NASA Solarsystem Collection

New Gullies on Martian Sand Dune

As part of extended-mission science investigation using the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft, the camera team is re-imaging many locations where previous observations revealed gullies. The intent is to see if gully-forming processes are operating on Mars at the present time.

The team has found one location where a new gully formed on a dune in an unnamed crater in the Hellespontus region of Mars, west of the Hellas Basin. This pair of narrow-angle images from the Mars Orbiter Camera shows the dune as it appeared on July 17, 2002, (left) and as it appeared on April 27, 2005, (right). The nearly three Earth years of intervening time amount to about 1.4 Mars years. During this period, a couple of gullies formed on the dune slip face. It is critical to recognize that the 2002 image was obtained at a time of year when the incident sunlight was coming in from a lower angle, relative to the horizon, than in the 2005 image. If the gullies had been present in 2002, their appearance would be sharper and more pronounced than they are in the 2005 image. The gullies simply did not exist on July 17, 2002. The steep walls of the gully alcove and channels suggests that the sand in this dune is somewhat cohesive, an observation common among martian sand dunes seen by the Mars Orbiter Camera over the past eight years.

Image Credit: NASA/JPL/MSSS

Solar System Exploration

SSE

Space

NASA

National Aeronautics and Space Administration

JPL

Jet Propulsion Laboratory

Planets

Mars

Surveyor

Crater

Earth

Mars Global Surveyor Orbiter (MGS)

Mars Orbiter Camera (MOC)

Jet Propulsion Laboratory

Mars

Jet Propulsion Laboratory (JPL)

2002

July 17, 2002

April 27, 2005

2002

2005

SPD-SLRSY-4103

http://solarsystem.…