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NASA NTRS2001

Ultraviolet-Optical Space Astronomy Beyond HST Conference (Origins Conference and UV-Optical Working Group Support)

This grant supported three major activities, from 1997-2001. (1) Origins Conference. The funds from this grant were used, initially, to support a Conference on "Origins", held May 19-23, 1997 at Estes Park, CO and attended by a wide range of astronomers, planetary scientists, and astrobiologists. The scientific proceedings of this meeting were published in 1998 by the Astronomical Society of the Pacific: "Origins" (1998) "Proceedings of the International Origins Conference". (2) UV-Optical Space Astronomy. Conference Additional funds provided by the NASA Office of Space Science were used to support a meeting held August 5-7, 1998 at Boulder, CO and attended by ultraviolet and optical astronomers and instrumentalists interested in a UV-O successor to the Hubble Space Telescope. The scientific proceedings of this meeting were published in 1999: "Ultraviolet-Optical Space Astronomy Beyond the Hubble Space Telescope" (1999), NASA provided funds and commissioned the UVOWG (Ultraviolet-Optical Working Group), charged with recommending a set of fundamental scientific problems and new space missions in the UV/Optical wavelength bands. The working group was chaired by J. M. Shull, and included ten other astrophysicists. Their report was published as a "White Paper" (Nov. 1999) entitled "The Emergence of the Modern Universe: Tracing the Cosmic Web" available. The results of this report were used in the NASA Strategic Planning ("Roadmap") exercise and by the NRC Astronomy/Astrophysics Decade Committee.

Shull, J. Michael↗
NASA NTRS2019

Ultrastable environment control for the NEID spectrometer: design and performance demonstration

Two key areas of emphasis in contemporary experimental exoplanet science are the detailed characterization of transiting terrestrial planets and the search for Earth analog planets to be targeted by future imaging missions. Both of these pursuits are dependent on an order-of-magnitude improvement in the measurement of stellar radial velocities (RV), setting a requirement on single-measurement instrumental uncertainty of order 10 cm∕s. Achieving such extraordinary precision on a high-resolution spectrometer requires thermomechanically stabilizing the instrument to unprecedented levels. We describe the environment control system (ECS) of the NEID spectrometer, which will be commissioned on the 3.5-m WIYN Telescope at Kitt Peak National Observatory in 2019, and has a performance specification of on-sky RV precision <50 cm/s. Because NEID’s optical table and mounts are made from aluminum, which has a high coefficient of thermal expansion, sub-milliKelvin temperature control is especially critical. NEID inherits its ECS from that of the Habitable-Zone Planet Finder (HPF), but with modifications for improved performance and operation near room temperature. Our full-system stability test shows the NEID system exceeds the already impressive performance of HPF, maintaining vacuum pressures below 10(exp −6) Torr and a root mean square (RMS) temperature stability better than 0.4 mK over 30 days. Our ECS design is fully open-source; the design of our temperature-controlled vacuum chamber has already been made public, and here we release the electrical schematics for our custom temperature monitoring and control system.

Paul Robertson↗
NASA NTRS2022

The TRAPPIST-1 Habitable Atmosphere Intercomparison (THAI). I. Dry Cases—The Fellowship of the GCMs

With the commissioning of powerful, new-generation telescopes such as the James Webb Space Telescope (JWST) and the ground-based Extremely Large Telescopes, the first characterization of a high molecular weight atmosphere around a temperate rocky exoplanet is imminent. Atmospheric simulations and synthetic observables of target exoplanets are essential to prepare and interpret these observations. Here we report the results of the first part of the TRAPPIST-1 Habitable Atmosphere Intercomparison (THAI) project, which compares 3D numerical simulations performed with four state-of-the-art global climate models (ExoCAM, LMD-Generic, ROCKE-3D, Unified Model) for the potentially habitable target TRAPPIST-1e. In this first part, we present the results of dry atmospheric simulations. These simulations serve as a benchmark to test how radiative transfer, subgrid-scale mixing (dry turbulence and convection), and large-scale dynamics impact the climate of TRAPPIST-1e and consequently the transit spectroscopy signature as seen by JWST. To first order, the four models give results in good agreement. The intermodel spread in the global mean surface temperature amounts to 7 K (6 K) for the N2-dominated (CO2-dominated) atmosphere. The radiative fluxes are also remarkably similar (intermodel variations less than 5%), from the surface (1 bar) up to atmospheric pressures ∼5 mbar. Moderate differences between the models appear in the atmospheric circulation pattern (winds) and the (stratospheric) thermal structure. These differences arise between the models from (1) large-scale dynamics, because TRAPPIST-1e lies at the tipping point between two different circulation regimes (fast and Rhines rotators) in which the models can be alternatively trapped, and (2) parameterizations used in the upper atmosphere such as numerical damping.

