NASA’s Lucy mission prepares to fly over Trojan asteroids


The Lucie mission derives its nickname from the fossilized partial skeleton of an ancient human ancestor, Australopithecus afarensis, discovered in 1974, which changed ideas about the origins and evolution of man. The research team hopes this spacecraft will do for planetary science what this skeleton did for paleoanthropology, giving us insight into the formation and evolution of our solar system.

At the very beginning of the solar system, debris gravitated in a crushed disc around a young Sun. Pieces and grains of material stuck together, snowballed and matured into the tidy planets we see today. Asteroids are essentially the discard pile of this process. “These are the remnants of that very ancient time before there were planets,” says Tom Statler, the scientist in the Lucy program at NASA.

He compares the study of asteroids to research of the pyramids – if the pyramids, in this metaphor, are Jupiter, Saturn, Uranus and Neptune, and the Trojan asteroids are the material from which they were built. You can only learn a lot about how these great structures arose out of the finished triangular product. Find the abandoned construction area and you can deduce a lot more about their genesis. “The objects that eventually became Trojans formed all over the outer solar system and were transported and trapped where they are now,” says Statler. “The Trojans are among the remains that were swept up and left there. “

And even though our own planet is rocky and not a gas giant, studying the outer planets will give us information on how it formed. “It has become increasingly clear that no planet develops in isolation,” says Statler. “The Earth is as it is because the solar system is as it is … To understand Earth, we have to understand how other planets formed and developed.”

Lucy will rely on three main instruments: L’LORRI, L’TES and L’Ralph. The “L” prefix indicates that they are part of the Lucy mission, as they are each based on devices that have previously flown. LORRI and Ralph were instruments aboard the New Horizons mission to Pluto and the Kuiper Belt. “L’ORRI” then means “Lucy Lorri”, explains Michael Vincent, deputy director of the space operations department at the Southwest Research Institute. OTES was part of the OSIRIS-REx Spaceship To Bennu asteroid, and it came in part from an instrument called TES, which had previously flown on the Mars Global Surveyor spacecraft. “The devil we knew is what we wanted to stick with,” says Vincent. (Also, one of the scientists on the mission is of French origin and, jokes Vincent, “was trying to classify the place.”)

The LORRI is essentially a sophisticated camera, precise enough to take clear photos of craters 200 feet from 600 miles away, mapping them to reveal the history of an asteroid. He can also search for rings and satellites and will help Lucy navigate to asteroids. After all, choosing which distant point to aim for isn’t easy. “These things aren’t huge there, and we’re going to go our separate ways,” says Vincent.

The TES works much like those non-contact thermometers you may be familiar with from Covid-19 screens, but instead of aiming at a forehead, the instrument points to a location on an asteroid and takes its temperature by detecting infrared radiation. coming from it. “Over time, you kind of build a big picture by sweeping across different surfaces,” says Vincent. Their goal is to measure “thermal inertia,” or the rate at which parts of the asteroid heat up or cool down, an indicator of the materials it is made of. Sand, for example, retains heat differently from rock, which you might have noticed if you’ve ever taken a long stroll on the beach at sunset.



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