Building on its commercial spaceflight training experience, Virgin Galactic said it believes it can provide an "unparalleled, personalised customer experience for orbital space travel".
The company said that these trips may not be limited to people for space tourism purposes only.
Private astronaut experiences could range from private citizen expeditions to government-enabled scientific research missions, Virgin Galactic said, adding that the next generation of space traveller is interested in a variety of space experiences.
Under this Space Act Agreement agreement, Virgin Galactic will develop a new private orbital astronaut readiness programme.
This programme will include identifying candidates interested in purchasing private astronaut missions to the ISS, the procurement of transportation to the ISS, on-orbit resources, and ground resources.
Supporting and coordinating the use of ISS resources will be an important point of integration required for each private astronaut mission.
"We are excited to partner with NASA on this private orbital spaceflight programme, which will not only allow us to use our spaceflight platform, but also offer our space training infrastructure to NASA and other agencies," George Whitesides, CEO of Virgin Galactic, said in a statement.
"Based on the unsurpassed levels of spaceflight customer commitments we have secured to date, we are proud to share that insight in helping to grow another market for the new space economy. We want to bring the planetary perspective to many thousands of people."
NASA is seeing greater demand for use of the ISS for scientific and technological research and development, commercial activity, and international collaboration.
As part of this partnership, NASA will leverage Virgin Galactic's commercial expertise and industry knowledge.
Virgin Galactic will also contribute end-to-end programme management and integrated astronaut training packages for private passengers, tailored to meet the needs for a commercial orbital space flight experience.
The space tourism company has already developed a customised Future Astronaut Readiness programme for its customers flying out of Spaceport America in New Mexico.
Virgin Galactic's existing space experiences could play an important role in the training for orbital travel, allowing passengers to become familiar with the environment in space, such as gravitational forces and zero gravity.
Spaceport America, Virgin Galactic's home base, will be utilized for some elements of the training programme, using the facilities designed for private astronaut training, the company said.