{"id":11461,"date":"2022-06-15T00:47:40","date_gmt":"2022-06-14T16:47:40","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/ninth-asteroid-added-to-lucy-mission-optimism-grows-on-solar-array-issue\/"},"modified":"2022-06-15T00:47:40","modified_gmt":"2022-06-14T16:47:40","slug":"ninth-asteroid-added-to-lucy-mission-optimism-grows-on-solar-array-issue","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/ninth-asteroid-added-to-lucy-mission-optimism-grows-on-solar-array-issue\/","title":{"rendered":"Ninth asteroid added to Lucy mission; optimism grows on solar array issue"},"content":{"rendered":"
\"\"
The UltraFlex solar arrays on NASA\u2019s Lucy spacecraft unfold during a ground test at a Lockheed Martin test facility in Colorado. Credit: Lockheed Martin<\/figcaption><\/figure>\n

Engineers have made progress in attempts to fully unfurl a solar array wing that snagged on NASA\u2019s Lucy asteroid explorer shortly after launch last October, adding to optimism that the spacecraft can complete its 12-year mission as planned.<\/p>\n

One of Lucy\u2019s two UltraFlex circular solar arrays opened to about 96% of its fully deployed state after arriving in space last October following a launch from Cape Canaveral. The other solar array fully unfurled as the spacecraft began a robotic science mission to fly through swarms of unexplored asteroids that lead and trail Jupiter in its orbit around the sun.<\/p>\n

In recent weeks, ground teams at a Lockheed Martin control center in Colorado have uplinked commands for Lucy run primary and backup motors to drive the stuck solar array closer to full deployment.<\/p>\n

NASA believes a lanyard used to pull the solar array open somehow lost tension and fell off a spool during the initial deployment last October, preventing the array from completely opening.<\/p>\n

Additional attempts to pull the solar array open have further reeled in the lanyard. The first try May 9 involved running the deployment motors in a series of short intervals to avoid overheating. Ground controllers sent more commands May 12, further advancing the solar array deployment and adding tension to the structure, helping stabilize the array.<\/p>\n

Engineers made more progress during two additional deployment attempts May 26 and June 2. \u201cWhile the array still did not latch, the data indicates that it continued to further deploy and stiffen throughout the attempt,\u201d NASA said.<\/p>\n

Most recently, the Lucy ground team sent another command to run the deployment motors June 9, which continued to \u201cfurther stabilize the array,\u201d NASA said. \u201cThere are future opportunities to repeat the deployment commands if necessary.\u201d<\/p>\n

Officials are increasingly optimistic that the Lucy mission can proceed without any issues, even if the solar array does not latch into place. Before the recent tries to fully deploy the array, the spacecraft\u2019s power system was generating more than 90% of the expected level of 18,000 watts.<\/p>\n

\u201cWhile there is no guarantee that additional attempts will latch the array, there is strong evidence that the process is putting the array under more tension, further stabilizing it,\u201d NASA said in a statement. \u201cEven if the array does not ultimately latch, the additional stiffening may be enough to fly the mission as planned.\u201d<\/p>\n

\u201cWe are seeing significant tensioning of the array,\u201d said Hal Levison, Lucy\u2019s principal investigator from the Southwest Research Institute. \u201cThese things are made out of cloth, and where you get a lot of the strength is by putting it under tension. And we\u2019re clearly at a point where we\u2019re tensioning the array, which makes it likely, even if we don\u2019t get the thing latched, we\u2019ll be able to fly the mission as is.\u201d<\/p>\n

One concern engineers have studied is the effect of engine burns on the partially deployed array. The Lucy spacecraft completed its first trajectory correction maneuver June 7 to help guide it toward a flyby with Earth in October, the first of multiple gravity assists to slingshot the probe toward Jupiter\u2019s orbit in the distant solar system.<\/p>\n

Lucy has also extended the platform holding its scientific instruments, and the sensors are all working as designed, Levison said.<\/p>\n

