A laser in space to measure changes in polar ice

Screenshot from NASA video

The reporter here is obviously sold on endless warming of planet Earth, but ignoring the propaganda, there are some technical details of the mission which is due to last three years but could be extended up to ten. NASA says: ‘The ICESat-2 laser will pulse 10,000 times a second; each pulse will release about 20 trillion photons. Only about a dozen photons hit Earth’s surface and return to the satellite.’

NASA is poised to launch Saturday its most advanced space laser ever, ICESat-2, a $1 billion dollar mission to reveal the depths of the Earth’s melting ice as the climate warms, says Phys.org.

The half-ton satellite, about the size of a smart-car, is scheduled to blast off atop a Delta II rocket on September 15 from Vandenberg Air Force Base in California.

The 40-minute launch window opens at 5:46 am local time (1246 GMT).

The mission is “exceptionally important for science,” Richard Slonaker, ICESat-2 program executive at NASA, told reporters ahead of the launch.

That’s because it has been nearly a decade since NASA had a tool in orbit to measure ice sheet surface elevation across the globe.

The preceding mission, ICESat, launched in 2003 and ended in 2009. From it, scientists learned that sea ice was thinning, and ice cover was disappearing from coastal areas in Greenland and Antarctica.

In the intervening nine years, an aircraft mission, called Operation IceBridge, has flown over the Arctic and Antarctic, “taking height measurements and documenting the changing ice,” NASA said.

But an update is urgently needed.
. . .
Advanced lasers

ICESat-2 is equipped with a pair of lasers—one is on board as a back-up—that are far more advanced than the kind aboard the preceding ICESat mission.

Though powerful, the laser will not be hot enough to melt ice from its vantage point some 300 miles (500 kilometers) above the Earth, NASA said.

The new laser will fire 10,000 times in one second, compared to the original ICESat which fired 40 times a second.

The result is a far higher degree of detail, akin to taking 130 images of a single football field, compared to one shot of each goal post.

Measurements will be taken every 2.3 feet (0.7 meters)along the satellite’s path.

“The mission will gather enough data to estimate the annual elevation change in the Greenland and Antarctic ice sheets even if it’s as slight as four millimeters – the width of a No. 2 pencil,” NASA said in a statement.

Importantly, the laser will measure the slope and height of the ice, not just the area it covers.

Full report here.