2026-03-30T05:00:11-0400 / 哥伦比亚广播公司新闻
经过数周的推迟，美国航天局终于准备于本周启动一项历史性飞行任务，将四名宇航员送往月球并往返，全程九天，开创先河。
阿尔忒弥斯II号任务将由指挥官里德·怀斯曼、飞行员维克多·格洛弗、宇航员克里斯蒂娜·科赫以及加拿大宇航员杰里米·汉森组成，定于美国东部时间4月1日周三下午6点24分发射，搭载全球最强大的现役运载火箭太空发射系统。气象预报员预测发射当日天气达标概率为80%。
“嘿，咱们登月去！”怀斯曼在他和机组人员周五抵达肯尼迪航天中心后，对围堵上来的记者们喊道，“我认为国家乃至全世界都已等待太久，盼着再次做到这件事。”
他们原本计划于2月初发射，但此次飞行因氢燃料泄漏问题推迟，之后又因上面级推进剂加压系统出现故障再度延后。美国航天局表示，两个问题均已解决，终于为发射扫清了障碍。
兼具多项首次的测试任务
这将是该火箭首次搭载载人飞行，也是其整体第二次飞行任务。同时，这也将是猎户座深空载人舱首次由载人驾驶。
本次任务的一大核心目标是对这艘名为“坚韧号”的载人飞船进行全面测试。
“这是一次测试任务，”怀斯曼说道，“我们离开地球后，可能直接返回地球，也可能在地球轨道停留三四天，也可能前往月球。我们的目标是前往月球，但这毕竟是测试任务，我们已经做好准备，应对任何突发状况，搭乘这艘搭载在猎户座飞船中的卓越太空发射系统，前往25万英里之外的太空。这一定会棒极了！”
一轮满月在太空发射系统火箭后方升起，提醒着人们建造该火箭的初衷。 美国航天局
怀斯曼、格洛弗和科赫都是美国航天局的资深宇航员。汉森将迎来自己的首次太空飞行，成为首位脱离地球轨道的加拿大宇航员。
凭借此次绕月飞行任务，他们成为自50多年前阿波罗17号载人登月任务以来，首批前往月球的宇航员。
迈向未来月球着陆的重要一步
这是美国航天局与中国展开新一轮太空竞赛的重要里程碑，中国计划于2030年前将本国“航天员”送上月球表面。美国航天局希望在2028年发射一次甚至两次阿尔忒弥斯登月任务，以此赢得这场竞赛。
但首先，该机构计划在此次阿尔忒弥斯II号绕月飞行期间，对猎户座舱进行全面测试，这也是该舱首次搭载载人飞行。
阿尔忒弥斯II号宇航员，从左至右：指挥官里德·怀斯曼、飞行员维克多·格洛弗、宇航员克里斯蒂娜·科赫以及加拿大宇航员杰里米·汉森。 美国航天局
次年，美国航天局计划让宇航员在近地轨道与太空探索技术公司和蓝色起源公司正在建造的新型登月着陆器进行交会对接，以测试关键系统并验证操作流程。在那之后，美国航天局宇航员将在短短两年内，在月球南极附近开展登月任务。
与此同时，美国航天局将专注于提升发射频率，并设计一座月球基地，让宇航员能够在那里停留数周或数月，开展研究和技术开发工作。
美国航天局局长贾里德·艾萨克曼于2月公布了更新后的计划，预计七年内耗资200亿美元。他表示，这种“循序渐进的方式”正是“美国航天局在20世纪60年代阿波罗计划中实现近乎不可能的目标的方式”。
“但这一次，我们的目标不再是插上旗帜、留下脚印。这一次，我们的目标是常驻月球，”他补充道，“美国永远不会再放弃月球。”
太空“疯狂的首日”
为后续的开拓者们铺平道路，阿尔忒弥斯II号宇航员将在佛罗里达州搭乘太空发射系统火箭升空，该火箭推力接近900万磅。
起飞时总重570万磅的火箭将在八分钟内将猎户座载人飞船送入太空，此时飞船的速度将接近每秒5英里——快到足以在一秒内飞越约70个首尾相连的足球场。
美国航天局的太空发射系统，这款目前在役的最强大火箭，将搭载阿尔忒弥斯II号飞行任务绕月飞行。 法新社通过盖蒂图片社供图的图表
两次火箭点火，分别在升空后50分钟和约一小时后进行，将把飞船送入远地点为43760英里的椭圆轨道，这一高度高于自1972年最后一次阿波罗登月任务以来任何宇航员到达过的轨道高度。
猎户座舱将在发射后3小时23分钟与临时低温推进级（ICPS）分离。
所有这些操作将让飞船完成一次24小时的轨道飞行，让宇航员有充足时间检查猎户座舱，确保通信、导航、推进和生命维持系统运行正常，随后再前往月球。
这些测试包括“废物收集”，这是美国航天局对使用飞船狭小卫生间的说法。所有测试都将在飞船距离地球足够近、能够在出现重大问题时快速返回的情况下进行。
