Why NASA Needs Laser Communication
Astrum
- One degree of misalignment at a distance of 25,000 miles (geosynchronous orbit, for instance) will cause you to miss your target by 70 miles.
- One second of misalignment (1/60 of a degree) will put you off target by a mile.
- One arcsecond (1/60th of an arcminute or 1/3600th of a degree) will put you off by 100 feet.
The Webb Space Telescope has a similar problem with aligning its mirrors, but they seem to have figured that out. Then there is the problem of the beam spreading. The beam of a laser beam sent from the Earth might be a quarter mile wide by the time it reaches the moon. Now imagine how wide that beam would be by the time it got to Pluto. There are some lasers that have tighter beams that would not spread as much.
This is not the first laser communication system in space. There have several others, some still in use. I imagine what makes this one different is in the details.
2 comments:
Saying the enemy will not be able to hear your comms may not stay true. if there are detectors sensitive enough to pick up laser side, or reflected scatter.
You're talking science fiction now. You might be able to pick up scatter from Earth bound transmissions, i.e. those going through the air, but it's going to be much harder in space. But who knows what next week will bring?
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