荷馬·阿爾并未登上過月球。

但是阿爾和他在IBM的幾千名同事，以及美國國家航空航天局（NASA）的地勤人員們，卻以另一種特殊的方式，在人類的登月史上留下了印記。他們是一群默默無聞的計算機專家，然而沒有他們，阿波羅11號飛船上的宇航員們就不可能在1969年7月20日成功登月，之后活著返回地球。沒有這些與美國政府簽約的工程師、技師、分析師和程序員，就不可能成就載人航天這一壯舉。

現(xiàn)任IBM研究部門執(zhí)行副總裁的約翰·凱利表示：“NASA把一切都押在了我們身上，我們也把一切都押在了他們身上。”他還記得自己十幾歲時，在電視上看到登月成功的畫面的場景。“如果當時出了什么問題，如果計算機出了故障，那天肯定不會是開心的一天。”

實際上，那天的確出了一些問題，好在它并未嚴重到毀掉人類歷史上的這次壯舉。

《財富》雜志近日采訪了前IBM公司數(shù)學家、軟件程序員阿爾。在阿波羅11號載人登月任務期間，他就在NASA位于休斯頓的約翰遜航天中心工作。阿爾今年73歲，已經(jīng)退休了。采訪中，他向《財富》雜志批露了這次登月任務中發(fā)生的一個幾乎葬送了整個任務的重大險情。

起步

阿爾于1968年加入了IBM，也就是阿波羅11號任務的前一年，那年他才21歲。作為一名少年老成的工程師和一名剛畢業(yè)的大學生，他毅然拒絕了為得克薩斯州的一家大型建筑公司寫軟件的工作，決定到NASA去實現(xiàn)自己的抱負。而IBM公司剛好滿足了他的三大標準：工作有挑戰(zhàn)性、能報效國家、工作地點在得州。

同年12月，阿爾完成了他在NASA的第一個大項目——為阿波羅8號編寫飛控軟件。阿波羅8號也是人類第一艘實現(xiàn)了載人繞月飛行并返回的飛船。飛船的操作有相當一部分是在他的幫助下完成的。他回憶道：“我可能是控制臺里最年輕的人了——甚至可能是整個休斯頓飛行系統(tǒng)部門里最年輕的一個。”

在經(jīng)過了7個月和4次發(fā)射任務后，NASA終于做好了登月的準備——阿爾也是一樣。他負責向IBM的電腦里輸入指令，這些指令最終會被傳輸?shù)桨⒉_11號飛船上，由飛船上的宇航員執(zhí)行。

阿爾說道：“肯尼迪的想法是把一個人送上月球，然后把他安全地帶回家，但是后半部分被很多人忘掉了。不過我向你保證，那些為任務控制中心編寫軟件的人，和那些在任務控制中心里工作的人，無時無刻都在想著這件事的重要性。”

奔月

NASA征用了IBM在紐約州奧韋戈的聯(lián)邦業(yè)務部門，用于制造和運行登月任務的指揮控制儀器以及計算器。這些儀器主要用于收集火箭遙測數(shù)據(jù)，確定飛行路徑，并且為美國航天項目的“水星計劃”、“雙子星計劃”和“土星計劃”改進軌道。到1966年，IBM已經(jīng)應用了現(xiàn)在十分著名的System/360 Model 75系列計算機。正是該系列計算機的成功，開啟了IBM電腦的黃金時代。

“這些新計算機的性能是‘雙子星計劃’所使用的計算機的三倍（NASA在“雙子星”計劃時使用的是前一代的IBM 7094 II型計算機），計算能力是‘水星計劃’所使用的計算機系統(tǒng)的50多倍。”當年的一份IBM公司的檔案如是說。

這種技術水平在當時雖然很了不起，但跟現(xiàn)在我們習以為常的技術相比，卻相形見絀。比如光是一部蘋果iPhone的計算能力，就比安裝在阿波羅飛船的控制艙和登月艙上的制導計算機還要強大幾百萬倍。

就在阿波羅11號開始向月面降落，即將邁出“人類的一大步”的關鍵時刻，危機陡然發(fā)生了。阿爾回憶道：“飛船里響起了警報聲，場面非常混亂，在你耳朵里響個不停。”

阿爾先是在耳機里聽到了警報聲。很快，任務控制中心里警燈閃爍，警報聲大作——出大事了！

大家起初并不清楚是什么觸發(fā)了警報。不過阿爾的團隊已經(jīng)排練過類似場景很多次了。他回憶到，他的團隊當時每周要演練3天，每天進行12次預案模擬，連續(xù)演練了3個月，總共進行了400多次測試。很多試驗故意設置了一些難題，比如在推進器失靈的情況下應該怎么辦——當然，90%的情況下都只有放棄任務這一條路。

回憶起當時IBM的計算機大樓里壓抑的氣氛，阿爾說道： “那一瞬間，我感覺整個30號樓里的空氣都被抽干了，因為任務在不應該的情況下被要求終止了。你絕對不希望發(fā)生這種事。”

