(单词翻译:单击)
If there's anything that we've learned about space travel over the last 56 years, it's that it's dangerous.
如果我们从过去56年的太空旅行中得到了什么经验的话，那就是它很危险。
So space agencies like NASA do all they can to minimize the risks, most importantly, the risks to astronauts' lives.
所以像宇航局这样的太空机构会尽一切可能降低风险，最重要的是，降低对宇航员生命的威胁。
But learning how to deal with those risks has been an ongoing process.
但学习如何应对这些风险一直是个持续的过程。
And in some cases, NASA has had to learn from profound tragedy.
在某些例子中，宇航局不得不从深刻的悲剧中吸取教训。
One of those tragedies was the Apollo 1 fire on January 27, 1967,
其中一个悲剧是1967年1月27日的“阿波罗一号”着火。
which claimed the lives of the three astronauts involved: Gus Grissom, Ed White, and Roger Chaffee.
有三名宇航员丧命，分别是维吉尔·格里森，埃迪·怀特和罗杰·查菲。
Both Congress and NASA immediately launched investigations,
国会和宇航局立即展开了调查，
and what they learned changed a lot about how we've approached spaceflight ever since.
从此以后，他们根据吸取的教训对航天飞行做了很多改变。
The plan for the Apollo 1 mission was to test the command module, the capsule on a rocket where the astronauts sit, in low Earth orbit.
“阿波罗一号”任务的计划是测试航天员坐的指令舱，它在近地轨道上运行。
Since eventually, NASA wanted to send that command module to the Moon.
因为最终，宇航局想把指令舱送到月球上。
The fire happened during a sort of rehearsal for the launch.
大火是在一次发射演习中发生的。
It was what's known as a "plugs-out" test, meaning that the rocket was unfueled,
这是所谓的“拔除插头”测试，意思是火箭未加燃料，
and it didn't have the explosive bolts that would separate the different stages of the rocket in flight.
而且该火箭没有爆炸螺栓，它可以在飞行中将火箭的不同舱分开。
Since there weren't as many explosives or any fuel around, NASA mission control thought that the test would be safe.
因为周围没有那么多爆炸物或任何燃料，宇航局控制中心认为测试是安全的。
But obviously, they were wrong.
但显而易见，他们错了。
After the astronauts got inside the capsule, it was filled with 100% oxygen gas at 115 kilopascals,
宇航员进入太空舱后，里面充满了纯氧，气压是115千帕，
which is about 15% higher than standard air pressure at sea level.
这要比海平面的标准气压高15%。
There was an electrical failure during the test, and the resulting spark caused the fire.
测试中发生了电路故障，最终火花导致了大火。
The pure oxygen atmosphere was completely consumed within thirty seconds, and the astronauts couldn't open the hatch to escape.
纯氧在30秒之内消耗殆尽，宇航员没能打开舱口逃生。
Meanwhile, the smoke billowing out of the command module kept the launchpad personnel from being able to rescue the astronauts,
与此同时，指令舱内冒出滚滚烟雾，阻止了地面工作人员救援宇航员，
because there were no smoke masks at the launchpad.
因为发射台没有防烟面罩。
The investigations into the fire found that several factors,
火灾调查发现几个因素导致了这场悲剧，
both on an engineering level and on an organizational level, contributed to the tragedy.
工程水平和组织层面上都有。
NASA implemented every suggestion made by the investigation committees,
宇航局执行了调查委员会提出的所有建议，
leading to major changes that have made spaceflight much safer, even though it is still dangerous.
做了许多重大改变使得航天更安全，即使它仍相当危险。
One of the biggest engineering-related changes they made was to the gases they used to fill the capsule.
工程方面的一个最大改变是更换了填充太空舱的气体。
The first problem was the fact that they used pure oxygen, which was meant to make the capsule lighter, so it would take less fuel to launch.
