E-THEMIS camera (IMAGE) Arizona State University Caption Christensen holds a non-working replica of E-THEMIS that has the exact same dimensions and mass as the real flight instrument. To avoid unnecessary handling of the actual E-THEMIS camera, engineers use this mass model for tests that don't require a functioning instrument. These include doing initial vibration testing and checking that electrical cables fit properly in the space provided. Credit Charlie Leight/ASU News Usage Restrictions No restrictions. License Public Domain Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.