NASA Shows Off Trick to Defend Earth Against Asteroids

This is a collection of images from the WISE spacecraft of the asteroid 2305 King, which is named after Martin Luther King Jr. The asteroid appears as a string of orange dots because this is a set of exposures that have been added together to show its motion across the sky. These infrared pictures have been color-coded so that we can perceive them with the human eye: 3.4 microns is represented as blue; 4.6 microns is green, 12 microns is yellow, and 22 microns is shown as red. From the WISE data, we can compute that the asteroid is about 12.7 kilometers in diameter, with a 22% reflectivity, indicating a likely stony composition. (NASA)

DENVER (CN) – NASA trotted out advancements made by its Planetary Defense Coordination Office on Tuesday aimed at identifying near-Earth objects to help the planet prepare to defend itself against asteroid impacts.

“If we find an object only a few days from impact, it greatly limits our choices, so in our search efforts we’ve focused on finding near-Earth objects when they are further away from Earth, providing the maximum amount of time and opening up a wider range of mitigation possibilities,” said Amy Mainzer, a principal investigator of NASA’s asteroid-hunting mission at the Jet Propulsion Laboratory in Pasadena, California.

Mainzer presented research on identifying near-Earth objects conducted by NASA’s Planetary Defense Coordination Office on Tuesday at the American Physical Society meeting in Denver.

The challenge, Mainer said, is in picking out faint black needles in a galactic haystack.

“NEOs are intrinsically faint because they are mostly really small and far away from us in space. Add to this the fact that some of them are as dark as printer toner, and trying to spot them against the black of space is very hard,” Mainer explained, using the acronym for near-Earth object.

Using a thermal infrared camera, researchers identify and characterize asteroids via heat signature rather than by relying on visual cues.

NASA has identified tens of thousands of near-Earth objects using a survey team, ground-based telescopes, and a Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) telescope, which is actually “a repurposed astrophysics spacecraft” originally built to last seven months and deployed in 2009. In addition to requiring ground-based follow-up surveying, Mainzer said, “frankly just like an old car, NEOWISE could break down at any time so every day is a gift.”

On average, the NASA identifies 30 new near-Earth asteroids each week, with more than 19,000 named. First NASA prioritized identifying “the dinosaur killers,” asteroids that are larger than a kilometer and would devastate life on Earth upon impact.

Next, the agency moved on to the next-largest class: asteroids larger than 140 meters, but smaller than a full kilometer. NASA has not found two-thirds of the asteroids in this class, and researchers estimate it will take decades to complete the survey with current technology.

NASA first proposed a NEOCam specially designed to detect near-Earth objects using a 50 cm telescope and two 16-megapixel focal planes in 2005. Its Planetary Defense Coordination Office provided funding in 2016 to carry out further study of the NEOCam project but the agency has not committed to building the mission at this time.

By studying more near-Earth objects and asteroids, Mainzer hopes to develop better defense strategies but also to gain a better understanding of the universe.

“We study them for a variety of reasons. We treat them as time capsules filled with primordial materials,” Mainzer said, adding that many are made of materials as old as the solar system. 

The Japan Aerospace Exploration Agency is also collecting asteroid samples from space – a sign Mainzer sees as demonstrating the protection of the planet is a global mission.

“International participation is key because asteroids don’t care about national boundaries,” she said.

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