NASA’s Goldstone Planetary Radar System recently spotted two near-Earth asteroids, 2024 MK and 2011 UL21, passing by our planet. Perhaps somewhat alarmingly, one was only detected 13 days before it was safely bypassed Earthbut NASA scientists Current drive laboratory (JPL) in Southern California assures that it was never a threat. Still, the images they were able to collect were extremely informative.
“There was no risk of any of the near-Earth objects hitting our planet, but the radar observations made during these two close approaches will provide valuable practice for planetary defenseas well as information about their sizes, orbits, rotation, surface details, and clues to their composition and formation,” the team wrote in a press release.
The Goldstone Solar System Radar is located in the desert near Barstow, California. With its 70-meter (230-foot-long) fully steerable antenna (DSS-14) – the world’s only fully steerable high-resolution ranging and imaging radar – it provides full-sky coverage and has been used to survey objects of interest within Solar System over the past three decades.
During that time it was possible to collect invaluable information about other planets, from Quicksilver on Saturnand supported a number of exploration missions such as the Mars Exploration Rovers, the Cassini Saturn Expedition, the Hayabusa Asteroid Explorers, SOHO recovery of the solar probe, Lunar Prospector and Venus– study Magellan’s Endeavour.
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As seen this week, it has also been used to monitor and study the near Earth asteroidshelps prevent potential impact hazards and identify targets for future reconnaissance missions. Radar is a powerful tool for studying the properties and orbits of asteroids—a ground station sends radio waves to asteroids and then receives the reflected signals back, which scientists can use to obtain relevant information. If the object’s “echo” is strong enough, radar imaging can achieve spatial resolution to identify objects as large as 10 meters (32 meters).
Hello asteroids; goodbye asteroids
On June 27, the radar system tracked asteroid 2011 UL21 as it made its way around Earth at a distance of 4.1 million miles (6.6 million kilometers). As its name suggests, the asteroid was famous NASA scientists since 2011, which were discovered during the Catalina Sky Survey in Tucson, Arizona.
About a mile wide (1.6 kilometers wide), the object was the first to come close enough to be picked up by Earth-based radar, allowing scientists to determine that it is roughly spherical in shape and that it is accompanied by its own “moon”. which orbits at a distance of about 1.9 miles (3 kilometers) from the asteroid.
“About two-thirds of asteroids of this size are thought to be binary systems, and their discovery is particularly important because we can use measurements of their relative positions to estimate their relative orbits, masses and densities, providing key information about how they may have formed.” said Lance Benner, a JPL principal scientist who helped lead the observations.
While NASA scientists say that due to its size, UL21 2011 has been classified as potentially dangerous, calculations of the asteroid’s orbit suggest that it will pose no real threat in the near future.
Just two days later, another asteroid appeared. The same team observed asteroid 2024 MK passing our planet at a distance of just 295,000 kilometers, a little over three-quarters of the distance between Moon and Earth. Close approaches like this are relatively rare, the team says, but they provide valuable insights that would otherwise be difficult to obtain.
“This was an extraordinary opportunity to explore the physical properties and obtain detailed images of a near-Earth asteroid,” Benner said.
2024 MK was first identified on June 16 by the Asteroid Impact Last Alert System (ATLAS) at the Sutherland Observatory in South Africa. “Its orbit was altered by Earth’s gravity as it passed by, shortening its 3.3-year orbital period around sun in about 24 days,” the team said in a release.
On June 29, scientists again sent radio waves to 2024 MK – but that time, received the return signal using Goldstone’s 114-foot (34-meter) DSS-13 antenna rather than the DSS-14. “This ‘bistatic’ radar observation produced a detailed image of the asteroid’s surface, revealing concavities, ridges and boulders about 30 feet (10 meters) wide,” they wrote.
About 500 feet (150 meters) wide, this asteroid appears elongated and angular, with prominent flat and rounded areas. Although it is also classified as a potentially dangerous asteroid, calculations of its future motion show that it does not pose a threat to our planet in the foreseeable future.