A SpaceX Dragon cargo ship delivered the first inflatable room for astronauts to the International Space Station on Saturday, two days after launching from Cape Canaveral.

Astronauts, including the UK’s Tim Peake, orbiting 250 miles above Earth used a robotic arm to capture the Dragon, which holds three tonnes of freight and had as part of its payload a soft-sided compartment built by Bigelow Aerospace.

The pioneering pod, packed tightly for launch, should swell to the size of a small bedroom once filled with air. It has been attached to the space station but won’t be inflated until May.

The technology could change the way astronauts live in space. Nasa envisions inflatable habitats on Mars in a couple of decades, while Bigelow Aerospace aims to launch a pair of inflatable space stations for commercial lease in four years.

For now, the Bigelow expandable activity module will remain mostly off-limits to the station crew. Nasa wants to see how the experimental chamber functions, so the hatch will stay sealed except when astronauts enter a few times a year to collect measurements and change sensors.

This is SpaceX’s first delivery for Nasa in a year, after a launch accident last June put shipments on hold. In another development, for the first time a leftover booster came to a solid vertical touchdown on a floating platform, which is significant because SpaceX chief executive Elon Musk wants to reuse boosters to save money, a process that he says will open access to space for more people in more places, such as Mars. His ambition is to establish a city on Mars.

Nasa also has Mars in its sights and is looking to send astronauts there in the 2030s. In pursuit of that objective, the space agency has hired US companies such as SpaceX to deliver cargo and, as early as next year, astronauts to the space station. US astronauts currently have to hitch rides on Russian rockets.

In a sign of this new commercial era of space, a Dragon capsule is sharing the station for the first time with Orbital ATK’s supply ship, Cygnus, which has already been docked there for two weeks.

The Dragon will remain at the station for a month before returning to Earth with scientific samples, many of them from one-year spaceman Scott Kelly. He ended his historic mission last month. Cygnus will be there a little longer.