\"\"
Artist\u2019s illustration of the final phase of deploying the solar arrays on NASA\u2019s Lucy spacecraft. Credit: NASA<\/figcaption><\/figure>\n

Lucy will become the farthest spacecraft from the sun to ever rely on solar power, reaching a maximum distance of 530 million miles (853 million kilometers), nearly six times farther than Earth\u2019s orbit. When it reaches the Trojan asteroids, Lucy\u2019s solar arrays were expected to generate just 500 watts of power.<\/p>\n

That level of power output is sufficient to feed Lucy\u2019s three science instruments, which only need about 82 watts of power during each asteroid encounter. Lucy\u2019s flight computer, communications system, and other components will also draw on power generated by the UltraFlex arrays.<\/p>\n

The $981 million Lucy Mission is the first to explore the Trojan asteroids, which scientists say are leftover building blocks similar to objects that came together to form the solar system\u2019s giant outer planets. The probe will fly by eight Trojan asteroids between 2027 and 2033, plus one object in the main asteroid belt in 2025.<\/p>\n

That\u2019s one more asteroid than scientists expected Lucy to visit when it launched last year.<\/p>\n

One of the Trojan asteroids on Lucy\u2019s tour, named Polymele, has a companion. Scientists discovered an apparent satellite of Polymele during a ground-based occultation observation in March, when Polymele briefly passed in front of a star, temporarily blocking its light from reaching Earth.<\/p>\n

The occultation observations were intended to help the Lucy science team determine the shape of Polymele, which only appears as a point of light in telescope images.<\/p>\n

\u201cWe got a really nice projected shape of Polymele, and then we were very surprised to detect an object about 200 kilometers (120 miles) away from Polymele,\u201d Levison said last week in a presentation to NASA\u2019s Small Bodies Advisory Group. \u201cIt\u2019s 5 kilometers (3 miles) in diameter, and it\u2019s sitting almost exactly in Polymele\u2019s equatorial plane.\u201d<\/p>\n

Lucy\u2019s science team has temporarily named the object Shaun, after \u201cShaun the Sheep\u201d in the show \u201cWallace and Gromit.\u201d<\/p>\n

More data on the object\u2019s exact position and orbit are required to assign a permanent name to Polymele\u2019s companion, and that probably won\u2019t happen until after Lucy\u2019s flyby in 2027.<\/p>\n

Polymele itself has an \u201coblate spheroid,\u201d or gourd-like, shape and measures about 17 miles (27 kilometers) long and 8 miles (13 kilometers) wide. The shape of Polymele suggests it is likely a leftover remnant from the young solar system more than 4.5 billion years ago, and may have avoided any collisions with other objects throughout its history.<\/p>\n

\u201cIt\u2019s hard to imagine you can get that shape \u2026 out of an object that\u2019s collisionally evolved, so my thinking right now is Polymele is probably a primordial object, which is going to make seeing it really fascinating.\u201d<\/p>\n

Polymele\u2019s companion is not the first asteroid to be added to Lucy\u2019s flight plan since the mission was approved by NASA in 2017. Astronomers announced in 2020 that observations with the Hubble Space Telescope confirmed a small object, less than 1 kilometer in diameter, orbiting asteroid Eurybates, another Lucy target in the Trojan belt.<\/p>\n

Email the author.<\/i><\/b><\/p>\n

Follow Stephen Clark on Twitter: @StephenClark1.<\/strong><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

The UltraFlex solar arrays on NASA\u2019s Lucy spacecraft unfold during a ground test at a Lockheed Martin test facility in Colorado. Credit: Lockheed Martin Engineers have made progress in attempts to fully unfurl a solar array wing that snagged on NASA\u2019s Lucy asteroid explorer shortly after launch last October, adding to optimism that the spacecraft […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[],"class_list":["post-11461","post","type-post","status-publish","format-standard","hentry","category-news"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/11461"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=11461"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/11461\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=11461"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=11461"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=11461"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}