Why Curiosity can't touch that Mars waterCNET
Michelle Starr October 02, 2015
This article, Why Curiosity can't touch that Mars water, originally appeared on CNET.com.
Curiosity can't touch this. NASA/JPL-Caltech/MSSSThis week, NASA broke incredible news: It had found strong evidence that water still flows on the surface of Mars. This means, technically, Mars contains the ingredients to support life, at least according to our experience here on Earth.
But we're not going to be going anywhere near the hypothesized water streams, at least not with the Mars rovers currently rolling around collecting data.
The reasons for this are twofold. The first is access: Curiosity is physically unable to climb the steep slopes where the darkish streaks might indicate water flow.
The second? Even if it could, it's not allowed to, according to a United Nations treaty written in 1967. The Outer Space Treaty, which lays out the rules for space exploration along the principles of mutual cooperation, states that exploration will be conducted in such a way as to avoid contamination from Earth life, Quartz reports.
"Because liquid water appears to be present, these regions are considered special regions where we have to take extra precautions to prevent contamination by earth life," explained Rich Zurek, a scientist on the Mars Reconnaissance Orbiter team, in a Reddit AMA session.
"Our current rovers have not been sterilised to the degree needed to go to an area where liquid water may be present."
A "special region" on Mars is described by the Mars Exploration Program Analysis Group as places where terrestrial organisms might survive and breed under Mars conditions. Because Curiosity may harbour microbes from Earth, it is not allowed near these special regions.
We already know that bacteria can survive in space. A 2014 study found that microorganisms could very easily hitch a ride on Earth's spacecraft. In particular, spore-forming bacteria, which can survive harsh sterilisation procedures and have shown to be resistant to spacecraft-cleaning techniques, could survive on Mars. An experiment that placed spores of Bacillus pumilus on a facility on the outside of the International Space Station also saw the bacteria survive for 18 months.
But completely sterilising a spacecraft is impossible. The only surefire method involves intense heat, which would damage delicate instrumentation, so different techniques need to be used. Solar panels are cleaned with chemicals, for example, while microelectronics are placed in a vacuum chamber and treated with gas that oxidises biological material, which renders it harmless.
Evidence points to flow of briny water on Mars (photos)
NASA announced today that the Mars Reconnaissance Orbiter has revealed possible evidence of flowing water during the warmest months on Mars.
Dark spines of what scientists believe may be salt water has been repeatedly seen flowing down the steep slopes of middle latitudes of Mars' southern hemisphere.
"The best explanation for these observations so far is the flow of briny water," said Alfred McEwen of the University of Arizona.
This series of orbital imagery combined with 3D modeling shows warm-season features that might be evidence of salty liquid water active on Mars today. This map of Mars shows relative locations of three types of findings related to salt or frozen water, plus a new type of finding that may be related to both salt and water.
Shallow subsurface water ice found by the Gamma Ray Spectrometer and Neutron Spectrometer on NASA's Mars Odyssey orbiter is depicted in colors signifying concentrations.
The presence of hydrogen, shown in blue, signifies higher concentrations of water ice.
The white squares mark locations of impact craters in the northern hemisphere which exposed water ice close to the surface. Red squares mark locations where the Thermal Emission Imaging System on Mars Odyssey has found deposits of chlorite may have resulted from evaporation of salty water. On Earth, chilled but unfrozen brine in rocky permafrost environments provides habitats for the growth of organisms and could provide habitats in similar conditions on Mars.
Cryopegs are isolated pockets of highly saline, liquid water that is permanently subzero (Celsius) in temperature due to chilling by the surrounding permafrost.
In this graphic, mm-cm refers to depths below the ground surface of millimeters to centimeters in vertical scale (fractions of an inch); cm-m refers to depths of centimeters to meters scale (half an inch to several yards); m-km refers to depths of meters to kilometers scale (a yard to a few miles); and 10's km refers to depth of tens of kilometers (several miles or more). From Mars' Newton crater, at 41.6 degrees south latitude, 202.3 degrees east longitude, the HiRise Camera captured this series of images from early spring of one Mars year to mid-summer of the following year.
During warm seasons, small dark features, called recurring slope lineae, appear and incrementally grow during warm seasons and fade in cold seasons, extend downslope possibly signifying the presence of liquid water.
However, "The flows are not dark because of being wet," said Alfred McEwen of the University of Arizona. "They are dark for some other reason." These five images were taken from early spring of one Mars year to mid-summer of the following year, during the warm season when surface temperatures range from about 10 degrees below zero Fahrenheit to 80 degrees above zero Fahrenheit. Dark flows in Mars' Newton Crater extend downslope, right to left, from bedrock outcrops. More than 1,000 individual flows have been discovered from 0.5 to 5 yards wide with lengths hundreds of yards long. Even in the warm season Mars is too cold for pure water. This suggests the presence of salt water, which has lower freezing points.
Salt deposits over much of Mars indicate brines were abundant in Mars' past. These recent observations suggest brines still may form near the surface today in limited times and places.
When these slopes were checked with the orbiter's Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), no sign of water appeared, which means the features may either quickly dry on the surface or could be shallow subsurface flows.
These techniques are able to reduce the number of microorganisms to 300 per square metre, according to the European Space Agency, compared to the several billion that can be found in a square metre in a clean kitchen.
That doesn't mean a rover can't get to the water in the future; there are ways to work with the UN's restrictions.
"The rovers have been sterilized for their particular landing sites where there's been no evidence of present day liquid water," Zurek explained. "To go to the [water flows] rovers will be required to be sterilized to a higher level. We also take samples of microbes that might be on the spacecraft before they're launched, so we can compare with any future discoveries."
NASA's next Mars mission launches in 2020. Given that it's being designed to the same basic specifications of Curiosity, though, it won't be able to get to the water flows either. So our curiosity about Mars microbes is just going to have to continue unslaked... for now.
https://www.yahoo.com/tech/s/why-curiosity-cant-touch-mars-065626387.html
