Axiom-4 Continues to Expand Access to Station

The International Space Station, throughout its history, has played a major role in the development of an international and commercial economy in Low Earth Orbit, acting as a focal point for development across multiple sectors. Axiom Mission 4 (Ax‑4) is no different, as the fourth commercially operated flight by Axiom Space to the International Space Station (ISS) aims to carry out a wide variety of experiments from a diverse crew of astronauts, continuing to push the boundaries of access for modern spaceflight.

The crew of Axiom-4 launched aboard a SpaceX Crew Dragon spacecraft atop a Falcon 9 rocket from Kennedy Space Center’s LC‑39A at 2:31 AM local time. The first stage performed its burn and returned to the launch site, conducting a routine landing at LZ-1 at Cape Canaveral Space Force Station. Originally slated for June 10, 2025, liftoff was pushed to June 25 due to weather delays and a number of technical challenges that presented itself during the pre-launch campaign. Most notably, the Indian Space Research Organization, ISRO, raised concerns about leaks observed on the Falcon 9 first stage in the prelaunch checkouts, prompting a stand down alongside ongoing Station-side concerns within the Russian segment. Docking occurred in the early morning on Thursday, June 26 with the crew currently scheduled to spend 14 days aboard the ISS for research, outreach, and operational activities.

The four-person crew is led by former NASA astronaut and Axiom Space Director of Human Spaceflight Peggy Whitson as commander, completing her 5th mission to space. Whitson is joined by mission pilot Shubhanshu Shukla—India’s first astronaut to fly aboard the ISS—plus ESA-supported Polish specialist Sławosz Uznański‑Wiśniewski and Hungarian mechanical engineer Tibor Kapu. This historic flight marks the first time India, Poland, and Hungary will conduct government-backed ISS missions, each establishing several milestones in human spaceflight for their respective nations. The Crew Dragon used on this mission, C213, is the last new-build Dragon SpaceX currently plans to produce, with the crew of Ax-4 dubbing the spacecraft “Grace” upon reaching orbit. Originally slated for use on the upcoming Crew-11 mission, the capsule was swapped with veteran capsule Endeavour to maintain ISS schedule priorities and allow for additional time to complete Grace’s final checkout.  

Private astronaut missions are becoming an increasingly important element of ISS operations, with new nations and private consortiums sending their crews to the station. As the rapidly accelerating space economy has expanded access to low-Earth orbit, several nations have been eager to capitalize on lower cost access. These missions allow governments, private companies, and academic institutions to conduct microgravity experiments and technology demonstrations without relying solely on national space agencies, thereby accelerating innovation and diversifying the use of the ISS. ESA, and several non-affiliate European nations, have capitalized on Axiom’s flight opportunities to conduct short duration work on Station, with ESA’s 2022 astronaut class introducing a new rank of “project astronaut” to better facilitate short term missions.  In the case of India, ISRO hopes to gain experience operating in a complex multi-user environment to better inform their own spaceflight programs: the Gaganyaan crew capsule and the Bharatiya Antariksh Station.

Axiom has found success flying a number of international and private astronauts to the ISS as part of the Private Astronaut Mission (PAM) slots offered by the agency on Station. By facilitating microgravity research, advanced manufacturing, and international astronaut access, Axiom aims to expand their knowledge base  scientific and economic opportunities in low Earth orbit. Axiom has also acted as a broker for government missions to the station, enabling nations who are not represented in the ISS’ Intergovernmental Agreement to be represented on station, albeit for a shorter period of time. These missions also aim to build off a crucial central pillar of ISS research, one that arguably began during the Shuttle era: free, open and democratic use of space based infrastructure for the continued establishment of geopolitical goodwill. While the Intergovernmental Agreements that helped to establish a common, stable framework for ISS partnerships, private consortiums have acted as brokers to enable non-affiliate astronauts to participate in work on the world’s premier orbital laboratory. 

Axiom is banking on a continued presence aboard ISS, as well as brokerage between private industry and government agencies, to build experience and confidence for their own major human spaceflight project: Axiom Station. Axiom Station is the only awardee in the Commercial Destinations for ISS branch of the Commercial Low Earth Orbit Development program, enabling construction on a reserved port of the ISS. Axiom originally envisioned that its modular station would be built up while docked to the ISS, later separating to become an independent free-flying destination. But the United States Deorbit Vehicle (USDV), which will ultimately bring the ISS into Earth’s atmosphere at the end of its life, is currently planned to use the same forward docking port as Axiom Station, and delays to Axiom’s modules pushed these two users into conflict. 

In December of 2024, Axiom adjusted their plan to instead use a berthing port, underneath the ISS (known as the nadir position), allowing Axiom Station and the USDV to occupy the ISS at the same time. This revised assembly sequence means only one of Axiom’s modules, the Payload Power Thermal Module, will ever dock to the ISS. Upon the launch of the second module, Habitat 1, the Payload Power Thermal Module will separate and fly out to meet it, ultimately truncating the ISS-dependent period that the company had originally proposed for station operations. The new plan helps Axiom escape the ISS before deorbit operations begin, but also requires each module to loiter in orbit alone. 

It is unclear at this time, however, if Axiom’s dreams will become a reality as they currently envision it. Schedule delays, and an increasingly challenging environment for space present numerous technical and financial risks for the company. The complexity of developing modules in consortium with other technological partners, securing consistent launch opportunities, and integrating new technologies increases the likelihood of delays – already constrained by the ISS’ limited remaining lifespan. Supply chain constraints, workforce demands, and the need for rigorous safety certifications also contribute to the uncertainty in meeting its target deployment dates.

For the time being, work continues. Axiom continues to look ahead with their respective missions, and the nations represented onboard Axiom-4 can continue to formulate a roadmap for each of their home nation’s ambitions for the coming century. With the international crew of Axiom-4 now in space, and the company’s plans for increased access to space continuing to bear fruit, it is only a matter of time before the first modules of Axiom Station become a familiar sight to those who fly to ISS.

Special thanks to Nickolas Wolf for the schedule flexibility amid the launch date shifts.