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SpaceX CRS-3, also known as SpX-3,〔 was a cargo resupply mission to the International Space Station, contracted to NASA, which was launched on 18 April 2014. It was the fifth flight for SpaceX's uncrewed Dragon cargo spacecraft and the third SpaceX operational mission contracted to NASA under a Commercial Resupply Services contract. This was the first launch of a Dragon capsule on the Falcon 9 v1.1 launch vehicle, as previous launches used the much smaller v1.0 configuration. It was also the first time the F9 v1.1 has flown without a payload fairing, and the first experimental flight test of an ocean landing of the first stage on a NASA/Dragon mission.〔 The Falcon 9 with CRS-3 on board launched on time at 19:25 UTC on 18 April 2014,〔 and was grappled on 20 April at 11:14 UTC by Expedition 39 commander Koichi Wakata. The spacecraft was berthed to the ISS from 14:06 UTC on that day to 13:26 UTC on 18 May 2014.〔 CRS-3 then successfully de-orbited and splashed down in the Pacific Ocean off the coast of California at 19:05 UTC on 18 May.〔 ==Launch schedule history== The launch was notionally scheduled by NASA, , to be no earlier than 30 September 2013, with berthing to the station occurring three days later on 2 October 2013.〔 , the launch was scheduled by NASA for no earlier than 28 November 2013, with berthing to the station occurring three days later on 1 December 2013.〔 By August 2013, the launch date had been moved to no earlier than 15 January 2014,〔〔 but by October it was moved to 11 February.〔 As of 23 January, the launch was rescheduled again to 1 March 2014,〔 and then rescheduled to 16 March in early February. The several delays—from the nominal December 2013 date that had been in place since early 2013—have been mostly due to limited berthing windows in the ISS ''Visiting Vehicle'' schedule, and delays to both Orbital's Cygnus and SpaceX's Dragon resulted from the December 2013 cooling issue on the ISS which required several spacewalks to mitigate.〔 On 12 March 2014 the launch was rescheduled to 30 March or 2 April 2014, for a variety of reasons including data buffering issues, working some issues with the range, some operational issues with the new Dragon design, and some contamination of the impact shielding blanket. SpaceX ultimately decided to move forward and use the shielding blanket with the minor contamination problems, believing it would not impact the optical payloads being carried in the Dragon trunk.〔〔 On 26 March, a further delay was announced related to a fire at one of the radar facilities on the Eastern Range. There is mandatory radar coverage for any launches from Cape Canaveral, and the fire forced a delay until that section of the launch trajectory could be covered, possibly by alternative means that would have telemetry communication capability to the Air Force facility responsible for launch safety.〔 By 4 April, the Eastern Range radars were repaired and back online to support launches, and the CRS-3 launch was slated for no earlier than 14 April with a backup date of 18 April, contingent upon a ULA Atlas V flight scheduled for as early as 10 April.〔 On 11 April, the International Space Station (ISS) suffered a failure of an external computer known as a Multiplexer/Demultiplexer (MDM), which required a spacewalk on 22 April to replace in order to restore vital redundancy to the station. Despite the challenges, the CRS-3 mission – which could have been impacted by the MDM failure – was still on for Monday, 14 April,〔 with ISS berthing scheduled to take place two days later on 16 April.〔 However, during the launch attempt on 14 April, a primary helium supply valve used in the stage separation system failed a pre-launch diagnostic test approximately one hour prior to the scheduled launch, so the SpaceX launch manager scrubbed the mission. In ground tests following the scrub, the redundant backup helium supply valve tested okay so the mission would likely have succeeded; however, it is SpaceX policy to not launch with any known anomalies.〔 The launch was immediately rescheduled for no earlier than the Friday backup date, 18 April.〔 That date was confirmed two days later, following replacement of the defective valve, but also noted that weather constraints may prevent the launch on 18 April from occurring at the instantaneous launch window of 3:25 pm ET. If the launch had been scrubbed on 18 April, the next launch window would have been, Saturday, 19 April at 3:02 pm ET.〔 On Friday, 18 April 2014 at 7:25:21 p.m. UTC, the vehicle was successfully launched.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「SpaceX CRS-3」の詳細全文を読む スポンサード リンク
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