NASA is about to launch the most advanced laser instrument of its kind,
the Ice, Cloud and land Elevation Satellite-2, or ICESat-2,
will measure changes in glaciers, ice sheets and sea ice. So to prepare
for launch, we're counting down ten quick facts about ICESat-2.
Ten thousand. That's how many times the ICESat-2 laser will fire
each second. More pulses mean more height data. The fast-firing
laser will allow us to measure the average annual change in the vast ice sheets
down to the width of a pencil. Nine years of data from Operation
IceBridge will be added to ICESat-2's new data. The airborne mission
bridged the gap between the original ICESat and ICEsat-2 with
flights over the Arctic and Antarctica. Eight hundred picoseconds,
less than one-billionth of a second. That's the precision at which individual
laser photons will be timed as they complete their roundtrip journey from
the satellite to the Earth and back. Seven kilometers per second is
how fast ICESat-2 will zoom above the planet. It'll complete an orbit
around Earth in 90 minutes. The orbits will converge around the poles, focusing the data
in the regions with the most expected change. Six laser beams
split from one on board ICESat-2. That's six times the beams
of the original ICESat. More beams will cover more ground--or ice--and allow
scientists to assess the slope of the surface they're measuring.
Five hundred and thirty-two nanometers, the wavelength of the bright green laser.
When these laser photons return to the satellite, filters block any light that's not exactly
at this wavelength, keeping the amount of data noise down.
Four times a year, every 91 days, ICESat-2 will measure the same ground
tracks, allowing scientists to see how glaciers and other frozen features change
with the seasons, including over winter. A 3-D look at Earth.
Now with more height. ICESat-2 will measure elevation to see how much
glaciers, sea ice and ice sheets are rising or falling and give us a more
complete picture of our planet. There are two types of ice that ICESat-2 is after:
land ice and sea ice. Land ice builds up year after year
from snowfall, but sea ice forms when the ocean water freezes. It can last
for years or just one winter. Only one instrument,
but it's a really good one. The Advanced Topographic Laser Altimeter System,
or ATLAS, was built by hundreds of people at NASA's Goddard Space Flight Center
to exacting requirements so that scientists, very soon, can measure
minute changes in our planet's ice.