How ISS travels around the earth


Does the ISS (International Space Station) also rotate along with Earth, or does it stay at one point in space? originally appeared on Quora: the place to gain and share knowledge, empowering people to learn from others and better understand the world. Answer by Robert Frost, Instructor and Flight Controller in the Flight Operations Directorate at NASA, on Quora: The words revolve and rotate are often misused when it comes to the International Space Station and Earth. To revolve involves translational motion, while to rotate involves a change in orientation. Imagine it this way – your friend is standing in front of you. If you walk in a circle around your friend, you are revolving. If you do not change your location, but turn around to not face your friend, you are rotating. If you walk in a circle around your friend and constantly turn so that you are continually facing him, you are both revolving and rotating. That’s what the ISS does.
The ISS revolves around the Earth at about 17,500 mph (~28,000 km/h) resulting in it completing one revolution in about 90 minutes, and about 16 revolutions per day.
The ISS rotates about its center of mass at a rate of about 4 degrees per minute so that it will complete a full rotation once per orbit. This allows it to keep its belly towards the Earth.
Because the Earth is rotating, the ISS doesn’t pass over the same places on Earth each orbit. Each orbit is 22.5 degrees to the east of the previous orbit (360 degree rotation of the Earth in one day, divided by 16 orbits of the ISS about the Earth in one day). (…)“


Zum ganzen Artikel | See full article (extern)