【聯合報╱By KENNETH CHANG╱陳世欽譯】
Drifting for Years, Until Now
For 17 years, it has been drifting on a lonely course through space. Launched during the disco era and shuttered in 1997, the spacecraft is now returning to the civilization that abandoned it.
A group of civilians headquartered in a decommissioned McDonald’s have reached out and made contact with it — a long-distance handshake that was the first step toward snaring it back into Earth orbit. The zombie spaceship is coming home.
After 36 years in space the International Sun-Earth Explorer- 3 appears to be in good working order. The main challenge, the engineers say, is commanding it. Its fragmented operating manual is sometimes contradictory.
“We call ourselves techno-archaeologists,” said Dennis Wingo, an engineer and entrepreneur who, along with his company, Skycorp, took on the project as if it were a stray puppy.
“No one else was going to do it,” he said, “and it seemed like the right thing to do.” In May, using the Arecibo Observatory radio telescope in Puerto Rico, the team communicated with the spacecraft , making it the first private organization to command a spacecraft outside Earth orbit, he said. Mr. Wingo said the team should be ready to fire the engines within weeks.
NASA, the American space agency, launched ISEE-3 in 1978. The craft orbited the sun between the sun and the Earth, allowing scientists to observe for the first time the high-speed stream of particles known as the solar wind before it reached Earth. Then i t was aimed at Comet Giacobini-Zinner, passing through the tail in September 1985.
Since its retirement in 1997 , the craft has been looping around the sun on a 355-day orbit. Like a faster racecar lapping the rest of the field, ISEE-3 will catch up to and pass Earth in two months.
That is exactly what Robert W. Farquhar, the craft’s flight director, intended. Dr. Farquhar came up with the intricate orbits that moved ISEE-3 to various locations in the solar wind, and then with the idea of using ISEE-3 to visit Giacobini- Zinner.
Three rocket burns in 1986 set it on a course to zoom about 50 kilometers above the surface of the moon 28 years later, on August 10, 2014, swinging ISEE- 3 into orbit around Earth. Dr. Farquhar suggested that a space shuttle could bring it to the ground.
The rest of NASA was not looking that far ahead. In 1999, the agency upgraded its Deep Space Network, the system that communicates with distant space probes. The old transmitters that could talk with ISEE-3 were thrown away. But ISEE-3 was never turned off; it was still broadcasting, waiting for its next command.
NASA looked into reviving contact for the 2014 flyby, but concluded that the scientific payoff would not be worth the effort and money. In February, Leonard N. Garcia, a NASA employee who had set up a Facebook page promoting ISEE-3, conceded new transmitters “would be at a price no one is willing to spend.”
Mr. Wingo and Keith Cowing, the editor of NASA Watch, decided reviving contact with ISEE- 3 was a worthy effort. “Not only is it not impossible,” Mr. Wingo said, “I think it can work, and I know how to do it.”
About 20 others joined the effort, including many members of the first ISEE-3 team. On RocketHub, a crowdfunding website, they asked for $125,000 to help pay the costs. They collected nearly $160,000, from 2,238 donors.
Mr. Wingo has now persuaded NASA to use the Deep Space Network to pinpoint ISEE-3’s trajectory, to calculate the rocket burn required to put it on a path to Earth orbit. Dr. Farquhar’s 1986 calculations were close, but not exact. Slight errors are magnified over time, and now the spacecraft could be on course to splat into the moon.
Now 81, Dr. Farquhar is half-retired but collaborating with the reboot effort . He wants to send ISEE-3 out to visit yet another comet. Mr. Wingo protests that it would cost too much money.
“We’ll go to the comet,” Dr. Farquhar said. “Trust me.”
中譯
它已在太空孤獨漂泊17年。這艘太空船在迪斯可盛行的時代發射，1997年關閉，如今即將重回當初遺棄它的文明的懷抱。
一群以一間廢棄麥當勞餐廳為總部的民間人士已經與它搭上線。這種長距離握手是將它引回地球軌道的第一步。這艘僵屍太空船要回家囉。
「國際太陽-地球探險家3號」（ISEE-3）太空船進入太空已36年，狀況似乎還很好。工程師說，主要挑戰在於如何指揮它。它不完整的操作手冊裡時有矛盾。
工程師兼創業家溫戈與他的「天空公司」執行這項計畫，彷彿照顧一隻流浪幼犬。他說：「我們以科技考古學家自居。這事別人不會做，卻似乎該做。」
他說，該團隊五月以波多黎各艾里塞波觀察站無線電望遠鏡連絡ISEE-3，成為第一個指揮地球軌道外太空船的民間團體。溫戈說，該團隊應可在數周內做好發動引擎的準備。
美國太空總署（NASA）1978年發射ISEE-3。它在太陽與地球之間環繞太陽飛行，使科學家首次得以在又名太陽風的高速太陽粒子群抵達地球之前，觀察它們。它接著鎖定賈科比尼辛納彗星，並於1985年9月穿越它的尾部。
1997年除役後，ISEE-3不斷在一個355天的軌道環繞太陽飛行。它有如一輛繞著賽車場飛馳的更快速賽車，預計2個月後就會飛越地球。
這正是ISEE-3飛行計畫主管法庫哈爾的打算。他算出使ISEE-3移動到太陽風不同位置的複雜軌道，然後想到導引它去拜訪賈科比尼辛納彗星。
1986年火箭三次點火使ISEE-3預計在28年後，也就是2014年8月10日，進入可使它抵達距月球表面約50公里的軌道，同時使它進入地球軌道。法庫哈爾說，應該可以用太空梭把它帶回地面。
NASA並未想到這麼遠。1999年NASA把連繫遙遠太空探測器的「太空深處網絡」升級，並丟棄可與ISEE-3溝通的舊傳送器。然而ISEE-3從未關機，還在發送訊號，等候新指令。
NASA曾經考量趁2014年這次飛掠恢復接觸，最後認為科學上的回報有限，不值得投入如此大量的努力與金錢。NASA員工賈西亞今年二月設立一個有關ISEE-3的臉書網頁。他說，新傳送器價格高到「沒人願意負擔」。
溫戈與「NASA觀察」雜誌主編柯文認為，與ISEE-3恢復接觸值得嘗試。溫戈說：「我認為，這不僅不是不可能，而且可行。我知道如何辦到。」
大約另有20人加入這個行列，許多是ISEE-3最初團隊的成員。他們上群眾募資網站RocketHub籌募12.5萬美元以支應成本，最後獲得2238名捐款人捐贈將近16萬美元。
溫戈已經說服NASA利用「太空深處網絡」精準標出ISEE-3的軌道，同時計算使它進入地球軌道途徑所需的火箭點火。法庫哈爾1986年的計算結果非常接近，但不夠精準。經過一段時間後，細微的錯誤會放大。如今，ISEE-3可能已經進入衝向月球的路徑。
高齡81的法庫哈爾已經半退休，卻參與這項重新啟動的計畫。他想讓ISEE-3去與另一顆彗星相會。溫戈則認為，這勢必花費太多。
法庫哈爾說：「我們一定會拜訪彗星。相信我。」
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