Scientists are delighted with new test images from the Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment (HiRISE) camera.

The HiRISE camera -- the newest and most powerful camera orbiting Mars -- took four images of Mars on March 23 and four more on March 25.

The HiRISE team, directed by Alfred S. McEwen at The University of Arizona, released a preliminary black-and-white version of the first image on Mars 24.

The test images show that both NASA's Mars Reconnaissance Orbiter (MRO) and the HiRISE camera are working extremely well, McEwen said. And they've given the HiRISE team the data it needs to develop image processing techniques before the primary science mission begins this fall.

"The images are wonderful," McEwen said. "We're learning a great deal about how to best acquire and process these giant images from our very complicated camera."

HiRISE returns very large images, up to 20,000 pixels wide and 60,000 pixels long.

"I personally was bowled over by the range of different geological processes that operated at different times and scales that could be discerned from a 'single' HiRISE image," science team member Laszlo Keszthelyi of the U.S. Geological Survey in Flagstaff, Ariz., said.

The HiRISE operations team has made great strides in developing the processing "pipelines" that need to be as automated as possible to keep up with the flood of data that the camera will begin sending when the science mission begins in November.

"These images are being used to shake-out the processing for making precise image maps of Mars with accurate color information," HiRISE operations manager Eric Eliason said.

NASA and the HiRISE team are releasing three processed images this morning and will release more later today. The images are on the following NASA and UA Lunar and Planetary Laboratory Websites: http://hiroc.LPL.arizona.edu, http://www.nasa.gov/mro, http://marsoweb.nas.nassa.gov/HiRISE/, and http://mars.jpl.nasa.gov/mro

The images include an improved version of the black-and-white image released March 24 and six other black-and-white images. Each of these pictures is actually a mosaic of as many as 10 images made by 10 CCD detectors.

Two of these images were part of a "jitter" test, a test of how other science instruments and spacecraft systems affect HiRISE imaging. These images are important to HiRISE team members who are developing image processing techniques that correct parts of the pictures that are smeared or distorted as the result of other spacecraft operations.

The team is also releasing a central swath of the first March 24 image in color.

Low-angle illumination didn't give the scientists the best color data, McEwen said, "But this first image nevertheless shows some very interesting and informative color variations" that look promising for color imaging when the spacecraft reaches science orbit in September, two months before the science mission begins. "The first color image is beautiful!" McEwen added.

HiRISE team members from the U.S.G.S. - Flagstaff derived a digital elevation model for part of the March 24 image, and from that produced a topographic map and a series of perspective views. The team is releasing the map and five of the perspective views. The low sun angle that detracted from color mapping enhanced the topographic views.

Conditions were far from ideal when the HiRISE camera took its test images, before the spacecraft began aerobraking, a technique that will take the spacecraft into a nearly circular and lower science orbit. The camera was designed for its science orbit, a two-hour orbit at 300 kilometers (about 190 miles) above the planet at around 3 p.m. on Mars' dayside, McEwen said.

When HiRISE took test images, the MRO spacecraft was in a highly elliptical orbit that took 35 hours to complete and comes closest to Mars on its night side. This flight path geometry allowed HiRISE only 10 minutes of useful imaging time during each of its two orbits, and test images had to be taken at around 7:30 a.m., when the sun was barely over Mars' horizon, from a distance of 1,500 to 2,500 kilometers (about 900 to 1,500 miles) away.

The HiRISE team uses ISIS-3 software developed and maintained by the U.S.G.S.-Flagstaff for processing its images.

The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems is the prime contractor for the project and built the spacecraft.