October 1, 2019 — A Southwest Research Institute scientist is helping NASA observe and characterize near-Earth objects (NEOs) that could pose a threat to Earth or have potential for further exploration. SwRI’s Dr. Tracy Becker is part of an international team of scientists who will use the Arecibo Observatory in Puerto Rico to study nearby asteroids and comets through a $19 million grant managed by the University of Central Florida (UCF).
“We are going to be looking at the trajectory, spin, shape, mass, composition and size of NEOS, which allows us to look forward in time and understand if they pose a future impact risk to Earth,” said Becker, a co-investigator on the project. “The idea is that if an impact hazard is discovered far enough in advance, you can potentially avert that risk, perhaps by nudging the asteroid’s orbit to a safer distance.”
NEOs are discovered with conventional telescopes that image light reflecting off the bodies. Arecibo is home to one of the most powerful and sensitive radio telescopes in the world, a unique tool for then characterizing these relatively small objects. The active radar system is designed to emit a radio signal towards its target and then receive the reflected radio waves using parabolic dishes. Getting the more specific information requires radio telescopes to consider the Doppler effects produced as the objects travel past the Earth.
“Doppler radar systems are commonly used by police to identify speeders or by meteorologists to track weather,” Becker explained. “An example of the Doppler effect is the change in pitch of an ambulance siren as it approaches and then passes by. Using radar, we can learn all sorts of things about passing objects in space by studying these changes in wavelength.”
While a summer intern at Arecibo and then a graduate student at UCF, Becker created computer models of the NEO called 2001 SN263, an asteroid with two smaller satellites, which was also the first triple near-Earth asteroid ever discovered. In 2005, Congress prioritized this type of research, directing NASA to find and characterize at least 90 percent of near-Earth objects larger than 140 meters by 2020. These are objects about 50 percent larger than a football field.
“The data are also significant for identifying asteroids that may be of interest for future exploration,” said Becker. “For example, Arecibo did a great job of characterizing asteroid Bennu, data critical to NASA’s OSIRIS-REx mission, which will collect a sample from the asteroid’s surface next year. There’s even interest in mining useful resources available on these objects, but we have to know a lot more about them.”
UCF manages the Arecibo Observatory on behalf of NSF. The NASA grant will be used for operations, maintenance and upgrades to the radar system that directly relate to the Arecibo Planetary Radar Group, which leads this work. The international team will spend up to 800 hours a year analyzing NEOs during the four-year grant period.