Mars orbiter arrives March 10
NASA's Mars Reconnaissance Orbiter is anticipated to reach the Red Planet March 10.
March 7, 2006
Ground controllers await the signal from NASA's Mars Reconnaissance Orbiter (MRO) that it has begun the crucial engine burn that will slow the spacecraft enough to take it into low Mars orbit between 160 miles (257 kilometers) and 200 miles (322 km) above the planet. They expect that signal March 10 at about 4:24 P.M. Eastern time.
MRO ushers in the next phase of Mars exploration, even as the twin rovers Spirit and Opportunity continue their long-lived road trip over the planet's rocky, arid surface. The spacecraft's 5-year mission is threefold: to explore the planet in detail for historical evidence of water by using its six science instruments from a low-orbit vantage point; to scout out potential landing sites for future missions; and to provide telecommunications infrastructure for missions to follow.
The orbiter is expected to relay a staggering amount of data to Earth-based scientists during its 2-year primary science mission. "This spacecraft will return more data than all previous Mars missions combined," says MRO project manager Jim Graph of the Jet Propulsion Laboratory in Pasadena, California.
A typical orbit will take MRO about 35 hours to complete. The spacecraft will drop into Mars' atmosphere once per orbit to collect data over the course of 6 months. This technique is called "aerobraking" and helps slow MRO enough for it to settle into a nearly circular orbit about 190 miles (306 km) above Mars' surface. From this vantage point, MRO will not only study Mars' atmosphere but also probe the planet's surface and beneath for evidence of water and how it may have been distributed.
Science instruments aboard the orbiter include three cameras, a spectrometer, an atmospheric profiler, and a sounding radar. Additionally, MRO carries three engineering instruments, to assist with the spacecraft's navigation and communications, and two science facility experiments. Brief descriptions follow:
Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) splits visible and infrared light images into the colors that make up its spectrum.High Resolution Imaging Science Experiment (HiRISE) is a visible-light camera that will examine small-scale objects like debris blankets, craters, and deposits of layered materials.Context Camera (CTX) will give wide-field views of areas targeted by HiRISE and CRISM. In effect, this camera provides context for these targeted areas.Mars Color Imager (MARCI) is a weather-monitoring camera that will image the planet's clouds and dust storms each day.Mars Climate Sounder (MCS), an atmospheric profiler, detects vertical differences of temperature, water vapor concentrations, and dust in the atmosphere.Shallow Radar (SHARAD) is sounding radar that will search for water ice beneath the planet's surface at depths greater than 3.3 feet (1 meter).Electra UHF Communications and Navigation Package lets the spacecraft relay communications between landers on Mars' surface and Earth stations.Optical Navigation Camera is being tested to evaluate its navigational potential for use on future missions.Gravity Field Investigation Package tracks the orbiter during the primary science phase of its mission in order to map Mars' gravity field.Atmospheric Structure Investigation Accelerometers collects acceleration data during MRO's aerobraking to better understand the martian atmosphere's structure.