新型聚變晶體燃料可使飛船三個月抵達火星

新型聚變晶體燃料可使飛船三個月抵達火星

人類開啟航天時代已經超過半個世紀了，然而我們目前在太空中仍然不能以很高的速度飛行。著名的美國天文學家卡爾·薩根曾經這樣說道：“地球的表面是宇宙之海的海濱，就在最近，我們開始嘗試向外走出去一點距離，海水大約漫到了我們的腳踝。”薩根說這些話的時候是在1980年，但是遺憾的是在那之后我們也沒有再向前邁出一步。

造成這種情況的主要原因很簡單，那就是宇宙實在太大了，大的讓人絕望。美國宇航局在1970年代發射的旅行者-1號探測器是迄今人類制造的飛行器中飛行速度最快的，其速度達到了每秒10.5英里(約合16.9公里)，這一速度值跟光速相比簡直可以忽略不計。即便是抵達火星，使用傳統火箭發動機推動，我們也需要花費6～8個月的時間。而諸如曲率驅動之類的技術還仍然停留在科幻的程度上，在我們的有生之年都不太可能成為現實。然而如果使用一種聚變燃料，我們或許可以將前往火星的飛行時間縮減為3個月，這就是“二鋰晶體”——是的！就像《星際迷航》里那樣。

不過當然了，后者畢竟是科幻電影，兩者之間還是存在著差別。在電影中，這種晶體是一種罕見的物質，飛船的乘員們花費很長的時間找到這種物質晶體，而他們的飛船發動機可以使用這種物質達到超光速飛行。而在現實中，美國亞拉巴馬州亨茨維爾大學的一個科學家小組正和來自美國波音公司，美國宇航局以及橡樹嶺國家實驗室的研究人員一起研發一款新型推進技術，其可以實現相當于現有技術兩倍的推進速度。

根據通用電氣公司的在線科技雜志“Txchnologist”的說法，這種核聚變引擎將使用幾噸的氘(一種氫的同位素)和鋰-6(這是一種鋰的穩定分子)構成的晶體形態，也就是所謂的“二鋰”晶體。從技術上說，二鋰應當是兩個鋰原子相互結合而成的，而鋰-6則有6個鋰原子組成，但是對于這一點就讓我們忽略它吧，畢竟只是作為一個比喻。

當在高壓環境下將氘和鋰-6相互混合時，它們兩者將會發生聚變反應并釋放能量。盡管目前看來聚變還無法作為一種成熟的產能技術，但是在不久的將來我們或許就可以擁有這種技術。

這種引擎被稱作“充電-1號脈沖能量發動機”，按照設計它將和飛船的其它部分一起在太空中進行組裝，以便避開在各種精密的核聚變裝置配件在穿越大氣層時需要應對的技術困難，這種采用螞蟻搬家方式在外太空組裝的方式非常適合大型設備的組裝，國際空間站就是對此最好的例證。一旦準備就緒，人們就可以啟動反應堆。

飛船的理論最高速度可以達到10萬公里每小時。這幾乎已經和地球圍繞太陽運行的速度相當。

然而，正如《經濟參考》雜志指出的那樣，預計這種技術，不管是用于商業還是科學目的，只有當美國軍方允許時才可能被使用，事實上，開展這些研究所使用的設備也都來自此前軍方的相關研究項目。當然，這一計劃的實現也有賴于開發出一種產能大于耗能的核聚變技術。

'Dilithium crystals' could cut Mars travel time to three months

Humanity has been in space for a while, but we really haven't managed to go very far.Carl Sagan once said that "the surface of the Earth is the shore of the cosmic ocean, and recently we've waded a litile way out, maybe ankle deep" -- that was in 1980, and we haven't risked testing the water any deeper since then.

One of the main reasons for that, though, is that space is so frustratingly massive.Voyager 1 is the fastest manmade thing ever, but 17 kilometres per second is a piffling fraction of the speed of light.Even getting to one of our nearest neighbours, Mars, would take six to eight months using conventional spaceship engines.Ideas like warp drives are still theoretical, and unlikely to be seen within our lifetimes.However, it might be possible to cut that trip to Mars down to as few as three months using a form of fusion fuel -- "dilithium crystals".Yep, just like Star Trek.

It's not quite the same, of course.In the sci-fi series, the crystals are a rare substance that the crew spend an inordinate amount of time searching for, and their engines can use it to travel faster than the speed of light.This engine, currently under development at the University of Hunstville by a team working in collaboration with Boeing, Nasa and the Oak Ridge National Laboratory, would by comparison be about twice as fast as the best current technology.

According to Txchnologist, General Electric's online tech magazine, this fusion reactor would be fuelled by "a few tonnes" of deuterium (a heavy isotope of hydrogen) and lithium-6 (a stable molecule of lithium) in a crystalline structure -- hence the "dilithium crystal" claim.Technically, dilithium is a molecule with two covalently bonded lithium atoms, while lithium-6 features six bonded atoms, but we can forgive them for the temptation of using a litile poetic license.When the deuterium and the lithium-6 are forced together under high pressure they undergo a fusion reaction -- a process which they're still trying to turn into a net producer of energy.While fusion isn't yet a viable fuel source, recent developments in the fi eld seem to indicate that we can't be far away.

The engine, dubbed the "Charger-1 Pulsed Power Generator", would be constructed in space along with the rest of the spaceship to avoid the tricky engineering difficulties of getting all that delicate fusion equipment up through the atmosphere -- just like the International Space Station.Once ready, the reactor would be engaged, and millions of amps are passed through super-thin lithium wires in 100 nanosecond pulses -- this could generate up to three terrawatts of power.Those wires vaporise into plasma, which is collapsed onto the core of deuterium and lithium-6, inducing a fusion reaction.