第一个问题是他们过去使用纯氧，目的是使太空舱变轻，这样发射时所需燃料就会更少。
Plus, breathing pure oxygen would get rid of the nitrogen in the astronauts' bloodstreams,
而且呼吸纯氧会除去宇航员血流中的氮气，
which meant that they wouldn't have to worry about nitrogen bubbles forming in their blood during the launch and causing the bends.
这意味着他们不必担心发射过程中在血液里形成氮泡并导致关节疼。
But oxygen is really flammable, it's basically what fire runs on.
但是氧气助燃，火主要靠氧气来燃烧。
You don't want pure oxygen near any kind of spark, and you definitely don't want it anywhere that a fire could be fatal.
你不能让纯氧靠近任何火花，你也不能让它靠近致命的火灾。
The other issue was that the pressure inside the capsule was higher than the pressure outside, and the fire just made that worse.
另一个问题是舱内的压力比舱外高，火灾使事情变得更糟。
The hatch opened inward, and the extra pressure inside meant that the astronauts couldn't open it.
舱口向内开，多余的压力使得宇航员打不开它。
That's why, ever since, instead of using a high-pressure, entirely oxygen atmosphere,
这就是为什么从此以后，宇航局不再使用高压，纯氧的环境，
NASA has used a mix of gases at standard atmospheric pressure.
而是在标准气压下使用混合气体。
For the rest of the Apollo missions, the atmosphere inside the capsule during the launch was made up of 60% oxygen and 40% nitrogen,
在接下来的“阿波罗”任务中，发射期间舱内的大气是由60%的氧气和40%的氮气构成的，
while the astronauts breathed pure oxygen inside their spacesuits.
宇航员可以在太空服内吸收纯氧。
It was still a higher oxygen concentration than Earth's atmosphere,
它仍比地球大气中的氧浓度高，
but it was low enough that a fire wouldn't spread too rapidly for astronauts to escape.
但它已经足够低，以至于一场大火不会迅速蔓延，宇航员能够逃生。
NASA made another major engineering change, too:
宇航局也做了另一项重大的工程改变：
they started constructing the command module, and astronauts' suits, entirely out of non-flammable materials.
开始建造的指令舱和太空服，都是用非燃烧材料制作的。
This way, any electrical spark would have nothing to catch on.
这样，任何电火花都没办法燃着它们。
And to make sure the materials they used were up to scratch, the command module was tested to make sure that it would be safe in a fire.
为了保证他们使用的材料达到标准，指令舱要经过测试，保证在火灾中安全无虞。
But NASA changed more than just the gases and materials they used.
但宇航局不仅改变了使用的气体和材料。
They also overhauled their safety procedures and attitude toward spaceflight as a whole.
他们还彻底改革了他们的安全程序和对航天的态度。
The tragedy was a huge wakeup call for NASA.
这一悲剧给宇航局敲响了警钟。
They realized that, as an organization, they were so focused on beating the Soviet Union in the space race that they'd become somewhat...cavalier...about safety.
他们意识到，作为一个组织，他们太集中于在太空竞赛中打败苏联了，而忽略了安全。
Before the fire, for example, there were no fire safety procedures in place,
例如，在火灾之前，这里没有消防安全程序，
and they only had minimal firefighting equipment at the launchpad.
而且他们在发射台只有极少的消防设备。
The command module hadn't been tested in simulations to see if it met any safety standards,
该指令舱没有在模拟中进行测试，以确定它是否符合安全标准。
and when the test was underway, there were no emergency staff present, like EMTs or firefighters.
测试开始时，没有急救人员在场，比如急救医疗技术员或消防员。
So NASA implemented a whole series of changes to fix every one of those problems, and resolved to be a lot more cautious in general.
所以宇航局实施了一系列的改变来解决这些问题，决心要更加谨慎。
In the words of Gene Kranz, who led Mission Control for the Apollo program:
用控制中心“阿波罗”项目领导人克朗兹的话来说：
"We will never again compromise our responsibilities. Mission Control will be perfect."
“我们永远不会再对我们的责任妥协。控制中心将会更完美。”
