NASA has released a draft request for proposal (RFP) for commercial crew transportation to the International Space Station (ISS), including certification requirements and at least one flight.

The Commercial Crew Transportation Capability (CCtCap) builds on the ongoing Commercial Crew Integrated Capability (CCiCap) programme, a series of milestone-based awards going to three companies - Boeing, SpaceX and Sierra Nevada.

Contrary to previous rounds of commercial crew funding - CCiCap and Commercial Crew Development (CCDev1 & 2), the contracts will be based on Federal Acquisition Regulations (FAR), in which the government is able to set specific requirements and define approaches, with certain exceptions allowing contractors to retain property. Several involved companies have spoken out against the shift to FAR-based contracts, and the change was subject to contentious negotiations between NASA, the White House and members of Congress. Previous contracts were Space Act Agreements, which allow much greater leeway for contractors to design and build spacecraft.

CCtCap contracts will be milestone based, like their predecessors, releasing designated funds only upon the contractor's demonstration of achieving a series of checkpoints.

While previous rounds matured designs - CCiCap is intended to mature designs to the point of critical design review (CDR), the last major design stage before construction - CCtCap will involve construction and flight testing, leading to full NASA certification and at least one flight to the ISS with cargo.

SpaceX has flown an uncrewed version of the Dragon capsule to the ISS, but certification to carry humans requires significant work. Currently, all transportation of humans to the ISS is conducted by Russia's Soyuz launch vehicle.

Source: Flight International