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Now I want to build a CubeSat that will point a laser pointer at different population centers as it passes around the earth. E.g. this pass of North America you

Now I want to build a CubeSat that will point a laser pointer at different population centers as it passes around the earth. E.g. this pass of North America you choose LA, then NYC, then Houston, then Chicago... so you can see it streak by in the sky. My rough estimation is you could create a spot 2 miles across with a standard laser pointer at 400 miles high. Maybe you could use a different kind that would have a little more spread. And you'd have even more if you weren't beaming directly downwards -- maybe you could point it at 45 degrees or more with a powerful laser and get nice coverage.

wickedlasers 7y ago
Maybe check out the lasercube for a laser you can program https://wickedlasers.com/cube https://wickedlasers.com/cube
xhgdvjky 7y ago
cool idea for ten minutes but this is exactly the kind of pollution I don't want from cheaper satellites
- asdfman123 7y ago
  I guess this is the space equivalent of when Clark Griswold's redneck cousin Eddie comes into town. Move over, high falutin' space types! I want a laser pointer pointing at my house every night!
modeless 7y ago
You don't need a laser pointer. All you need to do is reflect sunlight. There was a recent attempt to deploy a cubesat that would become the brightest object in the night sky (besides the Moon), simply by deploying some white fabric. Unfortunately, or fortunately depending on your opinion (I lean toward the latter), it failed to fully deploy. http://spaceflight101.com/soyuz-kanopus-v-ik/mayak-lighthouse-in-the-sky-fails-to-deploy-solar-reflector/ http://spaceflight101.com/soyuz-kanopus-v-ik/mayak-lighthous... Many satellites are visible to the naked eye; some even brighter than the stars. If you want to see them, heavens-above.org is a great place to find out when to look. https://heavens-above.com/PassSummary.aspx?satid=42830 https://heavens-above.com/PassSummary.aspx?satid=42830
- vkou 7y ago
  > Many satellites are visible to the naked eye; some even brighter than the stars. And if you want to see an absolute cornucopia of satellites, grab a pair of binoculars, and look straight up, an hour or two after sunset. You'll see faint little lights, crossing your field of vision, to and fro, on a very regular basis.
- massimo-nazaria 7y ago
  > Many satellites are visible to the naked eye; some even brighter than the stars. If you want to see them, heavens-above.org is a great place to find out when to look. https://heavens-above.com/PassSummary.aspx?satid=42830 https://heavens-above.com/PassSummary.aspx?satid=42830 Interesting link. Another interesting one is https://spotthestation.nasa.gov https://spotthestation.nasa.gov about the ISS, which is probably the most visible to the naked eye.
snickmy 7y ago
For a while I thought you would need too much energy, then I realized I don't know well enough the physics of how a laser works. [Warning, very stupid idea ahead]: Since I don't know well enough the topic, why wouldn't be possible to use a satellite to collect solar energy (because outside the atmosphere you can collect ~40% more (edited) the solar energy due to lack of atmospheric filtering effect),and then transmit that energy back to earth via some sort of wireless energy distribution mechanism (laser?). I guess a YoYo satellite with real tens of KM of wire to earth has a lot of reasons for not be feasible.
- asdfman123 7y ago
  It's actually not a terrible idea and it's been considered in depth before: https://en.wikipedia.org/wiki/Space-based_solar_power https://en.wikipedia.org/wiki/Space-based_solar_power. Like so many things it's got a few unsolved technical difficulties thought that make it not-quite feasible.
- ohazi 7y ago
  It's not 40x more, it's barely 40% more. [1] > Average annual solar radiation arriving at the top of the Earth's atmosphere is roughly 1361 W/m^2. The Sun's rays are attenuated as they pass through the atmosphere, leaving maximum normal surface irradiance at approximately 1000 W /m^2 at sea level on a clear day. There are practical challenges, but otherwise, yes, it should work. [1] https://en.wikipedia.org/wiki/Solar_irradiance#Irradiance_on_Earth's_surface https://en.wikipedia.org/wiki/Solar_irradiance#Irradiance_on...
  - snickmy 7y ago
    Thank you for the pointer! I've updated the original comment, and my knowledge base too :)
- ChuckMcM 7y ago
  Search "Solar power satellites". Lots of research, some unsolved problems, downlink is typically microwaves to a rectenna.
- 7y ago

