About every 90 minutes. It is easy to see passing overhead, if you know where to look. Use the "Satellite Overflights" link below, and enter your zip code (in the USA) or your nation, province and city to get a list of the overflights for the next week.
The International Space Station orbits the earth every 91 minutes.
the iss orbit is an orbit which goes around the earth giving satalight signals
This is because of the Gravitational pull of the earth.
40,000 miles
The ISS is in Low Earth Orbit and can be tracked by several sites on the internet. See related link
I think the LEO (Low Earth Orbit) is economical than higher Earth Orbit for the ISS. The rocket is able to send heavier spacecraft to LEO. But spacecraft in LEO is sinking because of air drag. The ISS has to boost the orbit from time to time (for example several weeks ). The air drag is smaller in higher Earth Orbit.
the iss orbit is an orbit which goes around the earth giving satalight signals
This is because of the Gravitational pull of the earth.
ISS is an internationally developed research facility, which is being assembled in low Earth orbit.
40,000 miles
The ISS is in Low Earth Orbit and can be tracked by several sites on the internet. See related link
I think the LEO (Low Earth Orbit) is economical than higher Earth Orbit for the ISS. The rocket is able to send heavier spacecraft to LEO. But spacecraft in LEO is sinking because of air drag. The ISS has to boost the orbit from time to time (for example several weeks ). The air drag is smaller in higher Earth Orbit.
Earth's gravitational attraction keeps changing the direction of its movement continuously. This keeps orbits near Earth - such as the ISS - in an elliptical orbit.
The shuttle never leaves Earth orbit, it simply goes into orbit and then returns. Moving to a higher orbit requires additional speed and manuevering, as when visiting the ISS.
Depending on where the station is in its elliptical orbit around earth, it is between 190 and 192 nautical miles from earth.
The spaceshuttle Columbia was orbiting the earth in a low earth orbit. Because its mission was not to the International Space Station (Columbia never went to the ISS on a docking mission) it was lower than most, which would have excluded a rescue scenario involving the ISS. Columbia did not have sufficient fuel to boost to the height of the ISS.
The ISS orbits at an altitude of 400 km (250 miles) above Earth.
Nothing really. It is in orbit around Earth, so it doesn't need anything to propel it.