然而演習跟真正的戰(zhàn)斗終歸不是一回事。“在真正的任務中發(fā)生這種事，總是會更加混亂，更加有壓力，更令人不安。”他補充道。

登陸

即便是對于這些在當時看來全新的技術，最終的發(fā)言權也依然在人類手中。

阿波羅任務的首席飛控總監(jiān)吉恩·克蘭茲曾經(jīng)要求NASA的計算機與航電專家杰克·加爾曼寫下飛船所有可能的故障情形和應對預案（加爾曼也曾經(jīng)在IBM的電腦上訓練過）。加爾曼拿出了那張預案表格研究了一會兒，最終決定任務應該繼續(xù)。

阿爾回憶道：“警報第一次響了10到15秒鐘后，他才說道：‘繼續(xù)執(zhí)行。’然后警報一次次地再度響起。”警報每響起一次，阿波羅任務的登月艙朝月球表面的下降速度就加快一分。不過加爾曼仍然向上級表示應該繼續(xù)執(zhí)行任務。

最后，大家終于明白發(fā)生了什么——飛船上的計算機超載了。由于某些故障，計算機試圖處理的數(shù)據(jù)，超出了自身所能處理的極限。計算機無法完成所有要求它們完成的任務，便觸發(fā)了警報。（《探索》雜志對此做了很好的科學解釋。）

“從軌道的角度看，除了繼續(xù)前進，沒有別的選擇。”阿爾說：“登月艙降落得很成功，如果我們取消了任務，那將是一場悲劇。”

人類的一大步

當他回憶起50年的事時，他好幾次強行抑制住自己的情緒。他說，回想起這段往事，他的感覺就像二戰(zhàn)老兵回憶起諾曼底登陸一樣。在收看上個月的諾曼底登陸紀念活動時，一種想法擊中了他。“我的眼睛濕潤了，哽咽了起來。這種感覺跟我談論起飛船的著陸、降落、海上降落這些事時的感覺是一樣的。”

“我覺得7月20日就是我們的‘諾曼底登陸日’。”他激動地說：“這一天，我們將人類從地球上解放了出來，人類實現(xiàn)了在另一個天體上行走。我們將人類從地球的束縛中解放了出來。”

今天的科學家則希望把火炬?zhèn)鬟f得更遠。IBM研究部門執(zhí)行副總裁約翰·凱利表示，阿波羅11號登月任務“是一項驚人的成就。這個國家所冒的風險，NASA所冒的風險，IBM所冒的風險——這些宇航空將自己綁在一個火箭上，飛躍25萬英里，到一塊冰冷的石頭上——都是驚人的。”

凱利也贊揚了IBM和NASA這種公立部門和私營企業(yè)間的合作關系。“作為企業(yè)，作為國家，我們需要多一點這樣的合作。不僅僅是漸進性的合作，而是要做一些真正的反省。我們承擔足夠的風險了嗎？我們準備好去登月了嗎？我們準備好真的去攻克癌癥了嗎？我們準備好去解決環(huán)境問題了嗎？我們有勇氣和必要的手段去解決這些問題嗎？”

“人類可以做到幾乎任何事。”凱利補充道：“只要他們下定決心。”（財富中文網(wǎng)）

譯者：樸成奎

Homer Ahr never stepped foot on the Moon.

But Ahr (pronounced “are”) along with thousands of his International Business Machines colleagues and on-the-ground partners in NASA, made their mark on history another way. They were the unsung computer whizzes responsible, on July 20, 1969, for helping Apollo 11’s astronauts touch down on the lunar surface—and return home to Earth, alive. Without these government contracted engineers, technicians, analysts, and coders, that miracle of a manned moonshot surely would have failed.

NASA “bet everything on us and we bet everything on them,” says John Kelly, now executive vice president of IBM’s research division, who remembers watching a televised broadcast of the lunar landing as a teenager. “If something had gone wrong, if those computers had failed, it would not have been a happy day.”

In fact, something did go wrong. But not wrong enough to ruin one of the greatest achievements in human history.

Fortune spoke to Ahr, a former IBM mathematician and software programmer who worked at NASA’s Johnson Space Center in Houston during the Apollo 11 mission, about his experience. (From a perch near his self-described “mancave” in Texas, he introduces himself over the phone as Homer, “l(fā)ike a homerun.”) Ahr, now 73-years-old and retired, described for Fortune an unsettling incident that almost derailed that momentous occasion.

The first steps

Ahr joined IBM in 1968 at age 21, a year before the Apollo 11 flight. A precocious engineer and recent college graduate, he had turned down a lucrative gig writing software for one of Texas’s biggest construction companies to work for NASA. A job with Big Blue met his criteria: Do something challenging; do something for the country; and do it in Texas.

Ahr made his first mark in December of that year writing code for the Apollo 8 flight, the first crewed mission to orbit the Moon and return. His instructions helped the spacecraft maneuver. “I was probably the youngest person on the console—maybe the youngest person in FSD [flight systems division] Houston,” Ahr says.

