{"id":14853,"date":"2017-02-22T18:37:10","date_gmt":"2017-02-22T10:37:10","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/spacex-waves-off-space-station-cargo-delivery-for-a-day\/"},"modified":"2017-02-22T18:37:10","modified_gmt":"2017-02-22T10:37:10","slug":"spacex-waves-off-space-station-cargo-delivery-for-a-day","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/spacex-waves-off-space-station-cargo-delivery-for-a-day\/","title":{"rendered":"SpaceX waves off space station cargo delivery for a day"},"content":{"rendered":"
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File photo of a SpaceX Dragon supply ship on final approach to the International Space Station. Credit: SpaceX<\/figcaption><\/figure>\n

SpaceX\u2019s Dragon supply ship, loaded with nearly 5,500 pounds of cargo and experiments, aborted an approach to the International Space Station on Wednesday after encountering a problem in its GPS navigation system.<\/p>\n

The gumdrop-shaped, solar-powered spacecraft was about 1,200 feet, or 365 meters, from the space station when it automatically bailed out of the rendezvous, escaping the immediate vicinity of the research outpost as its safety system intended and setting up for another approach as soon as Thursday.<\/p>\n

NASA said SpaceX\u2019s mission director at the Dragon control center in Hawthorne, California, reported the aborted rendezvous at 3:25 a.m. EST (0825 GMT) when the spacecraft ran into trouble processing GPS navigation data.<\/p>\n

\u201cThe SpaceX engineers are tracing this issue to an incorrect value that was detected in the spacecraft\u2019s Relative Global Positioning System hardware, which basically tells Dragon\u2019s computers, for its burn plan, where it is in the sky relative to the International Space Station,\u201d said Rob Navias, a NASA spokesperson providing commentary on NASA TV.<\/p>\n

\u201cDragon itself is in excellent shape,\u201d Navias added. \u201cIts Global Positioning System hardware is also in excellent shape.\u201d<\/p>\n

The Dragon spacecraft\u2019s navigation system works by comparing position data derived from the GPS satellites to determine the range, direction and closing rate between the visiting supply ship and the space station.<\/p>\n

Once the cargo craft gets closer to the complex, the navigation system switches to inputs from a pulsed laser ranging instrument and a thermal camera to determine how far Dragon is from the space station.<\/p>\n

The rendezvous is fully automated, with the exception of some manual abort, retreat and hold commands.<\/p>\n

\u201cSpaceX mission officials are fully confident that that issue can be mitigated, and that the spacecraft can be protected from an incorrect value during the re-rendezvous attempt on Thursday morning,\u201d Navias said. \u201cThat will allow Dragon to safely approach the station for a grapple and a berthing to the Earth-facing port on the Harmony module.\u201d<\/p>\n

Wednesday\u2019s abort was the first such wave-off by a SpaceX supply ship in 10 cargo deliveries since 2012. NASA\u2019s other cargo transportation provider, Orbital ATK, had to upload a software patch to one of its Cygnus logistics freighters on a flight in 2013 to correct a GPS error, delaying its arrival at the space station by a week.<\/p>\n

NASA said the Dragon spacecraft went into a so-called \u201crace track\u201d course in front, above, and then behind the space station to set up for another rendezvous attempt Thursday, part of a predetermined trajectory to be used in case a problem prevents an on-time arrival.<\/p>\n

\u201cAt no time was the station or the crew in any danger,\u201d Navias said. \u201cDragon did exactly what it was supposed to do and broke out of its approach.\u201d<\/p>\n

Astronaut Mike Hopkins in space station mission control in Houston passed the news on to space station flight engineer Thomas Pesquet, who was preparing to capture the Dragon spacecraft with the lab\u2019s robotic arm.<\/p>\n

\u201cI just want let you know that Dragon is on a 24-hour safe trajectory,\u201d Hopkins said. \u201cWe had an RGPS filter unconverged, and we\u2019re currently in the works for planning a re-attempt for tomorrow.\u201d<\/p>\n

\u201cOK, I copy, thanks for the explanation, and I look forward to welcoming Dragon on-board tomorrow then,\u201d Pesquet replied.<\/p>\n

Shortly after 4:30 a.m. EST (0930 GMT), Hopkins radioed space station commander Shane Kimbrough that mission control aims to try for another rendezvous Thursday. If the rendezvous goes ahead, the Dragon cargo craft should be grappled by the station\u2019s robotic arm around 6 a.m. EST (1100 GMT).<\/p>\n

\u201cDragon has plenty of propellant,\u201d Navias said. \u201cIts other systems are in excellent shape, and all of the science on-board the Dragon can withstand a 24-hour re-rendezvous.\u201d<\/p>\n

The Dragon spacecraft would approach the space station from below, pausing at several hold points before reaching a \u201ccapture box\u201d around 30 feet, or 10 meters, from the outpost.<\/p>\n

Pesquet will maneuver the robotic arm to snare the free-floating spaceship, and then ground controllers will take command of the arm to berth Dragon to the station\u2019s Harmony module for unpacking.<\/p>\n

The astronauts will unload scientific gear, food and other items stowed inside Dragon\u2019s pressurized compartment, and the station\u2019s robotics systems will pull two experiment packages out of the spaceship\u2019s external payload bay for mounting outside the research complex.<\/p>\n

One of the external experiments developed by NASA will monitor changes in Earth\u2019s ozone layer, and the other payload hosts more than a dozen NASA and U.S. military investigations, including a lightning imager and a testbed to gather data for future satellite servicing missions.<\/p>\n

Wednesday\u2019s Dragon rendezvous wave-off came a few hours after a Russian Progress refueling and resupply freighter launched from the Baikonur Cosmodrome in Kazakhstan.<\/p>\n

The Progress MS-05 spacecraft is on track to dock with the space station\u2019s Pirs module at 3:34 a.m. EST (0834 GMT) Friday, less than 24 hours after Dragon\u2019s new arrival time.<\/p>\n

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

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

File photo of a SpaceX Dragon supply ship on final approach to the International Space Station. Credit: SpaceX SpaceX\u2019s Dragon supply ship, loaded with nearly 5,500 pounds of cargo and experiments, aborted an approach to the International Space Station on Wednesday after encountering a problem in its GPS navigation system. The gumdrop-shaped, solar-powered spacecraft was […]<\/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":[1395,159,3292,717,1602,1837,3402,3404],"class_list":["post-14853","post","type-post","status-publish","format-standard","hentry","category-news","tag-dragon","tag-earth-observation","tag-expedition-50","tag-international-space-station","tag-iss-cargo","tag-mike-hopkins","tag-raven","tag-sage-3"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/14853"}],"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=14853"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/14853\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=14853"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=14853"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=14853"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}