Scattering properties of dust in Orion and Epsilon Eridani exoplanetary system

Dust grain properties were investigated in two very different Galactic environments: the interstellar medium and an exoplanetary system. Two sounding rocket missions were developed to study these regions. Wide-field observations of the Orion OB stellar association were performed in the far-ultraviolet using the Spectrograph for Photometric Imaging with Numeric Reconstruction (SPINR) sounding rocket. These observations reveal the diffuse signature of starlight scattering off interstellar dust grains. The spectral-imaging data were used along with a three-dimensional radiative transfer model to measure the dust scattering parameters: the grain albedo (a) and the scattering asymmetry (g). The measured parameters are consistent with previous measurements made toward Orion. A sharp increase in albedo was measured at 〜1330 A. This feature is not explained by current grain models. The constructed three-dimensional model of Orion includes a two-component dust distribution. The foreground distribution is responsible for the small amount of visible reddening measured toward the bright stars in the Orion constellation.The background distribution represents the Orion Molecular Cloud, which dominates observations of dust emission in the infrared. This model was used to show that backscattered light from the molecular cloud alone cannot produce the observed scattered light distribution. The foreground dust, though optically thin in the visible, significantly contributes to the scattered light in the far-ultraviolet. This suggests that observations of Orion in the infrared and far-ultraviolet may probe entirely different dust populations. The Planetary Imaging Concept Testbed Using a Rocket Experiment (PICTURE) sounding rocket was developed to characterize dust grains in the nearby Epsilon Eridani exoplanetary system. This is a young, dusty system with a Jupiter-massed planet orbiting at 〜3.4 AU (astronomical units). PICTURE sought to capture a direct, visible-light image of dust-scattered starlight in this system with the aid of a high-contrast nulling coronagraph. The design and laboratory testing of the PICTURE science payload is presented. Although the mission returned no science data, several important technological advances were made to enable future direct imaging missions. Most notably, PICTURE demonstrated 5.1 milliarcsecond pointing stability using a fast optical tracking system

The low-order wavefront sensor for the PICTURE-C mission

The PICTURE-C mission will fly a 60 cm off-axis unobscured telescope and two high-contrast coronagraphs in successive high-altitude balloon flights with the goal of directly imaging and spectrally characterizing visible scattered light from exozodiacal dust in the interior 1-10 AU of nearby exoplanetary systems. The first flight in 2017 will use a 10[superscript -4] visible nulling coronagraph (previously flown on the PICTURE sounding rocket) and the second flight in 2019 will use a 10[superscript -7] vector vortex coronagraph. A low-order wavefront corrector (LOWC) will be used in both flights to remove time-varying aberrations from the coronagraph wavefront. The LOWC actuator is a 76-channel high-stroke deformable mirror packaged on top of a tip-tilt stage. This paper will detail the selection of a complementary high-speed, low-order wavefront sensor (LOWFS) for the mission. The relative performance and feasibility of several LOWFS designs will be compared including the Shack-Hartmann, Lyot LOWFS, and the curvature sensor. To test the different sensors, a model of the time-varying wavefront is constructed using measured pointing data and inertial dynamics models to simulate optical alignment perturbations and surface deformation in the balloon environment.United States. National Aeronautics and Space Administration (Grant NNX15AG23G S01

The low-order wavefront sensor for the PICTURE-C mission

The PICTURE-C mission will fly a 60 cm off-axis unobscured telescope and two high-contrast coronagraphs in successive high-altitude balloon flights with the goal of directly imaging and spectrally characterizing visible scattered light from exozodiacal dust in the interior 1-10 AU of nearby exoplanetary systems. The first flight in 2017 will use a 10^(-4) visible nulling coronagraph (previously flown on the PICTURE sounding rocket) and the second flight in 2019 will use a 10^(-7) vector vortex coronagraph. A low-order wavefront corrector (LOWC) will be used in both flights to remove time-varying aberrations from the coronagraph wavefront. The LOWC actuator is a 76-channel high-stroke deformable mirror packaged on top of a tip-tilt stage. This paper will detail the selection of a complementary high-speed, low-order wavefront sensor (LOWFS) for the mission. The relative performance and feasibility of several LOWFS designs will be compared including the Shack-Hartmann, Lyot LOWFS, and the curvature sensor. To test the different sensors, a model of the time-varying wavefront is constructed using measured pointing data and inertial dynamics models to simulate optical alignment perturbations and surface deformation in the balloon environment

