Search

HiRISE has been producing a large number of scientifically useful color products of Mars and other planetary objects. The three broad spectral bands, coupled with the highly sensitive 14 bit detectors and time delay integration, enable detection of subtle color differences. The very high spatial resolution of HiRISE can augment the mineralogic interpretations based on multispectral (THEMIS) and hyperspectral datasets (TES, OMEGA and CRISM) and thereby enable detailed geologic and stratigraphic interpretations at meter scales. In addition to providing some examples of color images and their interpretation, we describe the processing techniques used to produce them and note some of the minor artifacts in the output. We also provide an example of how HiRISE color products can be effectively used to expand mineral and lithologic mapping provided by CRISM data products that are backed by other spectral datasets. The utility of high quality color data for understanding geologic processes on Mars has been one of the major successes of HiRISE.

The High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter (MRO) acquired 8 terapixels of data in 9137 images of Mars between October 2006 and December 2008, covering ~0.55% of the surface. Images are typically 5–6 km wide with 3-color coverage over the central 20% of the swath, and their scales usually range from 25 to 60 cm/pixel. Nine hundred and sixty stereo pairs were acquired and more than 50 digital terrain models (DTMs) completed; these data have led to some of the most significant science results. New methods to measure and correct distortions due to pointing jitter facilitate topographic and change-detection studies at sub-meter scales. Recent results address Noachian bedrock stratigraphy, fluvially deposited fans in craters and in or near Valles Marineris, groundwater flow in fractures and porous media, quasi-periodic layering in polar and non-polar deposits, tectonic history of west Candor Chasma, geometry of clay-rich deposits near and within Mawrth Vallis, dynamics of flood lavas in the Cerberus Palus region, evidence for pyroclastic deposits, columnar jointing in lava flows, recent collapse pits, evidence for water in well-preserved impact craters, newly discovered large rayed craters, and glacial and periglacial processes. Of particular interest are ongoing processes such as those driven by the wind, impact cratering, avalanches of dust and/or frost, relatively bright deposits on steep gullied slopes, and the dynamic seasonal processes over polar regions. HiRISE has acquired hundreds of large images of past, present and potential future landing sites and has contributed to scientific and engineering studies of those sites. Warming the focal-plane electronics prior to imaging has mitigated an instrument anomaly that produces bad data under cold operating conditions.

We present in detail the laboratory apparatus and techniques that were used to complete a full radiometric calibration of two space-based lightning detectors developed at NASA Marshall Space Flight Center (MSFC). A discussion of the methods applied to geolocate lightning and to estimate lightning detection efficiency are provided.

Following its launch in August, 2005 and a year of interplanetary cruise and aero-braking, the successful Mars Reconnaissance Orbiter (MRO) mission is currently orbiting Mars and down-linking imagery from the High Resolution Imaging Science Experiment (HiRISE) camera. The primary objectives of the MRO mission are to characterize the present climate of Mars, look for evidence of water-related activities, and characterize potential landing sites. After only four months in the Primary Science Phase (PSP) of the mission, MRO has returned more data than any other previous Mars mission. Approximately one-third of this data volume is from the HiRISE camera, built by Ball Aerospace & Technologies Corporation (BATC), for the University of Arizona (UofA), Department of Planetary Sciences. With a 0.5-meter primary mirror, the HiRISE instrument includes the largest optical telescope ever sent beyond Earth's orbit, and is producing images with unprecedented resolution. It has detected objects of less than one meter size from the nominal orbit of 250 x 320 km. The highest resolution images have a scale of 25 to 32 cm per pixel (1.0 microradian IFOV). HiRISE is a "push-broom" camera with a swath width of 6 km in a broad red spectral band and 1.2 km in blue-green and near infrared bands. There are 14 CCD detector chips (2048 x 128 TDI elements each) on the focal plane. The HiRISE camera was designed to minimize use of spacecraft resources. Even with a half-meter primary mirror, through the use of lightweight glass optics and graphite-composite structures the final mass of the instrument is only 64.2 kg. It maintains a nearly uniform telescope temperature of 20°C yet its orbital average power consumption is less than 60 W. An overview is given of the NASA MRO mission and the HiRISE instrument. Pre-launch activities are detailed and the launch time discussed. An account is given of the cruise events, along with a description of aerobraking and the primary science phase. A sample of science results are presented, including a wealth of imagery.

[1] The HiRISE camera features a 0.5 m diameter primary mirror, 12 m effective focal length, and a focal plane system that can acquire images containing up to 28 Gb (gigabits) of data in as little as 6 seconds. HiRISE will provide detailed images (0.25 to 1.3 m/pixel) covering ∼1% of the Martian surface during the 2-year Primary Science Phase (PSP) beginning November 2006. Most images will include color data covering 20% of the potential field of view. A top priority is to acquire ∼1000 stereo pairs and apply precision geometric corrections to enable topographic measurements to better than 25 cm vertical precision. We expect to return more than 12 Tb of HiRISE data during the 2-year PSP, and use pixel binning, conversion from 14 to 8 bit values, and a lossless compression system to increase coverage. HiRISE images are acquired via 14 CCD detectors, each with 2 output channels, and with multiple choices for pixel binning and number of Time Delay and Integration lines. HiRISE will support Mars exploration by locating and characterizing past, present, and future landing sites, unsuccessful landing sites, and past and potentially future rover traverses. We will investigate cratering, volcanism, tectonism, hydrology, sedimentary processes, stratigraphy, aeolian processes, mass wasting, landscape evolution, seasonal processes, climate change, spectrophotometry, glacial and periglacial processes, polar geology, and regolith properties. An Internet Web site (HiWeb) will enable anyone in the world to suggest HiRISE targets on Mars and to easily locate, view, and download HiRISE data products.

The performance, development and testing of the prototype spectrometer are discussed as well as potential applications for future missions.

The Lightning Imaging Sensor (LIS) wide field-of-view solid-state camera can measure the global distribution of lightning from LEO, through the use of a narrowband interference filter to detect the neutral O band at 777.4 nm. Prelaunch testing and calibration of the LIS has required three separate laboratory systems; absolute radiometric calibration of the sensor will be furnished over the whole spectral range by a high resolution monochromator and motorized gimbals.

We examine the role of processing errors on diffraction efficiency of binary optical elements and the validity of the Fourier model to predict diffraction efficiency. We show that mask alignment error can significantly degrade efficiency. Models based on the Fourier theory can adequately predict both the magnitude of diffraction efficiency and its sensitivity to processing errors for optically slow elements (f/b). For optically fast elements (

For many applications, for example, in ground-based astronomy, detector systems using small arrays or small numbers of discrete IR. detectors are very useful. In particular, systems using indium antimonide (InSb) detectors are approaching background-limited performance throughout most of their useful wavelength band of 1 to 5 μm. The general requirements of preamplifiers for background-limited performance of InSb IR detector systems are presented. These amplifiers require a cryogenic Field-effect transistor (FET) first stage to achieve this level of performance. The electrical and thermal design tradeoffs of such amplifiers are presented. The noise performance of transimpedance amplifiers (TIAs) is estimated from a noise model. Measurements of noise voltage and noise current versus temperature are presented for a sample of commercially available junction FETs (JFETs). It is concluded that if JFETs with reasonably low values of noise voltage are selected, then the IR TIA system noise will be dominated by an input noise current from the JFET, typically 5 x 1047 A/.117z at 10-Hz frequency. Most significantly, this source appears to be correlated over temperature with the input noise voltage. This suggests that the voltage and current noise sources are caused by the same mechanism. A JFET selection procedure is proposed that includes a minimum of low-temperature testing.