Researchers say discovery of stains from summertime flows down cliffs and crater walls increases chance of finding life on red planet.
Observations from Mars by a flotilla of spacecraft: orbiters, landers and rovers, over a couple of decades, have completely rewritten what we know about Mars today, including what we know about water on Mars! The year was 2002: Mars Odyssey, a NASA orbiter, had released maps showing an abundance of hydrogen around the Martian Poles. The hydrogen could potentially be in the form of water — but that was just one hypothesis with competing hypotheses stating that the hydrogen could be present in a form other than water. Scientists are unsure where the water comes from, but it may rise up from underground ice or salty aquifers, or condense out of the thin Martian atmosphere. “There is liquid water today on the surface of Mars,” Michael Meyer, the lead scientist on Nasa’s Mars exploration programme, told the Guardian. “Because of this, we suspect that it is at least possible to have a habitable environment today.” In five years, NASA launched the Mars Phoenix mission, to specifically verify if hydrogen present at the Martian Poles was indeed water ice. Phoenix landed on the Martian North Pole in May 2008, and survived for about 150 days. The robotic arms of Phoenix scooped soil and ice from the surface, heated the material in eight ovens, and measured the composition of the gases with a mass spectrometer. As we discovered, this act is not as simple when you are remotely operating a spacecraft in extreme cold about 200 million miles away. The Phoenix mission established conclusively that the initial discovery of hydrogen by Mars Odyssey in 2002 was indeed water ice. Hence, for the first time in the history of Mars, NASA could map out huge deposits of ice, largely concentrated around the Poles.
The discovery of liquid water is equally, if not more significant, than the discovery of ice. The discovery of liquid water below the subsurface makes a human mission logistically easier and cheaper, enhances chances of life on Mars, and provides a way to generate rocket fuel on Mars.Imagine travelling to New York for six months. Imagine having to carry all the water that you would use. Now imagine travelling to Mars, or about 20,000 times the distance to New York, for 3 years, and having to carry all the water required from Earth. Imagine how much water would be required to be transported over 200 million miles! If the source of the liquid water in Monday’s announcement is not atmospheric but subsurface, if there are sizeable reserves of water under the ground, if this water can be extracted in a cost effective manner, we might have an answer to the water problem for potential visitors for Earth. Availability of water on Mars makes the journey logistically easier and significantly cheaper.
The discovery of water on Mars is significant because life on Earth has been associated with water. There is a very important qualifier: life on Earth is associated with water, but water on Earth is not necessarily associated with life. Water on Mars does not necessarily imply that life exists on Mars — but nevertheless, it does increase the possibility of life. Life on Mars, assuming that it mimics life on Earth, would presumably need a host of factors to evolve and survive: like protection from radiation.
Last but not the least, the largest cost of interplanetary travel is the cost of escaping Earth’s gravity and the gravity of Mars. The discovery of water on Mars can help pave the way for efficient conversion of the liquid water into oxygen that can be used as rocket fuel for the return trip. In fact, in the next Mars Rover Mission to be launched in 2020, NASA will test out the first experiment that will try to separate oxygen from water on Mars — this technology in future could be used to generate oxygen from Martian water. This oxygen could be used for rocket fuel or for use by humans — again causing the cost and complexity of a human mission to drop very significantly.Will humans ever live on Mars? The team describes how it found infra-red signatures for hydrated salts when the dark flows were present, but none before they had grown. The hydrated salts – a mix of chlorates and perchlorates – are a smoking gun for the presence of water at all four sites inspected: the Hale, Palikir and Horowitz craters, and a large canyon called Coprates Chasma. “These may be the best places to search for extant life near the surface of Mars,” said Alfred McEwen, a planetary geologist at the University of Arizona and senior author on the study. “While it would be very important to find evidence of ancient life, it would be difficult to understand the biology. Current life would be much more informative.” The flows only appear when the surface of Mars rises above -23C. The water can run in such frigid conditions because the salts lower the freezing point of water, keeping it liquid far below 0C. “The mystery has been, what is permitting this flow? Presumably water, but until now, there has been no spectral signature,” Meyer said. “From this, we conclude that the RSL are generated by water interacting with perchlorates, forming a brine that flows downhill.”
A hundred years ago, when Roald Amundsen and Robert Scott raced to reach the South Pole, the South Pole was perceived as a treacherous and inhospitable frontier. Today, McMurdo Station in Antarctica supports more than 1,000 researchers, who live in controlled environments throughout the year. In Mars, there is no reason humans cannot live in temperature- and pressure-controlled chambers that are shielded from radiation. The key will be to find resources on Mars that can be used to support humans during their temporary stay there. The discovery of liquid water, perhaps, is a small step towards this broader goal.