UPDATED 12:14 p.m. EDT

WASHINGTON — NASA has agreed to pay Russia $424 million for astronaut transportation to the international space station (ISS) in 2016, and for emergency crew rescue services through June 2017.

NASA announced the firm, fixed-price modification to its existing contract with the Russian space agency, Roscosmos, in an April 30 press release. NASA previously had left the door open to buy Soyuz rides through the middle of 2016 as the agency worked with U.S. industry to get at least one privately owned crew transportation system up and running by 2017. 

NASA’s latest order covers round-trips and training for six astronauts, which translates to roughly $70 million for each Soyuz seat, according to the agency’s April 30 press release. Russia had been charging NASA about $65 million a seat for Soyuz rides.

NASA’s top official said the latest order placed with Roscosmos is a direct result of Congress underfunding the agency’s Commercial Crew Program, an initiative to fund new, privately operated crew transportation systems capable of launching from U.S. soil and bringing astronauts to and from the ISS. Congress has consistently appropriated hundreds of millions of dollars less than U.S. President Barack Obama’s administration has sought for its signature human spaceflight project.

“If NASA had received the President’s requested funding for this plan, we would not have been forced to recently sign a new contract with Roscosmos for Soyuz transportation flights,” NASA Administrator Charles Bolden said in an April 30 statement posted to the agency’s website.

NASA is seeking $821 million for commercial crew in 2014 under a budget request released April 10. The program stands to receive about $490 million for 2013 under the Full-Year Continuing Appropriations Act of 2013 (H.R. 933) signed March 26 — a boost compared with the $406 million it got in 2012.

The Soyuz contract modification announced April 30 was foreshadowed back in January, when Obama signed the Space Exploration Sustainability Act (H.R. 6586). Among other things, the law, co-sponsored by Sen. Bill Nelson (D-Fla.) and then-Sen. Kay Bailey Hutchison (R-Texas) granted NASA relief from certain provisions of the Iran, North Korea, Syria Nonproliferation Act to permit the agency to trade with Russia for ISS products and services. The law extended an existing NASA waiver from mid-2016 to the end of 2020.

Back in August, NASA announced that Boeing Space Exploration, Sierra Nevada Space Systems and Space Exploration Technologies Corp. would split $1.2 billion in Commercial Crew Integrated Capability funding to develop competing crew transportation designs in a work period running through May 2014. NASA wants one of these systems to be ready to fly astronauts by 2017, but Bolden has repeatedly warned that unless Congress fully funds the White House’s request, that date will slip.

Meanwhile, NASA expects to winnow down the field of competition in the Commercial Crew Program next spring as part of a follow-on to the $1.2 billion round of funding released in August. The agency plans to release a draft request for proposal for follow-on work to the current Commercial Crew Integrated Capability contract this spring or summer, Bolden told members of the House Science, Space and Technology space subcommittee in an April 24 hearing.

“By next spring, we hope to be able to announce who the commercial crew provider is going to be,” Bolden told the panel.

Dan Leone is the NASA reporter for SpaceNews, where he also covers other civilian-run U.S. government space programs and a growing number of entrepreneurial space companies. He joined SpaceNews in 2011.Dan earned a bachelor's degree in public communications...