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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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All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Deformable Mirror Technology Roadmap: Architecting A Path to TRL5 for Future Exoplanet Direct Imaging Space Missions

The Deformable Mirror Technology Roadmap (DMTR) is a working group tasked by NASA’s Exoplanet Program Office to study the path to bring deformable mirror (DM) systems to a Technology Readiness Level 5. DMs, and their drive electronics and harnessing, are the critical component of any exoplanet direct imaging coronagraph, and there is no device that exists today which can meet the ambitious performance goals expected for NASA’s Habitable Worlds Observatory (HWO). Here we present progress on surveying the field of DM technologies, defining a first cut set of device requirements, and recommending a development and verification maturation program.

Tyler D. Groff↗
NASA NTRSDate not supplied

Impact of Near-Angle Scatter on Exo-Earth Coronagraphy

Near-Angle Scatter ( of the host star’s light may limit the ability of a potential Habitable Worlds Observatory (HWO) to detect and characterize an Earth-like planet around a Sun-like star via coronagraphy NAS from each optical surface produces an E-field across the dark hole that is coherent. These E-fields sum and could be as large or larger than the coronagraph mask leakage E-field. NAS E-fields contribute to the dark hole noise floor via both shot noise and heterodyne amplification of the wavefront instability. The amount of NAS is determined entirely by the statistical properties of the optical surface microroughness and the operating wavelength. Surface properties include not only the rms roughness, but also correlation length and the functional form of the distribution itself. We derive an expression that specifies the surface statistics required to achieve a given coronagraph error budget NAS throughput allocation.

H Philip Stahl↗
NASA NTRSDate not supplied

Impact of Near-Angle Scatter on Exo-Earth Coronagraphy

Near-Angle Scatter (NAS) of the host star’s light may limit the ability of a potential Habitable Worlds Observatory (HWO) to detect and characterize an Earth-like planet around a Sun-like star via coronagraphy. NAS from each optical surface produces an E-field across the dark hole that is coherent. These E-fields sum and could be as large or larger than the coronagraph mask leakage E-field. NAS E-fields contribute to the dark hole noise floor via both shot noise and heterodyne amplification of the wavefront instability. The amount of NAS is determined entirely by the statistical properties of the optical surface microroughness and the operating wavelength. Surface properties include not only the rms roughness, but also correlation length and the functional form of the distribution itself. This paper derives an expression that specifies the surface statistics required to achieve a given coronagraph error budget NAS throughput allocation. Analysis does not include scatter from coating columnar structure, edges, contamination, micrometeoroid impacts, or polarization.

H Philip Stahl↗
NASA NTRSDate not supplied

Experimental Verification of the Parabolic Deformable Mirror for the ExoSpec Project

For the Habitable Worlds Observatory (HWO), it is essential to broaden the controllable wavelength bandwidth for high-contrast imaging and spectroscopy to increase the exoEarth yield and characterization. The Parabolic Deformable Mirrors (PDM) subpackage, under the NASA Headquarters-directed Exoplanet Spectroscopy (ExoSpec) Work Package, is specifically tailored to do so. We have successfully procured a first-generation (Gen 1) PDM device and completed in-depth characterization of the device. This robust evaluation has become instrumental in informing subsequent stages of development, particularly in shaping the design and specifying requirements for the next generation, Gen 2, PDM device. We have built a testbed in an environmentally controlled cleanroom to experimentally demonstrate the use of a PDM in a coronagraph instrument with an integral field spectrograph (IFS). This versatile testbed is designed to test different DM architectures, low-order wavefront sensing schemes, and a lenslet-based IFS. This provides us with a basis for comparison with different DM configurations: 1) flat DM, 2) PDMs, and 3) a flat DM and PDMs. In this communication, we will discuss the testbed design and updates, PDM characterization, and Gen 2 requirement definitions.

