Roman around the Christmas tree | Space photo of the day for Dec. 25, 2025 For the engineers and scientists at NASA's Goddard Space Flight Center, the holiday season is always a busy time of year. As the world celebrates Christmas, the team responsible for the James Webb Space Telescope is working around the clock to prepare for the telescope's next major milestone: the deployment of its massive primary mirror. The year 2025 has been a momentous one for the Webb telescope. After years of delays and technical challenges, the ambitious successor to the Hubble Space Telescope was finally launched into orbit in late 2021. Since then, the engineering team has meticulously guided the telescope through a complex series of deployments, calibrations, and test observations, all while navigating the inherent risks and uncertainties of operating a one-of-a-kind, state-of-the-art instrument in the harsh environment of space. Now, as the end of the year approaches, the Webb team faces perhaps its most daunting task yet: the deployment of the telescope's primary mirror, a critical step that will allow the observatory to begin its scientific observations in earnest. Consisting of 18 individual hexagonal segments, the primary mirror measures an impressive 21 feet (6.5 meters) in diameter, making it the largest and most sophisticated mirror ever launched into space. The deployment process is a delicate and intricate ballet, requiring the careful coordination of numerous mechanisms and actuators to unfurl the mirror from its tightly packed launch configuration. It's a nerve-wracking procedure that the team has rehearsed countless times, both in computer simulations and in ground-based testing. But with the stakes so high – the success of the entire $10 billion mission rests on the successful deployment – there is little room for error. This is where the NASA engineers' holiday spirit comes into play. As they work through the long hours and intense pressure of the mirror deployment, they have found creative ways to keep morale high and maintain a sense of holiday cheer. One of the most notable examples is the "star on top of the telescope" tradition, where the team decorates the pristine cleanroom environment with a miniature Christmas tree and a specially designed star ornament perched atop the telescope. "It's a small gesture, but it really helps us stay connected to the holiday spirit and remember why we're doing this," says Dr. Sarah Milkovich, the deputy project scientist for the Webb telescope. "We're not just building a scientific instrument – we're creating something that will inspire people around the world, just like the star that led the Wise Men to the Christ child." The tradition has become a beloved annual ritual, with the team carefully selecting the perfect tree and ornament to adorn the cleanroom. This year, the star is a custom-made piece featuring intricate metalwork and a central crystal that refracts the room's bright lighting, casting a warm, festive glow over the entire workspace. "It's a reminder that even in the midst of all the technical challenges and high-stakes work, we're still part of a larger human story," Milkovich adds. "The Webb telescope is going to open up new frontiers in our understanding of the universe, but it's also going to inspire people, just like the star in the Christmas story." As the critical mirror deployment approaches, the team continues to work tirelessly, their focus laser-sharp but their spirits buoyed by the holiday cheer. They know that the successful completion of this milestone will be a true Christmas present for the entire world, ushering in a new era of scientific discovery and awe-inspiring images from the depths of space. And when that first stunning image from the fully deployed Webb telescope is released, the team at Goddard will no doubt take a moment to gaze upon it, their eyes drawn to the twinkling star at the top of the frame – a symbolic reminder of the holiday spirit that helped guide them through the challenges of this historic mission.