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As the frequency of rocket launches increases, accurately predicting their noise is necessary to assess structural, environmental, and societal impacts. NASA’s Space Launch System (SLS) is a challenging vehicle to model because it has both solid-fuel rocket boosters and liquid-fueled engines that contribute to its thrust at launch. This paper discusses measured aeroacoustic properties of this super heavy-lift rocket in the context of supersonic jet theory and measurements of other rockets. Using four measured aeroacoustic properties: directivity, spectral peak frequency, maximum overall sound pressure level, and overall sound power level, an equivalent rocket based on merged plumes is created for SLS. With the constraint that the effective thrust and mass flow rates should match those of the actual vehicle, a method using weighted averages of the disparate plume parameters successfully reproduces SLS’s desired aeroacoustic properties, yielding a relatively simple model for the complex vehicle. 

The extremely large slip that occurred on the shallow portion of the Japan Trench subduction zone during the 2011 Mw 9.1 Tohoku-oki earthquake directly contributed to the devastating tsunami that inundated the Pacific coast of Japan. International Ocean Discovery Program (IODP) Expedition 405 (Tracking Tsunamigenic Slip Across the Japan Trench) aimed to investigate the conditions and processes that facilitated the extremely shallow slip on the subduction interface during the 2011 Tohoku-oki earthquake to improve understanding of the factors that allow slip to the trench on subduction zones. Expedition 405 implemented a combined logging, coring, and observatory operational plan at two sites: Site C0026, ~8 km seaward of the Japan Trench, to characterize the input sediments to the subduction zone and Site C0019, ~6 km landward of the trench, where the plate boundary fault zone is present at ~825 meters below seafloor (mbsf). At Site C0026, the input section was logged to ~430 mbsf with a logging-while-drilling (LWD) assembly that characterized the succession of sediments and rocks from the seafloor to the basaltic rocks of the oceanic crust. Cores recovered from four holes as deep as 290 mbsf contain a sequence of hemipelagic and pelagic sediments that will be input into the shallow subduction system and therefore control both the localization of the plate boundary fault zone and the slip behavior of the plate boundary. Site C0019 was previously drilled in 2012 during Integrated Ocean Drilling Program Expedition 343 (Japan Trench Fast Drilling Project [JFAST]), and revisiting this site allowed temporal variations in the frontal prism and plate boundary fault zone to be evaluated. The LWD data to ~980 mbsf characterized the frontal prism, plate boundary fault zone, and lower plate to the basaltic volcanic rocks. Cores were recovered from multiple holes that contain a variety of muds from the frontal prism and the plate boundary fault zone, as well as lower plate materials. Comparison with the sediments from Site C0026 provides a basis to interpret the tectonic and sedimentological processes operating in the dynamic environment of the frontal prism. Cores from the plate boundary fault zone provide a unique window into the structural complexity of an active plate boundary fault that is known to host large seismic slip. Two borehole observatories were installed at Site C0019 that contain temperature sensors deployed to take measurements over a period of years and reveal the hydrogeologic structure of the shallow subduction system. These hugely successful drilling operations, combined with postexpedition work to measure the mechanical, frictional, paleomagnetic, and hydrogeologic properties of the core samples and to constrain the history of past seismic slip at Site C0019, will provide an unprecedented opportunity to advance our understanding of shallow subduction systems. Outreach during the expedition leveraged and elevated the success of the operations by sharing the outcomes with a variety of domestic and international audiences, including scientists, students, educators, stakeholders, and the general public. Thanks to the efforts of a large group of onboard outreach officers and their onshore support, activities included ship-to-shore broadcast events; interviews with science party members and crew; the publication of videos, blogs, magazine articles, and social media posts; and development of formalized classroom lesson plans and materials. 

Not AvailableThis paper investigates the measured far-field noise from the Space Launch System’s Artemis-I mission liftoff. Pressure waveform data were collected at seven locations 12 to 50 kilometers from Kennedy Space Center’s (KSC) Launch Complex 39B in Cape Canaveral, Florida. Reported are initial analyses of these measurements outside the perimeter of KSC, including waveform characteristics, overall sound pressure levels, and frequency spectra. Analyses build upon an initial publication [K. L. Gee et al., JASA Exp. Lett. 3, 023601 (2023)] that documented acoustical phenomena at stations 1.5 to 5.2 km from the pad and contributed to a more complete understanding of the noise produced by super heavy-lift launch vehicles. At the stations discussed in this paper, maximum overall sound pressure levels ranged from less than 65 dB to 116 dB with significant variations seen at equidistant locations. As distance increases, one-third-octave band spectra show a significant decrease in peak frequency from 18 Hz down to 3 Hz and a reduction in relative high-frequency content. 

Abstract. Ozone is a pollutant formed in the atmosphere by photochemical processes involving nitrogen oxides (NOx) and volatile organic compounds (VOCs) when exposed to sunlight. Tropospheric boundary layer ozone is regularly measured at ground stations and sampled infrequently through balloon, lidar, and crewed aircraft platforms, which have demonstrated characteristic patterns with altitude. Here, to better resolve vertical profiles of ozone within the atmospheric boundary layer, we developed and evaluated an uncrewed aircraft system (UAS) platform for measuring ozone and meteorological parameters of temperature, pressure, and humidity. To evaluate this approach, a UAS was flown with a portable ozone monitor and a meteorological temperature and humidity sensor to compare to tall tower measurements in northern Wisconsin. In June 2020, as a part of the WiscoDISCO20 campaign, a DJI M600 hexacopter UAS was flown with the same sensors to measure Lake Michigan shoreline ozone concentrations. This latter UAS experiment revealed a low-altitude structure in ozone concentrations in a shoreline environment showing the highest ozone at altitudes from 20–100 m a.g.l. These first such measurements of low-altitude ozone via a UAS in the Great Lakes region revealed a very shallow layer of ozone-rich air lying above the surface.