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Not feasible in the way you propose it.

Color of the light should be white: laser are monochromatic, with a few nm bandwidth. To make it appear white as perceived by the human eye, you would need to cover the whole visible spectrum, which makes for about 500, 1 nm wide bands. Good luck finding a laser for each wavelength with a tuning of 1 nm. I have seen PhD being made on tunable lasers, but not in the range of powers you are interested in. And I am not mentioning the difficulty of compensating for the different diffraction of each wavelength. Below you can see a qualitative comparison between the spectrum of a laser and the spectrum of a LED

Beam can be slightly angled, but the closer to 90° the better.: a satellite normally circles the whole planet in about 90 minutes. It covers one degree around the vertical of a given spot for 7 hundreds of a second. Spy satellites can get that sort of control, but they don't aim for an object the size of a watermelon (with all the due respect for your head), though they can resolve it in their images.

equipped with a powerful laser: last but not least, what makes you think that it is smart to stand under the shine of a laser powerful enough to shine through more than 100 km of atmosphere? Unless your goal is to impress the bystanders with the laser burns that you will get.

Not feasible in the way you propose it.

Color of the light should be white: laser are monochromatic, with a few nm bandwidth. Below you can see a qualitative comparison between the spectrum of a laser and the spectrum of a LED. To make it appear white as perceived by the human eye, you would need to cover the whole visible spectrum, which makes for about 500, 1 nm wide bands. Even using 3 colors to emulate white, you would still need about 150 lasers. Good luck finding a laser for each wavelength with a tuning of 1 nm. I have seen PhD being made on tunable lasers, but not in the range of powers you are interested in. And I am not mentioning the difficulty of compensating for the different diffraction of each wavelength.

Beam can be slightly angled, but the closer to 90° the better.: a satellite normally circles the whole planet in about 90 minutes. It covers one degree around the vertical of a given spot for 7 hundreds of a second. Spy satellites can get that sort of control, but they don't aim for an object the size of a watermelon (with all the due respect for your head), though they can resolve it in their images.

equipped with a powerful laser: last but not least, what makes you think that it is smart to stand under the shine of a laser powerful enough to shine through more than 100 km of atmosphere? Unless your goal is to impress the bystanders with the laser burns that you will get.

Not feasible in the way you propose it.

Color of the light should be white: laser are monochromatic, with a few nm bandwidth. To make it appear white as perceived by the human eye, you would need to cover the whole visible spectrum, which makes for about 500, 1 nm wide bands. Good luck finding a laser for each wavelength with a tuning of 1 nm. I have seen PhD being made on tunable lasers, but not in the range of powers you are interested in. And I am not mentioning the difficulty of compensating for the different diffraction of each wavelength. Below you can see a comparison between the spectrum of a laser and the spectrum of a LED

Beam can be slightly angled, but the closer to 90° the better.: a satellite normally circles the whole planet in about 90 minutes. It covers one degree around the vertical of a given spot for 7 hundreds of a second. Spy satellites can get that sort of control, but they don't aim for an object the size of a watermelon (with all the due respect for your head), though they can resolve it in their images.

equipped with a powerful laser: last but not least, what makes you think that it is smart to stand under the shine of a laser powerful enough to shine through more than 100 km of atmosphere? Unless your goal is to impress the bystanders with the laser burns that you will get.

Not feasible in the way you propose it.

Color of the light should be white: laser are monochromatic, with a few nm bandwidth. To make it appear white as perceived by the human eye, you would need to cover the whole visible spectrum, which makes for about 500, 1 nm wide bands. Good luck finding a laser for each wavelength with a tuning of 1 nm. I have seen PhD being made on tunable lasers, but not in the range of powers you are interested in. And I am not mentioning the difficulty of compensating for the different diffraction of each wavelength. Below you can see a qualitative comparison between the spectrum of a laser and the spectrum of a LED

Beam can be slightly angled, but the closer to 90° the better.: a satellite normally circles the whole planet in about 90 minutes. It covers one degree around the vertical of a given spot for 7 hundreds of a second. Spy satellites can get that sort of control, but they don't aim for an object the size of a watermelon (with all the due respect for your head), though they can resolve it in their images.

equipped with a powerful laser: last but not least, what makes you think that it is smart to stand under the shine of a laser powerful enough to shine through more than 100 km of atmosphere? Unless your goal is to impress the bystanders with the laser burns that you will get.

Not feasible in the way you propose it.

Color of the light should be white: laser are monochromatic, with a few nm bandwidth. To make it appear white as perceived by the human eye, you would need to cover the whole visible spectrum, which makes for about 500, 1 nm wide bands. Good luck finding a laser for each wavelength with a tuning of 1 nm. I have seen PhD being made on tunable lasers, but not in the range of powers you are interested in. And I am not mentioning the difficulty of compensating for the different diffraction of each wavelength.

Beam can be slightly angled, but the closer to 90° the better.: a satellite normally circles the whole planet in about 90 minutes. It covers one degree around the vertical of a given spot for 7 hundreds of a second. Spy satellites can get that sort of control, but they don't aim for an object the size of a watermelon (with all the due respect for your head), though they can resolve it in their images.

equipped with a powerful laser: last but not least, what makes you think that it is smart to stand under the shine of a laser powerful enough to shine through more than 100 km of atmosphere? Unless your goal is to impress the bystanders with the laser burns that you will get.

Not feasible in the way you propose it.

Color of the light should be white: laser are monochromatic, with a few nm bandwidth. To make it appear white as perceived by the human eye, you would need to cover the whole visible spectrum, which makes for about 500, 1 nm wide bands. Good luck finding a laser for each wavelength with a tuning of 1 nm. I have seen PhD being made on tunable lasers, but not in the range of powers you are interested in. And I am not mentioning the difficulty of compensating for the different diffraction of each wavelength. Below you can see a comparison between the spectrum of a laser and the spectrum of a LED

Beam can be slightly angled, but the closer to 90° the better.: a satellite normally circles the whole planet in about 90 minutes. It covers one degree around the vertical of a given spot for 7 hundreds of a second. Spy satellites can get that sort of control, but they don't aim for an object the size of a watermelon (with all the due respect for your head), though they can resolve it in their images.

equipped with a powerful laser: last but not least, what makes you think that it is smart to stand under the shine of a laser powerful enough to shine through more than 100 km of atmosphere? Unless your goal is to impress the bystanders with the laser burns that you will get.