Seven months and four missions later, NASA was ready for its moonshot—and so was Ahr. He was responsible for inputting commands into IBM’s computers that ultimately would be transmitted to the Apollo 11 spacecraft to be executed by the astronauts on board.

“Kennedy’s vision was to land a man on the Moon—and bring him home safely. That latter part gets forgotten by a lot of people,” Ahr says. “But I guarantee you the people writing software for Mission Control Center and the people in Mission Control Center lived every day of our lives knowing just how important that was.”

Big Blue moon

NASA tapped IBM’s federal business, based in Owego, N.Y., to build and run the command-and-control machines and calculators needed to collect rocket telemetry, determine flight paths, and redirect trajectories for the space program’s Mercury, Gemini, and Saturn series of missions. By 1966, IBM had installed its now-famous System/360 Model 75 computers, the super-popular mainframe that kicked off and defined the company’s golden era.

“These new computers are three times more powerful than the Gemini installation”—which used IBM 7094 II computers, a predecessor—“and more than 50 times the power of the computing system which supported the Mercury program,” a contemporary document from IBM’s archives says.

While the technology was cutting edge for the time, the systems were far less capable than the technology we’re familiar with today. An Apple iPhone, for instance, is millions of times more powerful than the guidance computers installed on the Apollo mission’s command and lunar modules.

But as the Apollo 11 mission neared the moment of truth, beginning its descent toward the lunar surface, crisis struck. “Audible alarms went off in the spacecraft,” Ahr recalls. “It was very chaotic. It was going off in your ears.”

Ahr first heard the sirens through his hands-free headset. Soon, alarms and flashing lights began to go off inside Mission Control Center. Something had gone wrong.

It wasn’t immediately clear what tripped the buzzers. But Ahr’s team had rehearsed similar scenarios—a lot. The group had run simulations 12 times a day, three times a week, for three months, summing to more than 400 test runs total, he says. The trials, many of which involved intentionally suboptimal circumstances, like what to do in the event that a thruster malfunctioned, ended in abortion as much as 90% of the time, Ahr estimates.

“We knew what it felt like for the air to be sucked out of building 30 because an abort had been called when it shouldn’t have,” Ahr says, referring to the instant onset of depression that befell workers inside the facility where IBM’s so-called real-time computer complex, the mechanical brains of the mission, was housed, when a test-run went awry. “Boy, you don’t want to do that.”

But practice is no match for game day. “It’s always more chaotic or emphatic or disconcerting when it happens during a real mission,” Ahr adds.

Go for moon landing

Even in the midst of all this then-new technology, humans had the final say.

Jack Garman, a NASA computer specialist and avionics expert trained on IBM’s computers, had been asked by Gene Kranz, the mission's chief flight director, to write down all possible error conditions to prepare for any contingency. Garman, who died in 2016, studied a table he had written down which described all the failure modes and what to do about them as the alarms blared. Looking over the alerts, he determined that the mission should proceed.

“It took 10-to-15 seconds the first time [the alarm] occurred for him to say ‘Keep going,’” Ahr remembers. “Then it happened again and again and again.” Each time an alarm triggered, as the Apollo mission’s lunar module descended faster toward the Moon’s surface, Garman told his superiors to continue the mission.

Eventually, people got a grip on what had happened: Onboard computers were overloaded. Due to some error, the machines were trying to process more data than they could handle. Because the computers couldn’t accomplish all the tasks asked of them, they sounded off. (Discover Magazine has a good technical explanation.)

“From a trajectory standpoint there was no other call but to keep going,” Ahr says. “It was a good descent. It would have been a travesty if we had aborted.”

One giant leap

As he recollects the events that transpired fifty years ago, Ahr has to stifle an upwelling of emotion. He compares his response to the reactions veterans might have when looking back on the invasion of Normandy during World War II. While watching a commemoration of the D-Day landing last month, a thought struck him. “I started getting teary-eyed and choked up the same way I do when I talk about landings, splashdowns, or descents,” he says.

“I got to thinking that July 20th was our D-Day,” Ahr continues, audibly moved. “It was the day we liberated mankind from just walking on the Earth. We walked on another celestial body. We liberated man from the bounds of the Earth—for good. ”

Today’s scientists hope to carry the torch further. The Apollo 11 mission “was an incredible accomplishment,” says IBM Research’s Kelly. “The risks that the country took, that NASA took, that IBM took—these astronauts strapped themselves onto a rocket to go a quarter million miles to a cold piece of rock—is just amazing.”

Kelly praises the gamble of a public-private partnership that IBM and NASA forged. “We as companies and countries need to do more of that. Not just the incremental—we need to do some real soul-searching,” he says. “Are we taking enough risks? Are we going for the Moon? Are we going to try to really cure cancer? Are we really going to try to understand what’s going on with the environment? And do we have the guts and wherewithal to do it?”

“Humans can do almost anything,” Kelly adds, “if they put their minds to it.”