New York, Jan 18 (IANS): NASA is considering to acquire two seats on the Russian Soyuz spacecrafts to transport crews for missions in 2017 and 2018 to the International Space Station (ISS), media reported.

NASA is considering to buy Soyuz seats, through an arrangement with Boeing, because no other vehicles are currently capable of transporting one crew member in 2017, one crew member in 2018, and three additional seats in 2019, Spacenews reported on Wednesday.

Boeing had obtained the rights to the seats from Soyuz manufacturer RSC Energia. The two seats in 2017 and 2018 became available to the other ISS partners after Russia decided to vacate them as a cost-saving measure.

Buying these seats for 2017 and 2018 missions will increase US crew size on the ISS from three to four and maximise ISS science utilisation.

Although the space agency has contracts with two US commercial companies -- Orbital ATK and SpaceX -- for transporting crew to the ISS, their vehicles are still in the developmental stage and can begin fully operational crew flights to the ISS by 2019.

NASA is considering to tap Boeing for the launch, return and rescue of US or US-designated astronauts and associated services.

The services BASA wants to hire are for the launch of US crew members to the ISS for planned six-month missions, on-orbit rescue services for the duration of six-month missions, provision of emergency rescue services and medical support, thei9r return to the Earth, and post-flight medical support, among others.