Currently logged out. Login
Currently logged out. Login

Why Does It Take So Long To Get To Space?

Why Does It Take So Long To Get To Space?

It’s always a blast to see astronauts go into outer space, but what takes them so long to get back to Earth? Northwestern University looks to the stars for the answer:


Outer space is unthinkably big, but there’s a line that separates planet Earth from the rest of it. We call that line the Kármán Line, and it’s only 62 miles above our planet! Objects below the line fall back into Earth’s atmosphere, and objects above that line float in space. Space shuttles can reach the Kármán Line in just a few minutes, so getting into outer space is the easy part of the journey. It’s getting around space that’s trickier.


Reaching a destination in space, whether that’s a planet or the International Space Station, isn’t a straight shot. Everything in our solar system revolves around the sun, so objects are never in a fixed location. That means spaceships can’t take a direct path to their destination; they need to go in a spiral so that they eventually cross paths with the orbit of the planet or space station they’re trying to reach. That takes a lot more time than flying in a straight line!


Depending on where you’re going in space, it can be a pretty quick trip. If you’re heading into Earth’s backyard, you’ll be traveling anywhere from a few hours to a few days. It’s when you start looking at the distance between Earth and other planets that you start to understand just how big outer space is:

  • International Space Station: 248 miles from Earth. This journey can be completed within a day.
  • Earth’s Moon: 238,900 miles from Earth. This journey takes around 3 days.
  • Venus, our closest neighboring planet: 27,900,000 miles from Earth. This journey takes 3 months.
  • Mars, a recent focus for space travel: 46,500,000 miles from Earth. This journey takes up to a year.
  • Neptune, the final planet in our solar system: 2,697,000,000 miles from Earth. This journey takes 12 years.

And that’s just within our solar system! The Voyager 1 spacecraft was the first man-made object to pass that boundary, which took 36 years to accomplish. 

Looking for more Never Stop Asking "Why?" questions? Catch up on all of the past "Whys" on the blog!