The History of Mars exploration

Discovering Mars

The first colour image from Viking 1.

The stuff of observation, examination and dreams, Mars has always been a favourite subject for astronomers and stargazers. Nonetheless, the intriguing Red Planet guards its secrets closely, even though scientists have never been so close to discovering its hidden mysteries as they are now. Let's peer back in time to see how our knowledge of Mars has grown over the years.

It is likely that early societies observed Mars as a reddish beacon in the night sky, but have left no records of their observations or understanding of the planet. When Egyptians noticed Mars appearing as a small reddish disc in the sky, they quickly realized a peculiar feature of the planet: due to its retrograde motion, Mars actually appears to go in the opposite direction of the other celestial bodies as t crosses the night sky. Evidence shows that all the great cultures of antiquity were aware that Mars behaves unlike the other heavenly bodies that populate the firmament.

Later, in the seventeenth century, Mars came to be better known and understood thanks to the observations of the Danish astronomer Tycho Brahe. Brahe's calculations with respect to the position of Mars in the night sky enabled German-born Johannes Kepler to formulate the first of his two laws of planetary motion, known as Kepler's laws, which describe the mathematical relationships that govern the movement of the planets. That same year, Galileo became the first person to observe Mars through a telescope.

Our knowledge of Mars continued to expand in the seventeenth and eighteenth centuries. The length of the Martian day was determined, as well as the planet's axial tilt. The first maps of Mars were also produced at this time. Little by little, the planet next door was giving up its secrets.

In the twentieth century, robotic explorers provided a much closer look at the Red Planet. In 1964, Mariner 4 became the first spacecraft to beam back close-ups of the surface of Mars. The Viking 1 and 2 probes took the study of Mars to a new level when they landed on its surface in 1976. The purpose of that mission was to determine whether there was life on the Red Planet. Its experiments were inconclusive; but, to scientists' surprise, Mars' surface, like that of the Earth, was found to be made up of chemically active components.

As we moved into the new millennium, the Mars Pathfinder and Mars Global Surveyor (MGS) robots were the forerunners of a new range of robot geologists. With its high-resolution cameras, MGS provided accurate mapping of the surface of Mars, enabling NASA to evaluate various landing sites for upcoming missions. The Mars Exploration rovers, Spirit and Opportunity, that landed in 2004 and Phoenix (2008), succeeded in taking Mars exploration to new heights as they found tangible evidence of water on the planet. The hypothesis that there were once quantities of water on Mars was confirmed by Opportunity's discovery of minerals that showed signs of having been affected by water, and later by Phoenix's discovery of water ice.

Over the years, observation gave way to exploration and scientific investigation. With the mobile laboratories now being sent to Mars, efforts are being made to find out whether there is life on Mars and whether humans could one day live there. The success of the latest Mars exploration missions indicates that a turning point is in sight. Researchers are continuing to examine and probe the surface of Mars in the hope that the Red Planet will give up its last remaining secrets.