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Sleep? Forget it: It's antacid time for Saturn team

Bashar Rizk is hardly sleeping. He arrived in Darmstadt, Germany, on Friday and has worked nonstop to pave the way for the rest of the U.S. Cassini-Huygens team - many from Tucson - who are traveling there this week. With 24 hours to go until the moment that makes or breaks 20 years of hard work and more than $700 million, the two dozen University of Arizona astronomers involved in the Huygens probe are on the edges of their seats. At 8:15 a.m. Tucson time Friday, the Huygens probe will finally do what it set out to do when it was launched in 1997: It will plummet through the mysterious atmosphere of Saturn's largest moon, Titan. It will spend several hours sending a flurry of pictures and information back to Earth, which scientists will study for years. Then it will be destroyed on impact - as expected - or it will spend about three minutes gathering "bonus science" on the surface. And if everything works as planned, the probe will finally address some of space exploration's most burning questions about Titan's perplexing atmosphere. The moon might experience a methane cycle like the water cycle on Earth. Its greenhouse gases could shed light on ours. There are carbon-based compounds in the atmosphere - carbon being the basis of life on Earth - that the probe will finally test. And there's a possibility that liquid on or under the moon's surface could allow for the organic precursors to life. The probe hitched a ride to the Saturn system onboard Cassini, its mother ship. Cassini dropped the 3-foot probe off last month, and it's been cruising toward Titan ever since with just enough power for an alarm clock to tell it when to wake up. That will happen Friday morning, when the probe is just 800 miles from Titan's surface. Cassini-Huygens scientists are hardly sitting still while they wait. "Chuck and I are in a splendid combination of isolation and contact," Rizk wrote in an e-mail from Germany, referring to his colleague, UA astronomer Chuck See. "We're away from all the distractions of home, free to devote 16, 18 or even 20 hours of the day on this project." Darmstadt is just south of Frankfurt. The U.S. researchers are joining others from France, Germany, Italy, Spain, Britain and the Netherlands at the European Space Operations Center, where they'll work shoulder-to-shoulder through several nights to decipher the Titan data. Closer to home, four scientists have stayed behind in Tucson to support the majority of the scientists who are abroad - and to host public events as the probe starts sending data back to Earth. Lyn Doose is one of those scientists. He's sleeping a little more than Rizk - but not by much. "It's beyond hectic," he said Wednesday. "I've been working basically 14 hours a day since I got back from the Christmas holidays. We're really preparing in large part for a rapid analysis of the data. There's going to be a lot of interest, so we're hoping to get the results out to the public." Although the probe will come to life and start sending data Friday morning, the information has to travel a billion miles at the speed of light, reaching Earth in about an hour and 20 minutes. It will be relayed through several networks on Earth before it gets to Tucson, expected at 11 a.m. Then the computer software Doose is repeatedly testing will do its work, translating the data into images he'll see on his screen. He expects that to happen by the early afternoon. By then, he and the Germany-based scientists will have begun their mad scramble to make sense of it all. Members of the interested public won't see the first photos until they're released by the European Space Agency, because of an agreement all the participating scientists have signed. They're likely to be made available Friday evening. The photos will be the first to penetrate a thick, orange haze that blankets the surface of Titan. The Descent Imager/Spectral Radiometer, an instrument on the probe designed by the UA's Martin Tomasko and his team, will take the photos in pie-shaped, panoramic collages. They'll show scientists what the surface looks like at about the resolution of the naked human eye - which will reveal large features like craters, faults or lakes. At minus 290 degrees, methane could occur in liquid form. If there's a significant amount of ammonia in the mix - which lowers water's freezing point - there could be liquid water just below the surface, opening the door for the exciting possibility of life. Most of the UA scientists on the Huygens mission have worked with Tomasko on the imaging team. Elsewhere, teams of scientists have developed and built five other instruments that will sample gases, clouds and the wind in the moon's atmosphere and measure the effects of sunlight at that distance from the sun. And then, less than three hours after it starts, the probe will crash-land on Titan's surface. It may or may not survive for another three minutes, so the sixth instrument, a Surface Science Package, can send back information about the crash site - such as whether it's solid or liquid. Despite all the planning and testing that's gone into this mission, all the scientists acknowledge it's a risky business. None can say with any certainty whether the probe will send back the data they've awaited - many of them for the majority of their careers. "If it works, there won't be enough superlatives to describe what results," wrote Rizk, "if it doesn't, well … we try not to think about that."