How astronauts get to the ISS

Published October 12, 2026 · Updated October 12, 2026

Two spacecraft, two routes

Today, astronauts reach the ISS on one of two spacecraft. Russia's Soyuz, with three seats, lifts off from the Baikonur Cosmodrome in Kazakhstan. SpaceX's Crew Dragon launches from Cape Canaveral, Florida, on top of a Falcon 9 rocket, carrying four crew members on NASA missions. Between them, they keep a regular crew of seven on board.

It wasn't always this way. From 1998 to 2011, the space shuttles carried astronauts and, above all, the pieces used to build the station. After the shuttle was retired, Soyuz was the only way up for almost nine years. In 2020, Crew Dragon made its first crewed flight and the United States regained its own access to the station. A third spacecraft, Boeing's Starliner, flew its first crewed test flight in 2024; it ran into thruster problems, and its two astronauts ended up coming home on a Crew Dragon in 2025.

A launch window that lasts an instant

To reach the ISS without burning extra fuel, the rocket has to lift off at the exact moment Earth's rotation carries the launch pad under the plane of the station's orbit. That happens once a day (twice in some cases) and doesn't last long. That's why crewed missions to the ISS have “instantaneous” launch windows: if something holds up liftoff by even a few seconds, the launch slips to the next day.

You can follow the countdowns for upcoming missions, with exact launch times and live streams, on our upcoming launches page.

The trip: catching something moving at 28,000 km/h (17,500 mph)

Reaching orbit is the quick part: about nine minutes after liftoff, the spacecraft is already circling Earth. What takes time is catching up with the station. The spacecraft starts out in an orbit a little lower than the ISS's, and since lower orbits are faster, it gains ground with every lap. A series of engine burns, timed to the second, gradually adjusts its altitude until it sits just behind and below the station.

• Soyuz, fast track: since 2020, Soyuz flights usually arrive in about three hours, after only two orbits of Earth. Before that, the trip took about six hours, and in the early years, two days.
• Crew Dragon: it takes its time, usually about a day. The crew eats, sleeps a few hours in their seats and checks the systems before arrival.

Approach and docking

The last few hundred meters are covered very slowly, at just a few centimeters per second by the end, with stops at hold points to make sure everything is going well. Both Soyuz and Crew Dragon dock on their own, guided by their sensors; the crew keeps watch and can take manual control if something goes wrong. With Soyuz, a cosmonaut inside the station can also fly it in remotely.

Each spacecraft has its own ports. Soyuz docks at the Russian modules, such as Rassvet, Poisk or Prichal. Crew Dragon docks at Harmony, the US segment's node, through docking adapters installed in 2016 and 2019. To see where each one is, check out our guide to the ISS modules.

Opening the hatch

Docking isn't the same as getting in. Before anything opens, the crew spends an hour or two confirming that the seal is airtight and there are no leaks, and the pressures on both sides are equalized. Then the hatches open and the new arrivals move into the station, where the crew already on board is waiting for them. There's usually a short welcome ceremony, with a live link to family members and mission control centers.

That's when the expedition begins. For a few days, the incoming and outgoing crews live together and use the overlap to hand over the work. That's why the number of people on board goes up for a while at every crew change.

Seat swaps and private missions

Since 2022, NASA and Roscosmos have been swapping seats: a cosmonaut flies on every Crew Dragon and a US astronaut on every Soyuz. That way, if either spacecraft had to stay on the ground for a while, there would always be someone from each country on board who could run their side of the station.

There are private missions too. Since 2022, Axiom Space has organized flights of about two weeks aboard Crew Dragon, with astronauts from several countries and private customers. Training for these flights is the same as for an official mission; we cover it in how astronauts train.

The trip home

The Soyuz trip home takes about three and a half hours from undocking. It reenters the atmosphere, opens its parachutes and, about 1 meter (3 feet) above the ground, fires small rockets to soften the landing on the steppe of Kazakhstan. Crew Dragon splashes down in the ocean under four parachutes, and a ship picks it up. Either way, after months of weightlessness, the crew needs help getting out: it takes the body a few days to get used to its own weight again.

Everything that doesn't fly on crewed spacecraft (food, water, experiments) arrives on automated cargo ships. We explain how in how the ISS is resupplied.

Frequently asked questions

How long does it take to get to the ISS?

It depends on the spacecraft. Soyuz, on its fast-track trajectory, arrives in about three hours. Crew Dragon usually takes about a day, because it makes a more leisurely approach.

Where do astronauts launch from to reach the ISS?

From Baikonur, in Kazakhstan, when they fly on Soyuz, and from Cape Canaveral, Florida, when they fly on Crew Dragon.

Why can a few seconds of delay scrub an ISS launch?

Because these launches have instantaneous windows: the rocket has to lift off exactly when the launch pad passes under the plane of the station's orbit. If it's late, it has to wait for the next opportunity, usually the following day.

Do the spacecraft dock on their own?

Yes. Soyuz and Crew Dragon dock automatically using their sensors. The crew supervises and can take manual control if needed.

How many people fit in each spacecraft?

Soyuz carries three. Crew Dragon is designed for seven, but it flies with four on ISS missions.