Radiation astronomy/Reflections

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This oblique astronaut photograph from the International Space Station (ISS) captures a white-to-grey ash and steam plume extending westwards from the Soufriere Hills volcano. Credit: NASA Expedition 21 crew.
This is a computer generated model of the Lunar Atmosphere and Dust Environment Explorer (LADEE). Credit: NASA.

Oblique images such as the one at right are taken by astronauts looking out from the International Space Station (ISS) at an angle, rather than looking straight downward toward the Earth (a perspective called a nadir view), as is common with most remotely sensed data from satellites. An oblique view gives the scene a more three-dimension quality, and provides a look at the vertical structure of the volcanic plume.

"The Lunar Atmosphere and Dust Environment Explorer (LADEE, at left) launched 07 September 2013 at 03:27 UT (06 September 11:27 EDT) on a Minotaur-V from Wallops Flight Facility. LADEE is designed to characterize the tenuous lunar atmosphere and dust environment from orbit. The scientific objectives of the mission are:(1) determine the global density, composition, and time variability of the fragile lunar atmosphere; and, (2) determine the size, charge, and spatial distribution of electrostatically transported dust grains and assess their likely effects on lunar exploration and lunar-based astronomy. Further objectives are to determine if the Apollo astronaut sightings of diffuse emission at 10s of km above the surface were Na glow or dust and document the dust impactor environment (size-frequency) to help guide design engineering for outpost and future robotic missions."[1]

"The orbiter will carry a Neutral Mass Spectrometer (NMS), an Ultraviolet/Visible Spectrometer (UVS), and a Lunar Dust Experiment (LDEX)."[1]

"The NMS is a quadrupole mass spectrometer designed ot detect species up to 150 amu and will look for CH4, S, O, Si, Kr, Xe, Fe, Al, Ti, Mg, OH, and H2O. The UVS will detect Al, Ca, Fe, K, Li, Na, Si, T, Ba, Mg, H2O, and O and will monitor the dust composition. The LDEX is an impact ionization dust detector designed to measure particles down to 0.3 microns at the spacecraft altitude. The LLCD is a test of a high data-rate optical (laser) communications system."[1]

Mercury[edit | edit source]

This is Mercury in real colors, processed from clear and blue filtered Mariner 10 images. Credit: Images processed by Ricardo Nunes.

"A higher-reflectance, relatively red material occurs as a distinct class of smooth plains that were likely emplaced volcanically; a lower-reflectance material with a lesser spectral slope may represent a distinct crustal component enriched in opaque minerals, possibly more common at depth."[2]

"The distinctively red smooth plains (HRP) appear to be large-scale volcanic deposits stratigraphically equivalent to the lunar maria (20), and their spectral properties (steeper spectral slope) are consistent with magma depleted in opaque materials. The large areal extent (>106 km2) of the Caloris HRP is inconsistent with the hypothesis that volcanism was probably shallow and local (10); rather, such volcanism was likely a product of extensive partial melting of the upper mantle."[2]

"Despite the dearth of ferrous iron in silicates, Mercury's surface nonetheless darkens and reddens with time like that of the Moon. This darkening and reddening has been interpreted to be the result of production of nanophase iron (e.g., Pieters et al., 2000; Hapke, 2001), which could be derived from an opaque phase in the crustal material or from delivery by micrometeorite impacts (Noble and Pieters, 2003). On the Moon, deposits that are brighter and redder than the average Moon spectrum appear to be lower in iron (e.g., highland material); deposits that are darker and redder than average are higher in iron (e.g., low-Ti mare material) (Lucey et al., 1995)."[3]

Moon[edit | edit source]

This image of Earth's moon is a three-colour composite of reflected near-infrared radiation from the Sun. Credit: ISRO/NASA/JPL-Caltech/Brown Univ./USGS.

"NASA's Moon Mineralogy Mapper, an instrument on the Indian Space Research Organization's Chandrayaan-1 mission, took [the image at right] of Earth's moon. It is a three-colour composite of reflected near-infrared radiation from the sun, and illustrates the extent to which different materials are mapped across the side of the moon that faces Earth. Small amounts of water were detected on the surface of the moon at various locations. This image illustrates their distribution at high latitudes toward the poles. Blue shows the signature of water, green shows the brightness of the surface as measured by reflected infra-red radiation from the sun and red shows a mineral called pyroxene."[4]

Hypotheses[edit | edit source]

  1. The use of satellites should provide ten times the information as sounding rockets or balloons.

A control group for a radiation satellite would contain

  1. a radiation astronomy telescope,
  2. a two-way communication system,
  3. a positional locator,
  4. an orientation propulsion system, and
  5. power supplies and energy sources for all components.

A control group for radiation astronomy satellites may include an ideal or rigorously stable orbit so that the satellite observes the radiation at or to a much higher resolution than an Earth-based ground-level observatory is capable of.

See also[edit | edit source]

References[edit | edit source]

  1. 1.0 1.1 1.2 Richard C. Elphic; Sarah Noble; P. Butler Hine III (September 7, 2013). Lunar Atmosphere and Dust Environment Explorer (LADEE). Washington, DC USA: National Space Science Data Center, NASA. http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=2013-047A. Retrieved 2014-01-07. 
  2. 2.0 2.1 Mark S. Robinson; Scott L. Murchie; David T. Blewett; Deborah L. Domingue; S. Edward Hawkins III; James W. Head; Gregory M. Holsclaw; William E. McClintock et al. (July 4, 2008). "Reflectance and Color Variations on Mercury: Regolith Processes and Compositional Heterogeneity". Science 321 (5885): 66-9. doi:10.1126/science.1160080. http://www.sciencemag.org/content/321/5885/66.short. Retrieved 2013-07-28. 
  3. Laura Kerber; James W. Head; Sean C. Solomon; Scott L. Murchie; David T. Blewett; Lionel Wilson (2009). [http://www.sciencedirect.com/science/article/pii/S0012821X09002611 "Explosive volcanic eruptions on Mercury: Eruption conditions, magma volatile content, and implications for interior volatile abundances"]. Earth and Planetary Science Letters 285: 263-71. doi:10.1016/j.epsl.2009.04.037. http://www.sciencedirect.com/science/article/pii/S0012821X09002611. Retrieved 2013-07-28. 
  4. Yvette Smith (September 25, 2009). Water Detected at High Latitudes on the Moon. NASA. http://www.nasa.gov/multimedia/imagegallery/image_feature_1478.html. Retrieved 2012-11-26. 

External links[edit | edit source]

{{Radiation astronomy resources}}{{Repellor vehicle}}