Science

NASA has solved the issues of the Lucy spacecraft, which was speaking with asteroids from hundreds of thousands of miles away

NASA Lucy Mission Solar Array Anomaly

Shortly after Lucy’s launch, one in all her photo voltaic arrays failed to completely function, placing the mission in danger. This artist idea animation depicts Lucy’s photo voltaic array anomaly. Credit score: NASA Goddard Area Flight Heart Idea Imaging Laboratory

after a profitable launch[{” attribute=””>NASA’s Lucy spacecraft on October 16, 2021, a group of engineers huddled around a long conference table in Titusville, Florida. Lucy was just mere hours into its 12-year journey, but a major unexpected challenge had surfaced for the first-ever Trojan asteroids mission.

Data indicated that one of Lucy’s solar arrays — designed to unfurl like a hand fan — hadn’t fully opened and latched. Since the solar arrays power the spacecraft’s systems, the team had to figure out what to do next.

To troubleshoot the problem, teams from NASA and Lucy mission partners quickly came together. Team members from Lockheed Martin’s Mission Support Area outside of Denver, who were in communication with the spacecraft directly, were on the phone.

Although the conversation was quiet, it was intense. At one end of the room, an engineer sat with furrowed brow, folding and unfolding a paper plate in the same way that Lucy’s enormous circular solar arrays operate.

There were so many unanswered questions. What happened? Was the array open at all? Was there a way to fix it? Without a fully deployed array, would Lucy be able to safely perform the maneuvers needed to accomplish its science mission?

Because Lucy was already speeding on its way through space, the stakes were incredibly high.


NASA’s Lucy mission is underway[{” attribute=””>Jupiter Trojans – two swarms of unexplored asteroids trapped in Jupiter’s orbit. Lucy made a picture-perfect launch on October 16, 2021, but when the spacecraft began to unfurl its solar arrays, it encountered an anomaly. One of the arrays failed to fully deploy and latch shut, putting the mission at risk. For months, Lucy’s flight operations team worked meticulously to address the issue and put Lucy back on its solar-powered journey to the Jupiter Trojans.

Within hours, NASA pulled together Lucy’s anomaly response team, which included members from science mission lead Southwest Research Institute (SwRI) in Austin, Texas; mission operations lead NASA’s Goddard Space Flight Center in Greenbelt, Maryland; spacecraft builder Lockheed Martin; and Northrop Grumman in San Diego, solar array system designer and builder.

“This is a talented team, firmly committed to the success of Lucy,” said Donya Douglas-Bradshaw, former Lucy project manager from NASA Goddard. “They have the same grit and dedication that got us to a successful launch during a once-in-a-lifetime pandemic.”

United in their pursuit to ensure Lucy would reach its fullest potential, the team began an exhaustive deep dive to determine the cause of the issue and develop the best path forward.

Given that the spacecraft was otherwise perfectly healthy, the team wasn’t rushing into anything.

“We have an incredibly talented team, but it was important to give them time to figure out what happened and how to move forward,” said Hal Levison, Lucy’s principal investigator from SwRI. “Fortunately, the spacecraft was where it was supposed to be, functioning nominally, and – most importantly – safe. We had time.”

Lucy Solar Panel Deployment Tests

At 24 feet (7.3 meters) across each, Lucy’s two solar panels underwent initial deployment tests in January 2021. In this photo, a technician at Lockheed Martin Space in Denver, Colorado, inspects one of Lucy’s arrays during its first deployment. These massive solar arrays will power the Lucy spacecraft throughout its entire 4-billion-mile, 12-year journey through space as it heads out to explore Jupiter’s elusive Trojan asteroids. Credit: Lockheed Martin

Staying focused during many long days and nights, the team worked through options. To evaluate Lucy’s solar array configuration in real-time, the team fired thrusters on the spacecraft and gathered data on how those forces made the solar array vibrate. Next, they fed the data into a detailed model of the array’s motor assembly to infer how rigid Lucy’s array was – which helped uncover the source of the issue.

At last, they closed in on the root cause: a lanyard designed to pull Lucy’s massive solar array open was likely snarled on its bobbin-like spool.

After months of further brainstorming and testing, Lucy’s team settled on two potential paths forward.

In one, they would pull harder on the lanyard by running the array’s backup deployment motor at the same time as its primary motor. The power from two motors should allow the jammed lanyard to wind in further and engage the array’s latching mechanism. While both motors were never originally intended to operate at the same time, the team used models to ensure the concept would work.

The second option: use the array as it was – nearly fully deployed and generating more than 90% of its expected power.


Shortly after Lucy’s launch, one in all her photo voltaic arrays failed to completely function, placing the mission in danger. This artist idea animation depicts Lucy’s photo voltaic array anomaly.

“Every path has concerned some ingredient of danger to attain key science objectives,” stated Barry Noakes, chief engineer for deep area exploration at Lockheed Martin. “A big a part of our effort has been to establish proactive measures to cut back danger in each situations.”

The group mapped and examined the doable outcomes of each choices. They analyzed hours of check footage of the array, constructed a floor reproduction of the array’s motor meeting, and examined the reproduction past its limits to raised perceive the dangers of additional deployment efforts. In addition they developed particular software program to simulate Lucy in area and measure the ripple results {that a} repositioning effort might need on the spacecraft.

“The collaboration and teamwork with the mission companions has been unimaginable,” stated Frank Bernas, Northrop Grumman’s vice chairman of area elements and strategic enterprise.

After months of simulations and testing, NASA determined to maneuver ahead with the primary possibility – a multi-step effort to utterly reposition the photo voltaic array. Seven occasions in Could and June, the group ordered the spacecraft to fireside the first and backup photo voltaic array deployment engines concurrently. If the try succeeds, pull the lanyard and additional open and tighten the array.

The mission now estimates that Lucy’s photo voltaic array is 353 to 357 levels open (out of 360 complete levels for a totally deployed array). Though the array will not be absolutely secured, it’s underneath vital stress, making the spacecraft steady sufficient to operate as wanted for mission operations.

The spacecraft is now prepared and might full its subsequent huge mission – Earth’s gravity help in October 2022. Lucy is scheduled to go to its first asteroid goal in 2025.

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