Engineering topics
Polanco, Otto
Publications and source records attributed to Polanco, Otto.
Habitable Exoplanet Observatory (HabEx) starshade-only architectures
The HabEx mission concept is intended to directly image planetary systems around nearby stars, and to perform a wide range of general astrophysics and solar system observations. The baseline HabEx design would use both a coronagraph and a starshade for exoplanet discovery and characterization. We describe a lower-cost alternative HabEx mission design, which would only use a starshade for exoplanet science. The starshade would provide excellent exoplanet science performance, but for a smaller number of detected exoplanets of all types, including exoEarth candidates, and a smaller fraction of exoplanets with measured orbits. The full suite of HabEx general astrophysics and solar-system science would be supported.
HabEx Lite: a Starshade-only Habitable Exoplanet Imager Alternative
The HabEx mission concept is intended to directly image planetary systems around nearby stars, and to perform a wide range of general astrophysics and solar system observations. Its main goal is the discovery and characterization of Earthlike exoplanets through high-contrast imaging and spectroscopy. The baseline HabEx concept would use both a coronagraph and a starshade for exoplanet science. We describe an alternative, “HabEx Lite” concept, which would use a starshade (only) for exoplanet science. The benefit is lower cost: by deleting the complex coronagraph instrument; by lowering observatory mass; by relaxing tolerances and stability requirements; by permitting use of a compact on-axis telescope design; by use of a smaller launch vehicle. The scientific penalty of this lower cost option is a smaller number of detected exoplanets of all types, including exoEarth candidates, and a smaller fraction of exoplanets with measured orbits. Our approach uses a non-deployed segmented primary mirror, whose manufacture is within current capabilities.
Starshade Design for Occulter Based Exoplanet Missions
We present a lightweight starshade design that delivers the requisite profile figure accuracy with a compact stowed volume that permits launching both the occulter system (starshade and spacecraft) and a 1 to 2m-class telescope system on a single existing launch vehicle. Optimal figure stability is achieved with a very stiff and mass-efficient deployable structure design that has a novel configuration. The reference design is matched to a 1.1m telescope and consists of a 15m diameter inner disc and 24 flower-like petals with 7.5m length. The total tip-to-tip diameter of 30m provides an inner working angle of 75 mas. The design is scalable to accommodate larger telescopes and several options have been assessed. A proof of concept petal is now in production at JPL for deployment demonstrations and as a testbed for developing additional elements of the design. Future plans include developing breadboard and prototype hardware of increasing fidelity for use in demonstrating critical performance capabilities such as deployed optical edge profile figure tolerances and stability thereof.
An eight-meter inflatable reflectarray antenna and its inflatable/self-rigidizable booms
This paper presents the analysis and test results related to buckling capability, modal characteristics, and thermal expansion coefficient of STR aluminum laminate inflatable/self-rigidizable booms with lengths up to 10 metes. STR booms are fundamental building blocks of space inflatable/self-rigidizable reflectarray antennas. These boom characteristics are essential for analyzing structural integrity, in orbit dynamic response, and in orbit thermal distortion of the 8-mter reflectarray antenna. Distinct advantages of the STR booms will also be identified and presented by this paper.