HUMANS have been trying to reach Mars since the early Sixties, using many of the opportunities that present themselves every two years when our two worlds come close.
The United States made its first bid to fly to the Red Planet in November 1964. The first mission, Mariner 3, failed when a shroud refused to jettison after launch. But the second, Mariner 4, was a success, returning 21 photos from Mars which it flew by in July 1965.
The pictures were crude by later standards but revealed that Mars had craters just like the Moon. A Russian probe, Zond 2, was also launched in November 1964 and flew past Mars the following August – but its radio failed and no data was sent back to Earth.
The US’s Mariner 6 and Mariner 7 made successful flybys of Mars in February and March 1969 radioing back more photos. But two years later, Mariner 8, which had been designed to orbit Mars, failed during launch in May. The same month, a Russian probe, Kosmos 419, which was meant to land on Mars got no further than Earth orbit.
Two more Soviet missions, Mars 2 and Mars 3, reached the Red Planet in November and December 1971. Mars 2, an orbiter/lander, sent back little data and the lander crashed on Mars. Its twin spacecraft, Mars 3, made the first successful soft landing on Mars, using retro-rockets and parachutes, but the instruments stopped working after just 20 seconds.
The US had enjoyed a major success in 1971 with the launch of Mariner 9. The probe went into orbit around Mars and, from November that year until October 1972, returned 7,329 photos in the first global mapping of the planet’s surface.
Four Soviet probes were launched in July and August of 1973. Mars 4 failed to go into orbit and flew past the planet. Mars 5 arrived in February 1974 and successfully returned 60 photos over 22 orbits.
Mars 6 landed on the Red Planet on 12 March and for 224 seconds returned the first data about the Martian atmosphere – much of it sadly unreadable due to a computer chip fault.
Mars 7 was due to land a probe on the surface but missed the planet, going into orbit around the Sun instead.