* Astronomy

MARS ODYSSEY THEMIS IMAGES May 14-18, 2007

o Dune Types (Released 14 May 2007)
o  Bright Dunes  (Released 15 May 2007)
o  Mangala Vallis  (Released 16 May 2007)
o  Small Dunes  (Released 17 May 2007)
o  Arsia Mons Flows  (Released 18 May 2007)

MARS ODYSSEY THEMIS IMAGES May 7-11, 2007

o Dunes and Gullies  (Released 07 May 2007)
o  Which Came First?  (Released 08 May 2007)
o  Dunes  (Released 09 May 2007)
o  Cloud Streamers  (Released 10 May 2007)
o  Moving Down Valley (Released 11 May 2007)

The Thermal Emission Imaging System (THEMIS) aboard NASA's Mars Odyssey orbiter is helping mark a milestone May 4. An image from THEMIS showing Martian lava flows and wind streaks mingling with impact craters, becomes the 1,200th "Image of the Day" posted online at http://themis.asu.edu.
The Mars Space Flight Facility at Arizona State University operates the site, which is updated every weekday with images and data from THEMIS. The first Image of the Day was posted March 27, 2002.


Image Credit: NASA/JPL/ASU

"We usually select the Image of the Day to show the wide variety of surface features present on Mars. Some images, however, are chosen purely for their aesthetic value" - Kelly Bender, THEMIS mission planner.

THEMIS is a multi-wavelength camera that photographs the Martian surface in 5 visual and 10 infrared bands. At infrared wavelengths, the smallest details it records are 100 metres wide, while at visual wavelengths as seen in the image the smallest details are 18 m wide.
Image of the Day #1200 shows a strip of ground on Mars that measures 18 kilometres wide by 63 km long.

"We're looking at the Daedalia Planum region, part of the large volcanic province of Tharsis. The lava flows came from the Arsia Mons volcano. Its summit lies about 500 kilometres beyond the image frame to the right. The rough textured lava surface traps dust and sand, while the impact craters act as obstacles to the wind" - - Kelly Bender.

The combination of readily available dust and turbulent winds passing the craters creates the bright and dark 'tails' extending the west (left) of the craters.

"These wind streaks indicate the direction the wind was blowing east to west in this case. From the very beginning of the THEMIS project I wanted to bring Mars alive for everyone. One of the most enjoyable ways has been to post a new image each day of the mission with a brief description of what we think we are looking at" - Philip Christensen, Regents' Professor of geological sciences in the School of Earth and Space Exploration, part of ASUs College of Liberal Arts and Sciences.

Christensen is the director of the Mars Space Flight Facility, and both designer and principal investigator for the THEMIS instrument.

"Many features we see in these images remain a mystery. More often than not we scratch our heads and mutter 'Wow, whats that?' But that's the fun of exploring Mars, and hopefully those who follow the mission through our images can share in the experience of looking at the unknown for the first time" - Philip Christensen.

MARS ODYSSEY THEMIS IMAGES April 16-20, 2007

o  Slope Failure (Released 16 April 2007)
o  Polar Textures  (Released 17 April 2007)
o  Not Only Ice  (Released 18 April 2007)
o  Frosty Dunes  (Released 19 April 2007)
o  Crater Features  (Released 20 April 2007)