Mars • Human mission to Mars • Solar maximum

                       

                    Oceans.... Even, some astronomers said;   artificial canals, serving Martian cities. Today, the planet is a desolate wasteland.   What happened to all that water and  might the same thing happen to Earth human mission to mars ?   Through history, people imagined  Mars might be a planet like our own.   Perhaps even our twin. Peering through crude  telescopes, early astronomers thought they saw   seas and continents. Even vegetation that changed  with the seasons. 

                    In his famous map of 1877,  Giovanni Schiaparelli called some features  Canali - meaning river or channel . Percival   Lowell took that word literally. He thought  the strange marks could be actual canals,   dug by intelligent Martians. It seemed that  many people agreed there must be water on Mars.   So the first actual photographs from the surface  were a shock. This barren, desert landscape wasn't   at all what many had imagined.

                 Mars seemed a  freezing, dead world nothing like our own.   The lack of water was also a  problem for human exploration. Would astronauts have to bring all  the water they needed from Earth human mission to mars ? Could a Mars base or city artificially make enough  water to sustain itself human mission to mars ? Any dreams of colonising   Mars suddenly seemed remote. As we began to study  the planet up close the mystery deepened. Orbiters   showed surface features that certainly looked  like they had been carved by flowing water.   Shorelines... Deltas...   Oceans, islands and continents.... Nearly 40,000 river valleys .   

            Perhaps the very channels that those early  astronomers claimed to have seen.   Were these really features created  by liquid human mission to mars ? Could there be some other   explanation human mission to mars ? And if water had been  present where had it gone and why human mission to mars ?  As we sent more and more probes and  rovers to circle and roam the planet,   the evidence that the landscape had been shaped  by water grew stronger and stronger. But it   wasn't until 2012 that NASA's Curiosity rover  finally proved beyond all doubt that liquid   water really had flowed across Mars. Exploring it's landing site in Gale crater,   Curiosity imaged what had to be an ancient stream  bed. These pebbles were rounded and weathered in a   way that only liquid water could have managed. 

            And it seems there hadn't been just a small   amount of water on Mars. Using the geological  evidence found in the ancient rocks and clays,   scientists have estimated that there could have  been enough water to submerge the whole planet   in an ocean up to a mile deep. In the early  solar system, perhaps Mars and Earth really   had been very alike. So what happened human mission to mars ? How did Mars get from this..... To this human mission to mars ?   Is all the water long gone or does some remain human mission to mars ?  If so, where human mission to mars ? The question was so crucial,   that for it's missions in the 1990's and  2000's, NASA set itself a simple goal.  

             Follow The Water ! There were already signs  that Mars wasn't a completely arid world.   In 1976. The Viking 1 and 2 landers confirmed  the presence of water vapour in the atmosphere.   Other experiments strongly suggested water  chemically bound in the Martian soil.   As later probes explored, more and more evidence  was found of water locked in clays and minerals.   On Earth, this water would be released  periodically by volcanic and tectonic activity.   But Mars has little such activity if any. So  the water there has remained trapped in the   rocks and soils for billions of years. It was  the first clue where the water may have gone.   

            But water in rocks wouldn't sustain human life  on Mars. Future explorers and settlers might be   able to extract some of it by literally  cooking the rocks. But the energy and   time involved would be immense and still  produce very little. In July 2003, though,   it was announced that the Mars Odyssey orbiter had  detected huge amounts of water ice on Mars.   We knew Mars had ice caps of frozen carbon dioxide  now finally here was proof of frozen water too,   just inches from the surface. Those results were  confirmed in 2008, when the Phoenix spacecraft   sent these incredible images from  the Martian north polar region.   

