CALIPSO Lidar satellite can make incredibly sharp measurements of the atmosphere, ocean, and ground.

  CALIPSO Lidar satellite can make incredibly sharp measurements of the atmosphere, ocean, and ground. 

Lidar (light detection and ranging) or "laser radar" systems can accurately measure the atmosphere and its chemical construction. Laser systems can detect pollution and other anomalies by using laser spectroscopy.  The laser beam stresses molecules that send light quantum in their spectral frequency. 

Researchers use the same system that determines the elemental construction of the structures by using spectral analysis when they want to determine the star's chemical fingerprint. The same systems can determine any chemical compound in the world. 

The lidar systems can also search for pollution that is left in oceans and measure earthquakes. The idea is that the altitude of the laser- or lidar satellites can make many missions by using the different types of laser light. 

When a lidar satellite measures earthquakes that system measures land movements. The high-accurate lidar satellite can conduct seismic research in large areas. The explosive that shot on some ground sends seismic waves into the ground. The satellite can measure those seismic waves by using similar methods with laser microphones.

"Researchers used the space-based CALIPSO lidar to measure the planet’s largest animal migration, which takes place when small sea creatures swim up from the depths at night to feed on phytoplankton, then back down again just before sunrise. Credit: NASA / Timothy Marvel" (ScitechDaily.com/CALIPSO Concludes: Lidar Satellite Mission’s 10 Billion Measurements Yielded Vital Atmospheric Insights)

The laser systems can use the same lasers as lidar detectors, laser microphones, and laser weapons. 

The thing that determines how accurate those measurements are. Is how accurately the system knows the satellite's altitude. So the land-based lasers can measure the lidar-satellites altitude. That helps to calibrate the system that can make those extremely highly accurate measurements. 

The laser satellites have many kinds of missions in the civil and military sectors. Lidar satellites can be used to measure pollution. Laser systems can used to make spectro-analysis about jet engine exhaust gas and other types of smoke or chemical exhaust. 

The laser satellites also can use lasers as eavesdropping tools. The laser satellites can use their lasers as laser microphones. The laser ray's width is one thing that determines it's power. Lidar systems use large-area laser rays. The system uses concave lenses to disperse the laser ray. 

Then the receiver analyzes the echo. The receiver is a regular CCD camera with a multiband spectro-analyzing system.  The thing is that the system can use different lenses for making rays with different widths.

The Northrop-Grumman corporation reseaches a 10 Kw laser that it can mount Humwee. Engineers can mount similar lasers on satellites. The concave lenses allow to use of that laser system as a lidar. But the same laser can be used to destroy other satellites and incoming ASAT missiles. The same system that is used in Humwee can give laser satellites the killer-satellite option. 

https://www.nextbigfuture.com/2023/09/northrop-grummans-compact-10-kw-anti-drone-laser-and-humvee-mounted-laser-against-mortars-rockets-and-more.html

https://scitechdaily.com/calipso-concludes-lidar-satellite-missions-10-billion-measurements-yielded-vital-atmospheric-insights/

https://en.wikipedia.org/wiki/Lidar