[chris (OP)]

The International Space Station (ISS) is in low-Earth orbit at an altitude of about 190 miles. It's travelling at about 17,000 miles per hour and completes 16 laps of the planet (orbits) per day.

But what keeps it there? Presumably this orbit is decaying and there must be some drag from wisps of Earth's atmosphere so does the ISS periodically receive a push to speed it back up and prevent it from turning into a multi-billion dollar firework display?

Chris

[Vern]

According to this Wiki article regular boosts are required to keep space stations in orbit.

Orbital decay exerts a significant effect at the altitudes of space stations, space shuttles and other manned Earth-orbit spacecraft, and satellites with relatively high orbits such as the Hubble Space Telescope. Space stations typically require a regular altitude boost to counteract orbital decay (see also orbital station-keeping). Uncontrolled orbital decay brought down the Skylab space station, and (relatively) controlled orbital decay was used to de-orbit the Mir space station. Orbital boosts for the International Space Station (ISS) are regularly needed, and are one limiting factor for the length of time the ISS can go between visits from transit spacecraft. Regular orbital boosts are also needed by the Hubble Space Telescope, though on a longer time scale, due to its much higher altitude. However, orbital decay is also a limiting factor to the length of time the Hubble can go without a maintenance rendezvous, currently planned for May 12, 2009.

[syhprum]

I think that what origanally kept it up was a matter of keeping one up on the commies, now I expect its a matter of keeping one up on the Chinks.
I understand it is only meant to last till 2015 then no doubt this ridiculous white elephant will be dumped

[Vern]

But if we dump the ISS, how will we justify NASA spending more than 10 billion a year. Much of that goes to salaries of NASA workers, who seem to sit around in front of terminals all day; probably playing computer games. []

[RD]

Without boosts the infamous ISS lost toolkit will eventually become a $100,000 firework ...