Axiom Space's Ax-2: What to know about the 2nd private astronaut mission to the space station

Houston-based company Axiom Space is gearing up for its second astronaut mission to the International Space Station (ISS), known as Ax-2.

If all goes according to plan, a SpaceX Falcon 9 rocket will launch an international crew of four from Pad 39A at NASA's Kennedy Space Center in Florida on Sunday afternoon (May 21), kicking off the roughly 10-day Ax-2 flight.

Read on to learn more about the flight and how it fits into Axiom Space's ambitious plans in Earth orbit.

Related: SpaceX to launch 1st Saudi woman to space on private Ax-2 mission 

What time is the launch?

Ax-2 is scheduled to lift off at 5:37 p.m. EDT (2137 GMT) on Sunday, sending the Crew Dragon capsule Freedom skyward. The Falcon 9's first-stage booster will return to Earth shortly thereafter for a touchdown at SpaceX's Landing Zone-1, which lies downrange from the launch pad.

Freedom will take about 16 hours to reach the ISS, docking at the orbiting lab on Monday morning (May 22). The four Ax-2 crewmembers will live alongside the station's current crew for eight days, which they'll spend conducting independent research and technology demonstrations and performing education and outreach activities. 

Ax-2 is scheduled to undock from the ISS's Harmony module at the end of May. Freedom will then descend through Earth's atmosphere and splash down in the ocean off the coast of Florida. 

Meet the Ax-2 crew

Leading Ax-2 as mission commander will be former NASA astronaut Peggy Whitson, who has spent more time in space to date — 665 days — than any other woman or any other American. She has also performed 10 spacewalks, which together lasted for more than 60 hours. 

Whitson is currently director of human spaceflight for Axiom, and on Ax-2 will become the first female commander of a privately funded mission to orbit. Whitson was also the first female commander of an ISS mission, a position she held twice during her time at NASA.

Whitson, who holds a Ph.D. in biochemistry, has spent almost 40 years in the spaceflight industry. These are just some of the roles she held before serving as Axiom's director of human spaceflight.

• Chief of NASA's Astronaut Office
• NASA Astronaut Selection Board Chair
• NASA Operations Branch Chief
• NASA Medical Sciences Office Deputy Division Chief

Including an experienced astronaut to lead private mission crews has been part of Axiom's framework from the beginning. Retired NASA astronaut Michael López-Alegría was the commander of Ax-1, the company's first mission to the station, which flew in April 2022. And this setup won't change going forward; in August of last year, NASA made it a requirement. 

Also flying on Ax-2 is John Shoffner, who will serve as the mission's pilot. According to Axiom's website, Shoffner prides himself on his advocacy for STEM (science, technology, engineering and math) education and is viewed as a business pioneer. His company, the Dura-Line Corporation, found worldwide success in the fiber optic cable industry during the 1980s.

As a young boy during the Apollo era, Shoffner and other neighborhood friends formed their own "astronaut club," and by the age of 17, he was already flying airplanes. Now, with interests in photography and HAM radio, Shoffner is planning several photo and amateur radio projects during the Ax-2 mission. 

Ali AlQarni, one of two crewmembers representing the Kingdom of Saudi Arabia, will be a mission specialist on Ax-2. AlQarni has a strong background in aviation; he holds a bachelor's degree in aerospace engineering from Saudi Arabia's King Faisal Air Academy and served as a fighter pilot in the Royal Saudi Air Force. According to Axiom's website, AlQarni also enjoys bungee jumping, grilling steaks with his family and hiking through the mountains of Saudi Arabia's southern regions.

Rounding out the crew is another mission specialist from Saudi Arabia, Rayyanah Barnawi. Barnawi is a biomedical researcher, with expertise in cancer stem cell research and tissue reengineering. Many of Barnawi's experiments on the station will be in the field of breast cancer research. 

Ax-2 will make Barnawi even more well traveled; she spent years journeying around the world for her studies. She holds a master's degree in biomedical sciences from Alfaisal University in Saudi Arabia, for example, and a bachelor's degree in the same field from Otago University in New Zealand.

AlQarni and Barnawi are members of Saudi Arabia's first astronaut class. They'll be the first people from the kingdom ever to visit the ISS and just the second and third to fly to space. Barnawi will be the first Saudi woman to reach the final frontier.

