First contact with alien life will happen very soon, claims NASA's Chief Scientist Ellen Stofan.

During a panel discussion regarding NASA's search for habitable worlds and alien life, Stofan said: "I think we're going to have strong indications of life beyond Earth within a decade, and I think we're going to have definitive evidence within 20 to 30 years."

Stofan would be the one to know, having held the most senior science position at NASA since August 2013.

"We know where to look. We know how to look," she told event attendees along with those watching via webcast. "In most cases we have the technology, and we're on a path to implementing it. And so I think we're definitely on the road."

The Associate Administrator for NASA's Science Mission Directorate, John M. Grunsfeld, spoke in support of Stofan's suggestion that alien life would be discovered within "one generation", both in our own solar system and the galaxy beyond.

Within our own solar system, subsurface oceans beneath the icy crusts of Jupiter's moons Ganymede and Europa are considered to be viable locations for life, as is the internal water within Saturn's moon Enceladus, discovered in 2005 by the spacecraft Cassini.

It's widely contended that there once existed oceans of liquid water on the surface of Mars, and NASA's Curiosity rover has found organic molecules on the Martian surface which suggest life may have at one time been present on the planet.

NASA is scheduling its next Mars rover to launch in 2020, to search for signs of past life and cache samples for analysis if it's thought possible to return them to earth.

Alongside SpaceX, a US space transport services company, founded by Elon Musk with the intention of reducing space travel costs to enable the colonization of Mars, NASA is currently considering a "Red Dragon" mission in 2022 which could offer a low-cost way to achieve sample return.

While actual colonization seems a long time off, according to Stofan NASA aims to land astronauts on Mars in the 2030s, and return them to earth. Stofan believes human presence upon Mars is key to the search for alien life on the red planet.

"I'm a field geologist. I go out and break open rocks and look for fossils," Stofan told the panel. "I have a bias that [is] eventually going to take humans on the surface of Mars — field geologists, astrobiologists, chemists — actually out there looking for that good evidence of life that we can bring back to Earth for all the scientists to argue about."

Outside of our solar system but within the galaxy, it seems water is pretty abundant too. According to Paul Hertz, director of NASA's Astrophysics Division, the Milky Way is "soggy".

"We can see water in the interstellar clouds from which planetary systems and stellar systems form," said Hertz. "We can see water in the disks of debris that are going to become planetary systems around other stars, and we can even see comets being dissipated in other solar systems as [their] star evaporates them."

While evidence of alien life will prove more difficult to discover than merely identifying planets with potentially habitable environments, researchers are unquestionably closing in it, concludes Stofan. ®