HiRISE | Spiders in the Summer (PSP_004748

NASA/JPL-Caltech/UArizona

Spiders in the Summer
PSP_004748_0945 Science Theme: Seasonal Processes

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The south polar region of Mars contains numerous features dubbed "spiders." These are actually narrow shallow channels carved in the ground, probably by gas escaping as the seasonal dry ice cap sublimates (evaporates directly from solid ice to gas).

In the spring they are the source of fans of dust. In the summer, the dark fans are only barely discernible from the surface material, because they are the surface material. Dust gets blown to the top of—and deposited on— the seasonal layer of ice as the seasonal cap sublimates.

Although the fans fade away in the summer, the spider channels remain clearly visible (2254 x 1522; 3 MB). Small patches of bright seasonal ice still remain in a few places.

Written by: Candy Hansen (29 August 2007)

Acquisition date
01 August 2007

Local Mars time
16:53

Latitude (centered)
-85.413°

Longitude (East)
104.006°

Spacecraft altitude
246.5 km (153.2 miles)

Original image scale range
24.7 cm/pixel (with 1 x 1 binning) so objects ~74 cm across are resolved

Map projected scale
25 cm/pixel

Map projection
Polarstereographic

Emission angle
0.9°

Phase angle
65.4°

Solar incidence angle
65°, with the Sun about 25° above the horizon

Solar longitude
287.4°, Northern Winter

For non-map projected images
North azimuth: 125°
Sub-solar azimuth: 49.4°

JPEG
Black and white
map projected  non-map

IRB color
map projected  non-map

Merged IRB
map projected

Merged RGB
map projected

RGB color
non-map projected

JP2
Black and white
map-projected   (1235MB)

IRB color
map-projected   (488MB)

JP2 EXTRAS
Black and white
map-projected (626MB)
non-map           (753MB)

IRB color
map projected (362MB)
non-map           (685MB)

Merged IRB
map projected (323MB)

Merged RGB
map-projected (311MB)

RGB color
non map           (697MB)

ADDITIONAL INFORMATION
B&W label
Color label
Merged IRB label
Merged RGB label
EDR products
HiView

NB
IRB: infrared-red-blue
RGB: red-green-blue
About color products (PDF)

Black & white is 5 km across; enhanced color about 1 km
For scale, use JPEG/JP2 black & white map-projected images

USAGE POLICY
All of the images produced by HiRISE and accessible on this site are within the public domain: there are no restrictions on their usage by anyone in the public, including news or science organizations. We do ask for a credit line where possible:
NASA/JPL-Caltech/UArizona

POSTSCRIPT
NASA’s Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Mars Reconnaissance Orbiter for NASA’s Science Mission Directorate, Washington. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona.