At this point, I would prefer it if they would focus on arming systems that could orbit the earth with laser technology that can take out all hostile orbiting spacecraft and systems designed to end our way of life and that will put us back into the stone age, make us defenseless and unable to communicate!
Long OVERDUE IMHO.
Let's forget all the issues regarding the initiation of yet another arms race which the liberals in this nation have left us ill equipped to afford.
Let's just focus on the physical impracticality of orbital laser weapons platforms intended to destroy other orbital weapons or communications devices.
First to deal with are the power requirements of a weapons grade laser. You have to generate that power in place , and generate it fast enough to make your weapons system capable of repeating shots. It is one thing to do so on a naval vessel the size of a cruiser or aircraft carrier. (Which is just barely becoming practical) It is another to do so on equipment which must be lifted into high Earth orbit.
Second is that space is a great big environment. Your target could well be thousands, or tens of thousands of miles away. Laser beams do have an angle of dispersion. While your initial beam might have the energy to cut 1 inch plate steel at ten inches with a 1/4 inch beam diameter. When that beam has dispersed to a diameter of 20 feet, it is another matter entirely. The intensity is subject to the inverse square law
A laser becomes 1/4 as intense with every 100 meters it travels in space. My example of the 1/4 inch beam turning into a 20 foot beam occurs at 1000 meters. 1/4 inch X 2 to the tenth. If the beam diameter doubles with eveyr 100 meters then its intensity become 1/4 with every 100 meters. or 1 over 4 to the tenth power at 1000 meters.
We would be better off lifting a ma deuce into orbit and firing 750 gr slugs at the target.
Feel free to correct my math. I am a bit out of practice.
https://www.reddit.com/r/askscience/comments/uruuh8/if_spaceships_actually_shot_lasers_in_space/Diffraction guarantees that the energy spreads out as the laser beam travels through space. How fast this happens depends on the wavelength of light being used, and the initial cross section of the (close to) parallel beam as it was shot. The relation is that the angle of spreading is proportional to wavelength divided by the linear dimension of the cross section (diameter of the circle, say), or approximately theta = lambda/d, where theta is in radians.
If you draw an initial beam with diameter d, spreading from each side of that beam with half-angle theta/2 (so the full angular spread is theta), and use the small angle approximation (theta in radians = size of thing divided by distance to thing) then you can find that at some distance L, the new diameter D of the beam is now
D = d + L*theta = d + L*(lambda/d)
Let's run some numbers; I'm going to use lambda = 1000nm because I like round numbers more than I like sticking to the canonical visible wavelengths like red. 1000nm is in the near infrared.
Case #1, my personal blaster, with a beam diameter starting at 1cm = 0.01m = 107 nm. Then theta = lambda/D = 1000nm/107nm = 10-4. We can use the formula for D above to see that the beam has doubled in diameter by the time it's travelled 100 meters. Doubling in diameter causes the intensity of the beam (its "blastiness") to go down by a factor of four. By the time you're a kilometer away, the beam is about 10 times as big in diameter as it originally was, or 100 times less blasty.
Case #2, my ship's laser blaster, which is designed to blow a hole in an enemy ship, and has a starting beam diameter of 1 meter. Here theta = 1000nm/109nm = 10-6 radians. Using the formula above again, we can see the beam diameter doubles in 106 meters.
