The Goddard Space Flight Center (GSFC) is a major NASA space research laboratory located approximately 6.5 miles (10.5 km) northeast of Washington, D.C. in Greenbelt, Maryland, United States. Established on May 1, 1959 as NASA's first space flight center, GSFC employs approximately 10,000 civil servants and contractors. It is one of ten major NASA field centers, named in recognition of American rocket propulsion pioneer Robert H. Goddard. GSFC is partially within the former Goddard census-designated place; it has a Greenbelt mailing address.GSFC is the largest combined organization of scientists and engineers in the United States dedicated to increasing knowledge of the Earth, the Solar System, and the Universe via observations from space. GSFC is a major US laboratory for developing and operating unmanned scientific spacecraft. GSFC conducts scientific investigation, development, manufacturing and operation of space systems, and development of related technologies. Goddard scientists can develop and support a mission, and Goddard engineers and technicians can design and build the spacecraft for that mission. Goddard scientist John C. Mather shared the 2006 Nobel Prize in Physics for his work on COBE.GSFC also operates two spaceflight tracking and data acquisition networks (the Space Network and the Near Earth Network), develops and maintains advanced space and Earth science data information systems, and develops satellite systems for the National Oceanic and Atmospheric Administration (NOAA).GSFC manages operations for many NASA and international missions including the Hubble Space Telescope (HST), the Explorers Program, the Discovery Program, the Earth Observing System (EOS), INTEGRAL, MAVEN, OSIRIS-REx, the Solar and Heliospheric Observatory (SOHO), the Solar Dynamics Observatory (SDO), Tracking and Data Relay Satellite System (TDRS), Fermi, and Swift. Past missions managed by GSFC include the Rossi X-ray Timing Explorer (RXTE), Compton Gamma Ray Observatory, SMM, COBE, IUE, and ROSAT. Goddard.C.5 miles (10.5 km) northeast of Washington, D.C.
Planets orbiting M-dwarf stars are prime targets in the search for rocky exoplanet atmospheres. The small size of M dwarfs renders their planets exceptional targets for transmission spectroscopy, facilitating atmospheric characterization. However, it remains unknown whether their host stars' highly variable extreme-UV radiation environments allow atmospheres to persist. With JWST, we have begun to determine whether or not the most favorable rocky worlds orbiting M dwarfs have detectable atmospheres. Here, we present a 2.8-5.2 micron JWST NIRSpec/G395H transmission spectrum of the warm (700 K, 40.3x Earth's insolation) super-Earth GJ 486b (1.3 R$_{\oplus}$ and 3.0 M$_{\oplus}$). The measured spectrum from our two transits of GJ 486b deviates from a flat line at 2.2 - 3.3 $\sigma$, based on three independent reductions. Through a combination of forward and retrieval models, we determine that GJ 486b either has a water-rich atmosphere (with the most stringent constraint on the retrieved water abundance of H2O > 10% to 2$\sigma$) or the transmission spectrum is contaminated by water present in cool unocculted starspots. We also find that the measured stellar spectrum is best fit by a stellar model with cool starspots and hot faculae. While both retrieval scenarios provide equal quality fits ($\chi^2_\nu$ = 1.0) to our NIRSpec/G395H observations, shorter wavelength observations can break this degeneracy and reveal if GJ 486b sustains a water-rich atmosphere.
We evaluate the climate response of the NASA Goddard Earth Observing System (GEOS) coupled Atmosphere-Ocean General Circulation Model (AOGCM) to idealized quadrupling of CO2 concentrations. A pre-industrial simulation and an abrupt 4 & times; CO2 simulation are conducted with the GEOS AOGCM following the Coupled Model Intercomparison Project (CMIP) approach. The 4 & times; CO2 run shows expected tropospheric and stratospheric climate response features, including Arctic amplification, intensification of the hydrologic cycle, Hadley Cell expansion, a poleward shift of the Southern Hemisphere jet stream, acceleration of the Brewer-Dobson circulation, and a weaker Quasi-Biennial Oscillation. At the ocean surface, we see a complete disappearance of Arctic sea ice in July-December, and in the Southern Hemisphere, there is a poleward shift of the surface wind stress that drives the Southern Ocean meridional overturning circulation poleward. In the ocean, there is enhanced heat content but reduced heat export to the high northern latitudes coincident with a slowing of the Atlantic Meridional Overturning Circulation. The Equilibrium Climate Sensitivity (ECS) of the GEOS AOGCM is estimated to be 2.55 K, in the lowest quartile of the CMIP5 and CMIP6 ranges. The low ECS is due to a strong negative feedback and a weak effective radiative forcing.
