The Pioneers

Early unmanned Mars probes

This magazine is about the future exploration and eventual settlement of the planet Mars. But whilst we talk about sending humans to the Red Planet in the future, let us not forget those early robotic missions that allowed this to be possible. The first article in this magazine is therefore dedicated to those early explorers that gave us the knowledge we now have of Mars.

The first Mars probes were Soviet, part of the USSR's Mars Program. They had truly the worst spacecraft names in history; 1M No. 1, 1M No. 2, 2MV-4 No. 1, Mars 1, and 2MV-3 No. 1. They also all failed, but to their credit it was the rockets launching them that exploded, not the probes themselves.

The first series of successful expeditions were the American Mariners. Mariner 3 failed at launch, but Mariner 4 performed the first ever flyby of the Red planet on the 15th of July, 1965. Unfortunately, in doing so it proved once and for all that Mars was not the alien-inhabited world that most people had imagined, but rather a dead wasteland, which seriously depressed a great many space enthusiasts. It wouldn't be until decades later that scientists would realise Mars may have had life-harbouring conditions after all in the distant past.

Nevertheless, Mariners 6 and 7 undeterred by either this or the failure of the recent Zond 2 and 2M No. 521 Soviet Mars probes, successfully performed more flybys of the planet in July of 1969, only days after Neil and Buzz took the most famous steps in history.

Mariner 8 was meant to be the first spacecraft to enter orbit of Mars, but unfortunately it never made it there, as its rocket failed just after launch and it fell into the Atlantic. Mariner 9 had more success, becoming the first probe to orbit Mars. Then, the Soviets would again try to beat the West, and this time, their luck turned around. Not by much though. The 3MS No. 170 probe still failed like all the others, but the not quite as unromantically named Mars 2 and 3 did not. Both of them entered Martian orbit in late 1971, and both tried to deploy small landers.

Alas, it was here that their luck ran out. When they arrived a large global dust storm was encircling the planet, and the probes expended a large amount of their film snapping photos of featureless dust clouds. Their landers didn't do much better. Mars 2's lander entered the atmosphere too steeply and failed to deploy its parachute in time, impacting the surface. Mars 3's lander was able to land successfully, but the sandstorm quickly built up enough static charge on the small metal frame of the lander to fry its transmitter after spending just 20 seconds on the surface, and unsurprisingly all subsequent attempts to reestablish contact with either of them failed.

Attached to the sides of the Mars 2 and 3 landers were small ‘Prop-M’ rovers. Mars 2's was destroyed when the probe hit the surface, but whether Mars 3's successfully deployed is unknown. Even if it had deployed, it would have had no way of contacting Earth, and any data from it would have still been lost. The Soviets kept trying with the Mars 4, 5, 6, and 7 probes, but all of them except for five, which operated in Martian orbit for 9 days, failed. Despite their best efforts, the Soviet Mars program simply never managed to break free of their constant failures, in stark contrast to their extraordinary achievements in launching the first satellites and humans into orbit. The first age of Martian exploration ended as Mars 7 swung past the Red Planet, its lander having missed the atmosphere and been doomed to fly though deep space for all eternity.

The story of next probes to endure the long journey to Mars would be very different, and much more successful. The vikings were about to invade Mars.

NASA's Viking 1 launched in mid 1975, followed shortly by Viking 2 a few months later. Reaching Mars in 1976, they both snapped pictures of its surface, sending back data for many years to come. As well as a suite of orbital instruments, the Vikings also carried landers, like the soviet Mars probes had. These ones however, to everyones relief, actually worked.

Viking 1 touched down on Mars on July 20th, 1976, 7 years to the day after the Apollo 11 Lunar landing. It was followed by Viking 2 on September 3rd. What they did was astonishing. Both landers were massive, weighing half a ton each. Strapped to them was a whole host of scientific instrumentation, one piece of which famously suggested that a soil sample taken from the Martian surface had active bacteria in it, although that has since been strongly disputed.

Nevertheless, it was a huge win for the scientific community, and told us a lot about the Red Planet we would one day be visiting. Despite this huge success however, the fact that it found no conclusive proof of life caused the general public’s interest in Mars to wane for many years, and with the exception of the only partially successful Soviet Phobos probes in 1988, and the failed Mars Observer NASA probe in 1992, the next missions to the Red planet would have to wait until 1996, when Mars Global Surveyor entered orbit, operating for the next 7 years.

The Russians also tried to send a craft to mars in 1996, but apparently the universe insisted on not lifting its curse on them, and both the probe and the plutonium power sources powering it fell back to Earth as its fourth stage failed to reignite.

Meanwhile in America, a third Mars probe was launched in 1996, this one much more ambitious than the Mars Global Surveyor. The probe in question was Pathfinder, and on Independence Day, July 4th, 1997, it touched down on the Martian surface, and unfolded itself, to reveal a small rover named Sojourner. Sojourner travelled a total distance of just over 100 meters, and operated for 83 Sols (85 Earth Days), despite only being designed for 7. The success of the Pathfinder probe and Sojourner rover proved to be the start of a new golden era of robotic Mars exploration, lead by JPL. On Mars, the rovers had landed.

The same type of landing stage used on Pathfinder was later used for the Spirit and Opportunity Mars Exploration Rovers, launched in 2003. They were both much more successful than anticipated, with Opportunity outliving its expected design life by a factor of 56. Landing in 2004, both rovers were only expected to last 90 Sols (about three months). Spirit died in 2010, and Opportunity died in 2018 - after 2208 and 5351 sols respectively, and both rovers were mourned by space enthusiasts all over the world.

This pair of rovers were outstanding contributors to the scientific community, as they had both found huge amounts of evidence that at some point, hundreds of millions of years in the past, Mars had flowing water like Earth.

As well as the Mars Exploration Rovers, many other probes were sent to Mars after Pathfinder - Nozomi, Mars Climate Orbiter, Mars Polar Lander, Deep Space 2, Mars Odyssey, Mars Express, Beagle 2, Mars Reconnaissance Orbiter, Phoenix, Fobos-Grunt, Yinghou-1, Curiosity, Mars Orbiter Mission, MAVEN, ExoMars Trace Gas Orbiter, Schiaparelli, MarCO-A, and MarCO-B. Some of them have succeeded, some of them have failed. But they have all contributed to Mankind's knowledge of space, and of Mars.