For a long time the only way for normal people to get into space was to pay the Russians big bucks for a seat in the Soyuz capsule on its way to the ISS. The Russians allowed eight people to catch a ride to the ISS between 2001 and 2009. Private passengers weren’t able to go to the ISS with the Russian state space agency after NASA and other space agencies needed to use the seat to get their own astronauts to the ISS.
Now that the demand from those other space agencies for seats in the Soyuz capsules has declined, Roscosmos, the Russian state space agency, has now announced that it plans to start short-term commercial expeditions to the Russian segment of the ISS up again.
Part of the reason Roscosmos is starting the expeditions back up is to make up for the financial loss it will feel when the US gets its own capsules into service and can once again send its own astronauts into space. NASA and Roscosmos are expected to put one more agreement into place that will allow astronauts to hitch a ride with Russian missions to the ISS.
That agreement is expected to go into place in 2018. It is thought to be the last agreement since the US will have both the SpaceX Dragon and the Boeing CST-100 capsules complete by that time and ready to send astronauts into space.
SOURCE: The Verge