91 research outputs found
Micro-Pressure Sensors for Future Mars Missions
The joint research interchange effort was directed at the following principal areas: u further development of NASA-Ames' Mars Micro-meteorology mission concept as a viable NASA space mission especially with regard to the science and instrument specifications u interaction with the flight team from NASA's New Millennium 'Deep-Space 2' (DS-2) mission with regard to selection and design of micro-pressure sensors for Mars u further development of micro-pressure sensors suitable for Mars The research work undertaken in the course of the Joint Research Interchange should be placed in the context of an ongoing planetary exploration objective to characterize the climate system on Mars. In particular, a network of small probes globally-distributed on the surface of the planet has often been cited as the only way to address this particular science goal. A team from NASA Ames has proposed such a mission called the Micrometeorology mission, or 'Micro-met' for short. Surface pressure data are all that are required, in principle, to calculate the Martian atmospheric circulation, provided that simultaneous orbital measurements of the atmosphere are also obtained. Consequently, in the proposed Micro-met mission a large number of landers would measure barometric pressure at various locations around Mars, each equipped with a micro-pressure sensor. Much of the time on the JRI was therefore spent working with the engineers and scientists concerned with Micro-met to develop this particular mission concept into a more realistic proposition
Robert Burns Woodward
This poster for the Natural Sciences Poster Session at Parkland College features chemist Robert Burns Woodward (1917-1979). Woodward was awarded the Nobel Prize in Chemistry in 1965 for his work on organic synthesis. His work on total synthesis includes cholesterol, chlorophyll, colchicine, erythromycin, reserpine, and vitamin B12
Detectability of biosignatures in anoxic atmospheres with the James Webb Space Telescope: A TRAPPIST-1e case study
The James Webb Space Telescope (JWST) may be capable of finding biogenic
gases in the atmospheres of habitable exoplanets around low mass stars.
Considerable attention has been given to the detectability of biogenic oxygen,
which could be found using an ozone proxy, but ozone detection with JWST will
be extremely challenging, even for the most favorable targets. Here, we
investigate the detectability of biosignatures in anoxic atmospheres analogous
to those that likely existed on the early Earth. Arguably, such anoxic
biosignatures could be more prevalent than oxygen biosignatures if life exists
elsewhere. Specifically, we simulate JWST retrievals of TRAPPIST-1e to
determine whether the methane plus carbon dioxide disequilibrium biosignature
pair is detectable in transit transmission. We find that ~10 transits using the
Near InfraRed Spectrograph (NIRSpec) prism instrument may be sufficient to
detect carbon dioxide and constrain methane abundances sufficiently well to
rule out known, non-biological CH production scenarios to ~90%
confidence. Furthermore, it might be possible to put an upper limit on carbon
monoxide abundances that would help rule out non-biological methane-production
scenarios, assuming the surface biosphere would efficiently drawdown
atmospheric CO. Our results are relatively insensitive to high altitude clouds
and instrument noise floor assumptions, although stellar heterogeneity and
variability may present challenges.Comment: 21 pages, 7 figure
Is the Pale Blue Dot unique? Optimized photometric bands for identifying Earth-like exoplanets
The next generation of ground and space-based telescopes will image habitable
planets around nearby stars. A growing literature describes how to characterize
such planets with spectroscopy, but less consideration has been given to the
usefulness of planet colors. Here, we investigate whether potentially
Earth-like exoplanets could be identified using UV-visible-to-NIR wavelength
broadband photometry (350-1000 nm). Specifically, we calculate optimal
photometric bins for identifying an exo-Earth and distinguishing it from
uninhabitable planets including both Solar System objects and model exoplanets.
The color of some hypothetical exoplanets - particularly icy terrestrial worlds
with thick atmospheres - is similar to Earth's because of Rayleigh scattering
in the blue region of the spectrum. Nevertheless, subtle features in Earth's
reflectance spectrum appear to be unique. In particular, Earth's reflectance
spectrum has a 'U-shape' unlike all our hypothetical, uninhabitable planets.
This shape is partly biogenic because O2-rich, oxidizing air is transparent to
sunlight, allowing prominent Rayleigh scattering, while ozone absorbs visible
light, creating the bottom of the 'U'. Whether such uniqueness has practical
utility depends on observational noise. If observations are photon limited or
dominated by astrophysical sources (zodiacal light or imperfect starlight
suppression), then the use of broadband visible wavelength photometry to
identify Earth twins has little practical advantage over obtaining detailed
spectra. However, if observations are dominated by dark current then optimized
photometry could greatly assist preliminary characterization. We also calculate
the optimal photometric bins for identifying extrasolar Archean Earths, and
find that the Archean Earth is more difficult to unambiguously identify than a
modern Earth twin.Comment: 10 figures, 38 page
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