An illustration depicts NASA's Lucy spacecraft as its solar arrays unfold in space. Image courtesy of NASA
ORLANDO, Fla., Oct. 15 (UPI) -- One of the most complicated space journeys ever planned, NASA's Lucy mission to eight asteroids, is scheduled for liftoff early Saturday from Florida.
United Launch Alliance plans to launch the probe on its multibillion-mile trek during a 75-minute launch window starting at 5:34 a.m. EDT. The Atlas V rocket is to lift off from Complex 41 at Cape Canaveral Space Force Station.
Lucy will unfurl giant solar arrays 24 feet in diameter about one hour after launch. And it will circle the sun near Earth for three years to use the planet's gravity in two speed boosts to eventually spiral out through the solar system.
Lucy will fly by more asteroids than any other mission, according to the lead science organization for the project, the Southwest Research Institute in Texas.
The goal, according to NASA, is to learn about the mysterious dark Trojan asteroids that travel ahead and behind Jupiter in its orbit about 400 million miles from Earth's orbit. The space agency believes the Trojans date to the beginning of the solar system.
"We've learned that the Trojans are not related to Jupiter and its moons, except that they were captured by Jupiter's gravity," Keith Noll, NASA Lucy project scientist, said in a press conference broadcast Thursday from nearby Kennedy Space Center.
"So, the goal of Lucy is really to try to understand how and where the Trojans came from, but we're pretty sure it's not from anywhere near Jupiter," Noll said.
Lucy will send back data and photos of the asteroids, said Jessica Lounsbury, a Lucy project systems engineer for NASA.
"Those images come in black and white and color," she said. "We'll also see temperature data and mapping of the surface, and so we'll really be able to understand the geology, the surface properties of these asteroids."
NASA selected the 12-year mission in 2017 and has spent about $981 million on it.
Lockheed Martin built the spacecraft, while the company's mission architect, Brian Sutter, designed the trajectory. He's helped plot the course of other missions since Lockheed built the Mars Odyssey Orbiter that was launched in 2001.
"When they asked me to plot a course to study Trojan asteroids, it was like someone dumped a jigsaw puzzle on my desk with thousands of pieces because there are 5,000 Trojans," Sutter said.
He said he asked mission directors to narrow down the list to the best targets, and wound up with 20 asteroids, some of which are slightly reddish and some gray.
He used a simple numbers spreadsheet, Microsoft Excel, to plot the position and movement of the Trojans and determine how a spacecraft could visit several of them.
"At first, they thought maybe we can study two asteroids, and I thought maybe if I'm lucky, I can double that number and we could do four," Sutter said. "We wound up with eight."
The mission takes its name from the fossilized human Lucy skeleton found in Africa in 1974 that provided unique insight into humanity's evolution, according to NASA. The skeleton was named Lucy because teams of excavators at the discovery site routinely played the Beatles' tune, Lucy in the Sky with Diamonds.
Like the skeleton, the Lucy mission is geared to revolutionize knowledge of the past and formation of the solar system, according to NASA's mission profile.
One of the asteroids on the mission was named after the American paleoanthropologist Donald Johanson, one of two men who found the Lucy fossil in Ethiopia.
Lucy also will visit two binary asteroid systems, which actually are dual asteroids that circle each other -- Eurybates and Patroclus.
"I think the thing that we're certain about is that we'll be surprised," said Phil Christensen, a principal investigator on the mission from Arizona State University. "The excitement is we're exploring."
The International Space Station is pictured from the SpaceX Crew Dragon Endeavour during a flyaround of the orbiting lab that took place following its undocking from the Harmony module’s space-facing port on November 8. Photo courtesy of NASA