THIS DAY IN SPACE

Kepler Mission Discovers Earth-like Planet
On May 6, 2013, NASA’s Kepler Space Telescope announced the discovery of a planet named Kepler-62f, an Earth-size exoplanet located about 1,200 light-years away in the constellation Lyra. What made this discovery significant was that Kepler-62f resides in the habitable zone of its star, where temperatures might allow for the presence of liquid water—a key ingredient for life as we know it. This planet, along with Kepler-62e, made up one of the first known planetary systems with multiple habitable-zone planets. The Kepler mission’s goal was to understand how common Earth-like planets might be across the Milky Way. Using the transit method, where the spacecraft observed periodic dimming of stars caused by planets passing in front of them, the Kepler telescope amassed data that would revolutionize our understanding of planetary systems. The discovery of Kepler-62f offered one of the earliest concrete clues that potentially habitable planets were not just science fiction but scattered throughout the galaxy. It energized the scientific community and helped shape future missions, like the James Webb Space Telescope, which are designed to investigate the atmospheres of these distant worlds. Kepler-62f became a symbol of the expanding search for extraterrestrial life and remains a standout in the exoplanet catalog.

LAGEOS Satellite Launched
On May 6, 1976, NASA launched the LAGEOS (Laser Geodynamics Satellite), a passive satellite designed to provide precise geodetic measurements of Earth's shape, gravitational field, and tectonic plate motion. The satellite was a sphere covered with 426 retroreflectors, making it one of the most visible satellites for ground-based laser ranging. Weighing over 400 kilograms and orbiting at an altitude of approximately 5,900 kilometers, LAGEOS had no power source or onboard systems; its functionality was entirely reliant on laser pulses sent from Earth. Scientists would fire lasers at the satellite and measure the time it took for the beams to return, yielding highly accurate measurements of Earth's surface movements. LAGEOS allowed researchers to track continental drift, improve navigation systems, and refine our knowledge of Earth's gravitational field. It also played a vital role in confirming aspects of Einstein's General Theory of Relativity by helping detect the frame-dragging effect, or 'Lense–Thirring precession,' caused by Earth's rotation. This mission exemplified how space technology could directly support Earth sciences. A second satellite, LAGEOS-2, was launched in 1992 to enhance the mission’s capabilities. The original LAGEOS continues to orbit Earth and is expected to remain in space for thousands of years, silently aiding geophysical studies.