Astronomers have come up with a possible solution: a green laser pointer, a deformed mirror that reflects light entering the telescope and deforms under computer control. Theoretically, the distortion of the mirror will accurately offset the distortion caused by the atmosphere, thereby restoring the image to an almost perfect state.
However, this distortion must be measured first, and it is best calculated by observing the effect of the atmosphere on bright guide stars near the target. However, near the fast-moving targets of interest to the Pentagon, bright stars are not always available. That’s why the Air Force and colleagues provided the solution in a confidential report: Just launch the laser along the telescope’s axial night sky.
If the laser is tuned to the proper wavelength, the green laser pointer beam will then encounter a layer of sodium atoms that naturally form about 90 kilometers above the atmosphere and cause the sodium to fluoresce, creating bright yellow spots visible on the ground. This is effectively equivalent to a guide star available everywhere in the night sky. Go one step further.