Key ICESat-2/ATLAS Performance Specifications
|Nominal duration of mission||3 Years|
|Number of beams||6 organized in 3 pairs|
|Footprint size||17 m|
|Field of view||45 m|
|Pulse repetition frequency||10kHz (~0.7m on the ground)|
|Laser wavelength||532 nm|
|Pointing control||45 m|
|Pointing knowledge||6.5 m|
|Single-photon time-of-flight precision||800 ps|
ATLAS expected performance in range using the current best estimates for winter and
Lambertian surface reflectance
N signal photons per shot
N signal photons per shot
|100-shot std dev (weak beam)||100-shot std dev (strong beam)|
|Ice sheet (interior)||0.9 -0.98||0.4 - 3.0||1.6 - 12.0||4 - 9||2 - 4|
|Ice sheet (glaciers)||0.6 - 0.9||0.6 - 1.0||0.6 - 3.9||12 - 29||6 - 14|
|Sea Ice||0.8 - 0.9||0.6 - 2.1||2.3 - 8.5||5 - 8||3 - 4|
* - 0.2
(much higher when specular)
|0.05 - 0.2||0.2 - 1.0||2 - 5||2 - 5|
Orbit and coverage
ICESat-2 Ground Tracks
Below are links to the kmz files for all of the laser tracks over each 91-day repeat period. Kmz Files for other areas upcoming or on request. Note that the locations and times are estimates, but should be correct to within a few minutes in time and better than 100m in the predicted locations.
Overall Mission Orbits
These files contain the nominal mission orbits and beam locations, the files have seven tracks per orbit: one for each of the six beams of ICESat-2, and the seventh for the Reference Ground Track (RGT). The RGT is an imaginary line through the six-beam pattern that is handy for getting a sense of where the orbits fall on Earth, and which the mission uses to point the observatory. However, the six tracks for the six beams are our best estimate of where the beams will actually fall on Earth’s surface.
Western Hemisphere Ground Tracks
Eastern Hemisphere Ground Tracks
Time Specific Orbits
These files contain the reference ground track time and locations for specific date ranges. Updated KML files have been posted to this website containing individual files for each RGT with a date and time stamp posted every 420 kilometers along-track (roughly 1 minute of flight time in between each point). Our first RGT is #234; this is where the time series begins. The date of each RGT is in the file name, so the user can easily ascertain where and when ICESat-2 will be on a particular day.RGTs with Dates and Times (UTC) for October 13 - December 28, 2018
RGTs with Dates and Times (UTC) for December 28 (2018) - March 29, 2019
RGTs with Dates and Times (UTC) for March 29 - June 28, 2019
RGTs with Dates and Times (UTC) for June 28 - September 28, 2019 -- these RGTs represent the first cycle where off-pointing will occur in the mid-latitudes.
These files are posted at a fairly low resolution in order to make the file size manageable, with one point approximately every 7 kilometers.
Over the polar areas and oceans, ICESat-2 will repeat its ground tracks every 91 days as it orbits; over land the satellite will point slightly off the RGT to measure more of Earth’s forests. The transitions between repeat-track pointing and off-pointing are included in these ground tracks. Near the poles, the difference between the two is subtle, but it becomes more pronounced near the equator.
- The order of the off-point sequence has not yet been determined. During the first 91-day period, the satellite will point at the RGT, and after that it will follow one of seven off-pointing plans. The different sets of 91-day plans are included in the kmz files.
- Remember that while these represent the nominal location of the sub-satellite point with associated date/time of the ICESat-2 overpass, the mission requirements are for 45 meter pointing control which currently appears to be met.