NASA Lucy Mission Solar Array Anomaly

NASA discovers and repairs errors in the Lucy spacecraft attached to asteroids from millions of miles away

Shortly after Lucy’s launch, one of its solar arrays failed to fully deploy, compromising the mission. An artist’s concept animation depicts this anomaly in Lucy’s solar array. Credit: NASA’s Goddard Space Flight Center Conceptual Image Lab

After the successful launch of

NASA
Founded in 1958, the National Aeronautics and Space Administration (NASA) is an independent agency of the United States federal government that succeeded the National Advisory Committee on Aeronautics (NACA). He is responsible for the civilian space program, as well as aviation and space research. see her "To discover and expand knowledge for the benefit of mankind." core values "Safety, Integrity, Teamwork, Excellence and Inclusion."

“data-gt-translate-attributes=”[{” 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 headed to

Jupiter
Jupiter is the largest planet in the solar system and the fifth planet from the sun. It is a gas giant with a mass greater than all the other planets combined. Its name comes from the Roman god Jupiter.

“data-gt-translate-attributes=”[{” 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 of its solar arrays failed to fully deploy, compromising the mission. An artist’s concept animation depicts this anomaly in Lucy’s solar array.

“Each trajectory carries some element of risk to achieve basic science goals,” said Barry Knox, chief engineer for deep space exploration at Lockheed Martin. “A large part of our effort has been to identify proactive measures that mitigate risks in either scenario.”

The team plotted and tested the possible outcomes of both options. They analyzed hours of matrix test footage, built a replica of the matrix engine suite, and tested the replica that crossed its limits to better understand the risks of further deployment attempts. They also developed special high-resolution software to simulate Lucy in space and measure any potential ripple effects that the redeployment attempt could have on the spacecraft.

“The collaboration and teamwork with mission partners has been tremendous,” said Frank Bernas, Vice President, Space Components and Strategic Business at Northrop Grumman.

After months of simulation and testing, NASA decided to move forward with the first option – a multi-step attempt to completely redeploy the solar array. On seven occasions in May and June, the team ordered the spacecraft to run the primary and backup solar array deployment engines simultaneously. The effort worked, the rope pulled, opened and tightened the matrix.

The mission now estimates that the Lucy Solar Constellation is open between 353° and 357° (out of a total of 360° for a fully scattered array). Although the array is not fully sealed, it is subject to significantly more stress, making it stable enough to operate the spacecraft as needed for mission operations.

The spacecraft is now ready and able to complete the next big mission – Earth’s gravity assist in October 2022. Lucy is set to reach its first asteroid target in 2025.


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