格洛弗将在怀斯曼的协助下，测试猎户座的机动系统，接近并绕飞废弃的太空发射系统上面级，模拟未来机组人员与着陆器或美国航天局计划在月球轨道上建造的门户空间站交会对接所需的飞行操作。如果时间允许，怀斯曼也可以亲自上手操控一番。
“这将是疯狂的首日，”怀斯曼在接受哥伦比亚广播公司新闻采访时表示，“我们从肯尼迪航天中心的发射台升空后，大约有90分钟时间在近地轨道绕地球一圈……确保所有基础系统都运行正常。随后我们将前往距离地球4.4万英里的轨道，完成一次24小时的飞行。”
“这24小时的轨道飞行让我们有时间检查猎户座所有的环境控制和生命维持系统，”怀斯曼说，“它能否清除我们呼出的二氧化碳？能否保障我们的生命安全？我们能否饮用饮用水？能否正常使用卫生间？所有这些基本的人类生存功能都需要测试。……在我们向月球进发之前，必须先完成这些测试。”
假设未出现重大问题，阿尔忒弥斯II号宇航员将进行四小时的小憩，随后起身进行另一项关键的火箭点火操作。此次将使用猎户座服务舱的主发动机，将飞船送入一条远地点44555英里、近地点115英里的轨道。
宇航员随后将再次进行四小时的小憩，同时飞行控制人员评估猎户座的表现，随后做出最终的发射决策，将机组人员送往月球。
他们需要考量的因素有很多。由洛克希德·马丁公司建造的猎户座飞船将首次搭载全套生命支持系统进行飞行。此前太空发射系统和猎户座的唯一一次发射是2022年的无人驾驶阿尔忒弥斯I号测试飞行。
尽管当时的舱体本身表现良好，但猎户座的热防护盾在重返大气层时被5000华氏度的高温严重损坏。阿尔忒弥斯II号的猎户座舱配备了同款热防护盾，但经过 extensive的飞行后测试，美国航天局管理层认定可以按原样安全飞行，采用不同的重返大气层轨迹，这种轨迹可以避免导致阿尔忒弥斯I号出现问题的内部加热情况。
四天后抵达月球
假设工程师在飞船升空首日对数据进行评估后，确认猎户座状态良好，机组人员将在发射后约25小时开始准备关键的“ translunar injection（地月转移轨道注入）”，即TLI点火，使用服务舱的发动机完成操作。
此次持续6分5秒的发动机点火将使飞船的速度提升约900英里每小时，刚好足以将飞船推出地球轨道，开启为期四天的月球航程。
尽管宇航员们对火箭和猎户座舱能够安全地将他们送往月球并返回太平洋溅落区充满信心，但宇航员及其家属都清楚任务存在风险。
“这是一次测试飞行，我们必须愿意承担这种风险，”汉森在接受哥伦比亚广播公司新闻采访时表示，“这也是我和家人谈论最多的话题。我非常乐观，我坚信最有可能的结果是，九天半后我们都能平安无事地降落在太平洋上。
“但我希望所有人都明白，我们有可能会失去机组人员。如果真的发生这种情况，我们也不应感到意外。我们接下来要做的最重要的事情，就是堆叠好下一枚火箭，让下四位志愿者登上火箭，继续前行。”
半个世纪以来首次绕月飞行
阿尔忒弥斯II号机组人员不会像1968年阿波罗8号机组人员那样在月球着陆，甚至不会进入月球轨道——阿波罗8号是土星五号火箭首次载人飞行，也是首批将宇航员送出近地轨道的任务。
相反，阿尔忒弥斯II号机组人员将以“自由返回”轨道离开地球，绕飞月球前缘，并利用月球引力改变飞船航向，返回地球。
美国航天局的阿尔忒弥斯II号任务计划将四名宇航员搭载在猎户座飞船中送往月球并返回地球。 乔纳森·沃尔特和帕斯·皮萨罗 / 法新社通过盖蒂图片社供图的图表
地月转移轨道注入点火将精确设定重返大气层轨迹，仅需进行小幅调整即可实现精准溅落。换句话说，如果在前往月球后，猎户座的导航或推进系统出现重大问题，飞船仍可在无需推进器辅助的情况下自动返回地球。
这条自由返回轨道将让机组人员在最近距离时抵达距月球表面约4100英里的位置。
“如果你将篮球举到手臂之外看向它，这大概就是我们飞越月球时，宇航员透过舷窗看到的月球大小，”首席飞行导演杰夫·拉迪根说道。
月球背面——离家最远的距离
机组人员将成为首批亲眼看到月球背面大片平时无法观测区域的人类。
阿波罗宇航员曾在月球赤道附近飞越月球背面，但当时的任务时间安排确保了面向地球的着陆点处于白昼，而月球背面则处于黑暗之中。此次任务假设于4月1日发射，当阿尔忒弥斯II号宇航员飞越月球背面时，将有21%的月球背面区域处于阳光照射下，让机组人员有机会直接看到此前从未被人类肉眼观测过的月球背面区域。
