NASA is getting ready for a change in how it delivers astronauts to the International Space Station (ISS). Since the space shuttle was retired, the space agency has relied on Russia to ferry American astronauts to and from the ISS at a cost of $70 million apiece. By 2017, SpaceX and Boeing are expected to take over those duties at a cost of $58 million per astronaut.

This week, in preparation for that event, NASA will begin the first reconfiguration of the ISS since it was completed in 2011. The project will begin on Friday when Barry “Butch” Wilmore, the station commander, and flight engineer Terry Virts take one of three spacewalks that will be required to prepare communications gear and cables in preparation for new docking ports. The second spacewalk will take place on Tuesday, 24th and the last on Sunday, March 1.

In total, seven spacewalks are scheduled for this year to install communications systems, docking targets and other necessary equipment in preparation for the new Docking Adapters.

Two new Docking Adapters, for the Boeing’s CST-100 and SpaceX Dragon capsule will be delivered aboard a SpaceX Dragon cargo ship later this year. Before that can happen however, several existing pieces of the ISS need to be rearranged.

The Leonardo multipurpose module will need to be moved from the Unity connection node to the Tranquility connection node. That operation is expected to be done robotically from ground control.

“This is quite a bit of work. Our plan has always been to have a docking capability in place and operational by the end of 2015 and we’re on track to do that,” space station program manager Mike Suffredini told Discovery News.

The modifications are expected to be complete by the end of the year. Once the Docking Adapters are in place, one berthing slip will be located at the front end of the Harmony connecting node and the other on Harmony’s up-facing port.

Using the Boeing and SpaceX “space taxis” will allow NASA to fly four astronauts at a time instead of three and expand the live-about crew of the ISS from six to seven people at a time.

At present, SpaceX plans to send a Dragon V2 passenger ship on a test flight to the ISS in late 2016 and to be ready for manned flights in early 2017. For its part, Boeing plans on being ready for a unmanned test flight of the CST-100 in April, 2017 and to begin ferrying passengers in July 2017.

The new NASA Docking System (NDS) was originally the Low Impact Docking System (LIDS) and the international Low Impact Docking System (LIDS) before being transferred to Boeing from the Johnson Space Center and becoming the Soft Impact Mating and Attenuation Concept (SIMAC) design.

The Boeing’s CST-100 and SpaceX Dragon capsule should not be confused with NASA’s Orion spacecraft. The Orion Multi-Purpose Crew Vehicle, also expected to carry crews of four astronauts, is being designed for deep space missions. Orion, which made its first successful test flight in December of 2014, will carry astronauts to explore comets and eventually to Mars after it is completed in 2021.