When NASA’s Juno spacecraft flew past Earth on October 9, it received a boost in speed of more than 7.3 kilometers per second, which set it on course for a July 4, 2016, rendezvous with Jupiter, the largest planet in the solar system. One of Juno’s sensors, a special kind of camera optimized to track faint stars, also had a unique view of the Earth-moon system. The result was a low-resolution glimpse of what our world would look like to a visitor from afar.
“If Captain Kirk of the USS Enterprise said, ‘Take us home, Scotty,’ this is what the crew would see,” said Scott Bolton, Juno principal investigator at the Southwest Research Institute in San Antonio. “In the movie, you ride aboard Juno as it approaches Earth and then soars off into the blackness of space. No previous view of our world has ever captured the heavenly waltz of Earth and moon.” Shown above is a screen capture from the movie.
The Juno Earth-flyby movie is available on YouTube. The musical accompaniment is an original score by Vangelis.
During the flyby, timing was everything. Juno was traveling about twice as fast as a typical satellite, and the spacecraft itself was spinning at 2 rpm. To assemble a movie that wouldn’t make viewers dizzy, the star tracker had to capture a frame each time the camera was facing Earth at exactly the right instant. The frames were sent to Earth, where they were processed into video format.
“Everything we humans are and everything we do is represented in that view,” said the star tracker’s designer, John Jørgensen of the Danish Technical University, near Copenhagen.