Mars Orbiter spacecraft uses Rockwell Scientific sensors

Nov. 29, 2005
THOUSAND OAKS, Calif., 29 Nov. 2005. When NASA launched its Mars Reconnaissance Orbiter from Cape Canaveral Air Force Station in Florida on August 12, it carried six scientific instruments.

THOUSAND OAKS, Calif., 29 Nov. 2005. When NASA launched its Mars Reconnaissance Orbiter from Cape Canaveral Air Force Station in Florida on August 12, it carried six scientific instruments.

Rockwell Scientific Co. supplied two imaging sensor components for one of those, the CRISM (Compact Reconnaissance Imaging Spectrometer for Mars).

CRISM is a visible-infrared hyperspectral mapper developed by the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. NASA will use it to search for evidence of minerals that form in the presence of water, which might have been left by hot springs, thermal vents, lakes, or ponds far back in Mars' history when water may have been present on the surface. They will also use CRISM to aid in mapping the geology, composition and stratigraphy of Mars' surface features.

Rockwell Scientific contributed both a Mid-Wave Infrared (IR) and Visible IR subsystem to the project.

The MWIR subsystem is composed of a MWIR sensor and a three-zone order sorting multi-layer interference filter packaged in a cold shield. The MWIR sensor is a mercury cadmium telluride (HgCdTe) array with 640 (spatial) x 480 (spectral) pixel format for high resolution with a 980nm to 3960nm spectral bandpass. The three-zone filter consists of two broadband filters and one linear variable filter. The visible subsystem uses a silicon photodiode array with a 380-1050 nm spectral bandpass and a 2-zone order sorting filter. The visible array has the same pixel format and read-out integrated circuit (ROIC) as the MWIR sensor, greatly simplifying the data acquisition system.

The combination of the high-resolution sensors and the multi-zone order sorting filters provides the CRISM instrument a greater capability to map spectral variations than any similar instrument sent to Mars. The visible and infrared spectrometers will track regions on the Mars surface and map them at scales as small as 60 feet across, from an altitude of 186 miles. The instruments will read 544 "colors" to detect minerals in the Mars surface. Its highest resolution is about 20 times sharper than any previous look at Mars in mid-wave infrared wavelengths, and boasts five times better spatial resolution than any previous look in the thermal infrared spectral region.

"We are very excited to have played a significant role in this project," says Jianmei Pan, program manager of the CRISM program at Rockwell Scientific. "CRISM plays such an important role in Mars exploration, and our sensor systems are critical in collecting the data to identify the sites most likely to have contained water and which would make the best potential landing sites for future Mars exploration missions."

RSC is world renowned for their high performance sensor designs. They continue to develop focal plane arrays (FPAs) that operate within a broad spectrum of light from below 0.3 micron ultra-violet to 18 micron long-wave infrared for defense, astronomy/scientific, and commercial applications. RSC supplied NASA's Hubble Space Telescope with extremely sensitive FPA mosaics to capture light from distant galaxies.

Today, RSC is working on a contract for NASA to provide infrared FPA's for Hubble's successor -- the 2011 James Webb Space Telescope. RSC has meshed its diverse engineering expertise in sensor and readout integrated circuit (ROIC) design to offer complete sub-system packages that incorporate state-of-the-art sensors with custom mixed-signal CMOS ROIC design and fabrication.

Rockwell Scientific Co. LLC, based in Thousand Oaks, Calif., is an independent, privately owned high-technology enterprise with unique technical strengths in imaging sensors, electronics, optics, materials, and information science. Its range of activities includes U.S. government and private sector companies, as well as the manufacturing and sale of high-value products and licenses closely related to its R&D efforts. For more information, see

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