HAARP's low-frequency radio signals could be a vital tool for planetary defense

Scientists fired 9.6 million low-frequency radio signals at an asteroid for 12 hours.
Chris Young
The High-frequency Active Auroral Research Program site.
The High-frequency Active Auroral Research Program site.

HAARP 

NASA and the High-frequency Active Auroral Research Program (HAARP) successfully shot long wavelength radio signals at an asteroid last week, December 27, in a bid to learn more about the near-Earth object.

HAARP, which is part-funded by the U.S. Air Force, is a powerful high-frequency transmitter based in Alaska. As per a press release, NASA turned to the project with its proposal due to the fact that the target asteroid was making a near approach to Earth.

As asteroid 2010 XC15 came within two lunar distances of Earth, NASA and HAARP fired off a series of long-wavelength radio signals that bounced off the roughly 500-foot-diameter asteroid.

By analyzing the data that bounced back, they hope they can glean vital information about near-Earth asteroids and boost humanity's planetary defense capacities.

A new addition to the planetary defense arsenal

The results of NASA and HAARP's experiments could aid in an ongoing effort to bolster planetary defense technologies. Last year, for example, NASA's DART spacecraft slammed into an asteroid and successfully altered its trajectory. While long wavelength radio signals, like the ones fired by HAARP, aren't going to alter the course of a space rock, they could help to glean vital information.

"We will be analyzing the data over the next few weeks and hope to publish the results in the coming months,” explained Mark Haynes, lead investigator on the project and a radar systems engineer at NASA’s Jet Propulsion Laboratory in Southern California. "This experiment was the first time an asteroid observation was attempted at such low frequencies."

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"This shows the value of HAARP as a potential future research tool for the study of near-Earth objects," he continued.

Why probe an asteroid at such low frequencies?

NASA catalogs and analyzes asteroids via several instruments and methods, including the planetary radar of the Deep Space Network antennas based in the U.S., Spain, and Australia. However, radar imaging doesn't provide information about the interior of an asteroid.

Radar uses short-wavelength signals that provide high-quality surface images but don't penetrate space rocks. Long-wavelength radio signals, such as the ones emitted by HAARP, can reveal information regarding the interior of a distant asteroid.

Last week, on December 27, HAARP transmitted over 9.6 million long wavelength signals over the course of 12 hours with the help of three powerful generators. The data analysis of the signals is now expected to take several weeks, after which the scientists behind the project are expected to publish their findings.

Safeguarding the planet with low-frequency radio signals

Ultimately, knowing the interior composition of an asteroid can help to determine the best planetary defense strategy in the case that a massive space rock was headed toward Earth. According to Haynes, knowing the distribution of mass within an asteroid could help scientists to build an adequate craft, similar to NASA's DART, for deflecting the asteroid away from Earth.

In 2029, in fact, an asteroid called Apophis will make a close approach to Earth. It will come within about 20,000 miles of Earth, bringing it closer than many of the world's geostationary satellites. The asteroid is about 1,100 feet across, and it could potentially be on a collision course from Earth some hundred or so years from now. During that close approach, on April 13, 2029, scientists aim to carry out low-frequency readings to determine the interior composition of the asteroid.

It is, after all, better to be overprepared in the face of a potentially civilization-ending asteroid impact.