Pasadena's JPL is Part of First Successful International Asteroid Tracking Exercise

Published : Thursday, November 9, 2017 | 6:32 AM


2012 TC4's heliocentric orbit has changed due to the 2012 and 2017 close encounters with Earth. The cyan color shows the trajectory before the 2012 flyby, the magenta shows the trajectory after the 2012 flyby, and yellow shows the trajectory after the 2017 flyby. The orbital changes were primarily in semi-major axis and eccentricity, although there were also slight changes in the inclination. Credits: NASA/JPL-Caltech

An international team of astronomers led by NASA scientists has successfully completed the first exercise to test global response capabilities using a real asteroid, a NASA press release from the Jet Propulsion Laboratory (JPL) in Pasadena said Saturday.

According to the release, planning for the asteroid 2012 TC4 Observation Campaign started in April, with NASA’s Planetary Defense Coordination Office sponsoring. The goal was to recover, track, and characterize a real asteroid as a potential impactor, and to test the International Asteroid Warning Network (IAWN) for hazardous asteroid observations, modeling, prediction, and communication.

In late July, the exercise started in earnest, when the European Southern Observatory’s Very Large Telescope in northern Chile recovered the asteroid. The finale was a close approach to Earth on October 12, when 2012 TC4 safely passed Earth at a distance of only about 27,200 miles, or 43,780 kilometers above Earth’s surface.

In the months leading up to the flyby, astronomers from the U.S., Canada, Colombia, Germany, Israel, Italy, Japan, the Netherlands, Russia, and South Africa all tracked TC4 from ground- and space-based telescopes to study its orbit, shape, rotation, and composition.

“This campaign was an excellent test of a real threat case,” said Detlef Koschny, co-manager of the near-Earth object (NEO) segment in the European Space Agency (ESA)’s Space Situational Awareness program. “I learned that in many cases we are already well-prepared; communication and the openness of the community were fantastic.”

Koschny added he was personally was not prepared enough for the high response from the public and media, and that he was positively surprised by it.

“It shows that what we are doing is relevant,” Koschny said.

Boris Shustov, science director for the Institute of Astronomy at the Russian Academy of Sciences, said the 2012 TC4 campaign was a superb opportunity for researchers to cooperate internationally in addressing the potential hazard to the planet posed by near-Earth objects.

“I am pleased to see how scientists from different countries effectively and enthusiastically worked together toward a common goal, and that the Russian-Ukrainian observatory in Terskol was able to contribute to the effort,” Shustov said. “In the future, I am confident that such international observing campaigns will become common practice.”

With the observations collected during the campaign, scientists at NASA’s Center for Near-Earth Object Studies (CNEOS) at JPL were able to precisely calculate TC4’s orbit, predict its flyby distance, and look for any possibility of a future impact.

“The high-quality observations from optical and radar telescopes have enabled us to rule out any future impacts between the Earth and 2012 TC4,” said Davide Farnocchia from CNEOS, who led the orbit determination effort. “These observations also help us understand subtle effects such as solar radiation pressure that can gently nudge the orbit of small asteroids.”

Astronomers using NASA’s Goldstone Deep Space Network antenna in California and the National Radio Astronomy Observatory’s 330-foot Green Bank Telescope in West Virginia observed the asteroid’s shape and confirmed its composition.

“TC4 is a very elongated asteroid that’s about 50 feet (about 15 meters) long and roughly 25 feet wide,” said Marina Brozovic, a member of the asteroid radar team at JPL.

Due to adverse weather conditions, traditional NASA assets studying asteroid composition, such as the NASA Infrared Telescope Facility (IRTF) at the Mauna Kea Observatory in Hawaii, were unable to narrow down what TC4 was made of: either dark, carbon-rich, or bright igneous material.

Besides observing the asteroid’s movements, NASA also used this exercise to test communications between countries and internal government messaging, up through the executive branch and across agencies, as it would during an actual predicted impact emergency.

“We demonstrated that we could organize a large, worldwide observing campaign on a short timeline, and communicate results efficiently,” said Vishnu Reddy of the University of Arizona’s Lunar and Planetary Laboratory in Tucson, who led the observation campaign.

Michael Kelley, TC4 exercise lead at NASA Headquarters in Washington, added they are “much better prepared today to deal with the threat of a potentially hazardous asteroid than we were before the TC4 campaign.”

NASA’s Planetary Defense Coordination Office administers the Near-Earth Object Observations Program and is responsible for finding, tracking, and characterizing potentially hazardous asteroids and comets coming near Earth. It issues warnings about possible impacts, and assists coordination of U.S. government response planning, should there be an actual impact threat.

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