MEMS Deformable Mirrors for Space-Based High-Contrast Imaging

Micro-Electro-Mechanical Systems (MEMS) Deformable Mirrors (DMs) enable precise wavefront control for optical systems. This technology can be used to meet the extreme wavefront control requirements for high contrast imaging of exoplanets with coronagraph instruments. MEMS DM technology is being demonstrated and developed in preparation for future exoplanet high contrast imaging space telescopes, including the Wide Field Infrared Survey Telescope (WFIRST) mission which supported the development of a 2040 actuator MEMS DM. In this paper, we discuss ground testing results and several projects which demonstrate the operation of MEMS DMs in the space environment. The missions include the Planet Imaging Concept Testbed Using a Recoverable Experiment (PICTURE) sounding rocket (launched 2011), the Planet Imaging Coronagraphic Technology Using a Reconfigurable Experimental Base (PICTURE-B) sounding rocket (launched 2015), the Planetary Imaging Concept Testbed Using a Recoverable Experiment - Coronagraph (PICTURE-C) high altitude balloon (expected launch 2019), the High Contrast Imaging Balloon System (HiCIBaS) high altitude balloon (launched 2018), and the Deformable Mirror Demonstration Mission (DeMi) CubeSat mission (expected launch late 2019). We summarize results from the previously flown missions and objectives for the missions that are next on the pad. PICTURE had technical difficulties with the sounding rocket telemetry system. PICTURE-B demonstrated functionality at >100 km altitude after the payload experienced 12-g RMS (Vehicle Level 2) test and sounding rocket launch loads. The PICTURE-C balloon aims to demonstrate 10(-7) contrast using a vector vortex coronagraph, image plane wavefront sensor, and a 952 actuator MEMS DM. The HiClBaS flight experienced a DM cabling issue, but the 37-segment hexagonal piston-tip-tilt DM is operational post-flight. The DeMi mission aims to demonstrate wavefront control to a precision of less than 100 nm RMS in space with a 140 actuator MEMS DM.DARPA; NASA Space Technology Research FellowshipOpen Access JournalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Wavefront sensing in space: flight demonstration II of the PICTURE sounding rocket payload

© 2018 Society of Photo-Optical Instrumentation Engineers (SPIE). A NASA sounding rocket for high-contrast imaging with a visible nulling coronagraph, the Planet Imaging Concept Testbed Using a Rocket Experiment (PICTURE) payload, has made two suborbital attempts to observe the warm dust disk inferred around Epsilon Eridani. The first flight in 2011 demonstrated a 5 mas fine pointing system in space. The reduced flight data from the second launch, on November 25, 2015, presented herein, demonstrate active sensing of wavefront phase in space. Despite several anomalies in flight, postfacto reduction phase stepping interferometer data provide insight into the wavefront sensing precision and the system stability for a portion of the pupil. These measurements show the actuation of a 32 × 32-actuator microelectromechanical system deformable mirror. The wavefront sensor reached a median precision of 1.4 nm per pixel, with 95% of samples between 0.8 and 12.0 nm per pixel. The median system stability, including telescope and coronagraph wavefront errors other than tip, tilt, and piston, was 3.6 nm per pixel, with 95% of samples between 1.2 and 23.7 nm per pixel

End-to-end simulation of high-contrast imaging systems: methods and results for the PICTURE mission family

We describe a set of numerical approaches to modeling the performance of space flight high-contrast imaging payloads. Mission design for high-contrast imaging requires numerical wavefront error propagation to ensure accurate component specifications. For constructed instruments, wavelength and angle-dependent throughput and contrast models allow detailed simulations of science observations, allowing mission planners to select the most productive science targets. The PICTURE family of missions seek to quantify the optical brightness of scattered light from extrasolar debris disks via several high-contrast imaging techniques: sounding rocket (the Planet Imaging Concept Testbed Using a Rocket Experiment) and balloon flights of a visible nulling coronagraph, as well as a balloon flight of a vector vortex coronagraph (the Planetary Imaging Concept Testbed Using a Recoverable Experiment-Coronagraph, PICTURE-C). The rocket mission employs an on-axis 0.5m Gregorian telescope, while the balloon flights will share an unobstructed off-axis 0.6m Gregorian. This work details the flexible approach to polychromatic, end-to-end physical optics simulations used for both the balloon vector vortex coronagraph and rocket visible nulling coronagraph missions. We show the preliminary PICTURE-C telescope and vector vortex coronagraph design will achieve 10 -8 contrast without post-processing as limited by realistic optics, but not considering polarization or low-order errors. Simulated science observations of the predicted warm ring around Epsilon Eridani illustrate the performance of both missions

MEMS Deformable Mirrors for Space-Based High-Contrast Imaging

Micro-Electro-Mechanical Systems (MEMS) Deformable Mirrors (DMs) enable precise wavefront control for optical systems. This technology can be used to meet the extreme wavefront control requirements for high contrast imaging of exoplanets with coronagraph instruments. MEMS DM technology is being demonstrated and developed in preparation for future exoplanet high contrast imaging space telescopes, including theWide Field Infrared Survey Telescope (WFIRST) mission which supported the development of a 2040 actuator MEMS DM. In this paper, we discuss ground testing results and several projects which demonstrate the operation of MEMS DMs in the space environment. The missions include the Planet Imaging Concept Testbed Using a Recoverable Experiment (PICTURE) sounding rocket (launched 2011), the Planet Imaging Coronagraphic Technology Using a Reconfigurable Experimental Base (PICTURE-B) sounding rocket (launched 2015), the Planetary Imaging Concept Testbed Using a Recoverable Experiment - Coronagraph (PICTURE-C) high altitude balloon (expected launch 2019), the High Contrast Imaging Balloon System (HiCIBaS) high altitude balloon (launched 2018), and the Deformable Mirror Demonstration Mission (DeMi) CubeSat mission (expected launch late 2019). We summarize results from the previously flown missions and objectives for the missions that are next on the pad. PICTURE had technical difficulties with the sounding rocket telemetry system. PICTURE-B demonstrated functionality at > 100 km altitude after the payload experienced 12-g RMS (Vehicle Level 2) test and sounding rocket launch loads. The PICTURE-C balloon aims to demonstrate 10-7 contrast using a vector vortex coronagraph, image plane wavefront sensor, and a 952 actuator MEMS DM. The HiClBaS flight experienced a DM cabling issue, but the 37-segment hexagonal piston-tip-tilt DM is operational post-flight. The DeMi mission aims to demonstrate wavefront control to a precision of less than 100 nm RMS in space with a 140 actuator MEMS DM