Boeing's Starliner spacecraft arrived at the International Space Station (ISS) on Friday after facing a few hiccups.

After flying for around a day, the unmanned ship docked at the ISS some 400 kilometers (250 miles) above Earth. It carried about 225 kilograms (500 pounds) of NASA cargo and crew supplies and more than 130 kilograms of Boeing cargo.

The successful flight was an important test for the crisis-ridden starliner. A series of problems have put the project two years behind schedule.

Boeing plans to use the Starliner to transport astronauts to the ISS in the future, providing an alternative to the SpaceX "Crew Dragon" capsule.

Starliner is a partially reusable, next-generation spacecraft consisting of a reusable crew capsule and a service module to be launched by rocket. Once certified, it will carry up to four crew members to the station.

The spacecraft was originally due to set off for the space station in July 2021.

The mission was postponed several times, firstly due to problems after the arrival of the Russian research module Nauka, and then because of problems with the Starliner's propulsion system valves.

The United States aviation and aerospace firm developed and built the Starliner for NASA.

In a first test flight in December 2019, the spacecraft did not make it to the ISS, partly because of a problem with the automatic ignition of the drives./dpa