Life on Mars

On television, the Doctor has only visited Mars on two occasions. The planet has a greater significance in the programme than this suggests - having been visited by a number of other races, and producing two species of its own.
Millions of years ago, any developing life forms will have been destroyed when the planet was briefly visited by the Fendahl.

Later, the Ice Warriors evolved as a reptilian species - in the same way that we originally had Homo Reptilia on Earth. The reptiles remained in the ascendancy on Mars, however. To survive the thin atmosphere and low temperature, the Martians developed an organic armour shell. Like Homo Reptilia, they became a technologically very advanced society - including space flight capability. This was fortunate, as the Martians came upon another ancient life form locked within frozen water - the Flood. This probably led to the Ice Warriors abandoning their planet for another home. A scout mission to Earth crashed during the First Ice Age and its crew were frozen within a glacier.
Around 5000 BC, the inhabitants of Phaester Osiris fought a battle on Earth. Sutekh was captured and his brother Horus had him locked in an Egyptian tomb - held immobile by a forcefield generated from a pyramid complex that was placed on Mars.

In 1911, the Doctor and Sarah Jane Smith were forced to travel to the pyramid to prevent Sutekh's messenger freeing him. The pyramid proved to be full of deadly traps, but they were successful in stopping the Osirian thanks to the radio delay between Mars and the Earth.
By the 1970's, the Moon had already been reached and the UK space programme set its sights on Mars.
The planet was once again being visited by an alien race - using it as a base in an attempt to forge diplomatic relations with Earth.

One of the crew of Mars Probe 6 was inadvertently killed as the aliens were highly radioactive and deadly to the touch. The crews of Mars Probe 7 and its Recovery ship were replaced with alien ambassadors. The diplomatic moves broke down - as the aliens felt that humans weren't ready for contact.
In 2006, the space programme decided to return to Mars with the Guinevere One probe. The craft never made it - being captured by a Sycorax spaceship en route to invade the Earth. The Doctor had obviously given UNIT intelligence on the Ice Warriors - as they recognised the Sycorax were not Martian straight away.

In 2010, Sarah Jane Smith used her Xylox computer, Mr. Smith, to block a glimpse of the Osirian pyramid by the Mars Rover.
In 2058, an international team led by Adelaide Brooke landed on Mars and established Bowie Base One - named after the English rock star who had sung about "Life on Mars". A year later, whilst the Doctor was visiting, the expedition accidentally released the Flood. Rather than risk bringing the parasitical lifeform back to earth, Brooke decided to self destruct the base - killing everyone. The Doctor elected to change history - meaning two of the crew survived. Instead of perishing on Mars, Brooke killed herself back on Earth.
In 2070, the Doctor was on his way to Mars when knocked off course to the Moon by the weather controlling Gravitron.
The Doctor told Davros about an attack on Mars by the Daleks, when their insulation cables were attacked by a virus.
The need to rebuild Earth after the Dalek invasion of the mid 22nd Century led to an abandonment of Mars.

It was at this time that the Ice Warriors decided to return to their homeworld. They still had an eye on Earth and launched an attack via the T-Mat travel relay station on the Moon. They planned to seed earth with Martian plant-life that would alter Earth's atmosphere to be more agreeable to them. The invasion failed, and the Ice Warriors eventually decided to turn their backs on warfare and sign up to the Galactic Federation. They helped Peladon join the Federation, but later a rebel faction tried to seize the planet.
Ice Warriors made a brief reappearance on Earth when the crew of the ancient scout ship were resurrected during another Ice Age. Earth-Martian relations must have long ended, as no-one at Brittanicus Base recognised them.
Humans returned to Mars and by the year 200,000 there was a University there, which Adam Mitchell pretended to be attending.
In the far future, Mars became temporary home to the whole of mankind - before the Usurian Company moved it out to Pluto.