新型聚變晶體燃料可使飛船三個(gè)月抵達(dá)火星

人類開啟航天時(shí)代已經(jīng)超過半個(gè)世紀(jì)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(xué)家卡爾·薩根曾經(jīng)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(diǎn)距離，海水大約漫到了我們的腳踝?！彼_根說這些話的時(shí)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(shí)在太大了，大的讓人絕望。美國宇航局在1970年代發(fā)射的旅行者-1號(hào)探測(cè)器是迄今人類制造的飛行器中飛行速度最快的，其速度達(dá)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(jì)。即便是抵達(dá)火星，使用傳統(tǒng)火箭發(fā)動(dòng)機(jī)推動(dòng)，我們也需要花費(fèi)6～8個(gè)月的時(shí)間。而諸如曲率驅(qū)動(dòng)之類的技術(shù)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(xiàn)實(shí)。然而如果使用一種聚變?nèi)剂?，我們或許可以將前往火星的飛行時(shí)間縮減為3個(gè)月，這就是“二鋰晶體”——是的！就像《星際迷航》里那樣。

不過當(dāng)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(zhì)，飛船的乘員們花費(fèi)很長的時(shí)間找到這種物質(zhì)晶體，而他們的飛船發(fā)動(dòng)機(jī)可以使用這種物質(zhì)達(dá)到超光速飛行。而在現(xiàn)實(shí)中，美國亞拉巴馬州亨茨維爾大學(xué)的一個(gè)科學(xué)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(shí)驗(yàn)室的研究人員一起研發(fā)一款新型推進(jìn)技術(shù)，其可以實(shí)現(xiàn)相當(dāng)于現(xiàn)有技術(shù)兩倍的推進(jìn)速度。

根據(jù)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(wěn)定分子)構(gòu)成的晶體形態(tài)，也就是所謂的“二鋰”晶體。從技術(shù)上說，二鋰應(yīng)當(dāng)是兩個(gè)鋰原子相互結(jié)合而成的，而鋰-6則有6個(gè)鋰原子組成，但是對(duì)于這一點(diǎn)就讓我們忽略它吧，畢竟只是作為一個(gè)比喻。

當(dāng)在高壓環(huán)境下將氘和鋰-6相互混合時(shí)，它們兩者將會(huì)發(fā)生聚變反應(yīng)并釋放能量。盡管目前看來聚變還無法作為一種成熟的產(chǎn)能技術(shù)，但是在不久的將來我們或許就可以擁有這種技術(shù)。

這種引擎被稱作“充電-1號(hào)脈沖能量發(fā)動(dòng)機(jī)”，按照設(shè)計(jì)它將和飛船的其它部分一起在太空中進(jìn)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(shí)需要應(yīng)對(duì)的技術(shù)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(shè)備的組裝，國際空間站就是對(duì)此最好的例證。一旦準(zhǔn)備就緒，人們就可以啟動(dòng)反應(yīng)堆。

飛船的理論最高速度可以達(dá)到10萬公里每小時(shí)。這幾乎已經(jīng)和地球圍繞太陽運(yùn)行的速度相當(dāng)。

然而，正如《經(jīng)濟(jì)參考》雜志指出的那樣，預(yù)計(jì)這種技術(shù)，不管是用于商業(yè)還是科學(xué)目的，只有當(dāng)美國軍方允許時(shí)才可能被使用，事實(shí)上，開展這些研究所使用的設(shè)備也都來自此前軍方的相關(guān)研究項(xiàng)目。當(dāng)然，這一計(jì)劃的實(shí)現(xiàn)也有賴于開發(fā)出一種產(chǎn)能大于耗能的核聚變技術(shù)。

'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.