Radio Transmissions Seek to Measure Asteroid

An experiment conducted in Alaska used long-wavelength radio transmissions to hopefully map the mass distribution of a potentially hazardous asteroid.

IMAGE: A frosty landscape surrounds antennas at the High-frequency Active Auroral Research Program site in Gakona, Alaska, on Dec. 20, 2022. CREDIT: UAF/GI photo by JR Ancheta

From the high peaks of the Andes to the deep cold of the Arctic and Antarctic, space science happens in some amazing locales. The dry air, often clear skies, lack of surrounding buildings, and little light pollution help with any number of observations. Last week, one particular experiment wrapped up for the High-frequency Active Auroral Research Program, or HAARP, located in Gakona, Alaska.

Using a powerful transmitter, the experiment sent long wavelength radio waves into space for twelve hours, targeting a small asteroid cataloged as 2010 XC15. Discovered by the Catalina Sky Survey back in 2010, this asteroid is about 150 meters across and is considered a potentially hazardous object as its orbit is mostly within the orbit of Earth. On December 27, 2022, 2010 XC15 passed by our planet at about two lunar distances, allowing the HAARP team to use radio waves to observe the small body during that close approach.

While most programs use optical and radar telescopes to collect data about the orbits and shapes of asteroids, as well as somewhat image their surfaces, these observations use short wavelengths that simply bounce off the surface, providing little to no information about the interiors. The long wavelengths transmitted by HAARP, on the other hand, are capable of penetrating the surface and providing information about the characteristics such as density, similar to how ground-penetrating radar works here on Earth to detect anomalies underground.

HAARP sent the signals up to 2010 XC15, and two radio arrays received the return signals: the University of New Mexico’s Long Wavelength Array and the Owens Valley Radio Observatory Long Wavelength Array near Bishop, California. However, the results are pending, as lead investigator Mark Haynes notes: We will be analyzing the data over the next few weeks and hope to publish the results in the coming months.