A Russian Soyuz capsule has docked at the International Space Station (ISS), setting the stage for a pair of final shuttle missions to the orbital outpost.

Veteran cosmonaut Alexander Kaleri, rookie Oleg Skripochka and Nasa's Scott Kelly boarded the ISS joining three other astronauts who arrived in June.

It means the outpost is now fully staffed again. The new crew members will remain on the station for six months.

During that time, they will receive spare parts for the ISS, delivered on two further shuttle missions, scheduled for November and February.

Kelly's identical twin brother Mark Kelly, also a Nasa astronaut is commander of the latter mission. If schedules go to plan, it would be the first time blood relatives are together in space.

The shuttle programme is ending after 30 years of flights due to high operating costs of about $3 billion a year. The US does not have a replacement vehicle.

In preparation for the shuttles' retirement, NASA has turned over station crew ferry flights to Russia, at a cost of $51 million per person.

The NASA spending plan for the fiscal year that began October 1 includes seed funds for private sector development of space taxis. Under the plan, the government would oversee development of a new launching system for travel to destinations beyond the station's orbit such as asteroids, the moon and Mars.

An additional shuttle mission to deliver cargo to the station next summer also been approved by Congress, but not funded.