This rubble-strewn desert might once have been a Martian lake bed. Spirit, the NASA rover that landed on the Red Planet on 4 January, took this 360-degree panorama, here broken into two picture-perfect parts. The vista was imaged by assembling 225 separate frames taken by a camera mounted on a mast atop Spirit, some 1.3 meters above the ground [see inset, right].
The panoramic camera is actually composed of two CCD cameras spaced 30 centimeters apart, which allow it to take three-dimensional stereoscopic views in addition to normal 2-D pictures.
Each camera can generate a 1028-by-1028-pixel grayscale image, more than three times the resolution of the images provided by the 1996 Pathfinder lander camera.
Wheels mounted in front of the cameras contain a selection of narrow-band filters. By combining images of the same scene seen through different filters, color pictures can be produced. To calibrate the images, a sundial located at the rear of Spirit has grayscale and color targets.
Normally, images are sent back to Earth directly from the rover's high-gain antenna. As a backup, a separate UHF antenna can relay data via one of the three orbiters currently surveying Mars for NASA and the European Space Agency.
Communications are received by NASA's Deep Space Network, which uses large satellite dishes in California, Spain, and Australia to keep tabs on the fleet of probes currently exploring Mars and other parts of the solar system.
Once received, the data, which include telemetry from the spacecraft's systems as well as results from other scientific instruments, is sent to the Jet Propulsion Laboratory in Pasadena, Calif. The raw image data are extracted and then sent for digital processing to the science team's headquarters at Cornell University in Ithaca, N.Y.
Scientists hope that Spirit and its sibling rover Opportunity (scheduled to land on 25 January) will help answer questions about the history of water on Mars, a vital element in the search for life.