Russian ASAT development

Also elevation, using a laser with built in power supplies at 10km altitude massively improves performance when pointing at targets outside the atmosphere... something like 95% of the atmosphere and dust and crap is in the lower 20km of atmosphere so climbing up through that reduces its effect on the laser, remember if the target is not directly above then the beam might be pointing at an extreme angle before it reaches space... doing that from the ground at the thickest most moisture and dust filled part of the atmosphere gives maximum problems for the effect on target.

Even if the beam is pointed horizontally and remains in the atmosphere for 200km in a horizontal line the air it passes through will still be thinner than from ground level.

Mobility is also an important factor as well... they could take some to Syria if they wanted, and it does not need to destroy satellites... it could just dazzle them so they can't see what they want to see as they pass over the target area.

Remember at a divergence of 1mm per metre traveled a laser travelling 1,000km up will be 1km across... if they know the distance to the target they could focus the beam to concentrate the energy on a smaller area and would have to to do damage.

As the technology improves the performance will get better and its ability to do different things will expand, but such things don't improve as quickly in a lab.

Flying an ASAT laser at altitude also gets the weapon high above the majority of the water vapour in the planets atmosphere, important when the beam wavelength is in the near-IR range as it minimises energy losses due to absorption.