The near-ultraviolet (NUV) wavelength range contains a valuable ozone absorption feature for characterizing the atmospheric composition of Earth-like exoplanets. Both the LUVOIR and HabEx decadal mission concept studies baseline instrumentation for obtaining photometry of directly imaged exoplanets down to wavelengths of 200 nm. Both of their proposed implementations present challenges: in the case of the HabEx starshade occulter, a separate spacecraft is required; in the case of a NUV channel within the main coronagraph instrument, non-UV-optimized optics limit the performance. However, the science requirements allow the relaxation of some of the trades of a dedicated near-UV coronagraph. For instance, given that the inner working angle (IWA) of the coronagraph is a function of the wavelength, and one would only consider the characterization of planets detected in the visible, the IWA of the NUV coronagraph can be relaxed to meet the IWA of the visible coronagraph. In addition, given that a NUV coronagraph would be used for a follow-up observation after a visible detection, it could be designed to produce a half dark zone, allowing the simplification of the optical design. Here, we present the case for a standalone NUV coronagraph instrument for the Habitable Worlds Observatory based on the science requirements, developed as part of the Coronagraph Technology Roadmap study commissioned by NASA's Exoplanet Exploration Office. We describe the trades and rationale behind the recommendation of having a separate NUV coronagraph instrument and show the evaluation of several coronagraph designs in the NUV. We assess the effect of polarization aberrations, discuss relevant technologies, and describe potential NUV detectors and wavefront sensing and control strategies.
Stratospheric temperature, ozone, and constituent observations show significant perturbations in the 1-2 years following the January 2022 Hunga volcanic eruption. This study uses GSFC2D model simulations forced with satellite-based Hunga aerosol and water vapor anomalies to investigate the resulting impacts in the Southern Hemisphere stratosphere (tropics to midlatitudes) during the 2 & frac14; years following the eruption. The relative impacts of the volcanic forcings are quantified and compared with dynamical changes caused by the quasi-biennial oscillation (QBO), which exerts a substantial influence. Largest volcanic-driven chemical and radiative changes occur during 2022 and gradually diminish thereafter. Significant model enhancements in HNO3 and ClO, and corresponding reductions in NO2 and HCl, are driven by the Hunga aerosol via heterogeneous reactions, and the Hunga water vapor perturbation via gas-phase reactions. However, for model ozone, the net volcanic chemical impacts are small. For total column ozone, the aerosol-induced effects are mostly negative with maximum changes of -3 DU, while the water vapor-induced impacts are mostly positive with maximum changes of similar to+1 DU. Simulated total ozone anomalies driven by transport are significantly larger (+/- 5-12 DU), consistent with previous studies. Model temperature anomalies are driven mainly by a combination of the QBO (+/- 1-2 K) and radiative cooling of the Hunga H2O plume (-2-3 K). The Hunga aerosol had a minor impact on stratospheric temperature, causing a net warming of at most +0.5 K.
We describe the software package ESpRESSO - [E]xtragalactic [Sp]ectroscopic [R]oman [E]mulator and [S]imulator of [S]ynthetic [O]bjects, created to emulate the slitless spectroscopic observing modes of the Nancy Grace Roman Space Telescope (Roman) Wide Field Instrument (WFI). We combine archival Hubble Space Telescope (HST) imaging data of comparable spatial resolution with model spectral energy distributions to create a data-cube of flux density as a function of position and wavelength. ESpRESSO is designed to generate grism simulations for any Roman WFI SCA using detector-specific optical solutions; in this paper, the simulations are limited by the sky area of the deepest available input imaging and therefore focus primarily on SCA5, with a foreground scene spanning approximately two SCAs. We also demonstrate the ability to inject custom sources using the described tools and pipelines. In addition, we show that spectral features such as emission line pairs are unlikely to be mistaken as off order contaminating features and vice versa. These simulated scenes can be used in developing future spectral data analysis tools.