“我们四个人，两个舷窗正对月球表面，这需要一场高度编排的协作，谁负责操作相机，谁负责使用其他录音设备，以及我们如何支持那些实际采集数据和进行观测的人员，”科赫说道。
“当然，月球已经被众多遥感卫星拍摄过，但月球背面确实存在一些从未被人类肉眼看到的区域。……所以希望我们抵达那里时，已经做好准备，能够充分利用那几个小时的观测时间。”
格洛弗表示：“已有24名男性亲眼见过月球，而我们将成为首批让女性目光投向月球的人。人们认为女性或许能够看到一些我们男性可能看不到的颜色。”
假设发射准时，机组人员将比1970年阿波罗13号任务的机组人员飞得更远。阿波罗13号在前往月球的途中遭遇灾难性爆炸后，自行执行了自由返回轨道，当时他们创下了距地球248655英里的最远飞行纪录，随后才返回地球。
阿尔忒弥斯II号机组人员预计将比这一纪录超出约4000英里，创下252000英里的新纪录。
高速重返地球
假设阿尔忒弥斯II号发射顺利，且机组人员在轨道首日未发现重大问题，地月转移轨道注入点火将为月球飞越做好准备，并将飞船送入重返大气层和溅落的轨道，任务将于4月10日周五结束。
仅需进行小幅轨道修正即可精准对准重返大气层点。
在地球引力的牵引下，猎户座载人舱在以约25000英里每小时——约每秒7英里——的速度，在距太平洋上空约75英里处冲入可探测大气层。
当16.5英尺宽的热防护盾承受高达5000华氏度的高温时，载人舱将迅速被带电火球包裹，无线电信号将被阻断约五分钟。
汲取阿尔忒弥斯I号热防护盾受损的教训
猎户座将采用与2022年无人驾驶的阿尔忒弥斯I号飞行任务相同的热防护盾设计。该防护盾的设计目标是防止热防护盾与舱底连接处的温度超过500华氏度。
在阿尔忒弥斯I号任务期间，飞船遵循了规划好的“跳跃”轨迹，即先冲入上层大气，再冲出大气层，最终降落在溅落区。这种跳跃轨迹为美国航天局提供了更多的溅落区域选择，以防恶劣天气影响预定着陆点。
但飞行后分析显示，阿尔忒弥斯I号的热防护盾在再入大气层时遭受了意外损坏，外层“炭化”层的大块区域意外脱落。尽管舱体安全着陆，但美国航天局启动了全面调查，以确定热防护盾为何未按照计算机模型的预期运行。
2022年无人驾驶测试飞行中保护猎户座舱的热防护盾在再入大气层时严重受损。 美国航天局
工程师们确定，高角度的再入加热会使外层炭化层变得透气，使得下层在热解过程中产生的气体得以逸出。
在阿尔忒弥斯I号舱体长时间跳跃式脱离可探测大气层的过程中，再入加热程度减弱，外层变得不透气，下层热解产生的气体无法逸出。压力不断累积，气体膨胀将外层热防护盾的碎片推开。
工程师们得出结论，采用不同的再入轨迹，即初始冲入上层大气后，进行更短时间的爬升脱离，将能让外层炭化层更均匀地侵蚀和烧蚀，避免产生破坏性的亚表面裂纹和压力累积。一个独立审查小组同意了这一结论。
尽管美国航天局计划在明年的阿尔忒弥斯III号任务中采用不同的设计方案，但该局管理层选择继续使用阿尔忒弥斯II号猎户座舱上已安装的热防护盾。考虑到阿尔忒弥斯II号的自由返回轨迹，“我们能够安全且高成功率地控制再入环境，”美国航天局副局长阿米特·克沙特里亚说道，“这就是我们的计划。”
溅落与回收
从再入大气层到溅落全程耗时13分钟。
再入大气层9分钟后，恢复与任务控制中心的通信，阿尔忒弥斯II号机组人员将开始监控11个降落伞的展开操作，这些降落伞用于稳定飞船并将速度降至约15英里每小时的溅落速度。这是载人航天器史上最复杂的降落伞系统。
在穿过峰值加热区并迅速减速后，当飞船降至约36000英尺高度时，三个小型降落伞将被展开，拉开主降落伞储存舱的保护罩，此时猎户座舱的下降速度约为300英里每小时。
随后，两个23英尺宽的减速伞将在约24000英尺高度展开并充气，以稳定飞船，接着三个引导伞将拉出猎户座的三个116英尺宽的主降落伞。主降落伞将在8000英尺至4000英尺之间分阶段展开，将飞船的下降速度从约300英里每小时降至溅落速度。
该降落伞系统的设计目标是，即使一个减速伞或一个主降落伞未能展开，仍能将宇航员安全送回地球。如果出现更多故障，溅落速度会更高，但美国航天局未提供此类情况的详细信息。