Martin Turbet↗
NASA NTRS2012

Results from the PALM-3000 High-Order Adaptive Optics System

The first of a new generation of high actuator density AO systems developed for large telescopes, PALM-3000 is optimized for high-contrast exoplanet science but will support operation with natural guide stars as faint as V approx. 18. PALM-3000 began commissioning in June 2011 on the Palomar 200" telescope and has to date over 60 nights of observing. The AO system consists of two Xinetics deformable mirrors, one with 66 by 66 actuators and another with 21 by 21 actuators, a Shack-Hartman WFS with four pupil sampling modes (ranging from 64 to 8 samples across the pupil), and a full vector matrix multiply real-time system capable of running at 2KHz frame rates. We present the details of the completed system, and initial results. Operating at 2 kHz with 8.3cm pupil sampling on-sky, we have achieved a K-band Strehl ratio as high as 84% in approx.1.0 arcsecond visible seeing.

Palomar↗
NASA NTRSDate not supplied

The James Webb Space Telescope Mission Status

The James Webb Space Telescope (Webb) is a large, infrared space telescope that recently completed its on-orbit commissioning activities and will now embark on the first year of approved science. Its architecture includes many first-of-its-kind innovations for space, including a segmented primary mirror that is 6.6 m in diameter and a 5-layer sunshield used to passively cool the telescope and its four science instruments. Although Webb had an extensive test program, the system-level performance often relied on predictions based on integrated modeling, using conservative factors for the model uncertainties and primarily focusing on evaluating the performance requirements at end of life. A set of commissioning activities were designed for a system-level characterization of the performance. This proceeding will provide the status of the mission, including a discussion of the major events, on-orbit system performance, and early science highlights.

Michael McElwain↗
NASA NTRS2015

JWST Pathfinder Telescope Risk Reduction Cryo Test Program

In 2014, the Optical Ground Support Equipment was integrated into the large cryo vacuum chamber at Johnson Space Center (JSC) and an initial Chamber Commissioning Test was completed. This insured that the support equipment was ready for the three Pathfinder telescope cryo tests. The Pathfinder telescope which consists of two primary mirror segment assemblies and the secondary mirror was delivered to JSC in February 2015 in support of this critical risk reduction test program prior to the flight hardware. This paper will detail the Chamber Commissioning and first optical test of the JWST Pathfinder telescope.

Integration↗
DOE OSTI2025

First polarization study of the M87 jet and active galactic nuclei at submillimeter wavelengths with ALMA

We investigated the polarization and Faraday properties of Messier 87 (M87) and seven other radio-loud active galactic nuclei (AGNs) at λ0.87 mm (345 GHz) using the Atacama Large Millimeter/submillimeter Array (ALMA). Our goal was to characterize the linear polarization (LP) fractions, measure Faraday rotation measures (RMs), and examine the magnetic field structures in the emission regions of these AGNs. We conducted full-polarization observations as part of the ALMA Band 7 very long baseline interferometry (VLBI) commissioning during the April 2021 Event Horizon Telescope (EHT) campaign. We analyzed the LP fractions and RMs to assess the nature of Faraday screens and magnetic fields in the submillimeter emission regions. We find LP fractions between 1% and 17% and RMs exceeding 10 5 rad m −2 , which are 1–2 orders of magnitude higher than typically observed at longer wavelengths (λ>3 mm). This suggests denser Faraday screens or stronger magnetic fields. Additionally, we present the first submillimeter polarized images of the M87 jet and the observed AGNs, revealing RM gradients and sign reversals in the M87 jet indicative of a kiloparsec-scale helical magnetic field structure. Our results provide essential constraints for calibrating, analyzing, and interpreting VLBI data from the EHT at 345 GHz, representing a critical step toward submillimeter VLBI imaging.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2026

