Since the ancients named it for the God of War,

自從古人以戰神命名火星後，

it has had a unique hold over the human imagination.

它在人類的想像中佔有特別地位。

Even before humans set foot on the moon,

甚至在人類登陸月球前，

it was seen as the next step but why?

踏上火星就已決定是下一步，但是為什麼？

There are similarities between Mars and Earth.

火星與地球間有許多相似處。

It has a 24-hour day and four seasons.

一天有 24 小時還有四季。

Though its air is too thin to breathe,

雖然火星的空氣太過稀薄無法呼吸，

and its surface too cold for unsheltered life,

表面也太冷無法保護生命，

it is far more astronaut-friendly than any of the other planets.

但對太空人來說，火星的條件比其他任何行星都還友善。

It has huge canyons and vast volcanoes.

火星有巨大的峽谷和火山。

It's riverbeds, deltas, and dried lakes speak of a past more watery than its arid present.

其中的河床、三角洲和乾涸的湖泊，過去有著豐富的水，現在卻是一片乾燥。

Yet, although it is scarce and briny,

然而，雖然水分稀少、鹽分也高，

there are still some liquid water on Mars today, and water is key to life.

目前火星上仍有些液態水，而水正是生命的關鍵。

The possibility that Mars once had life

火星曾有生命的可能性，

or might just possibly still have it today

或現今仍可能有生命存在，

is one of the reasons more space probes have been sent there than to any other planet.

正是現在越來越多太空探測器送上火星，而不是其他行星的原因之一。

NASA's InSight probe,

NASA 的洞察號火星探測器，

which landed in November is the latest,

最近在去年 11 月降落在火星，

and Europe's ExoMars rover will arrive next year.

而歐洲火星探測計畫的漫遊車將於明年抵達。

NASA talks of sending humans to Mars on a new spacecraft within the next two decades.

NASA 談到在未來二十年內將人類送入火星的新太空船。

Elon Musk's space technology company SpaceX has plans as early as 2024.

伊隆．馬斯克的太空技術公司 SpaceX ，計畫最早在 2024 年就可以做到。

Such missions with crews would be among the biggest technical challenges humans have ever undertaken.

這樣的任務對相關人員來說，將是人類有史以來面對到最大的技術挑戰。

The journey can only be made when the planets are properly aligned.

只有當行星排成一線時，才能做到這樣的旅程。

That only occurs roughly every 26 months,

這種情況約每 26 個月發生一次，

but even then, it takes around nine months

但即便如此，大約需要 9 個月，

to travel from one planet to the other.

才能從一個行星到另一個行星。

The challenge of a life-support system that can operate for years without resupply is daunting.

維生系統有一大難題要克服，必須要在缺乏補給的狀況下運作多年。

The cost will be high and the hurdles immense.

成本高、挑戰也多。

But the challenge is so exciting,

但是，挑戰總是讓人興奮，

it seems certain that some will try it,

有些人似乎會想嘗試，

and quite likely that some will die trying.

而有些人很可能會死於嘗試中。

Coming up next Thursday, the hunt for oceans in space.

下週四將在太空中尋找海洋。