{"id":13613,"date":"2018-09-08T01:30:13","date_gmt":"2018-09-07T17:30:13","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/dwindling-fuel-levels-and-a-balky-thruster-cant-keep-kepler-down\/"},"modified":"2018-09-08T01:30:13","modified_gmt":"2018-09-07T17:30:13","slug":"dwindling-fuel-levels-and-a-balky-thruster-cant-keep-kepler-down","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/dwindling-fuel-levels-and-a-balky-thruster-cant-keep-kepler-down\/","title":{"rendered":"Dwindling fuel levels and a balky thruster can\u2019t keep Kepler down"},"content":{"rendered":"
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Artist\u2019s concept of the Kepler spacecraft. Credit: NASA<\/figcaption><\/figure>\n

After downloading science data and bypassing a balky thruster, NASA\u2019s Kepler mission has resumed its search for planets around other stars after a two-month pause in observations, but engineers expect the spacecraft to soon run out of fuel.<\/p>\n

NASA said in a statement Wednesday that the Kepler telescope began collecting new science data Aug. 29 for its 19th observation campaign after controllers assessed a problem with one of the spacecraft\u2019s eight thrusters used for pointing.<\/p>\n

Engineers suspended Kepler\u2019s science observations in early July after on-board sensors detected a drop in fuel pressure, a sign that the spacecraft is running low on fuel. Engineers are not sure of exactly how much hydrazine fuel remains in Kepler\u2019s tank, so they rely on pressure data, calculation of usage rates and other means to estimate the spacecraft\u2019s remaining fuel supply.<\/p>\n

Managers decided to put Kepler in a fuel-conserving hibernation-like state until early August, when the spacecraft was scheduled to radio Earth and begin downlinking science data stored in its on-board memory.<\/p>\n

Officials did not want to risk the spacecraft running out of fuel and losing the newest dataset captured by Kepler\u2019s telescope and 95-megapixel camera, designed to look for dips in light coming from distant stars that could be caused by a transiting planet.<\/p>\n

Kepler woke up from hibernation and downlinked the observations to scientists through NASA\u2019s Deep Space Network last month, but managers did not immediately proceed with the mission\u2019s next observing run \u2014 known as Campaign 19 \u2014 as planned. An update on Kepler posted by NASA on Aug. 24 said engineers were looking into the health of the spacecraft and determining a \u201cfull range of options and next steps.\u201d<\/p>\n

It turns out officials were studying the behavior of one of Kepler\u2019s thrusters.<\/p>\n

\u201cAfter being roused from sleep mode the spacecraft\u2019s configuration has been modified due to unusual behavior exhibited by one of the thrusters,\u201d NASA said in Wednesday\u2019s statement. \u201cPreliminary indications are that the telescope\u2019s pointing performance may be somewhat degraded. It remains unclear how much fuel remains; NASA continues to monitor the health and performance of the spacecraft.\u201d<\/p>\n

Alison Hawkes, a spokesperson at NASA\u2019s Ames Research Center, said engineers decided to remove the troublesome thruster from use during precision pointing of the spacecraft, according to a report published by Space News. She added that the unusual thruster behavior could be a symptom of Kepler\u2019s low fuel state, in which case other thrusters could start to show problems.<\/p>\n

\u201cBy eliminating the use of the thruster for precision pointing, we are protecting against it being an issue unrelated to the fuel,\u201d Hawkes told Space News.<\/p>\n

Launched in March 2009, Kepler now relies on its thrusters to keep its telescope steadily pointed toward star fields after two of the spacecraft\u2019s four reaction wheels failed earlier in the mission. Kepler needed at least three reaction wheels to maintain its gaze toward a pre-selected field of more than 150,000 stars in the constellations Cygnus and Lyra, and with the loss of the craft\u2019s second wheel in 2013, managers called an end to Kepler\u2019s primary mission phase.<\/p>\n

Engineers devised a new way for Kepler to search for exoplanets by using a combination of thruster firings, the two remaining reaction wheels and solar pressure to keep the spacecraft precisely pointed. Rather than focusing on a single star field, Kepler\u2019s extended mission \u2014 known as K2 \u2014 looks at one part of the sky for around 80 days, then shifts to aim toward another section of the sky for the next campaign.<\/p>\n

The observatory requires stable pointing to be able to detect faint planet transits, and the use of solar pressure for pointing stability depends on the sun\u2019s position relative to Kepler as the spacecraft flies around the solar system an Earth-trailing orbit.<\/p>\n

Since Kepler\u2019s launch, observations over the course of the primary and extended missions have allowed astronomers to confirm the discovery of 2,652 worlds circling other stars, plus more than 2,700 exoplanet candidates that need follow-up. NASA says scientists analyzing Kepler data have, so far, verified the existence of more than 30 near-Earth-sized planets in the so-called habitable zones of their stars \u2014 at the right distance to potentially harbor liquid water.<\/p>\n

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

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

Artist\u2019s concept of the Kepler spacecraft. Credit: NASA After downloading science data and bypassing a balky thruster, NASA\u2019s Kepler mission has resumed its search for planets around other stars after a two-month pause in observations, but engineers expect the spacecraft to soon run out of fuel. NASA said in a statement Wednesday that the Kepler […]<\/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":[1905,1690,1665,559,2826,190],"class_list":["post-13613","post","type-post","status-publish","format-standard","hentry","category-news","tag-ames-research-center","tag-astrophysics","tag-ball-aerospace","tag-exoplanets","tag-kepler","tag-nasa"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/13613"}],"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=13613"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/13613\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=13613"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=13613"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=13613"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}