NASA Probe Glimpses Unseen Side of Mercury The Messenger spacecraft came within 124 miles of Mercury's surface Monday, the closet encounter yet with the planet nearest to the sun. Messenger will soon send back more than 1,000 images it snapped during its rendezvous with the parched planet.
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NASA Probe Glimpses Unseen Side of Mercury

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NASA Probe Glimpses Unseen Side of Mercury

NASA Probe Glimpses Unseen Side of Mercury

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  • <iframe src="" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
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For the first time in 33 years, a NASA probe has taken a trip past Mercury. NASA's Messenger spacecraft blazed past the planet yesterday during the first of a series of visits.

NPR's Richard Harris was at mission control at the applied physics lab in Maryland for the encounter.

RICHARD HARRIS: Planetary flybys are usually pretty big deals. Some amazing robotic spacecraft spins past an exotic world and gives us dazzling new views. The Messenger mission, though, tests our patience a little bit. The spacecraft was operating on autopilot as it approached Mercury yesterday, and it was recording images but not sending them back right away. Sean Solomon, from the Carnegie Institution of Washington, is the lead scientist on the project. Yesterday, he was in a conference room, looking through a wall of glass into the Messenger mission-control center. He is fascinated by the parched and moon-like planet Mercury because it's one of our sister planets in the inner solar system.

Doctor SEAN SOLOMON (Lead scientist, Carnegie Institution of Washington): Though we have four siblings that all had a similar birthing process, four and a half billion years ago. Of course, we live on one of them. And to the extent that we claim to be shepherds of our own planet, it is incumbent on us to understand how our planet works, how it came to be. What are the processes that give rise to the phenomena we see today?

HARRIS: Mercury's story will help tell the story of Earth. Rob Gold, from the Johns Hopkins Applied Physics Lab, has also been working on the project since its inception. He's now watching colorful screens of data which tell engineers what Messenger is supposed to be doing. Messenger, by now, has disappeared behind Mercury, so even its faint radio signal has stopped reaching the Earth.

Doctor ROB GOLD (Staff scientist, Johns Hopkins Applied Physics Laboratory): I'm not too nervous today. I'm actually glowing because we're finally going to see what Mercury looks like.

HARRIS: It's been 33 years, huh?

Dr. GOLD: It's 33 years since the Mariner 10 flybys. And Mariner 10 only saw about 40 percent of the planet.

HARRIS: Messenger will eventually see all of Mercury, assuming it doesn't die an untimely death as many other space probes have.

Unidentified Man: The (unintelligible) that we're going through for this flyby is just over 13 minutes long. And we're just about 10 minutes away…

HARRIS: Things got suddenly got quite quiet around here. And we are waiting for our closest approach, which is coming up shortly.

Unidentified Man: We're coming up on one minute.

HARRIS: Scientist, engineers and a few journalist try to figure out what exactly we should be looking at other than the faces in the control room.

Unidentified Man: Okay, we are now 10 seconds away from closest approach. We're marking flyby one, just over 200 kilometers.

HARRIS: I see essentially no reaction in there right now. And I think the reason for that is that even though the spacecraft supposedly had its closest approach just a few moments ago, it will take 10 minutes for that signal travelling at the speed of light to get back here. So, no one has any indication that anything actually happened except by looking at their watch. Mission control takes on the feel of a waiting room outside the labor and delivery ward. People mill around, hands in pockets. Will they or won't they get a radio signal from their $400-million spacecraft? Finally…

Unidentified Man: (unintelligible)

(Soundbite of applause)

Unidentified Man: The applause says it all. Radio (unintelligible) does see the expected signal.

HARRIS: Engineer Michael Paul smiles broadly. That means the giant antenna in California has heard Messenger's dial tone.

Mr. MICHAEL PAUL (Systems engineer): We've at least gotten that far.

HARRIS: So it didn't crash into Mercury?

Mr. PAUL: Well, we'll — I'm not ready to make any definitive statements, but they were clapping, weren't they?

HARRIS: Indeed, they were. And today, the first of Messenger's recorded images are supposed to be beamed back to earth. In the coming week, scientists will soon have hundreds of brand new vistas of Mercury to relish.

Unidentified Man: Hey, it worked. (unintelligible) the money.

HARRIS: It's thought out, I mean, I'm going to…

Richard Harris, NPR News.

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