Astronomy || Our quest to understand the Red Planet

Space tracks: A look back at a dune that NASA's Curiosity Mars Rover drove across in 2014.
Space tracks: A look back at a dune that NASA's Curiosity Mars Rover drove across in 2014.

Mars is the nearest planet to Earth and is therefore the most explored of the planets in our Solar System.

Part of the interest also stems from the possibility that microscopic life exists on the red planet.

Mars is a long way away at the best of times so NASA and other space agencies time their launches to get their ships to Mars in the quickest time (7-8 months) using the least amount of fuel.

Roughly every two years Earth and Mars are lined up to make this easiest trip. But like a footballer passing the ball to a running teammate, we don't launch the rocket to where Mars is, but to where it will be in eight months' time.

Landing on another planet is also difficult. The probes lose 90% of their speed due to friction from the Martian atmosphere and parachutes, but still need to be slowed down more to land safely.

Three main options have been developed. Smaller landers can be covered in airbags and bounce onto the surface. Medium sized probes can use retro rockets to slow the probe to a gentle speed.

The largest probes have used a more complicated system of retro rockets, then the probe is lowered to the ground with cables.

The first successful Mars mission was Mariner 4 in July 1965. It flew past the planet at an altitude of 10,000 km, taking 21 photos. The total data from these photos was 655 kilobytes!

The first successful Mars mission was Mariner 4 in July 1965. It flew past the planet at an altitude of 10,000 km, taking 21 photos. The total data from these photos was 655 kilobytes!

The photos covered 1% of the Martian surface and showed a cratered landscape similar to the Moon. Mariner 6 and 7 followed in 1969 and discovered the Martian atmosphere and ice caps were mainly carbon dioxide.

The Viking orbiter took a photo in 1976 which looked like a face carved out of a hill.

The Viking orbiter took a photo in 1976 which looked like a face carved out of a hill.

Later photos showed 'the face' to be a natural feature.

Later photos showed 'the face' to be a natural feature.

Mariner 9 in November 1971 became the first spacecraft to orbit another planet and took 7,329 photos, including the largest mountain (Olympus Mons) and largest canyon (Valles Marineris) in our Solar System. It also took the first close up photos of Mars' two moons, Phobos and Deimos.

Viking 1 and 2 landed on Mars in 1976 and sent back the first photos from the surface. The landers lasted until 1982 and conducted experiments on the soil to search for life. One of the experiments produced ambiguous results and is still debated today.

The Viking orbiter also took an interesting photo in 1976 which looked like an immense face carved out of a hill on the surface. Later higher resolution photos in 1998 and 2001 showed this to be a natural feature and the facial resemblance a trick of the shadows and the tendency of the human brain to recognise patterns even when they are not there.

In more recent years, NASA has sent mobile rovers, Spirit (2004-2010), Opportunity (2004-2018) and Curiosity (2012-ongoing). Between them, these probes have proved that Mars had liquid water on the surface in the past, that the Martian soil could support microbial life, detected organic molecules in rock samples and changing methane levels in the atmosphere.

NASA is hoping to launch its next rover, Perseverance, in July or August of this year. Elon Musk's Space X has ambitious plans to send people to Mars in 2022, while NASA hopes to send people there within 10 years.

This story Our quest to understand Red Planet first appeared on The Northern Daily Leader.