NASA officials on Wednesday released the first of what could be a daily flow of images of the Red Planet, snapped by a camera aboard the Mars Odyssey spacecraft.

The new image shows in black and white a nearly four-mile wide section of a network of sinuous channels that snakes for about 300 miles across the planet's southern hemisphere.

Scientists are divided about how the network, called Nirgal Vallis, was carved. Some have suggested that water formed the smaller gullies and alluvial deposits previously spotted by the Mars Global Surveyor spacecraft.

Scientists previously released several other images from Odyssey. However, the latest image is the first in a series of new photographs expected to be released every weekday for the balance of the 917-day science mission that began Feb. 17.

The images are captured by the spacecraft's Thermal Emission Imaging System. Wednesday's image covers an area 14 miles by 37 miles in size.

The camera developed by Arizona State University peers at Mars in both the visible and infrared portions of the spectrum.

In the infrared, minerals on the surface of the planet radiate heat back to space in distinct ways that can be identified and mapped by the instrument.

Scientists are keen to prospect — from orbit — for minerals such as carbonates that form in wet environments. Finding such deposits would indicate locations on Mars that were once warm and wet, and may have harbored life.

The heat-seeking camera will also probe the night side of Mars for hot spots that might indicate geothermal activity, such as hot springs. Those sites also could shelter microbial forms of life, scientists said.

The information will help scientists select landing sites for future missions designed to explore the planet's surface.

The $300 million Odyssey was launched in April and arrived in orbit in October. It will eventually serve as a communications relay satellite for missions slated to land on Mars beginning in 2003.