Earth Gravity Assist Image Planning
Shortly after OSIRIS-REx performed its Earth Gravity Assist on Sept. 22, the cameras and other instruments on the spacecraft were powered on and collected data about Earth and the Moon. The images captured by OSIRIS-REx’s cameras are no point-and-shoot candid photos. While imaging, the spacecraft is moving at tens of thousands of miles per hour, and the cameras are fixed in place requiring the entire spacecraft to turn and point at the object being imaged at just the right time. Meanwhile, the target (Earth) is both orbiting the Sun and rotating on its own axis.
With the spacecraft making a one-time flyby of Earth, there are no retakes. Engineers and navigation specialists painstakingly planned each of the images taken by OSIRIS-REx’s cameras using software called Systems Tool Kit (STK). The plans they developed, working with the scientists and others on the mission team, were uploaded to the spacecraft’s computer weeks ahead of time. Within hours of the flyby, the first images on the ground—taken by one of the spacecraft’s navigational cameras—showed that they were right on target.
The upper half of this graphic was generated in STK. It shows the predicted view of Earth in NavCam 1’s field of view (orange outline) at 5:08 pm EDT (21:08 UTC) on Sept. 22. The lower half shows the actual image captured by NavCam 1 at that date and time.
Date Taken: Sept. 22, 2017
Credit: NASA/Goddard/University of Arizona/Lockheed Martin
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