Shortly after Lucy launched, certainly one of its photo voltaic arrays failed to completely deploy, placing the mission in danger. This artist’s idea animation depicts Lucy’s photo voltaic array anomaly. Credit score: NASA’s Goddard Area Flight Middle Conceptual Picture Lab
Simply after the profitable launch of NASA’s Lucy spacecraft on October 16, 2021, a group of engineers huddled round an extended convention desk in Titusville, Florida. Lucy was simply mere hours into its 12-year journey, however a significant sudden problem had surfaced for the first-ever Trojan asteroids mission.
Knowledge indicated that certainly one of Lucy’s photo voltaic arrays — designed to unfurl like a hand fan — hadn’t totally opened and latched. For the reason that photo voltaic arrays energy the spacecraft’s techniques, the group had to determine what to do subsequent.
To troubleshoot the issue, groups from NASA and Lucy mission companions rapidly got here collectively. Staff members from Lockheed Martin’s Mission Assist Space outdoors of Denver, who have been in communication with the spacecraft straight, have been on the cellphone.
Though the dialog was quiet, it was intense. At one finish of the room, an engineer sat with furrowed forehead, folding and unfolding a paper plate in the identical method that Lucy’s monumental round photo voltaic arrays function.
There have been so many unanswered questions. What occurred? Was the array open in any respect? Was there a technique to repair it? With out a totally deployed array, would Lucy have the ability to safely carry out the maneuvers wanted to perform its science mission?
As a result of Lucy was already dashing on its method by means of area, the stakes have been extremely excessive.
NASA’s Lucy mission is heading to the Jupiter Trojans – two swarms of unexplored asteroids trapped in Jupiter’s orbit. Lucy made a picture-perfect launch on October 16, 2021, however when the spacecraft started to unfurl its photo voltaic arrays, it encountered an anomaly. One of many arrays failed to completely deploy and latch shut, placing the mission in danger. For months, Lucy’s flight operations group labored meticulously to handle the difficulty and put Lucy again on its solar-powered journey to the Jupiter Trojans.
Inside hours, NASA pulled collectively Lucy’s anomaly response group, which included members from science mission lead Southwest Analysis Institute (SwRI) in Austin, Texas; mission operations lead NASA’s Goddard Area Flight Middle in Greenbelt, Maryland; spacecraft builder Lockheed Martin; and Northrop Grumman in San Diego, photo voltaic array system designer and builder.
“This can be a proficient group, firmly dedicated to the success of Lucy,” stated Donya Douglas-Bradshaw, former Lucy mission supervisor from NASA Goddard. “They've the identical grit and dedication that bought us to a profitable launch throughout a once-in-a-lifetime pandemic.”
United of their pursuit to make sure Lucy would attain its fullest potential, the group started an exhaustive deep dive to find out the reason for the difficulty and develop the very best path ahead.
Provided that the spacecraft was in any other case completely wholesome, the group wasn’t speeding into something.
“Now we have an extremely proficient group, however it was necessary to offer them time to determine what occurred and how one can transfer ahead,” stated Hal Levison, Lucy’s principal investigator from SwRI. “Happily, the spacecraft was the place it was purported to be, functioning nominally, and – most significantly – protected. We had time.”
At 24 toes (7.3 meters) throughout every, Lucy’s two photo voltaic panels underwent preliminary deployment exams in January 2021. On this photograph, a technician at Lockheed Martin Area in Denver, Colorado, inspects certainly one of Lucy’s arrays throughout its first deployment. These huge photo voltaic arrays will energy the Lucy spacecraft all through its whole 4-billion-mile, 12-year journey by means of area because it heads out to discover Jupiter’s elusive Trojan asteroids. Credit score: Lockheed Martin
Staying centered throughout many lengthy days and nights, the group labored by means of choices. To guage Lucy’s photo voltaic array configuration in real-time, the group fired thrusters on the spacecraft and gathered knowledge on how these forces made the photo voltaic array vibrate. Subsequent, they fed the info into an in depth mannequin of the array’s motor meeting to deduce how inflexible Lucy’s array was – which helped uncover the supply of the difficulty.
Finally, they closed in on the basis trigger: a lanyard designed to tug Lucy’s huge photo voltaic array open was seemingly snarled on its bobbin-like spool.
After months of additional brainstorming and testing, Lucy’s group settled on two potential paths ahead.
In a single, they'd pull tougher on the lanyard by operating the array’s backup deployment motor similtaneously its main motor. The facility from two motors ought to enable the jammed lanyard to wind in additional and interact the array’s latching mechanism. Whereas each motors have been by no means initially supposed to function on the similar time, the group used fashions to make sure the idea would work.
The second choice: use the array because it was – practically totally deployed and producing greater than 90% of its anticipated energy.
Shortly after Lucy launched, certainly one of its photo voltaic arrays failed to completely deploy, placing the mission in danger. This artist’s idea animation depicts Lucy’s photo voltaic array anomaly.
“Every path carried some component of threat to realize the baseline science aims,” stated Barry Noakes, Lockheed Martin’s deep area exploration chief engineer. “An enormous a part of our effort was figuring out proactive actions that mitigate threat in both situation.”
The group mapped out and examined attainable outcomes for each choices. They analyzed hours of the array’s take a look at footage, constructed a ground-based duplicate of the array’s motor meeting, and examined the duplicate previous its limits to raised perceive dangers of additional deployment makes an attempt. Additionally they developed particular, high-fidelity software program to simulate Lucy in area and gauge any potential ripple results a redeployment try may have on the spacecraft.
“The cooperation and teamwork with the mission companions was phenomenal,” stated Frank Bernas, vice chairman, area elements and strategic companies at Northrop Grumman.
After months of simulations and testing, NASA determined to maneuver ahead with the primary choice – a multi-step try to completely redeploy the photo voltaic array. On seven events in Could and June, the group commanded the spacecraft to concurrently run the first and backup photo voltaic array deployment motors. The trouble succeeded, pulling within the lanyard, and additional opening and tensioning the array.
The mission now estimates that Lucy’s photo voltaic array is between 353 levels and 357 levels open (out of 360 whole levels for a completely deployed array). Whereas the array isn't totally latched, it's beneath considerably extra rigidity, making it steady sufficient for the spacecraft to function as wanted for mission operations.
The spacecraft is now prepared and in a position to full the following massive mission milestone – an Earth-gravity help in October 2022. Lucy is scheduled to reach at its first asteroid goal in 2025.
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