How Many Kilometers Does the ISS Travel Per Day
The International Space Station travels approximately 661,824 kilometers every day around the Earth. That figure comes from multiplying its orbital speed by the 24 hours in a day, resulting in a daily trip equivalent to circling the planet about 15.5 times. Let’s break down exactly where these figures come from.
The ISS orbital speed: the base figure
The ISS travels at an orbital speed of 7.66 kilometers per second, equivalent to about 27,600 km/h. This speed isn’t arbitrary: it’s exactly what’s needed for the station to stay in orbit without falling to Earth or escaping into space. At that speed, in a single second the ISS covers a distance similar to what separates several medium-sized cities from each other.
To get a comparative idea of just how fast this is, you can check out how far light travels in one second, which is still thousands of times greater, but helps put into perspective the extreme speeds that exist in the universe.
How many kilometers the ISS travels per day
If we multiply 27,600 km/h by the 24 hours in a day, we get a daily distance of 662,400 kilometers. However, if we use the more precise figure of 7.66 km/s, the exact calculation is: 7.66 km/s × 86,400 seconds = 661,824 kilometers per day. This is the figure usually cited as the ISS daily distance.
- Orbital speed: 7.66 km/s
- Speed in km/h: approximately 27,600 km/h
- Daily distance: about 661,824 km
- Complete orbits of Earth per day: 15.5
Why the ISS needs to go so fast
The station orbits at about 400 kilometers of altitude, an area where Earth’s gravity is still almost 90% of what we feel on the surface. To avoid falling, it needs an enormous horizontal speed that compensates for the constant fall caused by gravity. In simple terms: the ISS is falling all the time, but it moves so fast sideways that the curvature of the Earth means it never actually touches it. This is known as free orbit or continuous orbital fall.
How many times it orbits Earth in 24 hours
The ISS completes a full orbit around the Earth every 92.68 minutes approximately. Dividing the 24 hours (1,440 minutes) by that orbital time, we get 15.5 complete orbits per day. This means the astronauts on board see the sun rise and set more than 15 times every 24 hours, something that completely breaks the earthly notion of “day” and “night”.
Comparing the ISS’s daily distance with familiar trips
661,824 kilometers a day is a figure that’s hard to picture without references. Here are some useful comparisons:
- It’s almost double the average distance between the Earth and the Moon (384,400 km).
- It’s equivalent to more than 16 complete trips around Earth’s equator (each 40,075 km).
- It’s a distance that a commercial plane, flying nonstop at 900 km/h, would take more than 30 days to cover.
If you’re interested in better understanding how these space scales relate to each other, you can check out what an astronomical unit is and exactly how many kilometers it equals, a key concept for measuring distances beyond our orbit.
The total daily distance since the ISS launch
The ISS has been orbiting the Earth since November 1998. Multiplying the daily kilometers by the years passed, the station has already accumulated several billion kilometers traveled, a distance that far exceeds several round trips to Mars at its closest point to Earth.
Factors that can vary the orbital speed
The ISS’s speed isn’t completely constant. There are small variations caused by:
- Residual atmospheric drag, which slightly slows the station over time.
- Orbit correction maneuvers performed periodically to prevent the ISS from losing altitude.
- Docking and undocking of spacecraft, which can minimally alter the trajectory for a few moments.
These corrections are necessary because, without them, the ISS would gradually lose altitude and end up reentering the atmosphere sooner than planned.
What this speed means for the astronauts on board
Despite moving at more than 27,000 km/h, astronauts don’t perceive that speed because there are no nearby reference points or friction generating a sense of movement, similar to what happens on a plane in stable flight. What they do notice is the constant cycle of sunrises and sunsets roughly every 45 minutes, a result of the 15.5 daily orbits mentioned earlier.
Frequently asked questions
How many kilometers does the ISS travel per day exactly?
The International Space Station travels approximately 661,824 kilometers per day, resulting from multiplying its orbital speed of 7.66 km/s by the 86,400 seconds in a full day.
What is the speed of the International Space Station?
The ISS travels at an orbital speed of 7.66 kilometers per second, equivalent to about 27,600 kilometers per hour, fast enough to complete a full orbit of the Earth in approximately 92.68 minutes.
How many times does the ISS orbit the Earth in 24 hours?
The ISS completes 15.5 full orbits around the Earth every 24 hours, meaning astronauts experience more than 15 sunrises and sunsets daily.
Why doesn’t the ISS fall to Earth if it’s going so fast?
The ISS is actually in constant free fall due to Earth’s gravity, but its horizontal speed is so high that the curvature of the Earth compensates for that fall, keeping it in a stable orbit at about 400 kilometers of altitude.
How many kilometers has the ISS traveled since its launch?
Since its launch in November 1998, the ISS has accumulated billions of kilometers traveled, adding approximately 661,824 kilometers to its total orbital distance every day.