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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 649 records · Page 36
All sourcesNASA NTRSDOE OSTI
NASA NTRS2021

Enabling Mars Radio Occultation by Smallsats

We introduce a Mars Radio Occultation (RO) mission concept leveraging on small satellite (smallsat) technologies that will enable measurements that address both Mars science and exploration priorities. The RO technique measures the Doppler shift of radio signals of a spacecraft occulting behind a planet’s limb that contains information about the planet’s atmospheric density, temperature, and pressure. We design a smallsat constellation and simulate “crosslink” RO observations between the smallsats to determine the expected accuracy and spatiotemporal coverage of Mars RO atmospheric profiles. Such measurements are key to spacecraft Entry, Descent, and Landing (EDL) and Ascent from the Surface (AST) of Mars. Today, there are limited number of Mars atmospheric profiles with high vertical resolution, especially measurements near the surface that are difficult to obtain from satellite-based passive instruments due to atmospheric absorption. We find that crosslink ROs between a constellation of six smallsats provide global and diurnal cycle coverage with dozens of occultations per day, providing temperature information from near-surface up to ~45 km with altitude-dependent accuracy that ranges between <0.5 K at lower altitude to <5 K in the middle-to-upper atmosphere. Ionospheric ROs reveal an expected electron density of ~5 – 10% at the peak ionospheric height between 100 and 140 km. We conclude that observations obtained from a smallsat constellation can augment existing observing platforms by reducing observational gaps and yield high resolution measurements required for safe spacecraft operations during EDL and AST.

Martinez, German↗
NASA NTRS2021

Toward a Global Planetary Boundary Layer Observing System: The NASA PBL Incubation Study Team Report

A global Planetary Boundary Layer (PBL) observing system is urgently needed to address fundamental PBL science questions and societal applications related to weather, climate and air quality. This PBL observing system should optimally combine new space-based observations of the PBL thermodynamic structure with complementary surface-based and suborbital assets, while taking advantage of, and helping improve, modeling and data assimilation systems.

Planetary boundary layer↗