Lost at sea, found in flash

Immersed in saltwater for days after a student research balloon plunged into the sea, flash memory cards live to tell a tale. Photos: Message in a memory card

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Leslie Katz
6 min read
A high-flying, student-assembled research balloon that appeared doomed after crashing into the Pacific Ocean has ended up yielding valuable astronomical data, thanks to hardy memory cards that survived the plunge.

As a result, astronomers now have information that will help them focus more clearly on galaxies, planets, stars, comets and other objects in space. And the California engineering students who first set the balloon afloat have been awarded special university honors for their efforts--and seen how a seemingly sunken venture can end up an unexpected treasure trove.

The balloon, set aloft by students at the University of California at Santa Cruz to measure atmospheric turbulence, plunged into the ocean and was assumed lost after it broke apart in flight.

"It was a sad feeling, thinking that we weren't going to see (the balloon) again," said Skye Vendt-Pearce, the 23-year-old leader of the student team. "It was, 'Oh, we have nothing to show for our four or five months of work.' It was like saying goodbye to a friend."

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Two inexpensive store-bought SanDisk memory cards survived the crash and a soaking in the ocean, raising intriguing possibilities for other uses of the sturdy consumer electronics storage devices, which are small and light, and don't have many moving parts.

"It doesn't happen often that this stuff gets destroyed or falls out of the sky, but when it does, it's quite often we're able to recover the data," says Norm Frentz, marketing manager for the mobile handset group at SanDisk.

Memory cards, which typically include several NAND flash memory chips, are one of the great supporting actors in the tech world. Increasing densities of flash cards have allowed digital-camera makers to come out with cameras that can hold far more pictures than standard film cameras. (Cell phones and most MP3 players rely on flash memory, as well, but it's typically embedded and doesn't come on removable cards.)

In the rough
The Santa Cruz students know firsthand how tough flash cards can be.

The journey started in March, when students at the university's Jack Baskin School of Engineering released a helium-filled balloon containing atmosphere probes, a transmitter, a digital camera and custom-built data recorder. The camera and the recorder each contained SanDisk SD flash memory cards to capture images and continuous telemetry readings.

The balloon was supposed to rise 75,000 feet and record information on atmospheric turbulence as indicated by wind shear and temperature changes. These parameters help astronomers measure light distortion in the atmosphere and adjust their telescopes to get the clearest image, according to John Vesecky, a professor of electrical engineering at UC Santa Cruz and the faculty mentor of the student team.

"These are little fluctuations in air temperature that occur in sizes of from 10 centimeters to a few hundred meters," Vesecky said. "They are like eddies in the atmosphere, and they create distortion--the 'twinkling' in the stars that people see from Earth--and generate fuzzy images for space telescopes. It's like looking at lights through a swimming pool."

With a GPS, or Global Positioning System, device indicating the balloon's position, the students were able to track its flight path for about two hours. They expected it to reach maximum elevation before deploying a parachute and returning to Earth. But things went awry when a shift in the wind pushed the balloon over the ocean, where it ruptured and splashed into the waves about two miles offshore. Team BAT (Balloon Atmospheric Telemetry) was ready to ditch the mission as a failure after gleaning only erratic bits of precrash numerical data from the transmitter via amateur radios placed aboard the craft.

The five-person team--which spent months on the project and made two unsuccessful attempts to send the balloon skyward before it finally took flight--was, to say the least, disappointed at the loss of the equipment.

But five days after the balloon disappeared, a beachgoer found the apparatus washed ashore about 20 miles north of where it had dropped into the ocean, and called the university. When the students arrived, they saw that a small padded lunch bag containing the circuit board for

the telemetry equipment and a SanDisk 1GB standard SD memory card had been thoroughly soaked by saltwater. Nearby were the shattered remains of the Aiptek PenCam SD digital camera, which had been separated from the bag. The camera's memory card, a SanDisk 128MB standard SD card that generally sells for about $20, was among the rubble.

Recovered memories
Back at UC Santa Cruz, students dried out the camera card using alcohol, slipped it into a PC card reader and saw a string of high-elevation photos, some taken at heights of up to 79,000 feet. The images showed various representations of the craggy coast, wave crests, rip currents and even the Watsonville, Calif., airport. The camera had snapped pictures every 10 seconds, Vesecky said, and not a single image was lost.

The data recovery "was very exciting," said Dave van Unen, a member of the engineering lab staff at UC Santa Cruz. "They thought the balloon was completely lost."

But the main SanDisk SD card from the data recording device--which tracked crucial information on temperature, pressure and the like every tenth of a second--was totally unreadable. As a last resort, the engineering lab sent the 1GB card (which usually costs between $75 and $100) to Sunnyvale, Calif.-based SanDisk.

After a week of repeatedly scanning the card with a special reading device and getting intermittent errors, a technician in SanDisk's engineering lab was able to extract all of the data on the card. She transferred it to another SD card, which was immediately sent to Team BAT.

While SanDisk has in the past produced industrial memory cards for use in aerospace projects and heavy industrial equipment, the SanDisk cards used by the Santa Cruz students were the consumer electronics kind one picks up at retailers such as Best Buy or Circuit City.

Other companies that have benefited from the popularity of cards include Lexar and Samsung, although chronic gluts--like one going on now--often mean that the good times quickly lead to price declines.

Roberto Menchaca, a member of the UCSC engineering team, said that although his group estimated a peak altitude of 60,000 feet for the balloon, the card data recovered by SanDisk showed a maximum of 81,863 feet--far higher than the original objective. And while the balloon transmitter radioed just 1,028 samples of data, the card yielded a whopping 53,406 samples. "This gave us more accurate data," Menchaca said, "and just as important, it was continuous, whereas the data we received by radio was full of gaps."

The student project was supported by astronomers from the Palomar and Lick observatories in California and funded by Cal Space, a state grant program that promotes space-related education within the university system, and the Center for Adaptive Optics at UC Santa Cruz.

By using the student balloon data, land-based astronomers can begin to profile the layers of turbulence and compensate for them, a process called "adaptive optics," Vesecky said. Another student balloon, named the HASTE project, was launched in June, and a third may be released this fall, he added.

Elated at the surprise success of their project, the students presented their report to their research sponsors. At graduation ceremonies in early June, the university gave them both the Dean's Award and the Chancellor's Award--a rare double honor.

"The five of us really were committed and excited about the project," Vendt-Pearce said. "The fact that it worked out is even better."

CNET News.com's Michael Kanellos contributed to this report.