The U.S. space agency will try again to launch an unmanned spacecraft to Mars following a series of delays over the past two weeks.
The Mars Exploration Rover is scheduled to blast off from Cape Canaveral, Florida, late Monday.
A failed battery cell caused space officials to cancel a launch on Sunday, while bad weather and technical problems caused other launches to be scrapped.
The rover - called Opportunity - was first scheduled to take off on June 25.
NASA said Opportunity is to join a twin unmanned spacecraft to roam parts of the Red Planet. The other rover, named Spirit, was launched last month.
The robotic crafts are to send back images and data for scientists to determine if enough water ever existed on Mars to sustain life.
Space officials say they have until July 15 to launch Opportunity to take advantage of a launch chance that comes around every 26 months.
If Opportunity makes the window, it would land on Mars in January with the twin craft.