但在正常下降过程中，猎户座将以15至17英里每小时的速度先以热防护盾底部接触水面，希望宇航员能借助海浪和风保持姿态，不发生侧翻。如果发生侧翻，安全气囊将把飞船重新扶正。
怀斯曼、格洛弗、科赫和汉森将被从舱中救出，由直升机转运至等候的海军两栖运输船坞舰（LPD）。在接受初步医疗检查并与亲友通话后，宇航员将返回岸边，搭乘航班前往约翰逊航天中心。
与此同时，猎户座舱将被吊运至回收船的浸水“井型甲板”，并固定在平台上，随船返回岸边。美国航天局工程师将花费数周时间分析阿尔忒弥斯II号飞行任务的数据，同时推进下一次任务的规划工作。
NASA to launch Artemis II crew on flight around the moon this week. Here’s everything to know about the mission.
2026-03-30T05:00:11-0400 / CBS News
After weeks of delays, NASA is finally poised for launch of a historic flight this week to send a crew of four astronauts on a trailblazing nine-day trip around the moon and back.
The Artemis II mission — with commander Reid Wiseman, pilot Victor Glover, astronaut Christina Koch and Canadian astronaut Jeremy Hansen — is scheduled to lift off Wednesday, April 1, at 6:24 p.m. EDT, atop a Space Launch System rocket, the most powerful operational booster in the world. Forecasters are predicting an 80% chance ofacceptable weatherfor launch.
“Hey, let’s go to the moon!” exclaimed Wiseman, speaking to a throng of reporters after he and his crewmates arrived at the Kennedy Space Center on Friday. “I think the nation and the world has been waiting a long time to do this again.”
They originally planned to launch in early February, but the flight was delayed, first by hydrogen fuel leaks and then later by problems with the upper stage propellant pressurization system. NASA says both issues have been resolved, finally clearing the way for blastoff.
A test mission, full of firsts
This will be the rocket’s first flight with a crew on aboard, and only its second flight overall. It will also be the first piloted flight of an Orion deep space crew capsule.
A major objective is to put the crew ship, named Integrity, through its paces.
