C Stuart Hardwick有关航天的回答收集(四)

谁是Eugene Shoemaker?,为什么美国航空航天局(NASA)将他的骨灰放在聚碳酸酯胶囊里并放在月球上?

Gene Shoemaker was an American geologist who determined that Barringer Crater was created by an impact and who assembled most of the pre-Apollo evidence that the moon’s craters were of meteoric, rather than volcanic origin. He went on to train the Apollo astronauts in geology and to lead early efforts to survey space for asteroids capable of threatening Earth.

Gene Shoemaker是一位美国地质学家,他确定巴林格陨石坑是由撞击产生的,在阿波罗计划之前的大部分证据都是他收集的,证明月球陨石坑是陨石而不是火山爆发的。 他继续对阿波罗(Apollo)宇航员进行了地质方面的培训,并领导了早期的工作,以调查太空中能够威胁地球的小行星。

土星五号火箭顶部的小型火箭是用来干什么的? What was the small rocket on the top of the Saturn V rocket used for?

The Launch Escape System.

请到wiki搜索 The Launch Escape System.

In the event of a failure during launch, a powerful solid rocket motor inside the LES tower would fire through multiple nozzles to carry the Command Module and crew to safety. A small rocket fired to one side to ensure the LES carried the CM clear of the main rocket stack.

如果在发射过程中发生故障,LES塔内的强大固体火箭发动机将通过多个喷嘴发射,以将指挥模块和机组人员带到安全地点。 一枚小型火箭向一侧开火,以确保LES携带CM离开主火箭堆。

In the event of a normal launch, a smaller motor would fire once the third stage ignited to carry the LES away along with the fiberglass Boost Protective Cover:


这个问题下的其他回答:@ Luc Boulesteix


Image: Apollo 11 Launch

That is indeed a small solid rocket motor.

What is its purpose?

As you might know, rockets aren’t exactly the most reliable form of transportation out there. You’re basically attaching yourself to a giant missile and riding off a huge controlled explosion, only to be propelled at speeds that would make the fastest military aircraft blush.

众所周知,火箭并不是最可靠的运输方式。 本质上来说,您就是坐到巨型导弹上,并让导弹进行巨大的受控爆炸,只是为了让以比军用飞机还快的速度飞行。

Rockets can contain thousands of parts, all of which need to work perfectly. By contrast, a single failure can result in rapid unscheduled disassembly.

火箭可以包含成千上万个零件,所有零件都需要完美工作。 相反,单个故障可能导致计划外的拆卸。

Because of this, rockets tend to do this a lot:


Image: Japanese private rocket crashes in flames right after launch

Extensive experimental data has shown that huge fireballs and rapid deceleration are hazardous to human health.


It is thus advantageous to be able to extract the crew from a failing launcher.


In the case of an emergency, this top-mounted rocket engine will fire, extracting the crewed capsule from the fiery pits of rocket-hell, and launching said capsule some distance away, to safety. Typically, a parachute will open once at a safe distance.

在紧急情况下,这种顶部安装的火箭发动机将起火,从火箭井的火坑中拉出乘员舱,并安全地将其发射到一定距离。 通常,降落伞会在安全距离打开一次。

Because of what it does, this rocket is generally reffered to as the Launch escape system. Once in orbit, the apollo spacecraft would jettison it to save weight. Newer capsules from Boeing and SpaceX are supposed to integrate this system within the capsule itself, so it might not be visible in future designs (though the Orion capsule will have it).

由于其功能,该火箭通常被称为发射逃生系统。 一旦进入轨道,阿波罗号航天器将抛弃它以减轻重量。 波音和SpaceX的较新舱应该将这个系统集成到舱本身中,因此在将来的设计中可能看不到它(尽管Orion舱会有)。

Finally, here’s a picture of it in action:


Image from Wikipedia.

如果你突然之中出现在月球的白天,没有宇航服,你会感到冷还是热?If you suddenly appeared on the moon during the lunar day without a space suit, would you feel hot or cold?

Cold, then hot, and also burning.


As soon at exposed to vacuum, all the moisture in or on or near the surface of the skin would boil, radically cooling the skin. This likely wouldn’t last long, and if you were standing in sunlight, you would quickly feel hot as the skin exposed to sunlight—now with no more moisture to cool it, started heating up in sunlight about 10% brighter than noon in the Sahara, with the insulation of vacuum to keep the temperature climbing.

一旦暴露于真空中,皮肤表面内或表面上或附近的所有水分都会沸腾,从根本上冷却皮肤。 这可能不会持续很长时间,而且如果您站在阳光下,当皮肤暴露于阳光下时,您很快就会感到发烫-现在皮肤中没有更多的水分可以冷却皮肤,因此开始在比地球撒哈拉的白天亮10%的阳光下升温。 真空隔热层会让你保持温度上升。

Then, in about the time it took to think “now isn’t that odd?” you’d pass out, likely for the last time.


Also, if you appeared standing in soil that had been sitting in the sun and wearing anything other then sturdy leather work boots, the 250 F would burn your feet.


火星因土壤生锈而变红,对吗? 如果是这样,这是否意味着火星有氧气?Mars is red because of the soil rusting, right? If that’s the case, does that mean Mars had an atmosphere of oxygen?

No. Mars is red because the soil rusted—several billion years ago.


And that’s very interesting, because on Earth, most of the iron was in non-oxidized forms, including vast quantities dissolved in the oceans, until life freed up enough oxygen to cause it to oxidize and precipitate out.


So the fact that Mars is red at all suggests that it once had life—or at least an ocean and some oxygen—which suggests life. But of course, all that iron could have just oxidized during the formation of the planet in some process different that what happened here.

因此,火星完全是红色的事实表明它曾经有生命-或至少是海洋和一些氧气-暗示了生命。 但是,当然,所有铁可能只是在行星形成过程中被氧化,其过程与此处发生的过程有所不同。

But to answer your question, whether that life has hung on or not, that fact that Mars is red now does not mean there is oxygen in its air—it means there once was, long ago.


如果月球运行在离地球400英里的轨道上,月球可能有大气吗?Would the moon have an atmosphere if it was stably orbiting 400 miles away from earth?

The moon could not hold onto an atmosphere in a 400 orbit—Earth would steal its atmosphere away.

That aside, if you were to give the moon enough atmosphere for liquid water to exist on the surface, it would take perhaps 100,000 years to lose it due to its insufficient mass. Being so close to Earth would partly shield the moon without our magnetosphere, but that wouldn’t be enough to stop the losses. The moon simply doesn’t have enough mass to hang on.


除此之外,如果要给月球提供足够的气氛以使液态水存在于表面上,由于其质量不足,月球会在100,000年之间失去它。 离地球太近会在没有磁层的情况下部分屏蔽月球,【??】但这不足以阻止损失。 月亮根本没有足够的质量来吸引。

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