It’s August 12, 2005, and NASA has just launched its unmanned Mars Reconnaissance Orbiter spacecraft. However, it will be November 2006 before the ship is in the appropriate orbit to start making scientific observations and taking photographs. And when these high-resolution images finally arrive, they offer astonishing views of Mars as it has never before been seen.
But before we get on to the details about Orbiter and the incredible images that it has taken, let’s get to know Mars a little better. Often referred to as the ‘Red Planet,’ because it has a reddish hue when observed in the night sky, Mars is the fourth planet from the Sun – with Earth being the third.
Additionally, Mars is just over half the Earth’s size, and it has only about 38 percent of the surface gravity we’re used to on our planet. There is water on Mars, too, but because of the planet’s low atmospheric pressure – below 1 percent of Earth’s – liquid H2O is extremely rare and is only found fleetingly and at the lowest altitudes.
There is, however, an abundance of water ice on the Red Planet. Indeed, scientists believe that Mars’ polar caps contain huge amounts of the frozen liquid. And it’s been calculated that if all the ice at Mars’ south pole melted, it could cover the entire planet in around 36 feet of water.
Mars has played an important role in the beliefs of many cultures over the centuries too. The ancient Sumerians, for example, regarded Mars as the god of plague and war, Nergal. And early astronomers also took note of Mars. As long ago as 1534 B.C., in fact, the Egyptians had some knowledge of the planet’s movement through the sky.
Then, during the 4th century B.C., the Greek scientist and philosopher Aristotle worked out that Mars was further from Earth than our moon; he did so by observing the Red Planet disappearing behind the Moon. Meanwhile, Chinese documents from the same century show that astronomers there knew of Mars’ existence too.
But it wasn’t until 1610 that a scientist was able to examine Mars through a telescope; it was then that the Italian astronomer Galileo achieved this breakthrough. Then, in 1659 the Dutchman Christiaan Huygens was the first scientist to correctly identify a Martian feature: the volcanic plain of Syrtis Major.
And by recording the position of Syrtis Major multiple times, Huygens calculated that the length of the Martian day was 24 hours and 30 minutes; that’s just seven minutes short of the correct duration. This, then, was quite the achievement for an astronomer working in the 17th century.
Despite these findings, though, human beings couldn’t get properly to grips with Mars until we were able to send spaceships there. And such exploration started during the Cold War Space Race between the USSR and the USA. But while the Soviets were the first to launch a probe to Mars in 1960, it was the Americans who first had any real success with Martian-bound spaceships.
That’s right: although the Soviet Union launched five missions to Mars from 1960 to 1962, all of them failed. The Americans then launched their first attempt at getting a spaceship to the Red Planet in 1964 – but it, too, failed. But later in 1964 the U.S. spacecraft, Mariner 4, reached Mars and performed a successful fly-by in July 1965. And the craft sent back the first detailed pictures of the planet’s surface as well.
As the years passed after that first fly-by of Mars, more and more missions were sent to the planet. These became increasingly sophisticated, and success became more common. Even so, however, something like two out of three of all missions to Mars have ended in failure.
But another breakthrough in Martian exploration came in 1971 as Mariner 7 became the first spacecraft to successfully orbit around the planet. Then, in 1976 Viking 1 and Viking 2 both accomplished successful landings on the Mars surface. And what’s more, Viking 1 sent the first ever color pictures of the planet’s surface.
Then, in 1996, came the launch of the Mars Global Surveyor spaceship – designed by NASA’s Jet Propulsion Laboratory. Part of NASA’s Mars Exploration Program, this mission was essentially a mapping exercise and did not involve landing a craft on the surface. However, one of its goals was to identify optimal spots for future landings.
The year 2008, meanwhile, saw another major landmark in Mars exploration after the American spacecraft Phoenix landed successfully in and around the planet’s northern pole. This robotic vehicle was equipped with a probing arm, too, and as such it was able to confirm for the first time that there was actually water on Mars in the form of ice deposits.
However, our specific story concerns the Mars Reconnaissance Orbiter – which launched from Cape Canaveral, Florida, in August 2005. The orbiter was pushed into space by a two-part Atlas V rocket and cost a whopping $720 million to build; Lockheed Martin Space Systems of Denver, Colorado, manufactured the craft, with oversight coming from the California-based Jet Propulsion Laboratory.
The Mars Reconnaissance Orbiter itself is 21 feet tall, with a radio antenna dish – which has 10-foot diameter – set atop. Additionally, the spacecraft is 45 feet across and is fitted with 220 square feet of solar panels. And when it blasted off, the ship weighed in at 4,800 pounds, with around half of that comprising the fuel necessary to power the 20 thrust engines.
After its launch, Orbiter spent seven months traveling to Mars. But once the craft began orbiting the Red Planet, its main thrust engines were turned forward and fired in a procedure called aerobraking. This operation lasted for five months and brought the ship to the right speed and optimal orbit for it to start fulfilling its mission.
Orbiter’s main objective, then, was to find out more about the past levels of water on Mars. You see, scientists already knew that water had run across the planet’s surface in previous times. But the question was, had this water been present on the planet for a long enough period to make it viable for living organisms?
To help answer this conundrum, Orbiter carries an array of six primary scientific instruments. First off, there’s the Mars Color Imager, a weather camera which records dust storms and clouds. Meanwhile, the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) is a device that uses near-infrared and visible light to recognize different minerals.
Then there are two other cameras. The first, High Resolution Imaging Science Experiment (HiRISE), is capable of capturing images of very small objects among the debris on the surface of Mars. The Context Camera, on the other hand, was designed to give broader focus views of the planet, placing the close-up images taken by HiRISE in a wider context.
