{"id":16422,"date":"2015-04-05T19:07:07","date_gmt":"2015-04-05T11:07:07","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/rosetta-probe-disoriented-by-comet-dust\/"},"modified":"2015-04-05T19:07:07","modified_gmt":"2015-04-05T11:07:07","slug":"rosetta-probe-disoriented-by-comet-dust","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/rosetta-probe-disoriented-by-comet-dust\/","title":{"rendered":"Rosetta probe disoriented by comet dust"},"content":{"rendered":"
\"This
This view of comet 67P\/Churyumov-Gerasimenko was taken by Rosetta\u2019s navigation camera on March 22, showing a cloud of dust and gas surrounding the nucleus. Credit: ESA\/Rosetta\/NAVCAM<\/figcaption><\/figure>\n

Ground controllers are analyzing a fault aboard Europe\u2019s Rosetta spacecraft after an encounter with comet dust confused the probe\u2019s navigation system, leaving the robot explorer in a temporary safe mode and halting regular science operations.<\/p>\n

Rosetta ran into trouble during a March 28 flyby near the nucleus of comet 67P\/Churyumov Gerasimenko, the oddly-shaped comet the mission has explored since August 2014.<\/p>\n

The spacecraft uses small cameras to locate bright stars in the sky, using the stellar fixes to determine its orientation in space.<\/p>\n

During the March 28 flyby, Rosetta zipped past the comet\u2019s icy core at a distance of about 14 kilometers, or 8.7 miles. The probe aimed for a flyby point over the larger of comet 67P\u2019s two lobes, according to the European Space Agency.<\/p>\n

The comet is heating up as it swings closer to the sun, triggering plumes of outgassing water vapor and dust particles. Scientists expect the comet\u2019s awakening to continue past perihelion \u2014 its closest approach to the sun \u2014 on Aug. 13, with the period of most activity forecast for September.<\/p>\n

ESA officials blame the growing cloud around the comet\u2019s nucleus for the pointing error during the March 28 flyby.<\/p>\n

The dust grains pushed against Rosetta\u2019s long power-generating solar arrays, causing increased drag as the craft approached the comet.<\/p>\n

But ground controllers observed a more serious effect on Rosetta\u2019s star trackers, which are supposed to find guide stars to self-monitor the spacecraft\u2019s alignment with Earth and the sun. The guidance system confused the flecks of dust for stars, rendering the trackers unable to set a navigation fix.<\/p>\n

\u201cDuring the most recent flyby, a number of issues were reported, starting with the primary star tracker encountering difficulties in locking on to stars on the way in towards closest approach,\u201d officials wrote in a blog post on ESA\u2019s website. \u201cAttempts were made to regain tracking capabilities, but there was too much background noise due to activity close to the comet nucleus: hundreds of \u2018false stars\u2019 were registered and it took almost 24 hours before tracking was properly re-established.\u201d<\/p>\n

\"Artist's
Artist\u2019s concept of Rosetta with comet 67P\/Churyumov-Gerasimenko in the background. Credit: ESA<\/figcaption><\/figure>\n

Rosetta initially recovered from the problem after its high-gain antenna drifted away from Earth.<\/p>\n

\u201cHowever, issues with false stars were still occurring,\u201d the blog post said. \u201cCross comparisons with other navigation mechanisms showed inconsistencies with the star trackers and some on board reconfigurations occurred.\u201d<\/p>\n

The spacecraft ended up in safe mode, a state where Rosetta switched off its scientific instruments and halted non-essential functions to ensure the probe\u2019s survival. The safe mode occurred the day after Rosetta\u2019s closest approach to the comet.<\/p>\n

Engineers at the Rosetta control center in Darmstadt, Germany, restored the spacecraft to normal status by March 30, but science operations remain mostly suspended as officials gauge the implications of the event.<\/p>\n

The March 28 encounter was Rosetta\u2019s closest brush with the comet since a 6-kilometer (3.7-mile) flyby Feb. 14. Rosetta\u2019s star trackers experienced similar issues then, but the spacecraft weathered the flyby without defaulting to safe mode.<\/p>\n

Rosetta performed a rocket burn April 1 to bring the spacecraft from a distance of 400 kilometers (248 miles) to about 140 kilometers (87 miles) from the comet by April 8, officials said.<\/p>\n

Limited science operations should resume in the coming days and weeks.<\/p>\n

Mission managers planned a series of flybys near comet 67P\u2019s nucleus in the next few months, including a targeted trip through one of the comet\u2019s active jets in July. Rosetta\u2019s struggles last week may prompt officials to reconsider how to execute future flybys.<\/p>\n

\u201cThe science and operations teams are currently discussing the impact of the recent navigation difficulties on the current planned trajectories, possibly resulting in further replanning in order to ensure that the spacecraft can operate safely as the comet activity continues to increase towards perihelion in August,\u201d the blog post said.<\/p>\n

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

This view of comet 67P\/Churyumov-Gerasimenko was taken by Rosetta\u2019s navigation camera on March 22, showing a cloud of dust and gas surrounding the nucleus. Credit: ESA\/Rosetta\/NAVCAM Ground controllers are analyzing a fault aboard Europe\u2019s Rosetta spacecraft after an encounter with comet dust confused the probe\u2019s navigation system, leaving the robot explorer in a temporary safe […]<\/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":[3097,3098,3373],"class_list":["post-16422","post","type-post","status-publish","format-standard","hentry","category-news","tag-comet","tag-comet-67p-churyumov-gerasimenko","tag-rosetta"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/16422"}],"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=16422"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/16422\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=16422"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=16422"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=16422"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}