NASA

Since 29 August 2015, the group lived in close quarters in a dome, without fresh air, fresh food or privacy.

Experts estimate that a human mission to the Red Planet could take between one and three years.

The Nasa-funded study run by the University of Hawaii is the longest of its kind since a Russian mission that lasted 520 days.

This week that determination paid off.

Lost...

NASA announced Sunday that it had re-established contact with STEREO-B after communications were lost in October 2014.

Contact with the spacecraft -- which works in tandem with a second spacecraft STEREO-A to study the sun -- was lost during a test of one of its timers.

"It suggests that it would be possible for there to be life today on Mars," NASA's science mission chief, John Grunsfeld, said at a news conference.

Scientists in 2008 confirmed the existence of frozen water on Mars. But instruments aboard NASA's Mars Reconnaissance Orbiter have yielded the strongest evidence yet that salt water in liquid form flows down certain Martian slopes each summer, according to the researchers.

The space agency's inspector general office said the company's upcoming flight plan contains significant risks, as its attempts to recover from last October's launch explosion. Orbital's Antares rocket failed seconds after liftoff from Virginia, destroying the space station goods and damaging the launch complex. It was Orbital's fourth supply mission, including a 2013 test flight.

The researchers announced their discovery Thursday based on observations from NASA's Kepler space telescope.

"It is the closest thing that we have to another place that somebody else might call home," said Jon Jenkins, the lead data analyst from NASA's Ames Research Center in California.

The long-awaited images were unveiled Wednesday in Maryland, home to mission operations for NASA's New Horizons spacecraft.

A zoom-in of Pluto reveals an icy range about as high as the Rockies. To the scientists' great surprise, there are no impact craters. On Charon, deep troughs and canyons can be seen.

The images were collected as New Horizons swept within 7,700 miles of Pluto on Tuesday, becoming Pluto's first visitor in its 4.5 billion-year existence.

On the eve of NASA's historic flyby of Pluto, scientists announced Monday the New Horizons spacecraft has nailed the size of the faraway icy world. Measurements by the spacecraft set to sweep past Pluto on Tuesday indicate the radius of the dwarf planet spans 736 miles, plus or minus six miles. That's 20 miles to 30 miles bigger than previous estimates. The diameter would be twice that.

Principal scientist Alan Stern says this means Pluto has a lower density than thought, which could mean an icier interior.

A computer overload prompted the spacecraft to partially shut down on July 4th — just days before the first-ever close flyby of Pluto. Flight controllers managed to regain contact with the spacecraft in just over an hour and correct the tense situation, occurring after a relatively quiet journey of 3 billion miles and 9½ years.

"We're on to Pluto!" NASA's director of planetary science, Jim Green, assured journalists Monday.