How long does it take to get to the ISS from Earth?
Last Updated: February 25, 2022
For years, we have looked up to the stars and dreamed of exploring the cosmos around us. Once considered a fantasy, the International Space Station has been a reality for more than 20 years now, thanks to the collaboration of NASA (United States), Roscosmos (Russia), JAXA (Japan), ESA (Europe) and the CSA (Canada).
In this article, we will take a look at how long it takes to travel to the Internal Space Station from Earth, as well as all of the intricacies involved in such a difficult journey.
How far away is the space station?
The International Space Station (ISS) is the largest man-made structure ever to orbit the Earth, and it can be seen at night as a slow-moving little point of light. Although we can see it with the naked eye, we should not overlook the fact that it is located very far away in the sky. The ISS orbits Earth at an altitude of about 253 miles (408 km).
Although the ISS is gradually losing altitude because of drag from the atmosphere, its orbital height is corrected with burns every 2 months. As we will see later in this article, the height and speed of the ISS play an important role in the time needed to reach the space station from Earth.
How long does it take to travel to the space station?
From launch to docking, a spacecraft typically takes between 6 hours and 3 days to travel from Earth to the International Space Station. The quickest travel time so far has been an amazing record-breaking 3 hours and 3-minute flight by the Russian spacecraft Soyuz MS-17 carrying Russian cosmonauts Sergey Ryzhikov, Sergey Kud-Sverchkov and NASA astronaut Kate Rubins.
Orbiting Earth every 90 minutes at a velocity of 17,500 miles (28,000 kilometres) per hour, you can imagine that reaching the ISS could seem like a momentous task just within itself and the timing for arrival is essential. Travel to the spectacular modular space station varies, all depending on the various capabilities and technologies. However, through the brilliant minds of today’s top scientists and engineers, the journey today is much smoother than it once was.
The journey to the space station is a carefully choreographed sequence of rocket burns or engine firings, that must be precisely timed to achieve the correct orbit. To help you make sense of the time and effort it takes to reach the ISS from Earth, we’ve created the below timeline explaining a rocket’s journey to the ISS.
The liftoff phase of a rocket is the point in its launch when it leaves the ground and begins to ascend into space. The engines fire up, providing thrust that pushes the rocket upwards.
2. Orbit activation
The orbit activation phase of a rocket is the process of transitioning from a suborbital trajectory to an orbital trajectory. The orbit activation phase typically lasts for around two minutes. However, the exact duration will vary depending on the specific rocket and its payload.
3. Phasing burns
This phase is used to fine-tune the rocket’s trajectory and ensure it reaches its destination safely. During phasing burns, the engines are fired in short bursts to make small adjustments to the rocket’s course.
4. Approach initiation
The approach initiation phase of a shuttle going to the ISS is an important step to ensure safe arrival. This phase begins once the shuttle has reached its orbit and is about to start its journey to the space station. The rendezvous timeline is based on the space station’s orbit, so it’s important to make sure that both orbits are accurately calculated.
5. Proximity operation
The proximity operations phase of a shuttle going to the ISS is the most dangerous part of the mission. The proximity operations are very risky because there is a danger of collision between the shuttle and the ISS. To avoid this, the shuttle spacecraft must be carefully manoeuvred into position by the pilot.
6. Docking & pressurization
Docking is the process of connecting two spacecraft together. The shuttle connects to the ISS by using a docking port, which is like a giant plug that fits into a socket on the ISS. Once the two spacecraft are connected, the pressurization process begins. Pressurization is the process of increasing the air pressure inside a spacecraft. This allows the astronauts to safely enter the ISS.
How long does it take SpaceX to get to the space station?
The Soyuz spacecraft was once the only way for astronauts to reach the ISS from Earth. That has changed thanks to SpaceX, Elon Musk’s aerospace company. SpaceX used to fly uncrewed spacecraft to deliver cargo (supplies, food, pieces of equipment, etc) to the ISS since 2012. However, since 2020, SpaceX has been transporting people to the ISS using their flagship “Crew Dragon” spacecraft.
So far, SpaceX has successfully completed three operational missions as part of the Commercial Crew Program. Those three missions consisted of sending 4 people to the International Space Station.
- SpaceX Crew-1 reached the ISS in 28 hours
- SpaceX Crew-2 docked to the ISS after a 24 hours journey.
- SpaceX Crew-3 arrived at the ISS after just 21 hours.
SpaceX has managed to reduce the duration of their spaceflights with each of the last 3 missions and it would not be surprising to see them achieve even shorter journeys to the space station. Time will tell!
Step by step flight plan of the dragon crew spacecraft to the international space station. Image credit: SpaceX
Written by Tom Urbain
I’ve been fascinated by space and astronomy from a very young age. When I’m not watching space-themed documentaries, movies or TV series, I spend most of my free time in my backyard admiring the planets and galaxies with my telescope.
As they experience nighttime about 16 times per 24 hours, it gives them many opportunities to observe the stars.
You could see the station a few times within a few hours, granted you are on the night side of the planet and you know where to look.