This story was updated at 9:02 p.m. EST.

After seven months of interplanetary spaceflight, NASA's Mars Reconnaissance Orbiter (MRO) successfully reached the red planet Friday to take an in-depth look at the dusty world.

Martian Video Path to Mars: Click to watch NASA's animation of MRO's seven-month trip to Mars from launch to orbit. Credit: NASA.

"Today was picture perfect," said James Graf, NASA's MRO project manager at the Jet Propulsion Laboratory in Pasadena, California, in a post-orbital arrival mission briefing. "I thought today was a simulation because we came so close to being right on."

Howard Eiesen, MRO's flight system manager at JPL, added jokingly that his fortune cookie from Thursday night - which read 'A Thrilling Time is in your Future' - heralded Friday's success.

"Today we earned our 'O,'" Eisen said in the press briefing. "We are the Mars Reconnaissance Orbiter, but we were not orbiting until today."

Tense times

Graf and other flight controllers, engineers and MRO mission scientists spent a tense half hour minutes waiting to hear from their spacecraft after it started its initial burn to enter Mars orbit. Six minutes before the maneuver was complete, the Lockheed Martin-built probe passed behind Mars as planned and out of contact with Earth.

"We've just lived through at least 27 minutes of high anxiety," said Colleen Hartman, NASA's deputy associate administrator for the agency's science mission directorate. "The nail-biting is finally over but my nails are actually gone."

At 5:16 p.m. EST (2216 GMT), just as expected, MRO's signal emerged from behind Mars. Applause and shouts rang out in the NASA's MRO control room at JPL during a webcast of the event, as flight engineers and scientists celebrated a significant feat. [Click here for an animation of today's MRO orbit insertion.]

"Mr. O is in orbit," said one observer at Lockheed Martin Space Systems' MRO control center near Denver, Colorado. "Yeah, for physics!"

Succeeding where others failed

Nearly two-thirds of all Mars spacecraft sent to the red planet have failed.

NASA's Mars Climate Orbiter and Mars Polar Lander were lost within months of each other in 1999, while NASA's Mars Observer mission fell silent three days before its own planned orbital insertion in August 1993. England's lost Beagle 2 lander and Japan's ill-fated Nozomi probes are the most recent losses at Mars.

"It's clear that we've learned from our mistakes," Hartman said.

So MRO's success places it in an elite club, and also offers researchers a chance to recoup some of their losses.

"This is a very emotional moment for me," said MRO project scientist Richard Zurek, of JPL, adding that two of the spacecraft's eight investigations replace those lost aboard the Mars Climate Orbiter, while another mirrors one lost aboard the Mars Observer. "So that completes the recover of all the lost Mars Observer investigations."

Some science team memebers also hope MRO's High-Resolution Imaging Science Experiment (HiRISE) camera will be able to find the Polar Lander's wreckage.

MRO joins NASA's Mars Global Surveyor and Mars Odyssey spacecraft, as well as Europe's Mars Express probe, currently circling the red planet. NASA's twin Mars rovers, Spirit and Opportunity, also continue to explore the planet's surface.

"We still have a long ways to go, but we're set up really well, said Joe Witte payload integration lead for Lockheed. "From paper to hardware to the launch site, it has been five years. It's like launch day. Now we've got a mission," an emotional Witte said, holding back tears.

An orbiter achievement

MRO carries six primary instruments on a frame that outsizes all three of its orbital counterparts circling Mars today.

"We'll be looking at things with a level of detail we've not seen before," Zurek said.

At almost 18 feet long (5.35 meters) and eight feet wide (2.53 meters), the probe's solar arrays are the largest ever sent to another planet. MRO's HiRISE camera alone, also the biggest to visit another world, can resolve objects the size of a kitchen table and is part of a comprehensive instrument suite to study Mars' surface, atmosphere and composition in more detail than ever before.

Chief among the goals for MRO's two-year, $720 million science mission are studies to find more evidence that water once existed on Mars. The spacecraft also carries a ground-penetrating radar to search for pockets of ice or even liquid water beneath the Martian soil.

The spacecraft will also use its extensive imaging cameras to pick out the best locations to send future landers or rovers to hunt for more the water story on Mars, NASA said. After its primary mission, MRO is expected to spend two years as a communications relay between Earth and future spacecraft, like NASA's planned Phoenix lander in 2008 and the Mars Science Laboratory rover in 2010.

"Now we have a permanent scientific presence around another planet," said Charles Elachi, director of NASA's Jet Propulsion Laboratory (JPL), after MRO entered orbit.

Aerobraking ahead

MRO has about six months of aerobraking maneuvers ahead of it to slow its initial elliptical orbit, the extremes of which range between 264.5 miles (425 kilometers) to 28,000 miles (45,061 kilometers) above Mars.

During that time, the probe will dip into Mars' upper atmosphere, and use the atmospheric drag to slow and circularize its orbit down to the planned 190-mile (305-kilometer) path.

"Everything occurred almost down to the second," said Kevin McNeill, Lockheed Martin MRO program manager of today's events. "So there was no waiting. There was no anticipation. Everything performed the way it was supposed to."

Given a total clean bill of spacecraft health, aerobraking can begin on March 29, he told SPACE.com.

More than 550 aerobraking passes will allow MRO to get a head start on its science observations - set to begin in full in the fall - by taking measurements of the atmosphere.

"It's just going to knock your socks off when we get these instruments opened up at Mars," Zurek said.

SPACE.com Senior Space Writer contributed to this story from Lockheed Martin Space System's MRO control center near Denver, Colorado. Staff Writer Tariq Malik reported from New York City.

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