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NASA has tested the functions of Lucy, the agency’s first spacecraft to study Jupiter’s Trojan asteroids, filled it with fuel, and is preparing to pack it into a capsule for launch Saturday, October 16, 2021. Named after characters in Greek mythology, these asteroids circle the Sun in two swarms, with one group leading ahead of Jupiter in its path, the other trailing behind it. Lucy will be the first spacecraft to visit these asteroids. By studying these asteroids up close, scientists hope to hone their theories on how our solar system’s planets formed 4.5 billion years ago and why they...

The South Pole of the Moon. (NASA GSFC Scientific Visualisation Studio) =========================================================================== A distant asteroid trailing in the gravitational wake of Mars has been observed in greater detail than ever before, and the close-up reveals a surprising resemblance – one that raises some interesting questions about the object's ancient origins. The asteroid in question, called (101429) 1998 VF31, is part of a group of trojan asteroids sharing the orbit of Mars. Trojans are celestial bodies that fall into gravitationally balanced regions of space in the vicinity of other planets, located 60 degrees in front of and behind the planet. Most...

Lucy team members presented the completed mission design, showing that they have met all the technical challenges of the mission and were ready to start building the actual hardware. At Lockheed Martin in Colorado over the course of four days, an independent review board, comprised of reviewers from NASA and several external organizations, heard all about the mission design. The Trojan asteroids orbit the Sun at a distance of Jupiter. The mission is set to launch in October 2021; with boosts from Earth's gravity, the spacecraft is expected to complete a 12-year journey to seven different asteroids.

…[S]ientists have discovered enough planets around other stars to offer a clearer picture of the average solar system, and to reveal the ways in which our own solar system is really weird. For instance, most systems have gas giant planets, but those "hot Jupiters" tend to orbit very close to their host stars. That makes our solar system an outlier. All our system’s gas giants orbit in the outer solar system, while the inner region is reserved for rocky planets like our own. But according to a new simulation, our home system is even weirder than we thought. One of...

In 2008, a group of astronomers led by Alex Parker did a study of the size distribution of asteroid families using data from the Sloan Digital Sky Survey. Asteroid families often have distinctive optical colors, the team said, and they were able to offer an improved way to separate out the family members into their colors. This resultant animation put together just this week by Parker shows the orbital motions of over 100,000 asteroids, with colors illustrating the compositional diversity and relative sizes of the asteroids. All main-belt asteroids and Trojan asteroids with orbits known to high precision are shown...