Star Tracker Captures Moon and Earth During Juno Spacecraft's Flyby (Video)

NASA's Juno spacecraft has made a spectacular recording of its flyby past Earth early in October 2013. The first-of-a-kind movie approach reveals the capabilities of Juno's onboard camera system, known as star tracker.

The approach was actually a way for the spacecraft to get some gravity assist. Essentially, Juno was using Earth's gravitational field as a type of slingshot to help hurl it toward Jupiter. In fact, its speed increased from about 9,000 miles per hour to more than 87,000 miles per hour. While it was gaining this boost, though, the scientists took advantage of its camera to snap both the Earth and its moon.

"Juno had a unique opportunity to give everyone a front-row seat for the flyby--to see Earth and its moon as an approaching spacecraft sees them," said Jack Connerney, lead investigator for Juno's magnetic field instrument, in a news release.

The star tracker had a terrific view from its vantage point near one of the spacecraft's three solar-array arms. As Juno approached Earth, it was turned so that the system's four cameras pointed toward the planet and away from the sun. The star tracker then began capturing frames for the movie when it was about 2.4 million miles from Earth.

Part of the star tracker's job during the course of its mission to Jupiter is actually to send occasional pictures back to Earth. But it's main mission is to snap images of the surrounding star field; this will help researchers determine the orientation of the spacecraft and is vital input for Juno's magnetic sensors. The sensors, together with the star tracker, make up the magnetic field instrument. This instrument in turn will take billions of high-definition readings of the strength and direction of the magnetic field to produce and unprecedented map of the magnetic environment around Jupiter.

In fact, the recent flyby didn't just provide a movie. It also gave Juno a rare opportunity for navigation purposes. Because the Earth and the moon were both in the star tracker's field of view, the spacecraft's position could be calculated using the two objects as reference points. This resulted in an autonomous deep space navigation system.

Currently, Juno is continuing its trek to Jupiter. On the way, the star tracker will look for asteroids, comets and other interesting objects as it maps the dusty debris left by asteroids and comets.

Want to see the video for yourself? Check it out below, courtesy of YouTube.