Engineering topics

Hansen, C.

Publications and source records attributed to Hansen, C..

23 records · Page 2

NASA NTRS2003

MRO's High Resolution Imaging Science Experiment (HiRISE): Polar Science Expectations

The Mars Reconnaissance Orbiter (MRO) is expected to launch in August 2005, arrive at Mars in March 2006, and begin the primary science phase in November 2006. MRO will carry a suite of remote-sensing instruments and is designed to routinely point off-nadir to precisely target locations on Mars for high-resolution observations. The mission will have a much higher data return than any previous planetary mission, with 34 Tbits of returned data expected in the first Mars year in the mapping orbit (255 x 320 km). The HiRISE camera features a 0.5 m telescope, 12 m focal length, and 14 CCDs. We expect to acquire approximately 10,000 observations in the primary science phase (approximately 1 Mars year), including approximately 2,000 images for 1,000 stereo targets. Each observation will be accompanied by a approximately 6 m/pixel image over a 30 x 45 km region acquired by MRO s context imager. Many HiRISE images will be full resolution in the center portion of the swath width and binned (typically 4x4) on the sides. This provides two levels of context, so we step out from 0.3 m/pixel to 1.2 m/pixel to 6 m/pixel (at 300 km altitude). We expect to cover approximately 1% of Mars at better than 1.2 m/pixel, approximately 0.1% at 0.3 m/pixel, approximately 0.1% in 3 colors, and approximately 0.05% in stereo. Our major challenge is to find the dey contacts, exposures and type morphologies to observe.

McEwen, A.↗

NASA NTRS1985

The AMPTE IRM Science Data Center

The creation of artificial ion clouds is a major aspect of the AMPTE program. The IRM Science Data center supports real-time decision for a release with real-time scientific data processing and display including model calculations of ion trajectories. Additionally, survey plots and summary data records are generated in near real time thus allowing to start the data analysis as early as possible. For detailed analyses, interactive programs were developed so that physical parameters of all IRM experiments can be combined to produce common spectra or line plots.

Bauer, O. H.↗

NASA NTRS1981

Volcanic eruptions on Io

Nine eruption plumes which were observed during the Voyager 1 encounter with Io are discussed. During the Voyager 2 encounter, four months later, eight of the eruptions were still active although the largest became inactive sometime between the two encounters. Plumes range in height from 60 to over 300 km with corresponding ejection velocities of 0.5 to 1.0 km/s and plume sources are located on several plains and consist of fissures or calderas. The shape and brightness distribution together with the pattern of the surface deposition on a plume 3 is simulated by a ballistic model with a constant ejection velocity of 0.5 km/s and ejection angles which vary from 0-55 deg. The distribution of active and recent eruptions is concentrated in the equatorial regions and indicates that volcanic activity is more frequent and intense in the equatorial regions than in the polar regions. Due to the geologic setting of certain plume sources and large reservoirs of volatiles required for the active eruptions, it is concluded that sulfur volcanism rather than silicate volcanism is the most likely driving mechanism for the eruption plumes.

Strom, R. G.↗

NASA NTRS1979

Jupiter's rings

Voyager 2 observations of the jovian ring system discovered by Voyager 1 are presented. The rings were observed both above and below the jovian equatorial plane and at extremely low and high phase angles. This ring system seems to represent a steady state configuration for small particles that are slowly moving in toward Jupiter. It must be resupplied from sources well outside Roche's limit.

Owen, T.↗

NASA NTRS1979

Volcanic eruption plumes on Io

Preliminary analyses of the eight volcanic eruption plumes detected on Io by Voyager 1 are presented. Plumes were observed on the bright and dark limbs of the satellite corresponding to half of the surface and range from 10,000 to 75 km in width and 280 to 70 km in height. Most plumes were observed to be umbrella-shaped, however one consists of a very diffuse cloud lacking columnar fountain characteristics. Plume sources are characterized by a dark central area, surrounded by a bright ring, which in turn is surrounded by a broad, diffuse region; the presence of similar markings in regions not observed at the limb indicates additional volcanic activity on Io. No changes were detected in the sizes or intensities of the eruptions over the 6.5-day viewing period, however a change in the appearance of a region near one plume suggests a short-lived eruption between observations. Seven of the eight plumes are located within 30 deg of the equator, implying that equatorial surfaces are generally younger than those in the polar regions.

Strom, R. G.↗