No, it’s not some 60s bubblegum group, not a comic book adventure, Lucy is a mission of scientific exploration. Starting her journey on October 16, 2021, Lucy perched atop an Atlas V as it roared away from Earth. Lucy’s mission, chase and catch some asteroids, then study them. That’s the gist, and that seems a worthy mission, but there’s more.
Lucy is the thirteenth mission of NASA’s Discovery program, started in 1992. The Discovery program began as a way to fly more missions and achieve good science from missions that have fewer but more focused objectives, at lower cost. Discovery also stimulates innovation as project scientists and engineers overcome challenges inherent in lower cost projects.
So, the plan is for Lucy to do good science by studying asteroids, eight to be exact! That seems a lot of big, spaced-out rocks to catch up with. These asteroids represent what astronomers think are some of our solar systems earliest objects. The plan is to find out more about our solar system’s origins by studying these Asteroids. You might ask, what makes them so “special”? Seven of the asteroids are not members of the main asteroid belt located between the orbits of Mars and Jupiter. They are found in the same orbit as Jupiter! Some travel ahead and some travel behind Jupiter in its orbit around the Sun. The asteroids of interest occupy two stable spaces, Lagrange 4 and Lagrange 5 (see my recent article about the James Webb for Lagrange explanations).
They are called Trojan asteroids. Why Trojan? It’s not a complete connection to the Trojans of Greek Mythology. Rather it comes from Vienna astronomer Johann Palisa’s suggestion to name these asteroids after Greek heroes of the mythical Trojan War. He was the first to accurately determine some trojan orbits. I don’t know how many heroes there were, but there are likely more than 500,000 trojans riding in Jupiter’s orbit. The magic of trojans is they are thought to consist of our solar system’s primordial materials. A window into our solar system’s past. This makes for a great Discovery class mission!
Lucy’s travelogue itself is an adventure. Even her name evokes awe. Lucy is named after the 3.2-million-year-old remains of early human origin, found in Ethiopia in 1974. Maybe she will be studying the preserved remains of an early planet forming epoch. Because the trojans exist in two distinct and very distant swarms, and Lucy is to study a main belt asteroid too, Lucy will use Earth’s mass to get several gravity boosts, ending up in three very different places, over a 12-year period.
Just heard, a glitch with one of Lucy’s solar arrays has occurred but the team is confident it will not jeopardize her mission. Hope so.
What’s in the Sky?
Early risers – get a glimpse of Mercury – put the coffee on.
October 25; pre-dawn; east: Mercury gets a little above the horizon before old Sol butts in.