What water on Mars means

Jeffrey Kluger has a Time article about Mars:

Mars may be the solar system’s most tragic planet. It once had a dense atmosphere; it once fairly sloshed with water; just one of its oceans may have covered two-thirds of its northern hemisphere. With seasons very much like Earth’s, it could have been home to who knows what kinds of life.
But Mars suffered an apocalypse that’s never quite been explained; perhaps meteorite bombardments blasted its atmosphere into space, and the planet’s weak gravity frittered away the rest. The result either way is the cold, dead, dry world we see today. Except now, it seems, it’s not so dry, and perhaps not so dead.
According to a paper just published in Nature Geoscience, there appears to be liquid water flowing on Mars. And in this case, it’s not the geological definition of contemporary, which can mean the past few million years, but the common definition, which can mean, say, Tuesday.
“Mars is not the dry, arid planet planet we thought of in the past,” said Jim Green, director of NASA’s planetary science division, at a packed press conference. “Under certain circumstances, liquid water has been found on Mars.”
The announcement goes back to a discovery that was first made in 2010, when then University of Arizona undergraduate student Lujendra Ojha was studying images from NASA’s Mars Reconnaissance Orbiter (MRO), and found transitory streaks along the sides of hills and cliffs that looked for all the world like the tracks of running water. The formations appeared in the Martian spring and summer, when water would be the likeliest to exist in liquid form, and disappeared in fall and winter.

Rico says Lily Rothman has another Time article about going to Mars:

There have been lots of times we thought we'd get to Mars in the near future, The new movie The Martian (video), the story of an ill-fated NASA mission to Mars, takes place in the relatively near future. While some of the science has been nit-picked—though relatively little, considering it’s a movie—one aspect is, historically speaking, completely believable: the idea that human beings would be sending manned missions to the Red Planet is the very near future.
As NASA recently revealed that scientists have found evidence of water on Mars, our solar system neighbor became the focus of renewed interest, but it’s been decades since humankind first heard that a Mars mission was imminent.
It started in the mid-1960s, even before the moon landing, as the fifth-ever class of astronauts chosen by NASA were told that a Mars mission could possibly be in their future. By 1969, with the lunar landing a success, they had a timeline: engineer Wernher von Braun said the American space program could get there by 1982, while the more cautious then-Vice President Spiro Agnew was aiming for the year 2000 at the latest.
A panel headed by Agnew was, later that year, settled on a middle ground: “If Congress compromises on a maximum NASA budget of eight billion dollars by 1980,” Time reported, “the Martian touchdown can be achieved in 1986.” Over the next few years, the 1986 deadline continued to be discussed. (Attention, Hollywood: by 1972, NASA even got into the weeds with the question of what to do about the astronauts’ inevitable romantic entanglements during a six-hundred-day mission.)
Fast-forward to the mid-1980s. Humankind was not on Mars.
But that didn’t mean we weren’t still trying. By 1985, the idea of a joint US-Soviet mission was floated by space experts from around the world. It was to be a Cold War-defying act of scientific greatness, made possible by splitting the bill. The deadline that time around: 2010.
Hopes of that idea becoming reality were temporarily dashed the following year by the Challenger space shuttle disaster, which led NASA to recalibrate its entire mission, but by 1988 it was back on track. “A manned trip to Mars, long the stuff of science fiction, now appears to be just a matter of time. The mystic planet, glowing red and ever brighter in the night skies, is heading toward its closest approach to the Earth in seventeen years this September, tantalizingly near and beckoning,” Time noted in a cover story about the progress the US and the then-USSR were both making in research and preparation for such a trip.
By the start of the 1990s, then-President George H. W. Bush had adjusted the target to aim for “astronauts on the red sands of Mars by 2019”. Science experts like Time’s Michael Lemonick agreed that 2020 was a “reasonable” estimate for when we’d get there. But, as the next decade progressed, there was more and more news of probes and rovers going to Mars, and less and less news of potential manned missions. At the dawn of a new century, that trend continued.
Then, however, George W. Bush announced that Mars was once again a priority for NASA. The summer before the 2004 election, he laid out a plan for returning to the Moon around 2015 and getting to Mars not too long after. “Though the year 2030 was bandied about in the press as a target for putting a man on Mars, the President was careful not to set a date,” Time's Jeffrey Kluger noted. Some experts at the time even saw 2030 as unnecessarily far away; with real dedication to the mission, they estimated, the 2010 date could have been met.
Now 2010 has come and gone, and 2030 is practically just around the corner. But we haven’t given up: just about a month ago, none other than former astronaut Buzz Aldrin declared that he wanted to see humans on Mars by 2039.
So The Martian may yet become even more scientifically accurate than its creators could have planned, something that future astronauts may well find worth raising a glass of Martian water to celebrate.

Rico says we oughta do it, expensive though it'll be...