40 years ago today, the very first satellite launched as part of the Landsat program, which has since become the longest-running Earth-observing satellite program ever. To celebrate that day in 1972, NASA has put together a video featuring some delightfully retro footage from its archives that really makes you feel like you're back in the 70s. It's a great look back at an important part of the space program, which has helped provide valuable information over the past four decades. "The first 40 years of the Landsat program have delivered the most consistent and reliable record of Earth's changing landscape," Michael Freilich, director of NASA's Earth Science Division, said. And it's still going strong — next February NASA will be launching Landsat 8, described as the "most technologically advanced satellite" in the program to date.