Reflecting on the Ice of Mars
The science teams for NASA's Mars Reconnaissance Orbiter (MRO) mission have been very busy of late, studying images of sub-surface water ice on the planet Mars. The images were taken by MRO’s High Resolution Imaging Science Experiment (HiRISE). The images show craters that were dug by meteorite impacts in 2008. One crater is 12 meters, or 40 feet, across and is located within Arcadia Planitia. Another crater is 8 meters, or 26 feet, across on the flat, dark plains of Vastitas Borealis. When HiRISE found these recent additions to the Martian surface, it also found something very exciting—ice. Other MRO mission instruments were put into play and the teams soon confirmed they were looking at sub-surface water ice that was 99 percent pure.
This discovery provided two big surprises about Mars. The first surprise was that the exposed water ice was so pure. They previously thought that the ice would accumulate between the soil grains, creating a 50-50 mix of dirt and ice. But by watching the ice slowly fade in progressive images, they estimate the mixture to be about one percent dirt and 99 percent ice. The second surprise was that, while scientists expected ice beneath the Martian surface at high latitudes, they did not expect it to stretch at least to 48 degrees of latitude—over halfway to the equator. This amazing discovery could have a major impact on the future and direction of Mars exploration. But what if this discovery had been made earlier? Say, 30 years earlier?
Flash-Back Time… Do you remember NASA’s Viking program? I sure do. It consisted of two ambitions orbiter/lander missions to Mars. Viking 1 launched August 20, 1975 and Viking 2 launched September 9. The probes reached Martian orbit on June 19 and August 7, respectively, of 1976. The Viking 1 Lander reached the surface July 20 and the Viking 2 Lander on September 3. Viking 1 touched down in Chryse Planitia (Greek for “Plain of Gold”) and Viking 2 landed in Utopia Planitia (Greek for “Plain of Utopia”). Trekkers in the know will remember that the U.S.S. Enterprise D, from TV series Star Trek: The Next Generation, was assembled in the Utopia Planitia Yards, a nod to the amazing achievements of the Viking program. The various Viking crafts operated for a significant time. Orbiter 2 until July 25, 1978, Lander 2 until April 11, 1980, Orbiter 1 until August 17, 1980, and Lander 1—the old man of the program—operated until November 13, 1982. Their combined data provided most of our knowledge about the Red Planet well into the early 2000s.
Viking was pretty big for me. Like many other teenagers in the southeastern U.S., I got an opportunity to see the mission up close and personal. It was, of course, 1976, the year of the U.S. Bicentennial celebration. NASA's Kennedy Space Center was hosting Third Century America, an exposition of what American science and technology had achieved and what was possible in the future. The event was assembled around the south end of the Vehicle Assembly Building and featured an Apollo Saturn V launch vehicle on display and a collection of geodesic-domed pavilions filled with exhibits. One pavilion featured a full-scale model of a Viking Lander with updates on the Lander activities and real-time feed of the downloaded images.
But what if those downloaded images had included sub-surface water ice? What if Viking had discovered it? The relative location of at least one of these meteorite craters is near to the Viking 2 Lander site. Could Viking 2 have discovered it? Well, the Viking scoops were designed for mission experiments to test the soil for organic compounds that would indicate the presence of current or past life. They were not designed to dig deeply, like the Mars Polar Lander of 1999 or the Phoenix Lander of 2008. But what if they had? What if those scoops were able to dig just three or four inches deeper? We would not have had to wait until the Mars Polar Lander (which failed) or the Mars Phoenix Lander before we saw water ice in the Martian soil. How would that discovery have affected our perception of Mars and the exploration of Mars for the next twenty years? Would this knowledge have encouraged the budgetary support for more robotic Martian probes through the 1980s and 1990s? Would the talk of human exploration of Mars have become a reality by now? Maybe…and maybe not.
The important question for us now is this: How does this discovery affect our perception of Mars and Mars exploration now? Will this encourage the budgetary support for more robotic probes? Will the talk of human exploration of Mars become a reality sooner than later?
To learn more about the discovery of sub-surface water ice on Mars, and to learn more about Mars exploration, please check out these great sites:
HiRISE Home Page
NASA’s Mars Reconnaissance Orbiter Home Page
NASA’s Mars Exploration Program Home Page
NASA’s Mars Polar Lander Mission Home Page
NASA’s Phoenix Mars Mission Home Page
NASA’s Viking Mission Home Page