“This is a test mission,” Wiseman said. “When we get off the planet, we might come right back home. We might spend three or four days around Earth. We might go to the moon. That’s where we want to go, but it is a test mission, and we are ready for every scenario as we ride this amazing Space Launch System in the Orion spacecraft, 250,000 miles away. It’s going to be amazing!”
A full moon rises behind the Space Launch System rocket, a reminder of what the rocket was built to do. NASA
Wiseman, Glover and Koch are NASA space veterans. Hansen, making his first space flight, will become the first Canadian to leave Earth orbit.
With their mission to circle the moon, they become the first crew to head for the moon since the Apollo 17 flight that landed there more than 50 years ago.
Big step toward a future moon landing
It’s a major milestone in a new NASA space race with China, which plans to put their own “taikonauts” on the lunar surface by 2030. NASA hopes to win that race by launching one and possibly two Artemis moon landing missions in 2028.
But first, the agency plans to thoroughly test the Orion capsule, making its first flight with a crew on board, during this Artemis II voyage around the moon.
The Artemis II astronauts, left to right: commander Reid Wiseman, pilot Victor Glover, astronaut Christina Koch and Canadian astronaut Jeremy Hansen. NASA
Then, next year, NASA plans for astronauts to rendezvous and dock in low-Earth orbit with new moon landers being built by SpaceX and Blue Origin to test critical systems and verify operating procedures. After that, NASA astronauts will embark on a moon landing near the lunar south pole in just two years.
In the meantime, NASA will be focusing on increasing the flight rate and designing a moon base where astronauts can spend weeks or months at a time carrying out research and technology development.
NASA Administrator Jared Isaacman, who announced the updated plans in February with an estimated cost of $20 billion over seven years, said this “step-by-step approach” is “exactly how NASA achieved the near impossible” with the Apollo program in the 1960s.
“But this time, the goal is not flags and footprints. This time, the goal is to stay,” he said, adding, “America will never again give up the moon.”
A “crazy first day” in space
Blazing a trail for the crews that follow, the Artemis II astronauts will climb away from Florida atop the SLS rocket’s nearly 9 million pounds of thrust.
Weighing 5.7 million pounds at liftoff, the rocket will accelerate the Orion crew ship on eight-minute climb to space, at which point it will moving at nearly 5 miles per second — fast enough to fly across some 70 football fields, end to end, in just one second.
NASA’s Space Launch System, the most powerful rocket in use, will launch the Artemis II flight to circle the moon. Graphic by AFP via Getty Images
Two rocket firings, one 50 minutes after liftoff and another about an hour later, will set the spacecraft on an elliptical orbit with a high point of 43,760 miles, higher than any astronauts have flown since the final Apollo moon mission in 1972.
The Orion capsule will separate from the Interim Cryogenic Propulsion Stage, or ICPS, three hours 23 minutes after launch.
All of those maneuvers combine to give the crew a 24-hour-long orbit, allowing plenty of time to check out their Orion capsule, making sure the communications, navigation, propulsion and life support systems are working properly before heading to the moon.
Those tests include “waste collection,” NASA’s way of referring to use of the capsule’s cramped toilet compartment. All of the testing will be carried out while the spacecraft is close enough to get home quickly in the event of any major problems.
Glover, assisted by Wiseman, also will test the Orion’s maneuvering system, approaching and flying around the spent SLS upper stage to mimic the sort of flying that will be required by future crews to rendezvous and dock with landers or NASA’s planned Gateway space station in lunar orbit. If time is available, Wiseman might get a bit of hands-on flying himself.
“It is a crazy first day,” Wiseman told CBS News. “We come off the pad here at the Kennedy Space Center, and we have about 90 minutes (for) one trip around the Earth at low Earth orbit … making sure everything looks really good at a basic level. And then we head out to (44,000) miles from Earth for a 24-hour orbit.
“That one 24-hour orbit gives us time to check out all of (Orion’s) environmental control, life support systems,” Wiseman said. “Can it scrub our carbon dioxide? Can it keep us alive? Can we drink water? Can we go to the bathroom? All those basic human functions. … We’ve got to go get those things tested before we press out to the moon.”
Assuming no major problems, the Artemis II crew will take a four-hour nap then get up for yet another critical rocket firing, this one using the main engine of Orion’s service module to put the craft in an orbit measuring 44,555 miles by 115 miles.
