Architectural Analysis of the Gateway

As humans move out of the low earth orbit and into cis-lunar-space new challenges must be faced. This paper analyzes and discusses a possible architecture, from the orbit selection to the life support System and concept of operations of a potential cis-lunar space station. The investigation will not focus directly on the planned Gateway concept, but will use an independent approach for the concept definition and the analysis. The final part of the analysis is the identification of differences between the newly developed architecture and the currently proposed architecture from NASA. The pro and cons of both concepts are then discussed. The first part of the architecture is the life support system, which is analyzed with a combination of multi-criteria analysis and Equivalent System Mass to select an optimal life Support system. Additionally, the required initial launch mass of the systems as well as the required continuous resupply mass is calculated based on the selected life support system. The next step is the selection of a suitable orbit, which is performed by using the System Tool Kit to develop an optimization tool for the overall delta-v demand of the mission. The ptimization considers the calculated mass and volume requirements from the initial analysis as transportation requirements for the Earth - Gateway orbit. In addition, different further mission to the lunar surface and/or Mars can be defined to identify trade of points between different orbits that might be preferable for different combinations of Earth - Gateway, Gateway - Moon and Gateway - Mars flights. For the further analysis a suitable orbit which minimizes the overall delta-v demand of the architecture is selected. Based on the calculated required delta-v and transport requirements possible launch vehicles and their suitability to the mission are discussed. In addition, a concept of operations is presented. The concept is based on an interface minimization approach which considers the number and complexity of interfaces and minimizes the overall complexity of interfaces between different international ground control centers and the individual console positions of the ground control centers. The developed architecture is then compared to the currently proposed architecture of Gateway where possible and applicable

Gravity wave characteristics derived from radiosonde observations at Lauder (45 S 169 E) during DEEPWAVE-NZ

The field phase of DEEPWAVE-NZ (DEEP propagating gravity WAVE experiment over New Zealand) took place in June and July 2014 on the southern island of New Zealand. One goal of DEEPWAVE-NZ was to explore the propagation of gravity waves into the middle atmosphere which were excited in the troposphere by the flow across the southern island. Airborne measurements with the NSF/NCAR GV and the DLR Falcon research aircraft were complemented with ground-based measurements at various stations on the southern island. At Lauder (45 S 169 E), long-lasting upper stratospheric and mesospheric observations were taken by the DLR Rayleigh lidar and the University of Utah Advanced Mesospheric Temperature Mapper and Airglow Imager. To provide data in the lower atmosphere up to 30 km altitude, radiosonde measurements were conducted in periods of mountain wave activity. On ICAM we present wave properties and propagation characteristics determined from 98 soundings reaching a mean height of 31.3 km. Therefore, different analysis methods such as rotary spectra and wavelet analysis are used. For selected cases those findings are combined with results from other instruments (e.g. ground-based lidar) and are related to the prevailing meteorological situation based on high-resolution ECMWF analyses

Depolarization ratio profiling at several wavelengths in pure Saharan dust during SAMUM 2006

Published under the terms of the Creative Commons Attribution-Noncommercial 3.0 Unported LicenseVertical profiles of the linear particle depolarization ratio of pure dust clouds were measured during the Saharan Mineral Dust Experiment (SAMUM) at Ouarzazate, Morocco (30.9 degrees N, -6.9 degrees E), close to source regions in May-June 2006, with four lidar systems at four wavelengths (355, 532, 710 and 1064 nm). The intercomparison of the lidar systems is accompanied by a discussion of the different calibration methods, including a new, advanced method, and a detailed error analysis. Over the whole SAMUM periode pure dust layers show a mean linear particle depolarization ratio at 532 nm of 0.31, in the range between 0.27 and 0.35, with a mean angstrom ngstrom exponent (AE, 440-870 nm) of 0.18 (range 0.04-0.34) and still high mean linear particle depolarization ratio between 0.21 and 0.25 during periods with aerosol optical thickness less than 0.1, with a mean AE of 0.76 (range 0.65-1.00), which represents a negative correlation of the linear particle depolarization ratio with the AE. A slight decrease of the linear particle depolarization ratio with wavelength was found between 532 and 1064 nm from 0.31 +/- 0.03 to 0.27 +/- 0.04.Peer reviewe

Unusual appearance of mother‐of‐pearl clouds above El Calafate, Argentina (50°21′S, 72°16′W)

Visual observations from the ground and from a glider soaring in the lowermost stratosphere revealed the existence of stratospheric mother‐of‐pearl clouds above El Calafate in the lee of the Andes on 11 September 2019. The appearance of these clouds is rather unusual considering the time – end of the austral winter – and the location at about 50°S, being far away from Antarctica. This paper presents the available observations and describes the overall meteorological situation that was related to the earliest sudden stratospheric warming recorded so far in the Southern Hemisphere. By using high‐resolution numerical simulations, we show evidence of mountain waves propagating up to the stratosphere that are responsible for generating the localised cold stratospheric temperature anomalies required for ice cloud formation. Snapshots of a mother‐of‐pearl cloud from the camera installed at the PERLAN 2 aircraft's tail wing. imageDeutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/50110000165

Depolarization ratio profiling at several wavelengths in pure Saharan dust during SAMUM 2006

Vertical profiles of the linear particle depolarization ratio of pure dust clouds were measured during the Saharan Mineral Dust Experiment (SAMUM) at Ouarzazate, Morocco (30.9◦N, –6.9◦E), close to source regions in May–June 2006, with four lidar systems at four wavelengths (355, 532, 710 and 1064 nm). The intercomparison of the lidar systems is accompanied by a discussion of the different calibration methods, including a new, advanced method, and a detailed error analysis. Over the whole SAMUM periode pure dust layers show a mean linear particle depolarization ratio at 532 nm of 0.31, in the range between 0.27 and 0.35, with a mean Ångström exponent (AE, 440–870 nm) of 0.18 (range 0.04–0.34) and still high mean linear particle depolarization ratio between 0.21 and 0.25 during periods with aerosol optical thickness less than 0.1, with a mean AE of 0.76 (range 0.65–1.00), which represents a negative correlation of the linear particle depolarization ratio with the AE. A slight decrease of the linear particle depolarization ratio with wavelength was found between 532 and 1064 nm from 0.31 ± 0.03 to 0.27 ± 0.04