Lucy's mission is on a 12-year journey to explore a unique set of asteroids that lead and follow Jupiter around the sun. As it heads to these Trojan asteroids, the probe is preparing to stop for the second stop on the main belt, approaching the mysterious space rock to practice the main event.
NASA's Lucy spacecraft will fly over the small asteroid Donaldjohanson at 1:51 pm ET on April 20, when it will be 596 miles (960 km) from its target. This is Lucy's second encounter with the asteroid, but it's much more complicated than the first flight, which NASA describes as “a comprehensive dress rehearsal for Lucy's main mission.”
Lucy first placed his robotic eyes on Donaldjohanson in February and has been tracking the asteroid for the past two months in preparation for its flight. Donaldjohanson, named after the discoverer of Lucy's human fossils, is a carbonaceous asteroid about 2.5 miles (4 kilometers) wide. The asteroid is the debris of a collision that took place about 150 million years ago, making it one of the youngest major asteroids ever visited by the spacecraft.
Although it is not a Trojan asteroid, it is located conveniently where Lucy swings on his way to the Jovian system. The upcoming Flyby will provide the team with the opportunity to test the Lucy system and use all three scientific tools of the spacecraft to observe.
The spacecraft will be directed within 30 minutes before it approaches to track the asteroid. During this time, the high-generated antenna of Lucy used to communicate with ground control will be turned away from the earth to pause communication. During the remaining flight, Lucy will spin herself autonomously, using its terminal tracking system to keep Donaldjohanson observing. Lucy will then use his scientific instruments to perform observation sequences of asteroids with observation sequences that will be performed once it reaches the Trojan.
However, before approaching the approach closest to the asteroid, Lucy will stop tracking Donaldjohanson to protect its sensitive instrument from intense sunlight. “If you sit on an asteroid and watch the Lucy spacecraft approach, you will have to keep your eyes shut and stare at the sun while waiting for Lucy to stand out from the glare. Statement. “These instruments are designed to photograph objects 25 times dimly illuminated by the sun, so looking towards the sun could damage our cameras.” ”
After its closest approach, the spacecraft will redirect its solar array toward the sun. It will re-establish communication with the Earth about an hour after the flight, hoping to return to all the valuable data collected. However, considering how far Lucy is from Earth, the team really has to be patient, so the process will take several days.
“One of the weird things that wrap our brains with these deep space missions is how slow the speed of light is,” Vincent said. “Lucy is 12.5 minutes from Earth, which means that any signal we send takes so long to get to the spacecraft. Then, it takes another 12.5 minutes to get Lucy's response, telling us that we're hearing our voice. So when we command data to play after the nearest approach, we ask for 25 minutes to see the image before we can get the image to the ground.”
Lucy launched in October 2021 and launched the flyover of the small belted asteroid Dinkinesh in November 2023. The mission's first asteroid encounter is much more meaningful than initially expected, as a brief conjunction reveals a pair of binary pairs, discovering a tiny satellite's spinning dinkinesh at close range.
The main focus of the mission is to study Trojan asteroids, a group of rocky corpses leading and following Jupiter as they orbit the sun. Lucy will begin access to the Trojan asteroid by visiting Eurybates and its binary partner Queta, followed by Polymele and its binary partners Leucus, Orus, and the binary pair Patroclus and Menoetius.
“Every asteroid has a different story to tell, and these stories are woven together to portray the history of our solar system,” Tom Statler, a scientist at NASA's Lucy Mission Program, said in a statement. “The fact that every new asteroid we visited will knock down socks means we only start to understand the depth and richness of history. Telescopic observations show that Donaldjohanson will have an interesting story that I totally expect to be surprised.”
