New Delhi, Jan 8 : US space agency NASA on Thursday postponed its scheduled spacewalk over a â??medical concernâ?? with an astronaut.

Two Expedition 74 NASA astronauts -- Mike Fincke and Zena Cardman -- were slated for the first spacewalk of 2026. They had planned to exit an airlock aboard the International Space Station for the power upgrade work.

The space agency, however, has not provided details about the medical issue or the name of the astronaut involved.

â??NASA is postponing the Thursday, January 8, spacewalk outside the International Space Station. The agency is monitoring a medical concern with a crew member that arose Wednesday afternoon aboard the orbital complex,â?? the US space agency shared in a blog post.

â??Due to medical privacy, it is not appropriate for NASA to share more details about the crew member. The situation is stable. NASA will share additional details, including a new date for the upcoming spacewalk, later,â?? the post added.

During the six-and-a-half-hour spacewalk, the Station Commander Fincke and Flight Engineer Cardman aimed to install a modification kit and routing cables for a future roll-out solar array.

The duo also planned to include installing jumper cables, taking hardware photos, and collecting microorganism samples.

The spacewalk would be a first for Cardman, a 38-year-old geobiologist who was selected for the astronaut corps in 2017.

On Wednesday, Fincke and Cardman organised their spacewalking tools and supplies inside the Quest airlock, where they were intended to exit the orbital outpost. They also finished configuring their spacesuits and the associated life support and emergency components, NASA said.

At the end of their shift, they were joined by Flight Engineers Chris Williams of NASA and Kimiya Yui of JAXA (Japan Aerospace Exploration Agency) for a final spacewalk procedures review and a readiness conference with mission controllers on the ground.

Williams and Yui will assist the astronauts in and out of their spacesuits, pressurise and depressurise the Quest airlock, and monitor the spacewalkers as they work outside the orbiting lab, it added.

/IANS