To Bennu and Beyond

By Dan Verderosa, July 9, 2019
IC physics students are helping NASA on a trailblazing asteroid mission.

Sitting at a computer in the University of Arizona’s Lunar and Planetary Laboratory in Tucson, Ithaca College student Robert Melikyan ’20 is just feet away from a priceless collection of meteorites. But his attention is focused squarely on his monitor, as he methodically scans photos of potential landing sites on a rock hurtling through space roughly 107 million miles from Earth.

Melikyan is one of three members of the IC community who have been working on NASA’s OSIRIS-REx mission, which aims to collect and return a sample from the surface of the asteroid Bennu. Recent graduate Salvatore Ferrone ’18 is working as a spectral mapping technician. Both found their way to Tucson after working as research assistants for Beth Ellen Clark, a professor in IC’s Department of Physics and Astronomy and OSIRIS-REx mission asteroid scientist.

Two young men looking at something

Robert Melikyan (standing) and Salvatore Ferrone working at the Lunar and Planetary Laboratory in Tucson, Arizona. (Photo provided)

To retrieve a sample from Bennu, the OSIRIS-REx spacecraft will maneuver perilously close to the 1,600-foot-wide asteroid, extending a special arm that will briefly touch and grab sediment from the surface. Before that can happen, the OSIRIS-REx team in Arizona must determine the best site to target, and safety comes first. If the spacecraft snatches rocks from the surface only to trip over a nearby boulder, the mission could end in disaster.

To avoid that outcome, Melikyan and a handful of team members are scouring photos of potential sample sites looking for any rocks measuring more than about eight inches across. It’s a painstaking task: on the images Melikyan is using, eight inches is equivalent to just four pixels. Each site is roughly 2,000-5,000 pixels, or 40-100 feet across.

“You can imagine that when you’re looking at pixels everything looks like a boulder or nothing,” said Melikyan. “It’s a totally meticulous task, but if it isn’t done it could make the craft trip. Like anyone walking on the sidewalk, if you hit the wrong step you’re going to fall over, and we can’t let that happen with our spacecraft.”

While Melikyan helps search for a safe site, Ferrone is helping the mission’s spectral analysis team learn about the mineral composition of Bennu and identify sites that will yield the most useful samples.

As a mapping technician, Ferrone builds computer software that plots spectral and other data onto the team’s shape model — a representation of Bennu’s surface based on radar data. He compares the resulting three-dimensional model to the graphics of a 22-year-old video game, Star Fox 64, which used rectangles and triangles to portray 3D characters and landscapes. “On the map that we use, the 3D shape is compiled the same way,” said Ferrone. “They approximate the surface of Bennu with a series of little triangles that we call facets.”

Ferrone’s software allows scientists to click on an individual facet and call up all the data the team has on it. Creating the program was no easy task. A physics major at IC, he took some computer coding classes, but didn’t have the computational skills he needed when he arrived in Arizona. So he found a textbook online and taught himself on the fly: “Here’s the book, pretend it’s lecturing to you, take notes, do the example problems and create little projects for yourself.”

Sample collection is anticipated to occur in summer 2020, and the OSIRIS-REx spacecraft is due to return to Earth in September 2023. Melikyan and Ferrone expect to keep busy until then. Melikyan will be working on his senior thesis, which focuses on the unexpected discovery of particles being ejected from Bennu’s surface. Ferrone plans on joining the U.S. Navy or Air Force, with the eventual goal of becoming an astronaut.