Hari B. Subedi↗
NASA NTRSDate not supplied

Mirror Surface Contamination Specification Derived from Coronagraphy Scatter Error Budget Allocation

Near-Angle Scatter (NAS) of the host star’s light may limit the ability of a potential Habitable Worlds Observatory (HWO) to detect and characterize an Earth-like planet around a Sun-like star via coronagraphy. NAS from each optical surface before the coronagraph’s focal plane mask produces an E-field across the dark hole that is coherent. These E-fields sum and could be as large or larger than the coronagraph mask leakage E-field. This paper assumes an error budget allocation for scatter of 20 ppt. NAS E-fields contribute to the dark hole noise floor via both shot noise and heterodyne amplification of the wavefront instability. While previous papers have developed specifications for scatter from surface scatter, this paper develops specifications for scatter from surface contamination and micrometeoroid impacts. The development process utilizes an expression that predicts scatter throughput into the dark hole based on surface BRDF. Analysis does not include scatter from coating columnar structure, edges, contamination, micrometeoroid impacts, or polarization.

near angle scatter↗
NASA NTRSDate not supplied

Mission Design Strategies for Rendezvous and Servicing of Sun-Earth Libration Point Missions

With the launch of the James Webb Space Telescope (JWST) and future launches of the Roman Space Telescope (RST) and larger telescopes such as the proposed Habitable Worlds Observatory (HWO), the questions of where and how to rendezvous to enable servicing of these telescope missions arise. To aid in determining the allowable locations to rendezvous for servicing from a trajectory design approach, our previous research and analysis has shown feasible transfer trajectories between the Sun-Earth Libration L2 region (Quasi-Halo orbit) and the Earth Moon vicinity (Distant Retrograde Orbit (DRO), Quasi-Halo Orbit, Halo Orbit, and Near Rectilinear Halo Orbit (NRHO)), along with the related transfer constraints and the corresponding total fuel mass costs. We now focus on operational-like optimal scenarios for these transfers to complete a rendezvous to permit servicing at various Libration orbit locations. In this paper, we address how operational navigation and maneuver execution uncertainties impact the rendezvous timing and fuel mass (via ΔV). While optimization techniques are applied to ensure minimal ΔVs, we also analyze various transfer trajectory durations and rendezvous arrival geometries. The analysis presented includes dynamical system approaches and applies optimization through several tools including the Adaptive Trajectory Design (ATD) module as an initial guess, numerical computation using the General Mission Analysis Tool (GMAT) and Systems Tool Kit (STK) with higher fidelity perturbation modeling, and recently developed optimization tools that incorporate dynamical systems directly into the optimization process. Transfer trajectory options examined include a direct transfer from Earth versus departures from the previously examined Earth-Moon regime orbits, e.g. NRHOs and DROs. A return from Sun-Earth to lunar vicinity for a complete servicing after a rendezvous in Sun-Earth orbit is also considered. The resultant ΔV’s for each scenario is provided with discussions on various transfer trades, rendezvous considerations, and orbital limitations from the dynamical systems. A Poincare-like mapping of trajectory and rendezvous conditions categorize feasible and optimum transfer approaches, dependent on Sun-Earth orbit mission parameters. The focus of this research addresses questions for upcoming trades regarding servicing options for current and future Sun-Earth L1 and L2 missions. By doing a comprehensive analysis approach (dynamical systems + high fidelity optimization with true operational constraints), this paper will serve as a guide for mission architecture and operational trade considerations.

Maneuver Design↗
NASA NTRSDate not supplied

Digital Engineering for HabWorlds

New role within HWOTM: Digital Architect, meant to help the program set up and execute digital engineering ONLY as appropriate for mission success. Reports directly to the Systems Engineering team. First principles look at engineering, collaboration, & communication requirements. Analysis of alternatives presented to the MSE and project team for decisions.

Jama↗
NASA NTRSDate not supplied

Servicing the Habitable Worlds Observatory

The Habitable Worlds Observatory is a large ultraviolet/optical/infrared space telescope being planned for launch in the 2040s. The project was recommended in the National Academies Decadal Survey for Astronomy and Astrophysics Pathways to Discovery in Astronomy and Astrophysics for the 2020s. The Habitable Worlds Observatory will be the first space telescope designed specifically to search for signs of life on planets orbiting other stars. This "super-Hubble" will provide powerful capabilities for transformational astrophysics, from our cosmic backyard of the solar system, to the distant universe, and everything in between. The project will leverage past NASA flagship investments from the Hubble Space Telescope, the James Webb Space Telescope, and the Roman Space Telescope. Critical to the success of the project is to draw on decades of lessons from the development of these previous telescopes and other NASA missions to streamline the development of the Habitable Worlds Observatory in order to decrease budget and schedule risks.

HWO↗