JPL Scientists Plan for Arrival of Asteroid Due for a Near-Miss Earth Flyby

Published : Thursday, May 2, 2019 | 11:27 AM

This animation shows the distance between the Apophis asteroid and Earth at the time of the asteroid’s closest approach. The blue dots are the many man-made satellites that orbit our planet, and the pink represents the International Space Station. Credit: NASA/JPL-Caltech

Scientists from Jet Propulsion Laboratory took the lead at discussions this week at the 2019 Planetary Defense Conference in Maryland about a 1,100-foot-wide asteroid that will hurtle by Earth in a near-miss flyby in 2019.

“The Apophis close approach in 2029 will be an incredible opportunity for science,” Marina Brozovi?, a radar scientist at NASA’s Jet Propulsion Laboratory in Pasadena, said. “We’ll observe the asteroid with both optical and radar telescopes. With radar observations, we might be able to see surface details that are only a few meters in size.”

The Apophis asteroid is expected to cruise harmlessly by Earth about 19,000 miles above the planet’s surface, on April 13, 2029.

That’s about as close as some of the spacecraft or satellites that now orbit the Earth are, NASA said in a news release Monday. And the international asteroid research community is excited.

The asteroid, Apophis, was discovered by a team of astronomers at the Kitt Peak National Observatory in June 2004. The team was able to detect Apophis for two days before technical and weather issues prevented further observations.

Luckily, another team rediscovered also the asteroid at the Siding Spring Survey in Australia later that year. The observations caused quite a stir when initial orbital calculations revealed that the asteroid had a 2.7 percent chance of impacting Earth in 2029. Fortunately, additional observations refined the orbit and completely ruled out that possibility.

The most important observations of the asteroid will occur in 2029, when asteroid scientists around the world will have an opportunity to conduct a close-up study of the Apophis’ size, shape, composition, and possibly even its interior.

At the Planetary Defense Conference in College Park, scientists gathered to discuss observation plans and science opportunities for the celestial event although it’s still a decade away.

Tuesday’s session on Apophis engaged scientists to discuss everything from how to observe the event, to possible hypothetical missions NASA and other space agencies could send out to the asteroid.

Questions about how Earth’s gravity could affect the asteroid as it passes by, whether they could learn about an asteroid’s interior during the flyby, and whether sending a spacecraft mission to Apophis would be feasible were asked.

“We already know that the close encounter with Earth will change Apophis’ orbit, but our models also show the close approach could change the way this asteroid spins, and it is possible that there will be some surface changes, like small avalanches,” said Davide Farnocchia, an astronomer at JPL’s Center for Near-Earth Object Studies (CNEOS), who co-chaired the April 30 session on Apophis with Brozovi?.

Apophis, looking like a moving star-like point of light, will first become visible to the naked eye in the night sky over the southern hemisphere, flying above Earth from the east coast to the west coast of Australia. It will be mid-morning on the U.S. East Coast when the asteroid is above Australia. It will then cross the Indian Ocean, and by the afternoon in the eastern U.S. it will have crossed the equator, still moving west, above Africa.

At closest approach, just before 6 p.m. Eastern, Apophis will be over the Atlantic Ocean – and it will move so fast that it will cross the Atlantic in just an hour. By 7 p.m. Eastern, the asteroid will have crossed over the continental U.S.

“Apophis is a representative of about 2,000 currently known Potentially Hazardous Asteroids (PHAs),” Paul Chodas, Director of JPL’s CNEOS, said. “By observing Apophis during its 2029 flyby, we will gain important scientific knowledge that could one day be used for planetary defense.”






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