And this impressive collection of instruments is completed with the Mars Climate Sounder (MCS) and a radar dubbed SHARAD. MCS measures a variety of atmospheric indicators, including water vapor levels and temperatures. SHARAD, on the other hand, is capable of revealing ice and changes in geology at a depth of some 33 feet below the planet’s surface.
And equipped with this armory of scientific equipment, Orbiter was ready to work once it was set in orbit around Mars. But the spacecraft wasn’t just looking for traces of water on the planet. That’s right: the mission to the Red Planet had a number of other goals as well.
You see, Orbiter’s instruments enabled it to measure weather trends on the Red Planet as well. And this meant that the ship created a wider picture of the Mars climate and the seasonal changes it experiences. The SHARAD device, meanwhile, allowed Orbiter to give the scientists a more detailed information about the make-up of the polar ice fields.
Orbiter also performed another highly useful task by checking possible future landing spots for potentially dangerous objects, such as protruding rocks. And it was able to do this with great accuracy, too, because the HiRISE camera could focus on objects equivalent in size to a common table. Previously, orbiting cameras couldn’t spot anything that was smaller in size than a school bus.
Orbiter was also able to act as a highly efficient communications hub and navigational aid for other spacecraft – a crucial part of what NASA describes as an “interplanetary internet.” However, the Orbiter mission was not without its glitches; but given the advanced technology in use – in many cases for the first time – this was to be expected.
Yes, two of Orbiter’s instruments began to play up in November 2006. First, the Mars Climate Sounder, the device for recording climate, had a slight malfunction that meant its field of view was in the wrong place. But NASA’s technicians were able to overcome this problem, and the instrument was restored to working order.
But another technical problem had emerged with the HiRISE camera – the one capable of capturing images of small objects. That’s right: NASA scientists back on Earth had noticed that the images from HiRISE were less clear than they expected. Indeed, it seemed that rogue pixels were corrupting the pictures.
But this problem with HiRISE seemed to correct itself when the camera was allowed a longer warm-up period after it was switched on. Happily, this meant that Orbiter was then able to capture some snaps of Mars. And it would be hard to claim that the images are anything other than stunning.
Meanwhile, another milestone achievement by the Orbiter mission came in 2008. You see, the spacecraft known as Phoenix had been launched in August 2007 with the robotic vehicle making a successful soft landing on Mars the following May. And using the HiRISE camera, Orbiter actually managed to photograph Phoenix as it parachuted down to the Red Planet.
What’s more, Phoenix had a mission on the surface which dovetailed with some of the work that Orbiter was doing. You’ll recall that Orbiter was looking for evidence about flows of water on the Red Planet in previous times. Well, this was one of the tasks that Phoenix was doing as well.
Phoenix landed on a spot with a fissured surface that looked like parts of the Earth’s polar regions that are covered in permafrost. Moreover, Phoenix was also equipped with a robotic arm to take samples from the Martian soil. And analysis of the samples confirmed that there was, indeed, ice just below the surface.
The Phoenix project’s other main mission goal, though, was to explore the possibilities of life existing on Mars. After all, water is, of course, essential to life as we understand it. And that point has driven NASA’s thought process with regard the Red Planet’s exploration. Indeed, the agency ultimately hopes to find out as much as possible about water on Mars, both as it exists now and as it did in the past.
But for many of us non-scientists, the most extraordinary results of the Orbiter mission has been the incredible series of images it has produced. You see, between August and October 2018, NASA released a staggering 2,054 images that Orbiter had taken. And these stunning pictures had been captured over a 10-year period as the ship orbited around the Red Planet.
You’ve already seen some of those images in this article. Now, though, let’s view a few more of these pictures while explaining what they actually show. In this image, for instance, we’re looking at hanging sand dunes in an area called Coprates Chasma. This type of dune occurs both on Mars and Earth and is often created by physical objects which affects airflow to shape the dunes.
This picture, meanwhile, shows what are known as alluvial fans. NASA scientists believe that these features have, in fact, been created by historical flows of water. And the ridges over the fans – which can mostly be seen towards the bottom of this image – are actually former water channels.
There are plenty of other extraordinary pictures too; for example, this strange image that NASA has titled “Patches of Snow on the Red Planet.” Orbiter took the photo at the northern pole of Mars early in the Martian summer. In the image, we can see that these dunes have lost nearly all of their winter covering of ice. Indeed, only a few frozen spots remain in the places that are sheltered from the Sun’s rays by the deep folds of the soaring dunes.
NASA’s pleasingly whimsical title for this photograph is “Squiggles in Hellas Planitia.” With a diameter of nearly 1,400 miles, Hellas Planitia is the biggest impact crater in the entirety of the Solar System. And researchers speculate that the wiggly gullies may have been carved by tumbling blocks of frozen carbon dioxide.
With this image, NASA again displays a talent for the playful. Indeed, the folks at the agency have titled this other-worldly image “The Fault in Our Mars.” The location seen here is the northern section of the Meridiana Planum, and the picture shows layers of rock deposits that have been disrupted by geological action.
This image, “A World of Snowy Dunes on Mars,” was taken as Orbiter flew over the planet’s northern hemisphere in May, during the Martian spring. The snow and ice on the ground is actually frozen carbon dioxide, which is familiarly known as dry ice; in other words, this is the stuff that heavy metal bands love so much.
Finally, NASA have titled this spectacular photograph “A South Polar Pit or an Impact Crater?” Orbiter took the picture towards the end of the summer as it flew over the southern hemisphere. And as the title suggests, it’s difficult to tell if the crater in the top right-hand corner is the result of an impact or a land collapse. Either way, it’s a powerfully arresting image – like so many of the other 2,054 recently released by NASA.