
NASA Mars Reconnaissance Orbiter’s HiRISE image of recurring slope lineae in Melas Chasma, Valles Marineris. Arrows point out tops and bottoms of a few lineae.
Credit: NASA/JPL-Caltech/University of Arizona
The revelation that dark streaks flowing downhill on Mars are likely signs of liquid water on the red planet have sparked debate on how best to investigate them.
Dubbed Recurring Slope Lineae (RSL), the new RSL findings may well bolster the odds that life is alive and well today on Mars. Moreover, RSL might be a literal draw for future human explorers as those sites could lead to underground aquifers on the planet.

Look, but do not touch? NASA’s Curiosity rover is on the prowl within Gale Crater/Mt. Sharp area that appears to have Recurring Slope Lineae (RSL).
Credit: NASA/JPL-Caltech
Evidence of running water on the surface of Mars has many implications. One contentious issue is safely surveying RSL up-close and not corrupting these features with Earth-transported bacteria – a planetary protection issue.
For my new Space.com story on these fascinating features, go to:
Mars Water Discovery Sparks Exploration Debate
by Leonard David, Space.com’s Space Insider Columnist
October 16, 2015 07:30am ET
http://www.space.com/30840-mars-water-life-search-debate.html