Regarding gully’s on Mars – gully formation likely involved water in some capacity. So why aren’t we going to gully’s directly in order to look for evidence of water? It comes down to planetary protection – locations with water may harbor life, and they get designated as planetary protection sites. However, gully’s aren’t as interesting as recurring slope linae (RSL) for the presence of briny flows of water. Recurring slope linae are small formations that incrementally grow and darken during the warmest parts of the year.

Some insiders say that the planetary protection paradigm is a big racket. However, JPL is not the origin of the planetary protection act. Requirements are imposed upon them from a treaty managed by the Committee on Space Research. The planetary protection office has recently been moved and the rigor has been relaxed in the face of the possibility of putting people on mars in the next decade or two.

From a scientific standpoint, we have a slanted view of Mars based on resolution limits and satellite distribution around the planet. It would be interesting to see what new data would emerge from having a more robust satellite network around Mars, maybe we could identify RSL and water easier.