ICESat: Space laser to get unprecedented view of Earth's ice

The American space agency is about to put a laser in orbit to measure the condition of Earth's ice cover.

The satellite mission, called ICESat-2, should provide more precise information on how these frozen surfaces are being affected by global warming.

Antarctica, Greenland and the ice floating on the Arctic Ocean have all lost volume in recent decades.

ICESat-2 will track ongoing change in unprecedented detail from its vantage point some 500km above the planet.

A Delta II rocket is booked to take the satellite laser into space on Saturday.

Lift-off from the Vandenberg Air Force Base in California is scheduled for 05:46 local time (12:46 GMT; 13:46 BST).

As the name suggests, ICESat-2 is a follow-on project. The original spacecraft flew in the 2000s and pioneered the laser measurement of the height of polar glaciers and sea-ice from space. But the mission was plagued by technical problems that limited its observations to just a couple of months in every year.

Nasa has since re-modelled the technology, both to make it more reliable and to give it a sharper view.

"ICESat-2 is going to observe the cryosphere with a spatial resolution at the level we have never seen before from space," explained Prof Helen Fricker from the Scripps Institution of Oceanography.

"The beam is split across-track into six - three pairs - so we can map more of the ice surface as well as estimating the surface slope, which can confuse our interpretation of height changes.

"The orbit reaches to two degrees of the poles, and the same ground tracks are sampled every three months, giving us seasonal snapshots of ice height. From these data we can unravel the processes responsible for the ice loss in the polar regions," she told BBC News.