内容来源：https://www.engadget.com/science/space/nasas-crewed-artemis-ii-launch-gets-pushed-back-again-this-time-due-to-a-helium-issue-231010042.html?src=rss

内容总结：

美国“阿尔忒弥斯2号”载人探月任务因氦气泄漏问题再度推迟发射

美国国家航空航天局（NASA）原计划于今年3月执行的“阿尔忒弥斯2号”载人绕月飞行任务，因运载火箭出现技术问题被迫再次推迟。这将是自50多年前“阿波罗”计划结束后，美国首次开展载人探月任务。

NASA在2月21日凌晨发现，用于“太空发射系统”（SLS）火箭上面级的氦气输送流程出现异常。氦气在该火箭系统中承担着维持发动机环境条件、为液氢和液氧推进剂储箱加压的关键作用。尽管此前在2月19日完成的发射演练中系统运行正常，但在后续常规操作与重新配置过程中，氦气输送未能按预期进行。

为确保安全，NASA决定将火箭从发射台转移回约6.4公里外的车辆装配大楼进行详细检测与维修。这项转移工作预计于2月24日开始，耗时数小时。NASA局长比尔·纳尔逊通过社交媒体表示，此次回撤意味着3月的发射窗口已无法实现。机构在公告中称，若后续检测与修复进展顺利，4月的发射窗口仍有可能保留，具体计划将于本周内通过新闻发布会进一步说明。

受此次推迟影响，此前已进入任务前隔离期的四名宇航员——指令长里德·怀斯曼、飞行员维克多·格洛弗、任务专家克里斯蒂娜·科赫及加拿大航天局宇航员杰里米·汉森——已暂时解除隔离状态。

“阿尔忒弥斯2号”任务原定于2026年4月执行，今年初NASA曾宣布将时间表大幅提前至2月，后又因演练中出现的问题调整至3月。此次任务计划为期10天，宇航员将乘坐“猎户座”飞船绕月飞行，这将是SLS火箭的首次载人发射。目前，NASA正全力开展故障排查，任务的最终发射时间将取决于维修进度。

中文翻译：

美国国家航空航天局（NASA）载人登月任务"阿尔忒弥斯二号"的发射计划再度推迟，此次延期归因于火箭氦气系统故障。该机构表示，太空发射系统（SLS）火箭上面级的氦气输送出现异常。

这意味着原定三月的发射窗口已无法实现——这将是自五十多年前阿波罗计划落幕以来，NASA首次载人探月任务。尽管肯尼迪航天中心此前正为3月6日的最早发射日期进行筹备，但本周末发现的氦气输送故障迫使火箭需从发射台撤回至运载火箭装配大楼进行检修。NASA计划本周召开媒体简报会说明故障详情及后续方案。

NASA局长比尔·纳尔逊在社交媒体平台X上证实，撤回检修将"排除三月发射的可能性"。该机构在官方博客中指出，当前处置方案"有望保留四月发射窗口，具体将取决于故障分析结果、维修进度以及未来数周的计划落实"。长达6.4公里的转运过程需耗时数小时，以谨慎移动巨型火箭及猎户座飞船，目前暂定2月24日启动转运。

故障发生于2月21日凌晨，监控显示"太空发射系统火箭临时低温推进级的氦气输送中断"。NASA解释称："上面级需依靠氦气维持发动机环境条件，并对液氢/液氧推进剂储罐进行加压。该系统在2月19日完成的发射演练中运行正常，但在后续常规操作与系统重置时出现异常。目前操作团队已启用备用方案维持上面级环境稳定，火箭整体处于安全状态。"

故障发生前一日，阿尔忒弥斯二号任务乘组——指令长里德·怀斯曼、飞行员维克多·格洛弗、任务专家克里斯蒂娜·科赫及加拿大航天局宇航员杰里米·汉森——刚进入发射前隔离期。NASA表示目前宇航员已解除隔离状态。

今年初，NASA曾宣布加快任务进度，将原定2026年4月的发射计划提前至2024年。作为SLS火箭首次载人飞行，本次为期十天的任务将搭载四名宇航员乘坐猎户座飞船绕月飞行。虽然最初瞄准二月初发射，但因演练期间出现技术问题推迟至三月。如今随着新故障出现，发射时间可能调整至四月，但这取决于检修工作能否迅速完成。

英文来源：

NASA's crewed Artemis II launch gets pushed back again, this time due to a helium issue
The space agency says it ran into a problem with helium flow to the SLS rocket's upper stage.
It looks like a March launch is no longer in the cards for Artemis II, NASA's first crewed trip to the moon's vicinity since the final Apollo mission over 50 years ago. While preparations were underway at the Kennedy Space Center for a launch as soon as March 6, the space agency says it ran into an issue with the flow of helium to its SLS rocket's upper stage this weekend and it now has to roll the rocket from the launch pad back to the Vehicle Assembly Building (VAB) to figure out what's wrong and fix it. A media briefing is planned for sometime this week to discuss the problem and what's next.
But in a post on X, NASA Administrator Jared Isaacman confirmed the rollback will "take the March launch window out of consideration." NASA noted on its blog that the current effort "potentially preserves the April launch window, pending the outcome of data findings, repair efforts, and how the schedule comes to fruition in the coming days and weeks." It's a four-mile trip back to the VAB that will take hours to carefully transport the massive rocket and the Orion spacecraft. NASA says it's eyeing February 24 for this trek.
The issue occurred overnight in the early hours of February 21, when NASA says it observed "interrupted flow of helium to the SLS (Space Launch System) rocket’s interim cryogenic propulsion stage." The space agency explained:
The upper stage uses helium to maintain the proper environmental conditions for the stage’s engine and to pressurize liquid hydrogen and liquid oxygen propellant tanks. The systems worked during NASA’s Artemis II wet dress rehearsals, but teams were not able to properly flow helium during normal operations and reconfigurations following the wet dress rehearsal that concluded Feb. 19. Operators are using a backup method to maintain the environmental conditions for the upper stage engines and the rocket, which remains in a safe configuration.
The Artemis II crew — Commander Reid Wiseman, Pilot Victor Glover, Mission Specialist Christina Koch and Canadian Space Agency astronaut Jeremy Hansen, Mission Specialist — had just entered quarantine a day before the issue arose. NASA says the astronauts have since come out of quarantine.
At the start of this year, NASA announced an accelerated timeline for Artemis II, which was previously set for April 2026 after experiencing delays in 2024. For this 10-day mission, which will be the first crewed flight of the SLS rocket, the Artemis II astronauts will take a trip around the moon in the Orion spacecraft. While it initially targeted early February, the launch was pushed to March due to issues that popped up during the wet dress rehearsal. Now, we're back to the beginning with a possible April launch, but that’ll depend on the fix being a quick one.