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NASA's Lucy mission is ready to launch and explore never-before-seen asteroids [cnn.com]:

NASA's Lucy mission is ready to launch and explore never-before-seen asteroids

Weather conditions will be 90% favorable on the morning of October 16, when the Lucy mission is set to leave Cape Canaveral Space Force Station at 5:34 a.m. ET. If it doesn't launch at that time, the window for liftoff remains open for 75 minutes.

Lucy will embark on a 12-year mission to explore Jupiter's Trojan asteroid swarms, which have never been observed. The Trojan asteroids, which borrow their name from Greek mythology, orbit the sun in two swarms -- one that's ahead of Jupiter, the largest planet in our solar system, and a second one that lags behind it.

So far, our only glimpses of the Trojans have been artist renderings or animations. Lucy will provide the first high-resolution images of what these asteroids look like.

Lucy is the first spacecraft designed to visit and observe these asteroids, which are remnants from the early days of our solar system. The mission will help researchers effectively peer back in time to learn how the solar system formed 4.5 billion years ago. Lucy's 12-year mission could also help scientists learn how our planets ended up in their current spots.

NASA's Lucy mission: 20 minutes of terror will define the next 12 years [cnet.com]:

On Saturday, NASA's Lucy spacecraft [cnet.com] will become the first-ever probe launched toward the Trojan asteroids, eons-old rocks trapped in Jupiter's orbit. These rocks are the fossilized building blocks of our solar system and may hold records of the giant planet's evolution.

But for Lucy to make history and ultimately unlock secrets of our corner of the universe, this weekend's liftoff must be flawless. Given the spacecraft's unique trajectory -- billions of miles will be covered over a dozen years by harnessing the power of the sun -- there are a few checkpoints poised to keep mission specialists on their toes.

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As outsiders, we usually only stare in astonishment as rockets launch, engulfed in flame and smoke. But there's much more to Lucy's success than just its fiery departure from Earth. I spoke with a NASA engineer and got the inside scoop on what milestones her team will be watching for during liftoff.

Read more: How to watch NASA's Lucy spacecraft launch live Saturday [cnet.com]

Here's the launch sequence from the eyes of NASA.

"When the rocket lifts off from the ground, that's very visual and exciting," said Emily Gramlich, a system integration and test engineer at Lockheed Martin and a Lucy mission specialist. "As the rocket ascends, we go through the atmosphere."

During that phase, Lucy will reach its maximum speed and pressure. "Then," Gramlich continued, "we have separation from the boosters and then the bearing will deploy and open us up to outer space."

Lucy's epic launch doesn't end there. Arguably the most crucial part of the launch pattern will be the unfurling of the spacecraft's two solar arrays after its 62-mile (100-km) journey up into space.

When fully open, the arrays together reach the height of a five-story building. "They are enormous," Gramlich said. It will take about 20 minutes to completely extend them from their origami-like folds.

They're so large because Jupiter's orbit, where Lucy is headed, is so far from the sun. And Lucy will need all the sun power it can get to travel those 530 million miles (853 million km).

"These 20 minutes will determine if the rest of the 12-year mission will be a success," NASA planetary scientist and principal investigator of the Lucy mission, Hal Levison, said in a statement [nasa.gov].

"Mars landers have their seven minutes of terror, we have this," he said.

After the solar arrays stretch out in their entirety, Lucy will have another vital task: It must adjust itself so the sun can shine onto all the solar panels that make up the two arrays. Without sun, the solar panels cannot provide power. Without power, the mission is over.

"Once we've done that," Gramlich said, "the spacecraft will then move itself a little bit more so that it can also point its antenna down at the Earth, so we can get our initial acquisition."

Let me repeat that last bit: "initial acquisition."That means every step up to that point is pre-programmed. That's right. No one will be controlling the spacecraft during its most crucial moments. Each precise movement has already been coded into its software.

"Lucy has been encapsulated since last week and so we have not seen it … other than through a small access window," Gramlich said. "The next time it will be open is out in outer space."

NASA engineers will just have to sit tight and keep their fingers crossed until Lucy finds its cosmic footing.

Lucy's bootcamp

You name it, Lucy's been through it. Several times.

"We do an acoustic test and a vibration test in a large building on the Waterton campus," said Gramlich referring to Lockheed Martin's testing grounds in Colorado. "We shake the spacecraft really hard and then we blast it with sound to simulate mostly the launch."

The most physically intense part of Lucy's 12-year journey, she said, will be the launch happening this weekend. Once it's in space, the situation will become much calmer. But space has its own extremes, so the team has tried to ensure that Lucy will be shielded from those, too.

"We take the spacecraft and put it into a giant thermal chamber and run it through all the temperature ranges that it is going to see in space -- hot and cold, light and no light," Gramlich said.

Lucy's complexities aren't only in regard to its mechanics. The software piloting the metal space explorer has a sizable number of integral components, like the computer, thermometer, cameras and battery. Each one had to be tested over and over again.

Gramlich explained one important device on Lucy is the star tracker [nasa.gov] that helps with navigation similar to how the north star aids in deducing what direction we're facing.

