The Mars Reconnaissance Orbiter (MRO) is a latecomer to what is arguably a bustling robotic neighborhood on and around the red planet.

The $450-million MRO probe will become the fourth operational orbiter around Mars and the sixth overall spacecraft to study the planet simultaneously. NASA’s twin Mars rovers are rolling across the planet’s surface, while its Mars Odyssey, Mars Global Surveyor and Europe’s Mars Express scan the world from orbit.