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Register a new userMeasuring Mars Atmospheric Winds From Orbit
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Wind is the process that connects Mars climate system. Measurements of Mars atmospheric winds from orbit would dramatically advance our understanding of Mars and help prepare for human exploration of the Red Planet. Multiple instrument candidates are in development and will be ready for flight in the next decade. We urge the Decadal Survey to make these measurements a priority for 2023-2032.
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The possibility of using optical communications in free-space as an improvement of current RF communication systems was analyzed in this Project. The particular case of a link Mars-Earth was studied and a link based in the future NASAs MLCD project, which is currently being developed, was designed. For this, an orbit simulator was programmed, evaluating the transfer orbit, analyzing the losses that occur in the transmission channel, using several atmospheric models, selecting the most adequate elements for the transmitter and the receiver, calculating the Doppler effect during the mission, and performing a budget link for the different orbit positions. From these results, the maximum bitrate through the MLCD mission was evaluated for the different astronomical observatories chosen as optical ground stations.
Differential atmospheric dispersion is a wavelength-dependent effect introduced by Earths atmosphere that affects astronomical observations performed using ground-based telescopes. It is important, when observing at a zenithal angle different from zero, to use an Atmospheric Dispersion Corrector (ADC) to compensate this atmospheric dispersion. The design of an ADC is based on atmospheric models that, to the best of our knowledge, were never tested against on-sky measurements. We present an extensive models analysis in the wavelength range of 315-665 nm. The method we used was previously described in the paper I of this series. It is based on the use of cross-dispersion spectrographs to determine the position of the centroid of the spatial profile at each wavelength of each spectral order. The accuracy of the method is 18 mas. At this level, we are able to compare and characterize the different atmospheric dispersion models of interest. For better future ADC designs, we recommend to avoid the Zemax model, and in particular in the blue range of the spectra, when expecting residuals at the level of few tens of milli-arcseconds.
In order for off-Earth top surface structures built from regolith to protect astronauts from radiation, they need to be several meters thick. Technical University Delft (TUD) proposes to excavate into the ground to create subsurface habitats. By excavating not only natural protection from radiation can be achieved but also thermal insulation because the temperature is more stable underground. At the same time through excavation valuable resources can be mined for through in situ resource utilization (ISRU). The idea is that a swarm of autonomous mobile robots excavate the ground in a sloped downwards spiral movement. The excavated regolith will be mixed with cement, which can be reproduced on Mars through ISRU, in order to create concrete. The concrete is 3D printed/sprayed on the excavated tunnel to reinforce it. As soon as the tunnels are reinforced, the material in-between the tunnels can be removed in order to create a larger cavity that can be used for inhabitation. Proposed approach relies on Design-to-Robotic-Production (D2RP) technology developed at TUD1 for on-Earth applications. The rhizomatic 3D printed structure is a structurally optimized porous shell structure with increased insulation properties. In order to regulate the indoor pressurised environment an inflatable structure is placed in the 3D printed cavity. This inflatable structure is made of materials, which can also be at some point reproduced on Mars through ISRU. Depending on location the habitat and the production system are powered by a system combining solar and kite power. The ultimate goal is to develop an autarkic D2RP system for building subsurface autarkic habitats on Mars from locally obtained materials.
This white paper, written in support of NASAs 2023-2032 Planetary Decadal Survey, outlines 10 major questions that focus on the origin, evolution, and current processes that shape the atmospheres of Uranus and Neptune. Prioritizing these questions over the next decade will greatly improve our understanding of this unique class of planets, which have remained largely unexplored since the Voyager flybys. Studying the atmospheres of the Ice Giants will greatly inform our understanding of the origin and evolution of the solar system as a whole, in addition to the growing number of exoplanetary systems that contain Neptune-mass planets.
The addition of an external starshade to the {it Nancy Grace Roman Space Telescope} will enable the direct imaging of Earth-radius planets orbiting at $sim$1 AU. Classification of any detected planets as Earth-like requires both spectroscopy to characterize their atmospheres and multi-epoch imaging to trace their orbits. We consider here the ability of the Starshade Rendezvous Probe to constrain the orbits of directly imaged Earth-like planets. The target list for this proposed mission consists of the 16 nearby stars best suited for direct imaging. The field of regard for a starshade mission is constrained by solar exclusion angles, resulting in four observing windows during a two-year mission. We find that for habitable-zone planetary orbits that are detected at least three times during the four viewing opportunities, their semi-major axes are measured with a median precision of 7 mas, or a median fractional precision of 3%. Habitable-zone planets can be correctly identified as such 96.7% of the time, with a false positive rate of 2.8%. If a more conservative criteria is used for habitable-zone classification (95% probability), the false positive rate drops close to zero, but with only 81% of the truly Earth-like planets correctly classified as residing in the habitable zone.
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