September 5, 2017 11am Pacific Time
Speaker: Eduardo Bendek (NASA/Ames)
Measuring masses of long-period planets around F, G, K or brighter stars is necessary to characterize exoplanets and assess their habitability. Imaging stellar astrometry offers a unique opportunity to measure exoplanet masses. However, its accuracy is limited by the non-systematic dynamic distortions that arise from perturbations in the optical train. We have tested a novel approach to measure and calibrate field distortion potentially enabling better than 1µas imaging astrometry accuracy. In this talk, we will review the architecture, milestones, and performance of the simultaneous astrometry and high-contrast imaging laboratory built at NASA Ames Research Center as part of a TDEM program. We will also discuss the impact and benefits of applying this technology to future flagship exoplanet missions, such as HABEX, STEP, and Theia.
Title: Detector Metrology for Ultra Precise Astrometry on LUVOIR
Speaker: Mike Shao (JPL)
Astrometry at the sub-micro-arcsec level can detect and Earth mass planets in the habitable zone around a large number of nearby FGK stars. Reducing and/or calibrating instrumental systematic errors is the key to achieving very high astrometric accuracy. There are two major sources of systematic error for astrometry with a large focal plane detector, one optical distortion the optics and the second is imperfections in the focal plane. This talk discusses the imperfections in the focal plane, how they can be calibrated both on the ground and in orbit. The metrology system is part of the LUVOIR high definition imager instrument concept and we'll summarize what the capabilities of such an instrument would be for exo-Earth detection.
May 11, 2017 1pm Pacific Time
Title: MEMS Deformable Mirrors for Astronomical Adaptive Optics
Speaker: Paul Bierden, Boston Micromachines Corporation
As the astronomical community continues its excitement about the progress being made toward the building of the high contrast imaging telescopes, technical development is ongoing for the components needed for these instruments. This presentation will show the progress that has been made by Boston Micromachines on the design and fabrication of micro-electromechanical (MEMS) deformable mirrors that will be needed for future scientific progress. Large actuator count, high yield, and stable deformable mirrors are being made for on-sky planet finding instruments as well as test beds where the next generation instruments are being developed. The challenges addressed in this design and fabrication and the results achieved will be presented as well as how this will translate to meet future needs. Also, presented will be the results from current instruments and test beds. Finally, future plans for mirror development will be presented.
April 11, 2017
Title: Colloidal Micro-Newton Thrusters for Precision Attitude Control
Colloid micronewton thrusters offer a precise, low-mass, low-vibration (0.1 µN thrust precision with ≤0.1 µN/rtHz thrust noise) solution for fine pointing of space observatories. These electric thrusters can meet pointing requirements of <0.1 milliarcseconds for Hubble-class telescopes, exceeding the state-of-the art for reaction wheels while using less mass and similar power levels. Vibrations induced by the thrusters have been shown to produce less than 4nm displacements for a 500 kg spacecraft. This technology has been advanced to a high level of readiness (TRL 7) through the Space Technology 7 Disturbance Reduction System (ST7-DRS) technology demonstration payload, which was part of LISA Pathfinder's test of precision, drag-free control for the future LISA gravitational wave observatory. Continuing technology development now focuses on validating thruster lifetime and improving reliability for a flagship class science mission.
Speaker: John Ziemer (JPL)
January 23, 2017
Title: Edge Sensors for Segmented Mirrors
Future astronomical telescopes in space will have architectures that must meet complex and demanding requirements in order to meet science goals. The missions now under consideration by NASA for imaging exoplanets and characterizing their atmospheres have technical challenges that are near or beyond the state of the art of telescope stability. This colloquium describes segment edge sensing and control technologies developed for ground based telescopes, and shows how they might be used to stabilize space telescopes to picometer-class wavefront errors.
November 29, 2016
Title: Segmented Coronagraph Design and Analysis (SCDA) Study
Reaching high contrast ratios at close angular proximity to a star is an extremely challenging undertaking for a coronagraph with a filled-aperture telescope and is even more challenging with segmented, partially obscured apertures proposed for a large space-borne observatory. The primary goal of the ExEP-funded SCDA study is to identify coronagraph designs that maximize exo-Earth detectability with a variety of segmented apertures including hexagonal-segment and pie-wedge segment architectures. Both on-axis and off-axis designs are considered. The SCDA study is funding the design of pupil-plane, image-plane, and hybrid coronagraph designs. In this presentation, we discuss the progress in coronagraph designs and science yield performance since the study began in January 2016
The intention of these web seminars is to provide a forum for sharing key technology advances and results that enable or enhance the direct imaging and characterization of exoplanets. Topics may include recent coronagraph and starshade demonstration results, advances in detector technology, deformable mirrors, LOWFS/C, telescope stability, polarization, RV, starshade tutorials, etc. Our target audience is the engineers and scientists working on the WFIRST project and the HabEx and LUVOIR study concepts, but all are welcome to attend.
The series will be recorded and publically archived on this page so that they can be viewed at later dates.
To subscribe to the colloquium series, receive announcements, or suggest topics for future telecons, please contact Brendan Crill, Organizer