wickedlasers 7y ago

Maybe check out the lasercube for a laser you can program https://wickedlasers.com/cube https://wickedlasers.com/cube

xhgdvjky 7y ago

cool idea for ten minutes but this is exactly the kind of pollution I don't want from cheaper satellites

asdfman123 7y ago
I guess this is the space equivalent of when Clark Griswold's redneck cousin Eddie comes into town. Move over, high falutin' space types! I want a laser pointer pointing at my house every night!

modeless 7y ago

You don't need a laser pointer. All you need to do is reflect sunlight. There was a recent attempt to deploy a cubesat that would become the brightest object in the night sky (besides the Moon), simply by deploying some white fabric. Unfortunately, or fortunately depending on your opinion (I lean toward the latter), it failed to fully deploy. http://spaceflight101.com/soyuz-kanopus-v-ik/mayak-lighthouse-in-the-sky-fails-to-deploy-solar-reflector/ http://spaceflight101.com/soyuz-kanopus-v-ik/mayak-lighthous... Many satellites are visible to the naked eye; some even brighter than the stars. If you want to see them, heavens-above.org is a great place to find out when to look. https://heavens-above.com/PassSummary.aspx?satid=42830 https://heavens-above.com/PassSummary.aspx?satid=42830

vkou 7y ago
> Many satellites are visible to the naked eye; some even brighter than the stars. And if you want to see an absolute cornucopia of satellites, grab a pair of binoculars, and look straight up, an hour or two after sunset. You'll see faint little lights, crossing your field of vision, to and fro, on a very regular basis.
massimo-nazaria 7y ago
> Many satellites are visible to the naked eye; some even brighter than the stars. If you want to see them, heavens-above.org is a great place to find out when to look. https://heavens-above.com/PassSummary.aspx?satid=42830 https://heavens-above.com/PassSummary.aspx?satid=42830 Interesting link. Another interesting one is https://spotthestation.nasa.gov https://spotthestation.nasa.gov about the ISS, which is probably the most visible to the naked eye.

snickmy 7y ago

For a while I thought you would need too much energy, then I realized I don't know well enough the physics of how a laser works. [Warning, very stupid idea ahead]: Since I don't know well enough the topic, why wouldn't be possible to use a satellite to collect solar energy (because outside the atmosphere you can collect ~40% more (edited) the solar energy due to lack of atmospheric filtering effect),and then transmit that energy back to earth via some sort of wireless energy distribution mechanism (laser?). I guess a YoYo satellite with real tens of KM of wire to earth has a lot of reasons for not be feasible.

asdfman123 7y ago
It's actually not a terrible idea and it's been considered in depth before: https://en.wikipedia.org/wiki/Space-based_solar_power https://en.wikipedia.org/wiki/Space-based_solar_power. Like so many things it's got a few unsolved technical difficulties thought that make it not-quite feasible.
ohazi 7y ago
It's not 40x more, it's barely 40% more. [1] > Average annual solar radiation arriving at the top of the Earth's atmosphere is roughly 1361 W/m^2. The Sun's rays are attenuated as they pass through the atmosphere, leaving maximum normal surface irradiance at approximately 1000 W /m^2 at sea level on a clear day. There are practical challenges, but otherwise, yes, it should work. [1] https://en.wikipedia.org/wiki/Solar_irradiance#Irradiance_on_Earth's_surface https://en.wikipedia.org/wiki/Solar_irradiance#Irradiance_on...
- snickmy 7y ago
  Thank you for the pointer! I've updated the original comment, and my knowledge base too :)
ChuckMcM 7y ago
Search "Solar power satellites". Lots of research, some unsolved problems, downlink is typically microwaves to a rectenna.
7y ago