Mars Reconnaissance Orbiter

The Mars Reconnaissance Orbiter (acronym: MRO) is a multipurpose spacecraft, launched on August 12, 2005 to advance human knowledge of Mars through detailed observation, in order to examine potential landing zones for future surface missions and perform transmissions for them. It is the fourth artificial satellite on Mars (joining Mars Express, Mars Odyssey and Mars Global Surveyor). On October 10, 2006, its insertion into Mars orbit began, concluding its aerobraking phase on September 4. His studies begin after the solar conjunction in November of the same year.

The HiRISE (High-Resolution Imaging Science Experiment) camera mounted aboard the MRO spacecraft obtained high-definition images during a low-altitude orbital passage on September 29, 2006. of the Victoria crater, on whose edge the Opportunity robot is located. In this image it is possible to detect the silver figure of the NASA robot and the trace of its trajectory on the Martian soil. These images of Victoria Crater will allow scientists to decide where to send Opportunity to conduct a field study.

On November 17, 2006, NASA announced the successful testing of the orbital communication system. Using the Spirit Rover as the transmission origin point, the MRO probe acted as a transmitter to send the information back to Earth.

Background

The MRO Probe was proposed to NASA in 1999, but called MSO. It was considered to be launched in 2003 taking advantage of this year's Mars launch window, but that window was used by the Rovers and it missed its opportunity. It was then lined up for release in 2005,[2] and its name changed to MRO in October 2000.[3]

The MRO is similar in design to its sister, the Mars Global Surveyor, but is differentiated by its high-resolution camera; NASA scientist Jim Garvin calls it a “microscope in orbit.”[4]

The contractor in charge of manufacturing the MRO is Lockheed Martin.[5] The probe was completed and transported to the JFK Center on May 1, 2005 to be prepared for launch.[6]

Mission Objectives

Its mission will last 2 years, from November 2006 to November 2008. Its main objective is to map Mars in high resolution to have better data on landing sites for future missions.

The MRO played a vital role for the Phoenix mission (probe) since it provided in detail the landing site in the Martian Arctic, the area known as Green Valley being chosen.[7]

MRO will also be able to study the climate of Mars, the composition of its atmosphere and its geology, it will also look for traces of water in the polar layers and its subsoil, another objective is to search for the remains of the failed Mars Polar Lander mission and The Beagle 2 spacecraft[8], which was found at the beginning of 2015, also provides the first link to create an Internet network to the planets of the solar system.

After completing its objectives, the mission will be extended to serve as a communication and navigation beacon for other probes and rovers.[9]

Launch and orbital insertion

The MRO was launched on August 12, 2005, aboard an Atlas-V rocket from Cape Canaveral using Rocket Launch Pad 41, the rocket launched the probe into Mars orbit for 56 minutes. ignition.

The journey to Mars lasted 7.5 months during which the instruments were reviewed and calibrated, along the way 4 corrections were also planned to have a better orbital insertion, however only 3 corrections were made to save fuel.

MRO arrived at Mars on March 10, 2006 and began the orbital insertion maneuver, passing over the Southern Hemisphere at only 370-400 km, its 6 engines were on for 27 minutes to reduce the speed to 2,900 m/ s at 1,900 m/s.

On March 30, 2006, the MRO began the aerobraking procedure to achieve a circular orbit. At the end of the operation, periapsis was achieved at the edge of the atmosphere on August 30, 2006, 445 orbits (approximately 5 months).

On November 17, 2006, NASA announced the successful testing of MRO instruments and the use of the probe as a communications beacon, the first test was with the Spirit Rover that transmitted its data to MRO and this It acted as a relay to earth.

The ship

The builder of the probe was Lockheed Martin, but the construction of the ship itself was carried out by the Jet Propulsion Laboratory, the scientific instruments were made by the University of Arizona, Johns Hopkins University and the Italian Space Agency. The total cost of the MRO ship was $720 million.