The astronauts then will grab another four-hour nap while flight controllers assess Orion’s performance before making a final go-no go decision to send the crew on to the moon.
They will have a lot to consider. The Lockheed Martin-built Orion spacecraft will be flying for the first time with a full suite of life support systems. The only other launch of an SLS and Orion was the unpiloted Artemis I test flight in 2022.
While the capsule itself performed well, the Orion’s heat shield was heavily damaged by the 5,000-degree heat of reentry. The Artemis II Orion is equipped with the same type heat shield, but after extensive post-flight testing, NASA managers deemed it safe to fly again “as is” using a different reentry trajectory, one that will prevent the sort of internal heating that caused the Artemis I problem.
Four more days to the moon
Assuming Orion gets a clean bill of health after after engineers review data from its first day in space, the crew will set up for the critical “trans-lunar injection,” or TLI, burn about 25 hours after launch using the service module’s engine.
The six-minute five-second engine firing will boost the ship’s velocity by about 900 mph, just enough to push it out of Earth orbit to begin the four-day coast to the moon.
While confident the rocket and their Orion capsule will carry them safely around the moon and back to a Pacific Ocean splashdown on April 10, the astronauts and their families understand the risks.
“It’s a test flight, and we have to be willing to take that risk,” Hansen said in an interview with CBS News. “And that’s the one that I talk to my family about. I’m very optimistic. I truly believe the most likely outcome is we’ll all be totally fine when we hit the Pacific Ocean nine and a half days later.
“But I want everyone to understand that you can lose a crew. And if we do, that shouldn’t shock us. And the most important thing we do next is we stack the next rocket, and we’d let the next four volunteers get on top of it and go.”
Flying around the moon for the first time in half a century
The astronauts will not land on the moon or even go into lunar orbit as the Apollo 8 crew did in their historic 1968 flight — the first piloted flight of a Saturn 5 rocket and the first to carry astronauts beyond low-Earth orbit.
Instead, the Artemis II crew will leave Earth on a “free return” trajectory, flying around the leading edge of the moon and using lunar gravity to bend the ship’s path back toward Earth.
NASA’s Artemis II mission plans to take a crew of four in the Orion spacecraft around the moon and back to Earth. Graphic by Jonathan WALTER and Paz PIZARRO / AFP via Getty Images
The trans-lunar injection burn will precisely set up the reentry trajectory with only minor tweaks required for an on-target splashdown. In other words, if there are major problems with Orion’s navigation or propulsion system after heading for the moon, the capsule will still make its back to Earth without any help from its thrusters.
The free return trajectory will carry the crew within about 4,100 miles of the moon’s surface at closest approach.
“If you held a basketball out from your hand and you looked at it, that’s about how big the moon will appear in the crew’s window as we do a fly by,” said lead flight director Jeff Radigan.
The far side of the moon — and the greatest distance from home
The crew will become the first humans to see large regions of the moon’s normally out-of-view far side.
While Apollo astronauts flew behind the moon near its equator, those missions were timed to ensure daylight at the landing sites facing Earth and the far side was in darkness. This time around, assuming an April 1 launch, 21% of the far side will be in sunlight when the Artemis II astronauts sail past, giving the crew a chance to directly see portions of the far side never before observed by human eyes.
“Four people, two windows pointing right at the lunar surface, and a highly choreographed dance, really, of who has the cameras, who has the other voice recording devices, and how we are supporting the people actually taking the data and making the observations,” Koch said.
“Of course, the moon has been imaged by so many remote sensing satellites, but there are actually places on the far side that have never been seen by human eyes. … So hopefully, when we get there, we’ll be ready to take that on and still make the most of those couple hours we have.”
Said Glover: “Twenty-four men have seen the moon, and we’re going to send the first set of woman’s eyes. And there’s actually some differences, they think that she can potentially see colors that, you know, we (men) may not see.”
Assuming an on-time launch, the crew will end up flying farther from Earth than the crew of Apollo 13, who flew an unplanned free-return trajectory of their own following a catastrophic explosion on the way to the moon in 1970. They reached a record distance of 248,655 miles from Earth before finally heading home.
The Artemis II crew is expected to beat that mark by about 4,000 miles, setting a new record of 252,000 miles.
