NASA released Sept. 25 a request for proposals (RFP) for its next round of contracts for private sector companies to deliver experiments and supplies to the International Space Station (ISS).

Under the Commercial Resupply Services (CRS) 2 RFP, NASA intends to award contracts to one or more companies for six or more flights per contract. As with the current CRS program, these missions would launch from United States spaceports and the contracted services would include logistical and research cargo delivery to and from the ISS.

The potential contracts would run through fiscal year 2020 with the NASA option to purchase additional launches through FY ’24, according to an agency statement. Earlier this year, President Barack Obama announced the decision to extend the life of the ISS through FY ’24.

Proposals are due Nov. 14. Awarded contracts will be firm-fixed price, indefinite-delivery/indefinite-quantity (ID/IQ). NASA expects to award a contract April 28. The RFP says the total maximum value of any contract awarded will not exceed $14 billion.

NASA awarded contracts for the original CRS program to Orbital Sciences [ORB] and Space Exploration Technologies Corp. (SpaceX). At the time of the award, NASA ordered eight flights valued at about $1.9 billion from Orbital and 12 flights valued at nearly $1.6 billion from SpaceX through December 2016. SpaceX has completed three of the contracted CRS delivery missions with a fourth currently underway while Orbital has done two. Orbital’s third CRS mission is scheduled for launch Oct. 20 from Wallops Island, Va.

PlanetSpace had bid for NASA’s original CRS contract, but lost out to Orbital and SpaceX. The company had a protest with the Government Accountability Office (GAO) denied in 2009.

SpaceX spokesman John Taylor declined comment on Sept. 26, citing company policy. Orbital spokesman Barry Beneski said Sept. 26 the company would “definitely” bid for CRS 2, but would not provide specifics. Potential CRS 2 bidders Lockheed Martin [LMT] and Sierra Nevada Corp. (SNC) did not return requests for comment by press time Sept. 26. SNC earlier in September lost out to SpaceX and Boeing for NASA’s Commercial Crew Program (CCP) to take astronauts to and from the ISS.

Boeing [BA] spokesman Adam Morgan said the company is “certainly” interested in CRS 2 and will be reviewing requirements to determine the business need from NASA and the company’s ability to support the agency’s requirements.