The Mars Reconnaissance Orbiter (MRO) has completed the first phase of its science mission. During this phase, the orbiter returned seventy-three terabits of science data to Earth, which is more than all earlier Mars missions combined. The next phase of the MRO mission will take two years.
The list of scientific discoveries and observations made by MRO is stunning. We know now that Mars has a long history of climate change and that water was present in liquid form on its surface for hundreds of millions of years.
Signatures of a variety of watery environments have been observed, so future missions will be aware of locations that might reveal evidence of past life on Mars, if it ever existed.
MRO has imaged nearly forty percent of the Martian surface at such a high resolution that house-sized objects can be seen in detail. MRO has also conducted a mineral survey of the planet, covering sixty percent of its surface. Global weather maps were assembled using the data returned by MRO, and profiles of the subsurface and the polar caps have been put together using the radar mounted on MRO.
“These observations are now at the level of detail necessary to test hypotheses about when and where water has changed Mars and where future missions will be most productive as they search for habitable regions on Mars,” said Richard Zurek, Mars Reconnaissance Orbiter project scientist.
The images returned by MRO have been used by the Phoenix team to change the spacecraftâ€™s landing site, and will help the NASA scientists select landing sites for future missions, like the Mars Science Laboratory (MSL).
Another role played by MRO was to relay commands to and to return data from the Phoenix lander during the five months the lander was operational on the Martian surface. MRO shared this task with the Mars Odyssey Orbiter.
MRO lifted off on August 12, 2005, from launch Complex 41 at Cape Canaveral Air Force Station. The cruise phase of the mission lasted seven months, the spacecraft reaching Mars orbit on March 10, 2006, after traveling on an outbound arc intercept trajectory.
MRO entered the final low orbit suited for science-data collection on November 2006, after slowing down in the Martian atmosphere by using aerobraking for five months. The first phase of the mission consisted in gathering information about Mars, and the remaining time left of its operational life will be dedicated mainly to using the spacecraft as a communication relay.
The declared goals of the MRO mission are: to determine whether life ever arose on Mars, to characterize the climate of Mars, to characterize the geology of Mars, and to prepare for human exploration.
The launcher of choice for the MRO mission was the Atlas V-401 launch vehicle, the smallest of the Atlas V family. This was the first launch of an Atlas V on an interplanetary mission.
The Atlas V-401 is a two-stage launch vehicle that does not use solid rocket boosters. The Atlas V-401 is fifty-seven meters tall and has a total mass at liftoff of 333,000 kg. Out of this, about 305,000 kg is fuel. In order to reach Mars orbit, MRO was accelerated to 11 km per second.
The first stage of the Atlas V, the Common Core Booster, is powered by liquid oxygen and RP-1. For the MRO mission, the first stage used a RD-180 engine. The RD-180 engine has an interesting story. It is a Russian-developed rocket engine, derived from the RD-170 used for the Zenit rockets.
Rights to use the RD-180 engine were acquired by General Dynamics Space Systems Division (later purchased by Lockheed Martin) in the early 1990s. The engine is co-produced by Pratt & Whitney and all production to date has been in Russia. According to Pratt & Whitney, RD-180 delivers a ten percent performance increase over current operational U.S. booster engines.
The stage weighs approximately 305,000 kg at launch and it provides about four million Newton of thrust for four minutes.
The upper stage of the Atlas V is the Centaur Upper Stage Booster. The Centaur is powered by liquid oxygen and liquid hydrogen. In the case of the MRO mission, it provided the remaining energy necessary to send the spacecraft to Mars.
The payload fairing used for the MRO mission was four meters in diameter. The role of the payload fairing was to protect the spacecraft from the weather on the ground as well as from the dynamic pressure during the atmospheric phase of the launch.
Lockheed Martin Commercial Launch Services developed the Atlas V as part of the US Air Force Evolved Expendable Launch Vehicle (EELV) program.
There are six science instruments, three engineering instruments, and two science-facility experiments carried by the MRO. The low orbit on which MRO is operating allowed the observation of the surface, atmosphere, and subsurface of Mars in unprecedented detail.
The science instruments are the HiRISE camera (High Resolution Imaging Science Experiment), the CTX camera (Context Camera), the MARCI camera (Mars Color Imager), the CRISM spectrometer (Compact Reconnaissance Imaging Spectrometer for Mars), the MCS radiometer (Mars Climate Sounder), and the SHARAD radar (SHAllow RADar).
The HiRISE camera provided the highest-resolution images from orbit to date, while the SHARAD can probe the subsurface using radar waves in the 15-25 MHz frequency band (these waves can penetrate the Martian crust up to one kilometer).
The engineering instruments assist the spacecraft navigation and communication. The Electra UHF Communications and Navigation Package is used as a communication relay between the Earth and landed crafts on Mars. The Optical Navigation Camera serves as a high-precision camera to guide incoming spacecrafts as they approach Mars. The Ka-band Telecommunications Experiment Package demonstrated the use of the Ka-band for power effective communications.
The science facility experiments are the Gravity Field Investigation Package, used for mapping the gravity field of Mars, and the Atmospheric Structure Investigation Accelerometers, which helped scientists understand the structure of the Martian atmosphere.
For more details on the MRO scientific payload, you can check out the dedicated page on the MRO mission web site.
The MRO was built by Lockheed Martin for NASAâ€™s Jet Propulsion Laboratory in California. Fully loaded, the spacecraft had a mass of almost two tons. The spacecraft carried 1,149 kg of propellant for trajectory correction maneuvers and for the burns needed for the Mars capture.
The main bus of the spacecraft presents two massive solar arrays that can generate 2,000 W of power. On top, the high-gain antenna is the main means of communication with both Earth and other spacecrafts. The SHARAD antenna is the long pole behind the bus.
Other visible features are the HiRISE camera, the Electra telecommunications package, and the Context Imager (CTX).
You can visit the home page of the MRO mission on the NASA web site.