NASA's Next Mars Probe Takes Aim at Red Planet
This is an artist's concept of the Mars Reconnaissance Orbiter during its critical Mars Orbit Insertion process. In order to be captured into orbit around Mars, the spacecraft must conduct a 25-minute rocket burn when it is just shy of reaching the planet. As pictured, it will pass under the red planet's southern hemisphere as it begins the insertion. Image
Credit: NASA.

CAPE CANAVERAL, Fla. -- The pieces are coming together for NASA's next Mars probe, a recon satellite designed to scout out red planet landing sites for future explorers.

The Mars Reconnaissance Orbiter (MRO) is awaiting launch atop its Atlas 5 rocket, which is set to loft the spacecraft toward the red planet on Aug. 10 in a 7:53 a.m. EDT (1153 GMT).

"It's a real mixture of feelings," MRO project manager James Graf told SPACE.com in the clean room. "We're elated that we're ready to go launch, but white-knuckled hoping that everything will go as we expect."

NASA researchers tout the MRO spacecraft as the largest orbiter aimed at Mars in the last 30 years. Standing about 22 feet (six meters) tall and spanning 44 feet (13 meters) wide, it certainly outsizes the agency's other red planet orbiters, Mars Global Surveyor and Mars Odyssey. The orbiter weighs about 4,806 pounds (2,180 kilograms), but came in about 112 pounds (51 kilograms) underweight allowing engineers to fill that weight with additional propellant, extending its flight lifetime out to about 2014.

"This is a big mission for us," said Doug McCuistion, director of NASA's Mars Exploration Program at the agency's science mission directorate, in a preflight press briefing. "It's the most powerful suite of instruments ever sent to another planet."

The MRO spacecraft is set to be integrated with its Atlas 5 booster, equipped with a Centaur upper stage, at Launch Complex 41 of Cape Canaveral Air Force Station on July 28, launch officials said.

A new pathfinder

MRO will carry a hefty science payload to Mars, with six instruments designed to track Martian weather, resolve objects the size of a kitchen table and measure the planet's composition and atmospheric structure with more detail than ever before.

"The MRO spacecraft is many things," said Richard Zurek, the mission's project scientist at NASA's Jet Propulsion Laboratory (JPL). "It's a weather satellite, it's a geological surveyor, and it's a scout for future missions."

The orbital spacecraft is expected to be the vanguard for two landers NASA plans to launch toward Mars in the next five years, and will identify potential landing targets. The Phoenix lander is currently scheduled to launch in 2007 and touchdown in the planet's polar region. A large rover, the Mars Science Laboratory, is expected to launch in 2009.

Eyes on Mars

To prepare for those missions, MRO carries three cameras, one spectrometer, a climate sounder and subsurface radar, all designed to shed new light on the structure and composition of Mars.

MRO's High-Resolution Imaging Science Experiment (HiRISE) will photograph Mars' surface with such detail, researchers expect to resolve objects as small as four feet (1.3 meters) wide. To get a wider view, the orbiter's Context Camera will gather images about 25 miles (40 kilometers) across, with a resolution of about eight kilometers per pixels.

A third camera, the Mars Color Imager, is expected to generate a global map of Martian weather and track large-scale dust storms, day-to-day weather conditions, as well as atmospheric and polar cap changes.

"Each day we will build up a full weather map of Mars," Zulek said of the Mars Color Imager. "And [the camera] is the size of a hand."

MRO's Compact Reconnaissance Imaging Spectrometer for Mars, or CRISM, will observe the red planet in the visible and infrared range to pick out minerals and other materials that may have formed in water or wet conditions some time in the planet's past.

The Mars Climate Sounder, an instrument designed to study the changes in Mars' atmospheric composition and temperature according to its height. The tool is expected to take measurements every three miles (five kilometers) between space and the Martian surface.

Finally, a shallow subsurface SHARAD radar - similar but smaller to one that rides aboard Europe's Mars Express probe - will probe for underground water down to the first few hundred feet or so (up to one kilometer) beneath the Martian soil. The MARSIS radar tool aboard Mars Express, on the other hand, will look deeper, probing as deep as three miles (five kilometers) beneath Mars' surface.

"The [SHARAD] radar profile will build up a 3D view of Mars," Zulek said.

Launch: the first step

Before the MRO spacecraft can cull secrets from the red planet, it must first leave its home world.

After launch, it should take MRO about six months to reach Mars, then another seven months or so to slow adjust its eccentric orbit into a 250-mile (400-kilometer) high circle. The orbiter will use aerobraking to adjust its orbit, swooping in close to Mars and using its atmosphere to slow the spacecraft.

Engineers are taking care not to damage any of MRO's components during the integration with its launch vehicle, including the spacecraft's massive solar arrays.

"These are the biggest solar arrays every sent to another planet," Graf said.

Craig Calvin, an MRO systems engineer for Lockheed Martin, said the orbiter's solar panels span a total of about 20 square meters and carry about 7,000 solar cells. All those cells are need to generate the five kilowatts of power in Earth orbit, though that power output will diminish to about two kilowatts of power at Mars, Calvin said, adding that MRO's instruments and equipment only requires one kilowatt to function.

"It's fantastic that after five years, we're ready to go," Graf said. "I'm looking forward to the first image that comes back from that first pass."