ANATOMY OF THE MRO

The orbiter has been studying the topography and composition of Mars for 17 years, making some fascinating discoveries

1 High Gain Antenna Theis is the Mars Reconnaissance Orbiter’s main means of maintaining communication with Earth.

2

SHARAD

The MRO’s onboard Shallow Subsurface Radar probes and defines the composition of Mars’s polar ice caps.

3

CRISM

A visible and near-infrared tool, the Compact Reconnaissance Imaging Spectrometer for Mars measures the surface mineralogy.

4

Gimbals

Two mechanisms make sure the solar arrays point to the Sun, and another ensures the High Gain Antenna points towards Earth.

5

Solar panels

The MRO’s only source of power is sunlight. Each panel is approximately 10m² (107.6ft²) and capable of generating

1,000 watts.

6

HiRISE

The largest and most powerful camera ever sent to deep space, the High Resolution Imaging Science Experiment is the MRO’s most important instrument.

7

Electra

Electra is a

UHF softwaredefined radio communications package used for communicating with other craft heading to and operating on Mars.

8

CTX

The Context Camera works in conjunction with MARCI and HiRISE to create large contextual maps for possible lander sites.

9

MCS

The Mars Climate Sounder is the other spectrometer on board the

MRO. It measures temperature, pressure, dust levels and water vapour.

10

MARCI

The Mars Color Imager is a wide-angle, lowresolution camera that can see in five visible and two ultraviolet bands.

studies for EDL (Entry, Descent and Landing) and Mars-based science.”

Even before it launched from Cape Canaveral in 2005, it was already turning heads, most notably for the hyperactive speed of its development. Most orbiters take around a decade from design to launch, but for the MRO, that turnaround was positively supersonic. “It was approved back in 2001 and was ready for launch in August 2005,” comments Dr McEwan. “This was very fast compared to the development cycles of today’s NASA.”

So what makes the MRO so different from the other Mars orbiters the American space agency has launched in the past?

The answer lies in the clarity of its images and the data it captures from the planet’s atmosphere and composition.

“MRO has the most capable science instruments at its disposal (highest spatial resolution at visible, infrared and radar wavelengths) and a much higher data rate than any other orbiter we’ve ever launched,” adds Dr McEwan on the craft’s unique instruments. “Orbiters provide the global view and landers/rovers study very tiny areas in great detail, so in that regard they’re quite synergistic in their capabilities.”

The main crux of those capabilities lies in its onboard camera – HiRISE. The largest camera ever carried on a deep space mission, this 0.5-metre (1.6-foot) reflecting telescope is the grandest of three lenses pointed at Mars’ surface (the Context Camera takes images in greyscale and provides context maps for the other

cameras, while the low-resolution MARCI – Mars Color Imager – gives daily Martian weather reports).

The heart of the MRO’s science mission (which was only meant to last two Earth years from 2006 to 2008) is centred around mapping the planet’s surface to determine ideal landing sites for future NASA landers, and studying the Martian atmosphere and landscape to better understand its composition and the nature of its aqueous deposits. Its trio of aforementioned cameras capture these maps with incredible clarity, a capability bolstered by its spectrometers CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) and MCS (Mars Climate Sounder). The MCS and the MRO’s Shallow Subsurface Radar (SHARAD) have been helping NASA scientists study another fascinating aspect of Mars – the presence of water in its various aqueous forms, much of which is contained in ice caps buried in the planet’s subsurface.

Using sounders and radars like CRISM and SHARAD, the MRO made a startling discovery – results published in the Science journal in September 2009 showed deposits of polar ice had been exposed to the surface by comet strikes. “Ice exposed (temporarily) by new impact craters was a brand new discovery made by the MRO, and there have been many advances in polar science,” says

“MRO has the most capable science instruments at its disposal”

Dr Alfred McEwan

Dr McEwan. “Another notable milestone is the discovery, by radar, of buried carbon dioxide ice in the south polar cap.”

Now ten years into its lifespan, the MRO’s future is far from grim. In fact, it’s now fully embracing its role as a communications support craft for future missions. It supports the InSight Mars lander, which arrived on Mars in November 2018 and the Perseverance rover in February 2021.

HIGH RESOLUTION IMAGING SCIENCE EXPERIMENT

The MRO’s High Resolution Imaging Science Experiment is a milestone in space-based camera technology. It’s the largest and most powerful camera ever sent into deep space and consists of a 0.5m (1.6ft) aperture reflecting telescope. It cost a whopping $40mn (£27.5mn) and can capture images of Mars’ surface with resolutions of 30cm/pixel (11.8in/pixel). It has even caught shots of the Curiosity and Opportunity rover missions.