What if we place an reflective object on the moon?
CuriousOne
Posts: 931
Inspired by recent news that UK scientists plan to bore a 100 meter deep shaft in moon...
As we know, actual moon surface is quite dark, reflects only small amount of sunlight. So what if some lunar mission will bring some, say, stainless steel foil sheet, and place It on the moon? what size of that foil should be, so we can see the reflected light with bare eye?
As we know, actual moon surface is quite dark, reflects only small amount of sunlight. So what if some lunar mission will bring some, say, stainless steel foil sheet, and place It on the moon? what size of that foil should be, so we can see the reflected light with bare eye?
Comments
That laser reflector is the most efficient means to reflect light without having 'active' aiming of the mirror.
http://en.wikipedia.org/wiki/Earth-Moon-Earth_communication
It may have some merits of scale over redirection via artificial satellite in a lower Earth orbit. But dust might be a problem... maybe a satellite in lunar orbit would be cleaner. One still has the problem of occasional eclipses.
the chance of correct alignment for a reflection is negligible - it'll just reflect the night sky
and be darker than the moon's surface!
If you were to choose a metal then steel is too heavy for space - aluminized mylar foil
would be more plausible.
And you want it facing us, not on the lunar south pole like the borehole mission.
A retro-reflector is very inefficient for being visible, its what's needed for range-finding
since you have to send and receive a laser pulse. For visibility you use sunlight, since
its plentiful and cheap.
The kind of features visible to the naked eye on the moon are 100's km, although
the albedo is low even for the "white" rays coming out of younger impact craters.
Perhaps something like a 20km white disc would be visible.
20km, sure?
If object is much brighter than surroundings, still need to be that big?
But we can still beat them then by writing Coca Cola on it...
Enjoy!
Mike
The original question "what size of that foil should be, so we can see the reflected light with bare eye?" did get me to Googling for a while. I would guess the answer is probably somewhere between 10 and 100 km, but that's just a very rough estimate.
Mylar type material has been used for decades as part of the insulation on spacecraft. The Lunar Module was wrapped in layers of it. I don't think it will melt on the Moon
http://en.wikipedia.org/wiki/The_Man_Who_Sold_the_Moon
Hello!
It was indeed. It was one of several DuPont materials that were created for the space age.
As for reflective objects up there, the Apollo Experiment packages that were parked up there by the astronauts which are still there, and unless the solar wind has degraded them, should still work.
Side point, note the name involved with the moon and most of his lunar stories after Rocketship Galileo and a number of others. Hint, the family is still with us, and he was the governor either before or after FDR, I do know he was all over Europe and passed away fairly recently.
Oh and oddly enough an individual with my IRL name (last name) was involved with the whole business, eventually he retired from that business and ran a building materials shop near where I grew up.
For the night time illumination, as I have read, russians had some prototype satellites flying on low orbit, but costs were considered too much, compared to benefits it offered.