According to the filing, the seats NASA is looking at belong to Boeing, which got them from a lawsuit against Russian aerospace company Energia. Boeing VP John Elbon revealed that NASA "expressed some interest" and that the two entities will "go through the process and figure out if there's an opportunity for [them] to make a deal." Ars Technica also notes that the solicitation was filed shortly before NASA Administrator Charles Bolden, a proponent of commercial space, leaves office.

In addition to the seats aboard flights scheduled for 2019, NASA is also looking to purchase two more for 2017 and 2018. Since Russia is reducing its ISS personnel, there's an extra space for a NASA astronaut on the spacecraft.