The NASA Lucy spacecraft is all set to begin its 12-year journey to the Trojan asteroids in the orbit of Jupiter. Liftoff time is 5:34 a.m. ET Saturday morning from the Kennedy Space Center in Florida.
In this diary, we will provide a brief overview of the mission (there are plenty of good articles at NASA and popular media on the mission) and take a look at some interesting facts about the mission.
The Mission
The Lucy spacecraft will fly-by, image and analyze one main belt asteroid and seven Trojan asteroids. The main asteroid belt is a group of asteroids in orbit around the sun between Mars and Jupiter. The Trojans are small bodies that are remnants of our early solar system. They orbit the Sun in two loose groups: one group leading ahead of Jupiter in its orbit, the other trailing behind, in locations known as the L4 and L5 Lagrange points.
The following diagram shows the asteroids that Lucy will visit and the approximate date of the fly-by.
Here is an animation of Lucy’s twisting trajectory in a Jupiter-rotating reference frame.
The trajectory is in fact a normal ellipse if seen from a “fixed” frame — but it is still quite a complex trajectory requiring multiple-gravity assists from earth.
An overview of the mission —
The Team
Why visit these asteroids?
From lucy.swri.edu/… - Planet formation and evolution models suggest that the Trojan asteroids are likely remnant of the same primordial material that formed the outer planets, and thus serve as time capsules from the birth of our Solar System over 4 billion years ago. These primitive bodies hold vital clues to deciphering the history of our Solar System and may even tell us about the origins of organic materials—and even life—on Earth.
What’s in a name?
Lucy is named after the hominin skeleton named Lucy, the remarkably complete fossil of a female of the hominin species Australopithecus afarensis. Lucy was discovered in 1974 in Africa, at Hadar, a site in the Awash Valley of the Afar Triangle in Ethiopia, by paleoanthropologist Donald Johanson of the Cleveland Museum of Natural History. Lucy is believed to have lived about 3.2 million years ago. Lucy’s bone structure indicates that she normally moved by walking upright.
The first asteroid that Lucy will visit is named DonaldJohanson.
Lucy the Australopithecus herself was named after the 1967 Beatles song "Lucy in the Sky with Diamonds" which was played loudly and repeatedly in the expedition camp all evening after the excavation team's first day of work on the recovery site.
And so it is time for a musical break -
The name asteroid was introduced by astronomer Sir William Herschel, coined in Greek as ἀστεροειδής, or asteroeidēs, meaning 'star-like, star-shaped', and derived from the Ancient Greek ἀστήρ astēr 'star, planet'. en.wikipedia.org/...
The Plaque
Lucy carries a plaque that acts as a time capsule not for some unknown aliens, but for our own descendants in the distant future. From lucy.swri.edu/… -
After the mission is over, the Lucy spacecraft will remain on a stable orbit—travelling between the Earth and the Trojan asteroids for hundreds of thousands, if not millions, of years. It is not hard to imagine that some day in the distant future our descendants may retrieve the Lucy spacecraft as a relic of the early days of humanity’s exploration of the Solar System.
Therefore the spacecraft carries a plaque as a time capsule, including messages from prominent thinkers of our time and a diagram showing the positions of the planets on the date of Lucy’s launch.
It may be difficult to imagine humans millions of years from now, given our worries about the demise of the planet in a hundred years or less, but let’s keep in mind that Lucy the hominin lived 3.2 millions years ago, the earliest hominins appeared 7 million years ago, dinosaurs ruled the earth between 243 and 65 millions years ago, and cyanobacteria and oxygenic photosynthesis evolved on earth over 3 billion years ago. We have come a long way.
Let’s look at some of the messages on the plaque —
Dava Sobel (1947–) American writer and science journalist, whose messages were also included in the pioneer plaques —
We, the inquisitive people of Earth, sent this robot spacecraft to explore the pristine small bodies orbiting near the largest planet in our solar system. We sought to trace our own origins as far back as evidence allowed. Even as we looked to the ancient past, we thought ahead to the day you might recover this relic of our science.
Albert Einstein —
The important thing is not to stop questioning. Curiosity has its own reason for existence. One cannot help but be in awe when he contemplates the mysteries of eternity, of life, of the marvelous structure of reality. It is enough if one tries merely to comprehend a little of this mystery each day. Never lose a holy curiosity. Try not to become a man of success, but rather try to become a man of value. He is considered successful in our day who gets more out of life than he puts in. But a man of value will give more than he receives.
Carl Sagan —
Cutting off fundamental, curiosity-driven science is like eating the seed corn. We may have a little more to eat next winter but what will we plant so we and our children will have enough to get through the winters to come?
Louise Gluck (1943–) American poet and essayist awarded the 2020 Nobel Prize in Literature —
Above the fields, above the roofs of the village houses, the brilliance that made all life possible becomes the cold stars.
Lie still and watch: they give nothing but ask nothing.
Brian May —
Who Wants to live Forever? – if love must die.
John Lennon, who was the primary author of “Lucy in the Sky with Diamonds” —
We all shine on . . . like the moon and the stars and the sun.
Joy Harjo (1951–) Member of the Muscogee Nation and United States poet laureate, the first native American to receive that honor —
Remember the earth whose skin you are: red earth, black earth, yellow earth, white earth, brown earth, we are earth.
Remember the plants, trees, animal life who all have their tribes, their families, their histories, too.
Remember you are all people and all people are you. Remember you are this universe and this universe is you.
Remember.
Yoko Ono
A dream you dream alone is only a dream. A dream you dream together is reality.
Martin Luther King Jr —
We are not makers of history. We are made by history.
Sir Paul McCartney —
And in the end the love you take is equal to the love you make.
Sir Ringo Starr —
Peace and Love.
Charles Simic (1938–) Serbian American Poet, Pulitzer Prize winner for poetry and Poet Laureate Consultant in Poetry to the Library of Congress.
I’m writing to you from a world you’ll have a hard time imagining, to a world I can’t picture no matter how hard I try. Do you still have birds that wake you up in the morning with their singing and lovers who gaze at the stars trying to read in them the fate of their love? If you do, we’ll recognize one another.
Imagine for a moment our descendants finding this spacecraft, millions of years from now and reading these words — what will they think of us? Will they look upon us fondly, like we look at Lucy the Australopithecus or will they look down on us with disdain?
Epilogue
We wish Bon Voyage and happy trails to our little spacecraft Lucy, who will help us better understand the Universe, the formation of our solar system, the origins of life and hopefully will tell our story to our descendants millions of years from now.
References
- Lucy wiki page — en.wikipedia.org/…
- Lucy NASA home page — www.nasa.gov/…
- The Lucy Plaque — lucy.swri.edu/…
- Lucy website at Southwest Research Institute — lucy.swri.edu
- Trajectory Design of the Lucy Mission to Explore the Diversity of theJupiter Trojans — ntrs.nasa.gov/...
Launch webcast —
Updates
Successful launch -
Successful solar panel deployment. And now the long wait for the first asteroid fly-by in 2025.