Mars has long held a special fascination for humans—in no small measure because of the possibility that life either presently exists or at some time in the past has existed there. In his classic work Cosmos, Carl Sagan asks an important question: “Why Martians?” Why do Earthlings not similarly obsess over “Saturnarians” or “Plutonians?” As a planet resembling our own, Sagan concludes, Mars “has become a kind of mythic arena onto which we have projected our earthly hopes and fears.”
NASA’s Mars Science Laboratory (MSL) Curiosity rover is scheduled to land on the Red Planet in the early morning hours of August 6, 2012 EDT. Thus, “Why Mars?” is a question that we will seek to answer for visitors to the National Air and Space Museum.
Curiosity on Mars (artist’s conception). Credit: NASA/JPL. Image number: PIA14156.
The size of a small car, the nuclear-powered Curiosity is dedicated — using its cameras, spectrometers, radiation detectors, and other instruments — to revealing the mysteries of Mars’ Gale Crater and environs. The first task and perhaps the greatest challenge facing Curiosity will be reaching the Martian surface safely. Much of the focus for NASA’s pre-landing publicity has been Curiosity’s complicated landing procedure, which evokes a science fiction-like “Seven Minutes of Terror,” a video that has all the makings of a trailer for a Hollywood blockbuster. The audacious landing, run entirely by computer, will bring Curiosity from a speed of 20,921 kilometers per hour (13,000 miles per hour) to stationary-touchdown using, in successive stages, a massive supersonic parachute, radar-imaging, rocket boosters, and a sky crane.
Curiosity during a mobility test. Credit: NASA/JPL. Image Number: PIA14256.
Further complicating Curiosity’s already daring arrival technique is the specificity of its landing target. The elliptical-shaped target landing area for the 1976 Viking Mars lander was gigantic by comparison: 300 kilometers (186 miles) across. Curiosity’s landing ellipse, only six kilometers (four miles) wide and 19 kilometers (12 miles) long, is so minute (relatively speaking) because its target is a specific area inside Gale Crater, an exciting location for scientists to explore on Mars. Gale is a low point located close to Aeolis Mons (also called “Mount Sharp”) which is six kilometers (3.7 miles) high (by comparison, Mount Everest is 8.8 kilometers or 5.4 miles high). This mountain, which sits in the center of the crater, is made up of layers of rock that enable geologists to trace the history of the planet’s evolution. Through investigation of Martian geology, scientists may well discover the secret of whether or not Mars ever held life. By employing a “follow the water” strategy—since H2O is the fundamental building block of life as we understand it—NASA is attempting on this mission not to actually find life but to locate environments where life may once have existed or perhaps could exist in the future.
Landing ellipses for Mars exploration missions: Viking (1970’s), Pathfinder (1997), Mars Exploration Rover (MER) (2003), Phoenix (2008), and Mars Science Laboratory (MSL) (2012). Credit: ESA/DLR/FU Berlin (G. Neukum).
Yet, hasn’t NASA sent robotic explorers to Mars in search of life already? The Viking missions of the 1970s were charged in part with searching for evidence of life on Mars and 2003’s twin Mars Exploration Rovers (MER), Spirit and Opportunity, conducted geological experiments seeking evidence of water/ice on Mars. Curiosity, then, indicates that NASA, despite previous failures, is seemingly unable to shake the possibility that there is, was, or could be in the future life not only elsewhere in the solar system, but specifically on Mars.
The lure of Mars has also helped determine another goal of MSL: to “prepare for human exploration.” No rovers are set to explore Venus, the Moon, or any of the planets beyond the asteroid belt, which have been definitively deemed uninhabitable, though both Venus and the Moon have shown some traces of water molecules. NASA’s quest to find life on Mars and investigate the potential of human colonies there indicates humanity’s seemingly inexorable quest to unmask the mysteries of universe, and in the process learn more about our own planet Earth and those who inhabit it.
As an institution devoted not just to the history and technology of aeronautics and spaceflight but also the scientific discoveries made about our universe, the National Air and Space Museum has long related the story of Mars exploration. The Museum features an entire exhibit on Exploring the Planets with a recently updated section on Mars exploration that probes how we understand our not-so-distant planetary neighbor and displays mock-ups of the MER rovers, Spirit and Opportunity. Furthermore, as discussed in our recent “Mars Day!” event, John Grant of the Museum’s Center for Earth and Planetary Studies (CEPS) is heavily involved in Curiosity’s success and he helped choose Gale Crater as the rover’s landing site and Mount Sharp as its destination point.
Those staying up to view Curiosity‘s landing live on TV will have a suspenseful watching experience: will news from the rover come back right away or take minutes, or even hours? Because of Mars’ distance from the Earth, signals from Curiosity take 14 minutes to reach Earth. The landing process, however, takes only seven minutes, hence the “seven minutes of terror.” When NASA receives its first signals from Curiosity, the rover will already have been sitting on the Martian surface, in one piece or otherwise, for seven minutes. Yet, as is the case with most space-based communication, “seven minutes” may turn into a number of hours, and the success of Curiosity’s complicated landing may not be known until a day or so later. The rover itself will not begin exploring Mars right away as NASA will spend some time assessing the condition of the rover, which will take and transmit its first photographs before beginning its journey up Aeolis Mons.
Even if Curiosity does not find evidence for the possible presence of life on Mars, NASA would like to continue efforts to learn more about the red planet. While Curiosity is slated to function for 687 Earth-days (one Martian year), humanity’s curiosity about Mars and its potential for life is seemingly never-ending.
Jonathan Cohen of McGill University is an intern in the Space History Division of the National Air and Space Museum.
Get the latest information on the mission at http://www.nasa.gov/mars and follow the Mars Curiosity rover’s progress on twitter https://twitter.com/marscuriosity
