The Dawn spectrometer (VIR) is a hyperspectral spectrometer with imaging capability. The design fully accomplishes Dawn’s scientific and measurement objectives. Determination of the mineral composition of surface materials in their geologic context is a primary Dawn objective. The nature of the solid compounds of the asteroid (silicates, oxides, salts, organics and ices) can be identified by visual and infrared spectroscopy using high spatial resolution imaging to map the heterogeneity of asteroid surfaces and high spectral resolution spectroscopy to determine the composition unambiguously. The VIR Spectrometer—covering the range from the near UV (0.25 μm) to the near IR (5.0 μm) and having moderate to high spectral resolution and imaging capabilities—is the appropriate instrument for the determination of the asteroid global and local properties. VIR combines two data channels in one compact instrument. The visible channel covers 0.25–1.05 μm and the infrared channel covers 1–5.0 μm. VIR is inherited from the VIRTIS mapping spectrometer (Coradini et al. in Planet. Space Sci. 46:1291–1304, 1998; Reininger et al. in Proc. SPIE 2819:66–77, 1996) on board the ESA Rosetta mission. It will be operated for more than 2 years and spend more than 10 years in space.

The VIR Spectrometer

The early development of life, a fundamental question for humankind, requires the presence of a suitable planetary climate. Our understanding of how habitable planets come to be begins with the worlds closest to home. Venus, Earth, and Mars differ only modestly in their mass and distance from the Sun, yet their current climates could scarcely be more divergent. Only Earth has abundant liquid water, Venus has a runaway greenhouse, and evidence for life-supporting conditions on Mars points to a bygone era. In addition, an Earth-like hydrologic cycle has been revealed in a surprising place: Saturn's cloud-covered satellite Titan has liquid hydrocarbon rain, lakes, and river networks. Deducing the initial conditions for these diverse worlds and unravelling how and why they diverged to their current climates is a challenge at the forefront of planetary science. Through the contributions of more than sixty leading experts in the field, Comparative Climatology of Terrestrial Planets sets forth the foundations for this emerging new science and brings the reader to the forefront of our current understanding of atmospheric formation and climate evolution. Particular emphasis is given to surface-atmosphere interactions, evolving stellar flux, mantle processes, photochemistry, and interactions with the interplanetary environment, all of which influence the climatology of terrestrial planets. From this cornerstone, both current professionals and most especially new students are brought to the threshold, enabling the next generation of new advances in our own solar system and beyond.

Comparative Climatology of Terrestrial Planets

[1] Simultaneous observations of Venus by Visible and Infrared Thermal Imaging Spectrometer and Venus Monitoring Camera onboard the Venus Express spacecraft are used to map the cloud top altitude and to relate it to the ultraviolet (UV) markings. The cloud top altitude is retrieved from the depth of CO2 absorption band at 1.6 μm. In low and middle latitudes the cloud top is located at 74 ± 1 km. It decreases poleward of ±50° and reaches 63–69 km in the polar regions. This depression coincides with the eye of the planetary vortex. At the same latitude and hour angle, cloud top can experience fast variations of about 1 km in tens of hours, while larger long-term variations of several kilometers have been observed only at high latitudes. UV markings correlate with the cloud altimetry, however, the difference between adjacent UV dark and bright regions does not exceed several hundred meters. Surprisingly, CO2 absorption bands are often weaker in the dark UV features, indicating that these clouds may be a few hundred meters higher or have a larger scale height than neighboring clouds. Ultraviolet dark spiral arms, which are often seen at about −70°, correspond to higher altitudes or to the regions with strong latitudinal gradient of the cloud top altitude. Cloud altimetry in the polar region reveals the structure that correlates with the thermal emission maps but is invisible in UV images. This implies that the UV optically thick polar hood is transparent in the near IR.

/pdf/altimetry-of-the-venus-cloud-tops-from-the-venus-express-3m4xqvtfgm.pdf

Altimetry of the Venus cloud tops from the Venus Express observations

[1] We present zonal and meridional wind measurements at three altitude levels within the cloud layers of Venus from cloud tracking using images taken with the VIRTIS instrument on board Venus Express. At low latitudes, zonal winds in the Southern hemisphere are nearly constant with latitude with westward velocities of 105 ms−1 at cloud-tops (altitude ∼ 66 km) and 60–70 ms−1 at the cloud-base (altitude ∼ 47 km). At high latitudes, zonal wind speeds decrease linearly with latitude with no detectable vertical wind shear (values lower than 15 ms−1), indicating the possibility of a vertically coherent vortex structure. Meridional winds at the cloud-tops are poleward with peak speed of 10 ms−1 at 55° S but below the cloud tops and averaged over the South hemisphere are found to be smaller than 5 ms−1. We also report the detection at subpolar latitudes of wind variability due to the solar tide.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2008GL033817

Variable winds on Venus mapped in three dimensions

Middle atmosphere dynamics

Scientific goals for the observation of Venus by VIRTIS on ESA/Venus Express mission

The article proposes the architecturefor event-driven Emergency Operation Center with Machine Vision Component. Sources of information are analyzed and approaches to machine vision events fortactical situations detection and estimation are discussed. Messages fromMachine Vision Components are converted to Common Alerting Protocol andprocessed by Operation Center environment for tactical situations recognition.

Event-Driven Platform for Machine Vision Component Integration with Operation Center

The article proposes the architecture for event-driven Emergency Operation Center with Machine Vision Component. Sources of information are analyzed and approaches to machine vision events for tactical situations detection and estimation are discussed. Messages from Machine Vision Com-ponents are converted to Common Alerting Protocol and processed by Operation Center environment for tactical situations recognition.

T. Z. Afanasenko

Papers

Scientific goals for the observation of Venus by VIRTIS on ESA/Venus Express mission

Event-Driven Platform for Machine Vision Component Integration with Operation Center

Event-Driven Platform for Machine Vision Component Integration with Operation Center