5 minute read•Updated 2:03 PM EDT, Sat April 5, 2025
NASA is looking ahead to the next wave of private astronaut missions to the International Space Station (ISS); in a new solicitation released April 2, the agency has formally invited proposals for the fifth and sixth Private Astronaut Missions (PAMs), and, in a noteworthy shift, may allow mission commanders from international space agencies other than NASA — a move that could redefine who gets to lead the next generation of commercial missions in low Earth orbit.
These upcoming missions, projected to launch no earlier than May 2026 (PAM 5) and mid 2027 (PAM 6), are part of NASA’s broader low Earth orbit commercialization strategy. The ultimate goal: to transition from the aging ISS to a new era of commercially owned and operated space stations, enabling NASA to become just one of many customers in a vibrant orbital economy.
“Private astronaut missions are a key part of this effort,...They provide companies with hands-on opportunities to refine their capabilities and build partnerships that will shape the future of low Earth orbit.” - Dana Weigel, NASA’s ISS Program Manager
Changing the Commander Requirement
Since the second PAM, NASA has required that each mission be commanded by a former NASA astronaut with prior spaceflight experience; a rule intended to ensure the highest levels of crew safety, operational familiarity, and ISS integration.
The new solicitation maintains that core requirement but adds nuance. Now, the commander must have not only flown in space but also completed a “long-duration” ISS mission, defined as a stay of 30 days or longer. They must also have participated in ISS operations within the past five years, or otherwise demonstrate active involvement in spaceflight activities, or commit to a training program to requalify.
However, for the first time, NASA is allowing companies to nominate an alternate commander; one who may not be a former NASA astronaut, but who has flown for an international partner agency such as the European Space Agency (ESA), the Canadian Space Agency (CSA), or the Japan Aerospace Exploration Agency (JAXA).
This alternate can be promoted to full commander status if NASA decides to broaden its current commander eligibility criteria and if the change doesn’t negatively affect the mission’s integration schedule.
“Should NASA broaden its PAM Commander experience requirements, the PAM Provider may designate its alternate Commander as its PAM Commander,”
Axiom’s Astronaut Roster Could Benefit
This change could have immediate implications for Axiom Space, the Houston-based company that has so far won all four PAM contracts.
Axiom has flown private missions in 2022, 2023, and 2024, with its fourth, Ax-4, scheduled for no earlier than May 2025. The company has been steadily building a bench of seasoned international astronauts.
In July 2024, Axiom announced the hiring of former ESA astronaut Tim Peake, who joined as part of a planned mission involving British astronauts; a collaboration with the U.K. Space Agency following a memorandum of understanding signed in October 2023.
In April 2024, Axiom also brought on Koichi Wakata, a veteran JAXA astronaut and former ISS commander, who now serves as the company’s Chief Technical Officer for the Asia-Pacific region. At the Spacetide conference in Tokyo last year, Wakata expressed interest in flying to space again, potentially on a regional mission involving astronauts from across Asia-Pacific.
Both Peake and Wakata meet many of the criteria outlined in NASA’s revised solicitation, and either could be in line to command a future Axiom-led mission; should NASA formally expand the eligibility rules in the coming years.
Competition on the Horizon
Until now, Axiom Space has enjoyed a monopoly on PAM contracts, but that may be changing. Vast, another player in the commercial space station race, has publicly stated its intention to compete for future PAMs.
The company, which is developing the Haven-1 station, is aiming to establish its presence with early ISS-based missions before launching its own platform.
Although NASA authorizes up to two private astronaut missions per year, the agency has so far maintained a pace of one mission annually, likely due to ISS traffic constraints and resource availability. That cautious cadence looks set to continue, with PAM 5 and PAM 6 spaced roughly a year apart.
The Bigger Picture: Building a Commercial LEO Economy
As NASA prepares for a post-ISS era; potentially as early as 2030, when the space station may be retired; PAMs offer a crucial stepping stone. These missions give commercial providers real-world experience in training astronauts, integrating with ISS systems, managing logistics, and operating human spaceflight missions.
“By leveraging our decades of expertise,...we’re helping industry gain the experience needed to train and manage crews, conduct research, and develop future destinations.” - Dana Weigel, NASA’s ISS Program Manager
The latest PAM solicitation reflects both continuity and evolution in NASA’s approach. While maintaining rigorous safety and experience standards, the agency is signaling a growing openness to international leadership in commercial spaceflight; a sign that the era of NASA-only commanders may be giving way to a broader, more global cadre of space leaders.
As private companies and partner agencies continue to forge deeper ties in low Earth orbit, the commander’s seat on future missions could soon be occupied by astronauts representing a far more diverse set of spacefaring nations and organizations.
