3-D delights from Mars

Posted: Friday, November 07, 2008 6:12 PM by Alan Boyle

NASA / JPL This 3-D image places a computer-generated rover in the midst of Spirit's surroundings on Mars as it rolls off its platform on Jan. 15, 2004. Click on the image for a larger version, and look through red-blue glasses for the 3-D effect.

When he was a kid, Jim Bell loved to look at rockets and astronauts through his 3-D Viewmaster toy. He grew up to become a planetary scientist at Cornell University rather than a toymaker - but he still revels in 3-D space scenes, as the leader of the panoramic camera imaging team for NASA's Mars rover missions.

Following up on his previous picture book, "Postcards From Mars," Bell offers more than 60 of his all-time favorite stereo images from the rovers in "Mars 3-D," a weirdly wonderful volume that comes with built-in geek glasses.

Several other books about Mars have served up a smattering of 3-D views, and several Web sites feature stereo images from the rovers as well as other space probes. But "Mars 3-D: A Rover's-Eye View of the Red Planet" puts a bookful of three-dimensional imagery right in the palm of your hand. Scores of 2-D pictures, in color or black-and-white, have been added to provide context for the stunning stereo imagery.

"Having all of the greatest hits in one place was the goal," Bell told me.

You can look over the lips of yawning craters, examine the nooks and crannies of Red Planet rocks in microscopic detail, marvel over Martian blueberries and take in long-range, over-the-hill views of Mars' thrilling landscapes. So which 3-D picture is Bell's favorite?

"I don't have a favorite," he answered. "I've got 100 favorites in the book. What's in the book is a distillation from thousands of stereo pairs."

The why of 3-D
Bell had thousands of pictures to choose from because the rovers routinely snap stereo pictures with double lenses that are spaced as far apart as a human's eyes. The rovers weren't built that way just for the coolness factor: As Bell points out in the book, the 3-D images make it easier for tour planners back on Earth to chart the rovers' course with a full understanding of the distances involved.

"There are really important reasons in terms of driving, mobility and trafficability to have that information," Bell told me.

He said there's a scientific benefit as well: "Using the parallax is a great way to determine the size of features, and to determine the slopes. ... If there was water here, would it flow in this direction, or that direction?"

How to see 3-D
Usually, you have to go to some effort to get the 3-D effect: The rover drivers use special LCD goggles (which aren't practical for regular folks). You could cross your eyes to look at a stereo pair of images (which is a trick I've never been able to master). Or you could scrounge up a cheap pair of red-blue glasses (which is something I always carry in my pocketbook).

The publishers of "Mars 3-D" makes it easier for you by turning the pictures sideways on the page and building the glasses right into the book's folding cover. Bell said this is a clever marketing technique that allows you to sample the 3-D views right in the bookstore.

And this won't be the last book done this way: Sterling Publishing was so pleased with the way "Mars 3-D" turned out that Bell is now working on "Moon 3-D," a collection of stereo lunar imagery that is due to come out next June, in time for the 40th anniversary of the Apollo 11 moon landing.

Some of the 3-D lunar views have been seen from orbit, or even from Earth. But a lot of the pictures featured in "Moon 3-D" were taken by moonwalkers. NASA developed a "walking stick" stereo camera that could take close-up views such as this one, and they also trained the astronauts to snap 3-D images on the fly.

"The astronauts had these wonderful Hasselblad cameras on their chests, and they did something called 'the stereo cha-cha,'" Bell explained. "They took one picture, and then they would lean to the right and take another one."

Coming attractions
"Moon 3-D" isn't Bell's only coming attraction. Here's a rundown of other sights to watch for in the months and years ahead:

• Bell and the rest of the imaging team have been toiling over panoramas that the Opportunity rover sent back to Earth from its stomping grounds at Victoria Crater. Meanwhile, Opportunity is on its way to an even bigger crater called Endeavour. "That's going to be a very long drive, and when we get there, it's potentially going to be even more dramatic topography than what we saw at Victoria," Bell said.
  
  
• On the other side of the planet, the Spirit rover has been gathering imagery for a 360-degree view of its surroundings, nicknamed the Bonestell Panorama in honor of classic space artist Chesley Bonestell. "It's taken more than six months to acquire that," Bell said. "About 20 percent of that [panorama] is still on the rover, and so we're downlinking that. That might be a nice holiday treat from Spirit."
  
  
• Bell is working on the stereo camera system for NASA's Mars Science Laboratory, currently due for launch next year. The mega-rover's dual camera has zoom lens and wide-angle lens capability, with a stereo "sweet spot" in the middle. It can also shoot video at rates of up to 15 frames per second. "We'll be able to take some videos of the vehicle driving, the arm moving around, maybe some dust devils or clouds moving through the sky," Bell said.

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