Mars Reconnaissance Orbiter

NASA's Mars Reconnaissance Orbiter searches for evidence that water persisted on the surface of Mars for a long period of time.

active Mission
An illustration of a spacecraft over Mars

NASA's Mars Reconnaissance Orbiter blasted off from Cape Canaveral in 2005, on a search for evidence that water persisted on the surface of Mars for long periods of time. While other Mars missions have shown that water flowed across the surface in Mars' history, it remains a mystery whether water was ever around long enough to provide a habitat for life.




Aug. 12, 2005




Gain better knowledge of the distribution and history of water on Mars

Meet the Mars Reconnaissance Orbiter

Key Facts

Aug. 12, 2005
Launch Location
Cape Canaveral Air Force Station, Florida
August 2005 - March 2006
Mars Orbit Insertion
March 12, 2006
4,806 pounds (2,180 kilograms) at launch, including fuel
Electrical Power
Solar panels
Atlas V
Mission Duration
2006 - ongoing
Harmakhis Vallis, an approximately 800-kilometer long outflow channel located in eastern Hellas on Mars. This is a large rock formation.
Image taken by the Mars Reconnaissance Orbiter’s High Resolution Imaging Experiment (HiRISE) instrument shows Harmakhis Vallis, an approximately 800-kilometer long outflow channel located in eastern Hellas. The valley probably formed by a combination of surface collapse and flowing water.
NASA/JPL-Caltech/University of Arizona

Studying the History of Water on Mars

After a seven-month cruise to Mars and six months of aerobraking to reach its science orbit, Mars Reconnaissance Orbiter began seeking out the history of water on Mars with its science instruments. The instruments zoom in for extreme close-up photography of the martian surface, analyze minerals, look for subsurface water, trace how much dust and water are distributed in the atmosphere, and monitor daily global weather.These studies are identifying deposits of minerals that may have formed in water over long periods of time, looking for evidence of shorelines of ancient seas and lakes, and analyzing deposits placed in layers over time by flowing water. The mission is examining whether underground martian ice discovered by the Mars Odyssey orbiter is the top layer of a deep ice deposit or a shallow layer in equilibrium with the atmosphere and its seasonal cycle of water vapor.

Looking at Small-Scale Features

In its survey of the red planet, the Mars Reconnaissance Orbiter is increasing tenfold the number of spots surveyed close-up. One of the orbiter's cameras is the largest ever flown on a planetary mission. Though previous cameras on other Mars orbiters could identify objects no smaller than a school bus, this camera can spot something as small as a dinner table. That capability has allowed the orbiter to identify obstacles such as large rocks that could jeopardize the safety of landers and rovers, including the Phoenix mission and Mars Science Laboratory mission. Its imaging spectrometer looks at small-scale areas about five times smaller than a football field, a scale perfect for identifying any hot springs or other small water features.

An overhead view of a rock formation on the surface of Mars
Liquid or gas flowed through cracks penetrating underground rock on ancient Mars, according to a report based on some of the first observations by NASA's Mars Reconnaissance Orbiter. These fluids may have produced conditions to support possible habitats for microbial life.
NASA/JPL-Caltech/Univ. of Arizona

The Interplanetary Internet

The orbiter's telecommunications systems provide a crucial service for Martian spacecraft, serving as the first link in a communications bridge back to Earth, an "interplanetary Internet" that can be used by numerous international spacecraft in coming years.

Learn More About the Mars Relay Network
Artists concept of communications relay supporting other Mars missions.
Artist's concept of communications relay supporting other Mars missions.


Mars Reconnaissance Orbiter is providing new information in unprecedented detail about the surface, subsurface, and atmosphere of Mars.

Learn More About MRO Science Findings
Tracks from the Perseverance Rover on the Mars surface