NASA has released the Broad Agency Announcement (BAA), which is part of the Next Space Technologies for Exploration Partnerships (NextSTEP).
The BAA seeks proposals for concept studies and technology development projects in three key areas: advanced propulsion, habitation and small satellites.
NASA has increasingly embraced public-private partnerships to expand the frontiers of knowledge, capability and opportunities in space.
"The next step for human spaceflight is the development of deep space exploration capabilities to support more extensive missions in the proving ground - around and beyond cis-lunar (Earth-Moon) space," the US space agency said in a statement.
The BAA is open to non-government US institutions (companies, universities, non-profit organisations) and foreign institutions.