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Satellites

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I've seen many Iridium flares. A cool way to freak out your date, because you know when they're coming.
 
starchkr said:
Satelites can be seen from sundown to sunup(nightly occurance for us)....

Don't ya mean 30 minutes after official sunset to 30 minutes before official sunrise as reported in the Airman's Almanac :)
 
Space station?

starchkr said:
...the space station is cool as well...

How can you tell the Space Station from an ordinary satellite?

(Sounds like a silly NASA joke but I'm totally serious)
 
mar said:
How can you tell the Space Station from an ordinary satellite?

(Sounds like a silly NASA joke but I'm totally serious)

I havent seen the station so I cant say for sure, but what I know is:

Most satellites orbit at higher altitudes. The station has to be serviced by the space shuttle which typicaly goes up to 150-200 miles altitude.

The space station is probably quite a bit larger than your average communications sat

Closer + bigger = brighter to your eye

How high do comm satellites orbit? Depends on the mission obviously.. a quick way to figure it out is if you know the orbital period: shorter period = lower altitude (just like tether ball goes around faster as the string gets shorter). Geosynchronous orbit (period = 24 hours) satellites are at an altitude of about 23,000 miles if I remember correctly. The space shuttle, at the altitudes it flies (and by extension the space station) makes an orbit every 90 minutes or so (which makes sense given that the station is approx 4100-4200 miles from the center of the earth).
 
mar said:
How can you tell the Space Station from an ordinary satellite?

(Sounds like a silly NASA joke but I'm totally serious)

The space station generally moves from west to east. Most of the satellites that fly over the U.S. are in high inclination orbits, which means they travel on a north-south trajectory. The space station will also be much brighter because of its size. Most satellites can't even be seen with the naked eye.
Using a tracking program, you can pick out a night when the space station will travel through the entire sky over a period of 5 minutes or so. This will have to be just after sunset or before sunrise.
 
mar said:
It's the Green Flash I'm still waiting to see.

I've seen it. North shore of hawaii, sunset beach, ironically

I remember seeing apollo/soyuz going over when I was a kid
 
You can actually find one particular Earth satellite on most clear nights and sometimes during the day with the naked eye... the Moon.

Most LEO, Low Earth Orbit satellites generally travel with the rotation of the Earth, from west to east, at an inclination that closely resembles their latitude of departure from the Earth unless a specific orbital inclination is required. This is due to the expenditure of fuel that is required to alter the orbital plane or defeat the rotational energy of the Earth. As a matter of fact, some launch sites are designed to be closer to the equator to take advantage of the rotational energy of the Earth thus providing added energy for the satellite. I.e., the closer a launch site is to the equator, such as Sea Launch or French Guiana, the more you take advantage of the Earth's rotational energy for low inclination orbits. Its less expensive.

A satellite in geosynchronous orbit would, (if you could see it), appear to wander north and south over a specific longitude on the Earth at constant altitude as it races with the rotation of the planet. These satellites are typically inserted into equatorial or low inclination orbits that are very far out in space and not visible with the naked eye. Kepler's Laws of Planetary Motion requires a 35,790 km high orbit based on a 23h56m4s day.

A geostationary orbit is a circularized geosynchronous orbit and may require what is called "station keeping" if the orbital inclination is not zero, (over the equator), and maneuvering is required. This satellite, usually a communications or meterological type, appears to hover over a specific spot on the earth.

There are also sun synchronous orbits, walking orbits, Hohmann transfer orbits, and polar orbits the latter of which are unable to elicit any help from the Earth's rotation due to their high orbital inclinations, and must provide all the energy to achieve their orbital objectives.

Since light is required to see most LEO satellites... but not too much light, they can usually be seen just after sunset and just before sunrise.
 
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