Lucy fırlatıldıktan kısa bir süre sonra, güneş dizilerinden biri tam olarak açılmayarak görevi riske attı. Bu sanatçının konsept animasyonu, Lucy’nin güneş dizisi anomalisini tasvir ediyor. Kredi: NASA’nın Goddard Uzay Uçuş Merkezi Kavramsal Görüntü Laboratuvarı
Başarılı bir lansmandan hemen sonra[{” 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.
https://www.youtube.com/watch?v=QaMuyQDKBBM
NASA’nın Lucy misyonu,[{” 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.”
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.
Lucy fırlatıldıktan kısa bir süre sonra, güneş dizilerinden biri tam olarak açılmayarak görevi riske attı. Bu sanatçının konsept animasyonu, Lucy’nin güneş dizisi anomalisini tasvir ediyor.
Lockheed Martin’in derin uzay araştırmaları baş mühendisi Barry Noakes, “Her yol, temel bilim hedeflerine ulaşmak için bazı risk unsurları taşıyordu” dedi. “Çabalarımızın büyük bir kısmı, her iki senaryoda da riski azaltan proaktif eylemleri belirlemekti.”
Ekip, her iki seçenek için olası sonuçların haritasını çıkardı ve test etti. Dizinin saatlerce süren test görüntülerini analiz ettiler, dizinin motor düzeneğinin yere dayalı bir kopyasını oluşturdular ve daha fazla dağıtım girişiminin risklerini daha iyi anlamak için kopyayı sınırlarını aşarak test ettiler. Ayrıca Lucy’yi uzayda simüle etmek ve bir yeniden yerleştirme girişiminin uzay aracı üzerinde sahip olabileceği olası dalgalanma etkilerini ölçmek için özel, yüksek kaliteli yazılım geliştirdiler.
Northrop Grumman’ın uzay bileşenleri ve stratejik işlerden sorumlu başkan yardımcısı Frank Bernas, “Misyon ortaklarıyla işbirliği ve ekip çalışması olağanüstüydü” dedi.
Aylarca süren simülasyonlar ve testlerden sonra, NASA ilk seçenekle ilerlemeye karar verdi – güneş enerjisi dizisini tamamen yeniden yerleştirmek için çok adımlı bir girişim. Mayıs ve Haziran aylarında yedi kez ekip, uzay aracına birincil ve yedek güneş enerjisi dizisi yerleştirme motorlarını aynı anda çalıştırmasını emretti. Bu çaba başarılı oldu, kordonu içeri çekti ve diziyi daha da açıp gerdi.
Görev şimdi Lucy’nin güneş dizisinin 353 derece ile 357 derece arasında açık olduğunu tahmin ediyor (tamamen konuşlandırılmış bir dizi için toplam 360 derecenin üzerinde). Dizi tam olarak kilitlenmemiş olsa da, önemli ölçüde daha fazla gerilim altındadır, bu da uzay aracının görev operasyonları için gerektiği gibi çalışması için yeterince kararlı olmasını sağlar.
Uzay aracı artık hazır ve bir sonraki büyük görev kilometre taşını – Ekim 2022’de bir Dünya-yerçekimi yardımı – tamamlamaya hazır. Lucy’nin ilk asteroit hedefine 2025’te ulaşması planlanıyor.