                This strangely-shaped landscape is ice hidden by a  layer of dust.... ...so thin that the probe itself   could dig down - and reveal the ice beneath. More  of the missing Martian water had been located.   Further research at NASA's Jet Propulsion  Laboratory suggests there could be a massive   1.2 million cubic miles of ice at or near  the surface... ... with more buried deeper   underground. This really was a game-changer for  possible exploration and settlement of Mars.   It seems there could be plentiful water within  easy reach. More than enough to supply astronaut   needs, from drinking and living, to agriculture.  

                We could perhaps even create rocket propellant for   the journey home - right there on Mars, rather  than having to carry it all the way from Earth.   Suddenly, Mars started to look like a place  we really might be able to survive in.   And planning is well underway You wouldn't need a backhoe to dig up this ice.   You could use a shovel,"  said Sylvain Piqueux of JPL.   "We're continuing to collect  data on buried ice on Mars,   zeroing in on the best places  for astronauts to land .   

            On this map, produced by the JPL team - cooler  colours represent ice found close to the surface.   Warmer colours show deeper deposits. The outlined  area could be the ideal place for astronauts to   land. A region giving easy access to the ice, but  avoiding the harsher polar conditions. So - you're   looking at the region of Mars where the first  humans may set foot just a few years from now.  

             Alongside these breakthroughs, other observations  are even more intriguing, What were these strange   streaks, imaged by the Mars Reconnaissance  Orbiter human mission to mars ? Why do they change and evolve over   time human mission to mars ? Could this be proof of liquid water -  still flowing at or near the surface human mission to mars ? It seemed   impossible: Mars today is just too cold, with too  little atmospheric pressure. It still remains a   mystery - and some scientists think the marks  could be caused by sand, rather than water.   

            According to Astro-geologist Gretchen Bendix: Based on what we know about how water behaves....   if you're going to find it, it's  going to be underground."   One great mystery remains though: what happened  to those vast ancient oceans, lakes and rivers human mission to mars ?   Their ghosts still mark the landscape so clearly  today so why did they vanish human mission to mars ? To answer that....   we need to look to the Martian skies. As well  as studying the surface of Mars, we've also been   investigating it's atmosphere. And that's where  scientists have found clues that could explain   where the rest of the water has gone. As there  definitely was liquid water on the surface at   one time, the Martian atmosphere must have  been far thicker and warmer than it today.   

            It's now believed that, as Mars lacks a  protective magnetic field and ozone layer,   much of that atmosphere was stripped away away by  solar radiation, early in the planet's life. Water   molecules in the atmosphere were destroyed causing  a gradual reduction in pressure, allowing surface   water to evaporate and escape into space. As pressure and temperature dropped ever further   liquid water could no longer survive on the  surface for any length of time. Gradually   the oceans would have shrunk and receded...  before the remnants froze over for ever. 

            That   process of water loss still continues today. On Earth, water vapour that evaporates from the   surface is carried in to the atmosphere. There,  it condenses from gas into rain-filled clouds,   falling back to the surface. But on Mars, that  doesn't happen. Instead, the water molecules   are broken down and lost from the planet forever.  New findings from the Mars Express Orbiter shows   dust storms and even the planet's distance from  the sun can increase the rate of water loss.   

            So for billions of years, water has been  slowly leaking away from Mars into space.   Gradually, it's atmosphere has thinned and the  surface has cooled. The water that remained froze   into ice, sank into salty underground lakes, or  became locked into the crust of the planet itself.   Estimates of how much of the water that was on  Mars still remains vary wildly from a few percent   to more than 90%. Only further research perhaps  by humans in person, will tell us for sure.   

            What is certain is that while Mars may not have  it's oceans any more it still has some of it's   water. You just have to know where to look. Luckily for us here on Earth, our planets   magnetosphere provides ample protection  from the deadly radiation of the Sun.   From this currently stable planet, we can launch  many more missions to Mars to carry on the search   for any remaining water. The most recent mission  with this objective is the Mars 2020 mission, or   more commonly known as the Perseverance rover. So far it has captured amazing images, strange   noises, and revealed many secrets about Mars. Click here to see our new special series