The ship was built with titanium, honeycomb, carbon and aluminum composites, in the shape of a box 7.1 m long. At the top is a large 3 meter high gain satellite dish. The electronic equipment, wiring, and propulsion systems are mounted in the box. On both sides of the box, there are 2 solar panels, divided into 2 and with a total surface area of 10 meters. At the bottom of the box are mounted the scientific instruments, the UHF antenna, and the cameras. Behind the box are the propulsion motors. The ship weighed 2,180 kg at launch, of which 1,149 kg was fuel. The mechanisms used in the spacecraft are: 1 gimbal to move the high gain antenna, 2 gimbals to move the position of the solar panels, so that they can move from left to right.

The propulsion system is used to keep the ship in position by burning hydrazine. The fuel tank contained 1187 kg of hydrazine to give a speed of 1.4 km/s, only 70% was used for orbital insertion into Mars. A high-pressure gaseous helium tank is used to boost the fuel and engines. The ship contained pipes, valves and regulators to control the propulsion system. It had 20 rocket engines on board: 6 main engines of 170 N each, for orbital insertion, 6 engines of 22 N to perform course correction maneuvers, and 8 small ones for position control. Thermal control is used to keep the ship at an exact temperature, using radiators to radiate heat, insulating thermal blankets that insulate and protect the ship in space, surface coatings to absorb heat, and electric heaters, which are simple resistant cables. to heat, each consuming 300 W.

To obtain electricity, 2 solar panels with 10 m length are used, with 3744 photovoltaic cells, which could produce 3000 W on Earth and 1000 W on Mars. The voltage was 32 Volts. The panels were used for aerobraking. The electricity was accumulated in 2 NiH2 (Nickel-Hydrogen) batteries with a capacity of 50 Amperes/hour for use in the dark and maximum power charges. Orientation is determined by using 8 pairs of sun sensors to locate the Sun in space, two star trackers with a complete map of thousands of stars each, and a double inertial measurement unit that uses 4 gyroscopes to stabilization and an accelerometer to measure speeds. The rocket motors are also used to adjust speed and position, and the 3 reaction wheels plus one as a spare to maintain the position of the ship.

Telecommunications were carried out in X-band, with a frequency of 8 GHz. The ship carried two 100-W X-band amplifiers and one 35-W Ka-band amplifier; two transponders that transmit and receive. For this, a high-gain parabolic antenna with a diameter of 3 meters was used, and 2 low-gain antennas for auxiliary communications. Control and data systems are the 'brain of the ship'. On board there is a 133 MHz PowerPC computer, and a RAD750 32-bit processor, for management of the entire ship. A VxWorks software with numerous applications is to control the ship, and is capable of solving problems on the ship. The data is stored in a solid-state recorder using more than 700 256 MB memory chips, in total its capacity is 160 GB for subsequent transmission to Earth.

The scientific instruments consist of: A HiRISE camera to obtain high resolution photos, a CTX (Context Imager) for real-time observations with a resolution of 6 m/pixel, the MARCI (Mars Color Imager) to study the variations of the climate on Mars, the CRISM (Compact Reconnaisance Imaging Spectrometer Mars) to measure the distribution of humidity, heat, minerals and traces of water, MCS (Mars Climate Sounder) to measure temperature, humidity and Martian dust, the SHARAD (Shallow Radar) to track water ice up to 1 km with a resolution of 3 km, the Electra for telecommunications with the robots on the ground, an optical navigation camera to navigate the spacecraft to Mars, a Ka-band experiment to improve power communications minor, a Doppler experiment to measure the gravitational field of Mars, and an atmospheric structure research accelerometer to obtain data on Mars' upper atmosphere, and the density of the upper atmosphere.

Events and discoveries

Thanks to high-resolution photos from the MRO, new details of Martian geology have been discovered, resulting in the discovery of terrain indicating the presence of liquid carbon dioxide or water on the surface in its geological past. recent.

On September 29, 2006, the MRO took its first high-resolution photographs, in which objects as small as 90 centimeters in diameter can be distinguished. On October 6, 2006, NASA released a detailed image of Victoria Crater with the Opportunity rover just off the shore. [10] In November 2006, operational problems began to arise in 2 instruments on the spacecraft. In August 2015, the MRO celebrated ten years since its launch, continuing the observation of Mars from an orbit around it and sending information about the red planet to Earth.

Current situation

In December 2020, the MRO completed 15 years of operations, doubling the useful design service period.