NASA will this week announce the key findings of an exploration of Mars' thick atmosphere.
It is believed the protective covering could have sustained life many eons ago.
The announcement is the culmination of a ten-month exploration of the Red Planet's upper atmosphere and comes two months after Nasa's Curiosity Rover discovered the planet was home to water.
In 2013, NASA launched the MAVEN (Mars Atmosphere and Volatile Evolution) mission to examine how solar winds penetrates the atmosphere and may lead to a loss of water and carbon dioxide into space.
The press conference will be charred by Jim Green, director of planetary science at NASA headquarters, who announced the presence of water on Mars.