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a b s t r a c tThis paper presents the conceptual design and analysis of a system intended to increase the range, scientific capability, and safety of manned lunar surface exploration, requiring only a modest increase in capability over the Apollo mission designs. The system is intended to enable two astronauts, exploring with an unpressurized rover, to remove their space suits for an 8-h rest away from the lunar base and then conduct a second day of surface exploration before returning to base. This system is composed of an Environmental Control and Life Support System on the rover, an inflatable habitat, a solar shield and a solar power array. The proposed system doubles the distance reachable from the lunar base, thus increasing the area available for science and exploration by a factor of four. In addition to increasing mission capability, the proposed system also increases fault tolerance with an emergency inflatable structure and additional consumables to mitigate a wide range of suit or rover failures. The mass, volume, and power analyses of each subsystem are integrated to generate a total system mass of 124 kg and a volume of 594 L, both of which can be accommodated on the Apollo Lunar Roving Vehicle with minor improvements. & 2015 IAA. Published by Elsevier Ltd. on behalf of IAA. This is an open access article under the CC BY-NC-SA license (http://creativecommons.org/licenses/by-nc-sa/4.0/).

This paper describes the investigation and implementation of a combined synthetic aperture (SA) and compounded plane wave (CPW) ultrasound imaging technique. Individually, these methods offer unique benefits over the conventional transmit beamforming used in ultrasonography (higher resolution and increased signal-to-noise ratio, respectively), and both have the potential for a higher physical frame rate limit. The technique described combines the individual benefits while maintaining a higher frame rate, by adaptively compounding the resulting images from SA and CPW sequences at half the standard number of transmits. Tests on a phantom with both point scatterers and occlusions showed overall improvements of 14.5% in lateral resolution and 7.5% in axial resolution over CPW, and a 14.5 dB improvement in signal-to-noise ratio (SNR) for occlusions over SA. Both resolution and SNR were an improvement over that for conventional transmit beamforming with two focus depths, and offer double the physical frame rate limit.

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