Washington ? Mars is about to get another visitor.

On March 10, an advanced scientific satellite, the Mars Reconnaissance Orbiter, will join three orbiting spaceships and two on-the-ground rovers to dissect the secrets of our neighboring planet and scout sites for a possible human landing.

The MRO, as it’s known, has almost completed a seven-month, 300-million-mile voyage from its launch pad at Cape Canaveral, Fla.

If it makes it the rest of the way and enters orbit successfully, it will be in a position to provide “more data than all previous Mars missions combined,” said Michael Meyer, NASA’s chief Mars scientist.

The 2,200-pound spacecraft, crammed with six cameras and other scientific instruments, will use radar to peer half a mile beneath the Martian surface, checking for water that might indicate past or present life.

Its camera eyes are sharp enough that it might be able to make out the little rovers, Spirit and Opportunity, that have been prowling the planet since 2003.

But first, the MRO must slow down enough to be captured by Mars’ gravity and enter a safe orbit around the planet, a tricky feat at which several previous missions have failed. It will be a hair-raising experience, said Doug McCuistion, the director of NASA’s Mars Exploration Program.

Starting at 3:25 p.m. CDT on March 10, the spaceship will fire its thrusters for 27 minutes. That will slow its speed enough that it will be captured by Mars’ gravity instead of zipping on past.

For part of that time, the MRO will be behind Mars, out of contact with Earth, leaving NASA controllers biting their nails.

This artist rendering provided by NASA shows the Mars Reconnaissance Orbiter over the Martian landscape. The five year mission will cost 20 million.

The spacecraft then will spend the next seven months shrinking its orbit from a 27,000-mile ellipse to a circle 160 to 200 miles above the ground. Its north-south orbit will allow it to study the entire surface of the red planet in much greater detail than ever before.

“We’re especially interested in water, whether it’s ice, liquid or vapor,” said Richard Zurek, a project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “Learning more about where the water is today and where it was in the past will guide future studies about whether Mars ever supported life.”

The MRO will join two less-advanced American satellites, the Mars Global Surveyor and Mars Odyssey, and the European Space Agency’s Mars Express in the increasingly crowded skies over the planet.

The price tag for the five-year mission is $720 million, which comprises $450 million for the spacecraft plus operating costs.