A high-speed plunge back to Earth
Assuming the Artemis II launch goes well and no major problems are found during the crew’s first day in orbit, the TLI burn will set up the lunar flyby and put the ship on course for reentry and splashdown at the end of the mission on Friday, April 10.
Only minor course corrections will be needed to precisely target reentry.
Pulled in by Earth’s gravity, the Orion crew capsule will be moving at some 25,000 mph — roughly 7 miles per second — when it slams back into the discernible atmosphere about 75 miles above the Pacific Ocean.
The crew capsule will be quickly engulfed in an electrically charged fireball as its 16.5-foot-wide heat shield endures temperatures as high as 5,000 degrees. It will block radio signals for about five minutes.
Lessons from damage to heat shield on Artemis I
Orion will return to Earth using the same type heat shield used in the unpiloted Artemis I flight in 2022. It is designed to prevent temperatures where the shield joins the base of the capsule from exceeding 500 degrees.
During the Artemis I mission, the capsule followed a planned “skip” trajectory that caused it to drop into the upper atmosphere, then back out again before making its final descent to splashdown. The skip trajectory offers NASA a wider range of splashdown options in case bad weather makes a targeted landing site problematic.
But post-flight analysis showed the Artemis I heat shield suffered unexpected damage during entry, with large chunks of the outer “char” layer unexpectedly popping off. The capsule landed safely, but NASA kicked off an exhaustive investigation to determine why the heat shield failed to behave as computer models suggested.
The heat shield protecting the Orion capsule during an unpiloted test flight in 2022 was seriously damaged during reentry. NASA
Engineers determined that high entry heating is what makes the outer char layer permeable enough for gas generated in lower layers, through a process called pyrolysis, to escape.
During the Artemis I capsule’s long skip back out of the discernible atmosphere, entry heating lessened, the outer layer became impermeable and gas generated by pyrolysis in lower layers had now way to escape. Pressure built up and the gas pockets pushed chunks of the outer heat shield away.
Engineers concluded that a different entry trajectory, one with an initial dip into the upper atmosphere followed by a shorter-duration climb back out, would allow the outer char layer to erode and burn away more evenly without creating damaging sub-surface cracks and pressure build ups. An independent review team agreed with those conclusions.
While NASA is planning to use a different design on the Artemis III mission next year, agency managers opted to stick with the heat shield already in place on the Artemis II Orion. Given the Artemis II free return trajectory, “we can safely, and with high degrees of success, control that entry environment,” said Amit Kshatriya, NASA’s associate administrator. “And so that’s the plan.”
Splashdown and recovery
From the start of reentry to splashdown: 13 minutes.
Nine minutes after the start of reentry, now back in touch with mission control, the Artemis II crew will begin monitoring the deployment of 11 parachutes intended to stabilize and slow the capsule to a splashdown velocity of just 15 mph or so. It is the most complex parachute system ever flown on a piloted spacecraft.
After rapidly decelerating during passage through the peak heating zone, the Orion capsule will be descending at about 300 mph when when three small parachutes will be deployed, pulling a protective cover away from the main parachute storage bay as the spacecraft passes through an altitude of about 36,000 feet.
Two 23-foot-wide drogue chutes then will unfurl and inflate at around 24,000 feet to stabilize the capsule followed by three pilot chutes that will pull out Orion’s three 116-foot-wide main parachutes. They will inflate in stages between 8,000 feet and 4,000 feet, slowing the ship’s descent from around 300 mph to splashdown velocity.
The parachute system is designed to bring a crew safely back to Earth if one drogue or one main parachute fails to inflate. Additional failures would mean higher impact velocities, but NASA has not provided any detailed information about such outcomes.
But in a normal descent, Orion will hit the water heatshield first at a velocity of 15 to 17 mph and, hopefully for the crew, stay in that orientation without flipping over due to waves or wind. If it does, airbags will flip it back upright.
Wiseman, Glover, Koch and Hansen will be helped out of the capsule and airlifted by helicopter to a waiting Navy amphibious transport dock, or LPD. After initial medical checks and calls to family and friends, the astronauts will head back to shore for a flight home to the Johnson Space Center.
The Orion capsule, meanwhile, will be hauled into the recovery ship’s flooded “well deck” and secured on a platform for the trip back to shore. NASA engineers will spend weeks reviewing data from the Artemis II flight while pressing ahead with planning for the next mission.
