Lets say you get the weight of the mirror down to 1gram per square meter, that is 12 MILLION kg per pixel… The cost per kg to land something on the moon is in the neighborhood of 1 million dollars- so 12 TRILLION dollars per pixel… and you have to send people up to wipe down the mirror every few years… that is a few million kg of windex you have to send over and over again, and then there are all the paper towels!

A 10-100 Watt highly collimated laser transmitted from the moon to the earth would be naked eye visible…

This is really the only way to go, Robert.

I’m afraid even the budget option of placing lasers on the Moon is out of the question at the moment, what with the recent dental work and all. Maybe next year.

An active emitter array seems overly complicated anyway. Have you considered mirrors? Per your calculations, a one-pixel mirror would receive something like 1.56e13 watts, more or less, with much better than the “fair reflectance” of the lunar soil. Give that puppy a gentle parabolic curve, put remote-control jacks at the corners for steerage, and there you go.

Right?

At 360,000 km, this means a pixel will be 108km square… this means each pixel will have an area of nearly 12 billion square meters.

The moonlight we see is reflected solar light which has an intensity of ~1300 watts per square meter at the moon’s surface.

we would need ~16 petawatts to illuminate the pixel with an intensity comparable to the solar intensity…

Lets say we use a laser at 532nm near the peak of the human eye response, and lunar soil has fair reflectance at that wavelength…Lets be optimistic and say we could then get away with 10 W/m2 illumination during a new moon, we still need 0.12 Petawatts – or 120 Gigawatts of laser power.

Lets say the laser is very efficient, with 33% wall-plug efficiency- so we need to provide ~360GW of power…. that is 360 nuclear reactors per pixel… and you may need ~ 20 pixels to just print “HZ” on the moon…

We can ask Robert, but I think that is outside of what he is willing to spend…

It would be cheaper, and more efficient to launch an array of lasers to the moon to transmit back at the earth… That wouldn’t require anywhere near the resources required to write on the moon with a laser from Earth… a few hundred cheap solar powered 10-watt lasers at maybe half a million dollars apiece transmitting collimated beams back to earth would be much more efficient than relying on re-scattered light from an earth based laser. They could be directed to different spots on earth every 10 seconds so everyone would get to see it over time.

Lunar dust would degrade the laser optics and solar panels over time, but you might get a few years operation out of them.

THAT might be in Robert’s budget…

…c’mon, ya know ya wanna. Every other website on the planet would turn florescent green with jealousy.

I made a few executive decisions while you were out- the ad hits the Japanese markets tomorrow, so be ready for increased traffic!