ISS: Expedition 73

ISS Expedition 73 began with undocking of Soyuz MS-26 on April 19, 2025.

On April 21, 2025 at 08:15 UTC unmanned freighter Dragon SpX-32 or CRS-32 filled with nearly 6,400 pounds (2,900 kilograms) of supplies, a SpaceX Dragon spacecraft on a Falcon 9 rocket lifted off from Launch Complex 39-A at NASA's Kennedy Space Center in Florida. Along with food and essential equipment for the crew, Dragon is delivering a variety of experiments, including a demonstration of refined maneuvers for free-floating robots. Dragon also carries an enhanced air quality monitoring system that could protect crew members on exploration missions to the Moon and Mars, and two atomic clocks to examine fundamental physics concepts, such as relativity, and test worldwide synchronization of precision timepieces.
The Dragon spacecraft is scheduled to remain at the space station until May 2025, when it will depart and return to Earth with research and cargo, splashing down off the coast of California.
SpaceX SpX-32 or CRS-32 Dragon spacecraft docked to the space-facing port of the International Space Station's Harmony module on April 22, 2025 at 12:40 UTC.

On May 01, 2025 Anne McClain and Nichole Ayers performed a spacewalk (5h 44m). The NASA duo installed a modification kit on the port side of the station's truss structure enabling the future installation of the orbiting lab's seventh iROSA (International Space Station Roll Out Solar Arrays). They also relocated an antenna that communicates with approaching and departing commercial crew and cargo spacecraft.

The Dragon SpX-32 or CRS-32 spacecraft undocked from the zenith, or space-facing, port of the station's Harmony module on May 23, 2025 at 16:05 UTC and fired its thrusters to move a safe distance away from the station under command by SpaceX's Mission Control in Hawthorne, California.
After re-entering Earth's atmosphere, the spacecraft splashed down on May 25, 2025 off the coast of California.
Some of the scientific hardware and samples Dragon returned to Earth include MISSE-20 (Multipurpose International Space Station Experiment), which exposed various materials to space, including radiation shielding and detection materials, solar sails and reflective coatings, ceramic composites for reentry spacecraft studies, and resins for potential use in heat shields. Samples were retrieved on the exterior of the station and can improve knowledge of how these materials respond to ultraviolet radiation, atomic oxygen, charged particles, thermal cycling, and other factors.
Additionally, Astrobee-REACCH (Responsive Engaging Arms for Captive Care and Handling) is returning to Earth after successfully demonstrating grasping and relocating capabilities on the space station. The REACCH demonstration used Astrobee robots to capture space objects of different geometries or surface materials using tentacle-like arms and adhesive pads. Testing a way to safely capture and relocate debris and other objects in orbit could help address end-of-life satellite servicing, orbit change maneuvers, and orbital debris removal. These capabilities maximize satellite lifespan and protect satellites and spacecraft in low Earth orbit that provide services to people on Earth.
Books from the Story Time from Space project also returned. Crew members aboard the space station read five science, technology, engineering, and mathematics-related children's books in orbit and videotaped themselves completing science experiments. Video and data collected during the readings and demonstrations were downlinked to Earth and were posted in a video library with accompanying educational materials.
Hardware and data from a one-year technology demonstration called OPTICA (Onboard Programmable Technology for Image Compression and Analysis) also returned to Earth. The OPTICA technology was designed to advance transmission of real-time, ultra-high-resolution hyperspectral imagery from space to Earth, and it provided valuable insights for data compression and processing that could reduce the bandwidth required for communication, lowering the cost of acquiring data from space-based imaging systems without reducing the volume of data. This technology also could improve services, such as disaster response, that rely on Earth observations.
Finally, space suit EMU No. 3009 was returned to Earth.