NASA tracked two near-Earth asteroids and captured important data about their trajectories and physical characteristics using radar technology that supports ongoing planetary defense efforts. (Concept artist.) Credit: SciTechDaily.com
The Deep Space Network’s Goldstone Planetary Radar had a busy few days observing asteroids 2024 MK and 2011 UL21 as they safely passed Earth.
Researchers in NASAJet Propulsion Laboratory (JPL) in Southern California recently tracked two asteroids as they passed by our planet. One was shown to have a small moon orbiting it, while the other was discovered just 13 days before its closest approach to Earth.
Although there was no risk of any of the close objects impacting our planet, the radar observations made during these two close approaches will provide valuable practice for planetary defense, as well as information on their sizes, orbits, rotation, surface details and clues. on their composition and creation.
The Goldstone Solar System Radar, part of NASA’s Deep Space Network, made these observations of the recently discovered 500-foot-wide (150-meter-wide) asteroid 2024 MK at its closest approach—at a distance of about 295,000 kilometers. Earth – June 29. Credit: NASA/JPL-Caltech
Insights from the 2011 UL21 Asteroid Encounter
Asteroid 2011 UL21, which passed Earth on June 27 at a distance of 4.1 million miles (6.6 million kilometers), about 17 times the distance between the Moon and Earth, was discovered in 2011 by the NASA-funded Catalina Sky Survey in Tucson. Arizona. But this is the first time it has come close enough to Earth to be picked up by radar. While the nearly mile-wide (1.5 kilometer wide) object is classified as potentially hazardous, calculations of its future orbits show that it will not pose a threat to our planet anytime soon.
The Goldstone Solar System Radar (GSSR) is a large radar system used to investigate objects in the Solar System. Located in the desert near Barstow, California, it includes a 500kW X-band (8500MHz) transmitter and low-noise receiver on a 70m DSS 14 antenna at the Goldstone Deep Space Communications Complex. Credit: NASA
Using the 230-foot-wide (70-meter) Goldstone Solar System Radar, called Deep Space Station 14 (DSS-14), near Barstow, California, JPL scientists sent radio waves to the asteroid and received the reflected signals. same antenna. In addition to determining that the asteroid is roughly spherical, they discovered that it is a binary system: A smaller asteroid, or moon, orbits it from a distance of about 3 km.
“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, JPL principal scientist who helped lead the observations.
These seven radar observations from the Deep Space Network’s Goldstone Solar System Radar show the mile-wide asteroid 2011 UL21 during its close approach to Earth on June 27 from a distance of about 4 million miles. The asteroid and its small moon (the bright dot at the bottom of the image) are circled in white . Credit: NASA/JPL-Caltech
The second close approach
Two days later, on June 29, the same team observed asteroid 2024 MK pass our planet from a distance of just 184,000 miles (295,000 kilometers), a little more than three-quarters the distance between the Moon and Earth. About 500 feet (150 meters) wide, this asteroid appears elongated and angular, with prominent flat and rounded areas.
For these observations, the scientists also used DSS-14 to transmit radio waves to the object, but used Goldstone’s 114-foot (34-meter) DSS-13 antenna to receive the signal that bounced off the asteroid and returned to Earth. The result of this “bistatic” radar observation is a detailed image of the asteroid’s surface, revealing concavities, ridges and boulders about 30 feet (10 meters) wide.
Because close approaches to asteroids the size of 2024 MK are relatively rare, the JPL Planetary Radar team gathered as much information as possible about the near-Earth object. This mosaic shows the asteroid spinning in one-minute increments about 16 hours after its closest approach to Earth. Credit: NASA/JPL-Caltech
Close approaches to near-Earth objects the size of 2024 MK are relatively rare, occurring on average every few decades, so the JPL team tried to gather as much data as possible about the object. “This was an extraordinary opportunity to explore the physical properties and obtain detailed images of a near-Earth asteroid,” Benner said.
Observations from NASA’s Goldstone Solar System Radar, composited into this animation, show the falling asteroid 2024 MK shortly after it made its closest approach to our planet on June 29. The path of the 150-meter-wide asteroid was slightly altered by Earth’s gravity during the flyby. Credit: NASA/JPL-Caltech
Contributions to planetary defense
Asteroid 2024 MK was first reported on June 16 by the NASA-funded Asteroid Terrestrial-Impact Last Alert System (ATLAS) at the Sutherland Observing Station in South Africa. Its orbit was altered by Earth’s gravity during the flyby, shortening its 3.3-year orbital period around the Sun by about 24 days. Although it is 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.
The Goldstone Solar System Radar Group is supported by NASA’s Near-Earth Object Observing Program of the Planetary Defense Coordination Office at the agency’s headquarters in Washington. The Deep Space Network, managed by JPL, receives programmatic oversight from the Space Communications and Navigation Program Office within the Space Operations Mission Directorate, also at NASA Headquarters.