Hopkins astro scientists pursue “universal” truths

October 15, 2021 by Renee Fischer

APL launches DART mission; Krieger professor seeks Earth 2.0

Building on a history of contributions to space exploration — dating back to Henry A. Rowland in the 1880s — Johns Hopkins scientists continue to push boundaries by devising planetary defense tactics against asteroids and searching for planets with climates like Earth.

As mission systems engineer for the Double Asteroid Redirection Test (DART), Elena Adams of the Applied Physics Lab explains that DART is the first-ever effort to investigate whether kinetic impact can deflect an asteroid’s path.

Funded by NASA’s Planetary Defense Coordination Office, the mission involves launching a spacecraft this November and starting it on a trajectory to collide with Dimorphos, the smaller of two asteroids in the binary asteroid system called Didymos, to see if its orbit can be altered.

“DART will not hit an asteroid that’s actually coming towards Earth, but we are the first test of that kinetic impact technique,” Adams says. “And the threat is real,” she adds, citing an asteroid that hit Chelyabinsk, Russia, in 2013, which hospitalized more than 1,000 people.

The mission pulls in teams from both APL and NASA, who will be testing other innovations, including SMART Nav (Small-body Maneuvering Autonomous Real Time Navigation), an autonomous algorithm that enables the spacecraft to hit Didymos — even though it will be 6.8 million miles away from Earth when DART reaches it around September 2022.

“Johns Hopkins Applied Physics Lab is really the right institution to collaborate with NASA on this mission,” Adams says, referencing its work in the defense arena and its blended expertise in science and engineering. “And APL prides itself on making critical contributions to critical challenges.”

While scientists at APL are springing to the defense, David Sing and his team are on the offense, seeking to better understand planets outside our solar system known as exoplanets.

Like DART, Sing’s research is also intertwined with NASA, utilizing images captured by the Hubble Telescope — and soon NASA’s new James Webb Space Telescope — to employ spectrographic methodology.

“A planet will pass in front of a star, and some of the light from the star will pass through the atmosphere and leave a spectral fingerprint,” says Sing, a Bloomberg Distinguished Professor in the Krieger School of Arts and Sciences, with joint appointments in the Department of Physics and the Department of Earth and Planetary Sciences.

“Different atoms and molecules high in the atmosphere of a planet will then absorb light at very specific colors,” Sing explains, noting that this allows him to create such detailed models of these distant atmospheres.

With more than 4,000 exoplanets identified, this field has grown exponentially over the last decade, driven by the goal to find planets with atmospheres similar to that on Earth.

“So, we are looking in depth about which planets could be habitable. We basically want to find planets that are Earth-like, sort of an Earth 2.0,” Sing says.

“And being a Bloomberg Distinguished Professor has been pretty transformative, especially because it was designed from the beginning to be cross-disciplinary,” he adds, pointing out how the study of exoplanets combines classic astronomy techniques with knowledge of spectra and atmospheres.

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Topics: Alumni, APL, Bloomberg Distinguished Professor, Krieger School of Arts & Sciences, Applied Physics Laboratory, Krieger School of Arts and Sciences, Fuel Discovery