Two bits of history I learned from the article: 1. The last human to touch the spacecraft was a physicist inspecting two detectors — probably part of the low-e

Two bits of history I learned from the article: 1. The last human to touch the spacecraft was a physicist inspecting two detectors — probably part of the low-energy telescope system (LET). Although many scientists have worked on the Voyagers over the decades, Cummings can make a unique claim. “I was the last person to touch the spacecraft before they launched,” he says. Cummings was responsible for two detectors designed to measure the flux of electrons and other charged particles when the Voyagers encountered the giant planets. Particles would pass through a small “window” in each detector that consisted of aluminum foil just three microns thick. Cummings worried that technicians working on the spacecraft might have accidentally dented or poked holes in the windows. “So they needed to be inspected right before launch,” he says. “Indeed, I found that one of them was a little bit loose.” 2. Carl Sagan not only commented on the “Pale Blue Dot” but also persuaded NASA to take the photograph in the first place. Sagan urged NASA officials to have Voyager 1 transmit one last series of images. So, on Valentine's Day in 1990, the probe aimed its cameras back toward the inner solar system and took 60 final shots. The most haunting of them all, made famous by Sagan as the “Pale Blue Dot,” captured Earth from a distance of 3.8 billion miles. It remains the most distant portrait of our planet ever taken. Veiled by wan sunlight that reflected off the camera's optics, Earth is barely visible in the image. It doesn't occupy even a full pixel. Sagan, who died in 1996, “worked really hard to convince NASA that it was worth looking back at ourselves,” Spilker says, “and seeing just how tiny that pale blue dot was.”