Related: Pioneering women in space: A gallery of astronaut firsts

The science on Ax-2

Once aboard the space station, the Ax-2 crew will have a busy schedule of research experiments and technology demonstrations. 

In total, the crew plans to conduct 20 or more investigations, including an assemblage of DNA-based nanomaterials with uses in cartilage repair; microgravity effects on mRNA decay; photographing lightning strikes and high-altitude transient luminous events (TLEs) known as sprites from the ISS Cupola window; and several educational collaborations to perform STEM-focused activities with school children across the globe. Here are a few of the experiments Ax-2 is taking on:

Gravity Loading Countermeasure Skinsuit: The Massachusetts Institute of Technology has developed a wearable suit to simulate Earth's gravity and help counteract the negative effects of microgravity on astronauts' bodies. The suit aims to supplement rigorous exercise regimens required to mitigate issues like spinal elongation, muscle atrophy and sensorimotor changes during long-term space missions.

Axiom Space Communication Systems: This technology demonstration will explore alternative communication methods for astronauts aboard the ISS. The new system aims to enhance communication between crewmembers and mission control as well as other contacts on Earth, providing more communication flexibility and broader connectivity.

Multifunctional Shielding Polymer: Using a specialized internal radiation environment aboard the ISS, the Ax-2 crew will evaluate a new hydrogen-rich polymer's shielding capabilities. The polymer was developed in collaboration with the Cosmic Shielding Corporation and designed to protect astronauts against radiation in space. 

Cloud Seeding in Microgravity: This project is part of a partnership with King Fahd University of Petroleum & Minerals, the Saudi Space Commission and Nanoracks. The process of cloud seeding involves the injection of different particles, such as silver iodide crystals, into clouds in order to create rain. The practice has been used by many countries stricken with drought in efforts to increase rainfall in those areas. Using a moist air reaction chamber in the absence of actual clouds aboard the space station, Ax-2 researchers will observe water vapor condensation on silver iodide crystals. The findings may have implications for weather control technologies on Earth and the creation of artificial rain on future off-world habitats. 

Related: How living on Mars could challenge colonists (infographic)

TRISH Essential Measures: The Translational Research Institute for Space Health (TRISH) has given the Ax-2 crew a myriad of tests to perform on themselves to investigate how commercial spaceflight crewmembers, who lack the extensive training undergone by NASA astronauts, adapt to microgravity. These tests include physical evaluations, questionnaires, biological (blood and urine) sampling and wearable devices to monitor microgravity adaptation speed, cognitive performance and physiological changes during spaceflight. The hope is to develop countermeasures to the negative effects of microgravity, in order to reduce recovery times for short-term crews like the kind Axiom sends to the space station.

Cancer in Low-Earth Orbit: This project piggy-backs on a tumor-organoids modeling investigation from Ax-1, in collaboration with the Sanford Stem Cell Institute, and aims to improve the detection and treatment of precancerous and cancerous cells. The development of stem cell models in space can aid in cancer prevention and other diseases on Earth. The study will expand on previous tumor organoid research by adding triple-negative breast cancer cells to the analysis and will focus on understanding immune dysfunction and drug challenges related to spreading cancers and immunodeficiencies. 

Axiom Space's plans in low Earth orbit

Axiom's first mission to the ISS, Ax-1, launched just over a year ago, on April 8, 2022, and was extended from 10 days to 17 days due to bad weather conditions near the crew's ocean splashdown site. There likely won't be such a long gap between Axiom missions to the ISS going forward: Ax-3 is currently scheduled for the end of this year. 

Further down the road, Axiom is among a number of commercial entities that aim to build a private space station in low Earth orbit (LEO) for research, manufacturing and tourism. The company is currently constructing the first module of its private station, which is scheduled to launch to the ISS in late 2025. Several more modules will link up with this first one over the next few years; the complex will then detach from the ISS and become a free flier in LEO in the late 2020s.

Axiom also won a NASA contract to develop new lunar surface spacesuits for the agency's Artemis program of crewed moon exploration. Artemis 3 is currently slated to lift off in late 2025, sending the first humans to the moon since the Apollo program ended in 1972.