RSL (2 of 2) (image) Georgia Institute of Technology Caption Dark elongated streaks called Recurring Slope Lineae observed in HiRISE images of Mars. The RSL form on sun facing slopes during warm season and fade during cold season. Credit NASA/JPL Usage Restrictions None 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.