"We have extra ground support equipment to simulate the star that it might be seeing," she said. "And to rotate those stars and make sure that the star tracker detects that the stars [actually] rotated on its little simulator."

Once Lucy stabilizes and beyond

"I am beyond excited to see Lucy lift off on Saturday," Gramlich said. "We have been working towards this launch date for a long time, and there are a lot of long hours in the pandemic, and I have been just extra energetic for the last few weeks."

If all goes well on NASA's launch day on Saturday [cnet.com], Lucy will continue on toward the Trojan asteroids at about 39,000 mph (62,764 kph). It will use Earth's gravitational pull as leverage during the long journey and visit seven of the prized ancient rocks. It'll also make a pit stop on another world between Mars and Jupiter.

During the expedition, Gramlich said the team will check up on Lucy about once every two weeks to input commands based on newly discovered information, such as photographs and spectroscopic data, about the asteroids that Lucy sends back to Earth. Each command will take about 55 minutes to reach the craft, she said.

And after the mission wraps up next decade, the possibilities are endless.

"Our last flyby is in 2033," Gramlich said. "We will have done three Earth flybys by then, and have learned a lot about our trajectory and how to make it most efficient to continue exploring other asteroids."

Calling that an extended mission, Gramlich says Lucy's solar arrays can continue powering the spacecraft as it traverses through the solar system indefinitely. That means Lucy can theoretically continue sending information back about other forms of cosmic matter.

"The solar arrays that we have for Lucy are incredibly efficient and will allow us to operate the spacecraft for a long time," she said. "Even out at the distances of Jupiter. And the battery on board is also designed to be used and recharged."

But first, Lucy must get past its legendary launch.

"I am so honored that I was part of this team to see how much everybody cares and put into it," Gramlich said.

"We are just ready for a successful science mission to the Trojans."

NASA’s Lucy mission will soon be in the sky, with a launch set for Saturday [arstechnica.com]:

Less than five years have gone by since NASA selected the "Lucy" mission for development as part of its Discovery Mission program, and now the intriguing spacecraft is ready for launch.

The $981 million mission will fly an extremely complex trajectory over the span of a dozen years. The spacecraft will swing by Earth a total of three times for gravitational assists as it visits a main-belt asteroid, 52246 Donaldjohanson, and subsequently flies by eight Trojan asteroids that share Jupiter's orbit around the Sun.

The Lucy mission is scheduled to launch on Saturday at 5:34 am ET (09:34 UTC) from Cape Canaveral Space Force Station in Florida. An Atlas V rocket carrying the 1.5-ton spacecraft rolled to the launch pad on Thursday in advance of the launch attempt. The weather looks fine Saturday morning, with a 90 percent chance of favorable conditions. The launch will be covered live on NASA TV.

Lucy will fly by its first asteroid target in April 2025, a main-belt asteroid named after Donald Johanson, the American anthropologist who co-discovered the famed "Lucy" fossil in 1974. The fossil, of a female hominin species that lived about 3.2 million years ago, supported the evolutionary idea that bipedalism preceded an increase in brain size.

The Lucy asteroid mission, in turn, takes its name from the famed fossil. By visiting Trojan asteroids, scientists expect to glean information about the building blocks of the Solar System and better understand the nature of its planets today.

No probe has flown by these smallish Trojan asteroids, which are clustered at stable LaGrange points trailing and ahead of Jupiter's orbit 5.2 astronomical units from the Sun. The asteroids are mostly dark but may be covered with tholins, which are organic compounds that could provide raw materials for the basic chemicals of life.

"When we look at nature, whether it's looking at deep space or at these small objects, each one of these tells us a chapter of the story that we're all a part of," said NASA's science chief, Thomas Zurbuchen, during a media briefing this week in advance of the launch. "When you look at one of those planetary bodies and you add science, it turns into a history book."

So in some sense, the Lucy asteroid mission will be looking at fossil remnants of our early Solar System. To accomplish all of these fly-bys in a single mission, scientists and engineers this year devised a complex orbital track, which necessitated a launch this month.

This gave mission planners a short deadline to complete the Lucy project after NASA selected it in January 2017. Since that time, planners experienced a government shutdown, the COVID-19 pandemic, and supply chain issues. Through it all, NASA and the spacecraft's manufacturer, Lockheed Martin, have remained on schedule and within the mission's budget.

According to Donya Douglas-Bradshaw, Lucy project manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, the pandemic struck during a critical time period when the spacecraft was assembled with its four major scientific payloads. It took about 14 months to integrate the spacecraft bus with the instruments and verify that the craft could survive for a full 12-year mission in space. If Lucy is successful, the mission will travel farther on solar power than any previous spacecraft.

"I think the largest challenge in doing that certainly had to do with the pandemic," she said. "Obviously, when you're building hardware and integrating and testing it, there's a lot of hands-on, and so it was particularly challenging to build it and maintain the safety of the workforce."

But now, the spacecraft is buttoned up, and the rocket is ready to go. Somewhat ironically, although Lucy is visiting the "Jupiter trojans," it will never be closer to Jupiter than when it is on Earth. This is because the Trojans trail Jupiter at a greater distance than the distance that lies between Earth and the Solar System's largest planet.

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