth a month earlier, 2024 ON is likely a contact binary, with two rounded lobes separated by a pronounced neck, one lobe about 50% larger than the other. The radar images determined that it is about 1150 feet (350 meters) long. Features larger than 12.3 feet (3.75 meters) across can be seen on the surface. Bright radar spots on the asteroid's surface likely indicate large boulders. The images show about 90% of one rotation over the course of about six hours.

Radar is the principal technique for discovering contact binaries, dozens of which have been imaged by planetary radar. At least 14% of near-Earth asteroids larger than about 200 meters (660 feet) have a contact binary shape.

This asteroid is classified as potentially hazardous, but it does not pose a hazard to Earth for the foreseeable future. These Goldstone measurements have allowed scientists to greatly reduce the uncertainties in the asteroid's distance from Earth and in its future motion for many decades.

The Goldstone Solar System Radar Group is supported by NASA's Near-Earth Object Observations Program within the Planetary Defense Coordination Office at the agency's headquarters in Washington. Managed by NASA's Jet Propulsion Laboratory, the Deep Space Network receives programmatic oversight from Space Communications and Navigation program office within the Space Operations Mission Directorate, also at NASA Headquarters.

More information about planetary radar and near-Earth objects can be found at: https://www.jpl.nasa.gov/asteroid-watch