On April 11, 1991, NASA attempted to deploy the high-gain antenna of the Galileo spacecraft, a large dish designed to send high-quality images of Jupiter back to Earth. However, the deployment failed, leaving three of the eighteen metallic ribs connected to the central mast. This partial deployment reduced the antenna's effectiveness, as the high-gain antenna was crucial for transmitting data at a much higher speed than the smaller low-gain antenna. The problem was traced back to the loss of lubricant on the antenna's pins, which had occurred during transport after the Challenger shuttle disaster. This forced the Galileo probe to be returned to the Jet Propulsion Laboratory (JPL) for repairs and reintegration before being sent back to Cape Canaveral for launch. The issue was discovered through telemetry data—data sent from the spacecraft to Earth—which showed that the motors had stalled and the antenna only partially opened. A team of over 100 engineers and scientists from JPL and industry partners analyzed the data and tested an identical backup antenna. They found that the failure was likely due to friction between the pins and their sockets, caused by the loss of a dry lubricant used during the antenna’s manufacturing in Florida. This loss was linked to vibrations during storage and transport before the launch. Efforts to fix the antenna included repeated attempts to fold and re-deploy it, expose it to sunlight and shadow, and use short bursts of electric motors to generate force. These attempts continued for nearly two years but were ultimately unsuccessful. With no mechanical solution available, the Galileo team shifted strategies, developing new software for the spacecraft and improving NASA’s Deep Space Network. These upgrades allowed the spacecraft to compress scientific data into a narrower data stream, while ground-based antennas were made more sensitive to capture information from Jupiter. Despite the antenna failure, Galileo managed to achieve about 70 percent of its original scientific goals. It made history by flying by asteroids Gaspra and Ida, discovering a moon orbiting Ida, and observing the dramatic collision of comet Shoemaker-Levy 9 with Jupiter. The probe eventually entered orbit around Jupiter in December 1995 and continued its mission until September 2003, when it was intentionally crashed into Jupiter’s atmosphere to prevent potential contamination of Europa, one of Jupiter’s moons, which may harbor a subsurface ocean. The Galileo antenna failure underscored the importance of selecting the right lubricants and designing systems that can tolerate unexpected problems. The lessons learned were added to NASA’s technical archives, influencing future spacecraft design and ensuring greater reliability in deployment mechanisms.