NASA reports that on April 20, 2025, the Lucy probe sent to Jupiter made a close flyby of its second target, the asteroid Donaldjohanson. The flyby took place at a distance of about 1,000 km, which did not prevent Lucy’s cameras and instruments from obtaining stunning images of the object. It will take about a month to transmit all the collected information. In the meantime, NASA is providing an opportunity to get to know this peanut-shaped celestial body in general terms.
An artist’s rendering of NASA’s Lucy probe. Image Credit: NASA
Scientists had previously suspected that the asteroid Donaldjohanson, named after the archaeologist who discovered one of the human ancestors, might be a contact asteroid – that is, made up of two asteroids stuck together. The first images from Lucy confirmed this hypothesis, unless the asteroid was formed by some rarer and stranger process. It also turned out to be longer than previously thought: its length is about 8 km, and its width at its widest point is 3.5 km.
Observations have shown that the asteroid rotates slowly on its axis. It is a main-belt object between Mars and Jupiter. This is the second object studied by the Lucy probe on its way to its main scientific goal – Jupiter’s Trojan asteroids. Before that, the probe flew past the small asteroid Dinkinesh and also collected enough valuable data to improve our knowledge of asteroids and the evolution of the solar system.
Image of asteroid donaldjohanson
The entire Lucy mission is a kind of cosmic archaeology. The probe is heading to the Jupiter system to the so-called Trojan asteroids – ancient rocky bodies “stuck” at the Lagrange points of the gas giant’s orbit since the birth of the solar system. Lucy will study their composition and shapes to get an idea of the “primordial matter” from which everything in our system, including humanity, was formed.
The probe will arrive at the first Trojan in the summer of 2027 and will visit about a dozen Trojan asteroids by 2033. The visits to asteroids Dinkinesh and Donaldjohanson were a kind of “reconnaissance in force” for the probe’s scientific equipment and the NASA engineering team. The device, which cost about $1 billion, has already demonstrated outstanding capabilities in collecting scientific data and promises many discoveries upon arrival in the Jupiter system.