How far will Curiosity take us?
Since our first footprints on the grey dust of the Sea of Tranquillity in 1969, humankind has been itching to explore other worlds. Astronomers are constantly identifying new exoplanets, spacecraft like the Voyager I and II give us incredible glimpses of our neighbourhood, and we send out probes and satellites to explore the mysteries of our own solar system—but the Mars rovers mark a whole new chapter in space exploration. They are man’s representatives on the surface of another world.
In 1971, the lander of the Mars 2 probe became the first man-made object to tough the Martian surface (albeit in a crash landing). This was part of the Mars Probe program, which was followed by the Viking program, the Mars Pathfinder (which included a rover that took our first steps (or rather, our first wheel) on Mars), and the Beagle 2...but none have been quite so successful as the Mars Rovers. The program began in 2004 with the twin rovers Spirit and Opportunity, who landed three weeks apart on opposite sides of the planet. Their mission goal was to act as geologists, searching for and characterizing rocks and soils that could hold clues to past water activity, and amazingly, Opportunity has outlasted the planned mission by over 3,000 days, and is still trawling the red sands. The rovers were designed to be laboratories on wheels, carrying out carefully documented observations and experiments as controlled remotely by teams back on Earth, and the exploration of the red planet continues with the successful touchdown of the new rover, Curiosity—who is in a league of her own.
Launched on November 26th 2011 and landing on August 6th 2012, Curiosity is the largest man-made object to ever touch down on the surface of another planet. She clearly outstrips her predecessors, standing 2.2 metres tall and weighing 900 kilograms—including 80 kg of the most advanced scientific instruments yet, which will be used to work towards the mission’s overarching goal of assessing whether Mars is or ever has been habitable. This involves analysing climate and geology to search for environmental conditions favourable to microbial life, especially in the carefully-chosen landing site: Gale Crater, at the foot of the imposing Mt. Sharp near the equator, which is expected to contain hydrated minerals. Curiosity will devote much of her time looking for subterranean water, as liquid water is thought to be one of the key requirements for habitability.
Just a few months into the mission, Curiosity has made many meaningful discoveries: she has measured the radiation on the Martian surface; found bedrock with rounded pebbles, which is the strongest evidence so far for ancient, fast-moving streams; investigated a strange pyramid-shaped rock and discovered it was a kind of Martian basalt; and is currently analysing soil in hopes of identifying its elements and constituent minerals.
But although Curiosity has been named and affectionately assigned a personality and gender, she’s not a perfect substitute for a human scientist. She naturally has different capabilities and different efficiencies than humans, but at the moment, she is far more equipped to actually survive on Mars. She is powered by a specially-designed nuclear generator, and so doesn’t have to rely on limited food and water; she is able to withstand the cold of the Martian surface, which can drop to temperatures as low as -153 degrees Celsius; and is also able to withstand the high levels of radiation that blast through Mars’ thin atmosphere.
Preparation to equip a human to survive on Mars would be a completely different story—it would take a book to discuss the issues surrounding it. But perhaps most interesting is the fact that there would we would generally expect human astronauts to return Earth. An exception to this would be in the proposed Mars One program, a private endeavour in which astronauts would stay and build a permanent settlement on Mars. Currently, though, the rovers have no way back. They’ll live out their days on the cold red sands, sun powering their small bodies until they grow frail and old and dust sweeps in to blanket their tiring brows. Curiosity still has a long life ahead of her, and Opportunity has outlasted predictions so far, but when the rovers are gone, I can’t help but ask: What next?
I suppose it depends on the mysteries that our robot ambassadors unearth, but by merely successfully landing Curiosity, we have taken a huge step towards continued space exploration—and towards sending manned missions to other worlds.