Phobos over Mars (IMAGE) American Geophysical Union Caption Phobos, the larger of Mars' two tiny satellites, pictured near the limb of Mars by the robot spacecraft Mars Express in 2010. Credit G. Neukum (FU Berlin) et al., Mars Express, DLR, ESA; Acknowledgement: Peter Masek Usage Restrictions include credit License Licensed content 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.