The Vera C. Rubin Observatory Data Preview 1

We present Rubin Data Preview 1 (DP1), the first data from the National Science Foundation–Department of Energy Vera C. Rubin Observatory, comprising raw and calibrated single-epoch images, coadds, difference images, detection catalogs, and ancillary data products. DP1 is based on 1792 optical–near-infrared exposures acquired over 48 distinct nights by the Rubin Commissioning Camera (LSSTComCam) on the Simonyi Survey Telescope at the Summit Facility on Cerro Pachón, Chile in late 2024. DP1 covers ∼15 deg 2 distributed across seven roughly equal-sized noncontiguous fields, each independently observed in six broad photometric bands, ugrizy. The median FWHM of the point-spread function across all bands is approximately 1"14, with the sharpest images reaching about 0." 58. The 5σ point-source depths for coadded images in the deepest field, the Extended Chandra Deep Field South, are u = 24.55, g = 26.18, r = 25.96, i = 25.71, z = 25.07, and y = 23.1. Other fields are no more than 2.2 mag shallower in any band, where they have nonzero coverage. DP1 contains approximately 2.3 million distinct astrophysical objects, of which 1.6 million are extended in at least one band in coadds, and 431 solar system objects, of which 93 are new discoveries. DP1 is approximately 3.5 TB in size and is available to Vera C. Rubin Observatory data rights holders via the Rubin Science Platform, a cloud-based environment for the analysis of petascale astronomical data. While small compared to future LSST releases, its high quality and diversity of data support a broad range of early science investigations ahead of full operations in 2026.

Ground-based astronomy↗
NASA NTRS2004

Spitzer Space Telescope : observatory desciption and performance

The Spitzer Space Telescope, the last of the four Great Observatories commissioned by the National Aeronautics and Space Administration, was successfully launched on August 25, 2003 from Kennedy Space Center. The engineering systems for Spitzer were developed by the Jet Propulsion Laboratory, Lockheed Martin Space Systems Company, and Ball Aerospace & Technology Corp. This paper provides an overview of Spitzer, a technical description of all the engineering subsystems, and the associated challenges involved in developing them to satisfy the mission requirements. In addition, this paper describes the performance of the engineering subsystems during the In-Orbit Checkout phase, the Science Verification phase, and the early portions of the Nominal Mission.

Space Infrared Telescope Facility (SIRTF)↗
NASA NTRS2007

Optical Modeling Activities for NASA's James Webb Space Telescope (JWST): Wavefront Aberrations due to Alignment and Figure Compensation - 3

This is part three of a series describing the ongoing optical modeling activities for James Webb Space Telescope (JWST). The first two discussed modeling JWST on-orbit performance using wavefront sensitivities to predict line of sight motion induced blur, and stability during thermal transients. The work here investigates the aberrations resulting from alignment and figure compensation of the controllable degrees of freedom (primary and secondary mirrors), which may be encountered during ground alignment and on-orbit commissioning of the observatory. The optical design of the telescope is a three-mirror anastigmat, with an active fold mirror at the exit pupil for fine guiding. The primary mirror is over 6.5 meters in diameter, and is composed of 18 hexagonal segments that can individually positioned on hexapods, as well as compensated for radius of curvature. This effectively gives both alignment and figure control of the primary mirror. The secondary mirror can be moved in rigid body only, giving alignment control of the telescope. The tertiary mirror is fixed, however, as well as the location of the science instrumentation. Simulations are performed of various combinations of active alignment corrections of component figure errors, and of primary mirror figure corrections of alignment errors. Single field point and moderate field knowledge is assumed in the corrections. Aberrations over the field are reported for the varying cases, and examples presented.

Howard, Joseph↗
NASA NTRS2017

Getting NuSTAR on Target: Predicting Mast Motion

The Nuclear Spectroscopic Telescope Array (NuSTAR) is the first focusing high energy (3-79 keV) X-ray observatory operating for four years from low Earth orbit. The X-ray detector arrays are located on the spacecraft bus with the optics modules mounted on a flexible mast of 10.14m length. The motion of the telescope optical axis on the detectors during each observation is measured by a laser metrology system and matches the pre-launch predictions of the thermal flexing of the mast as the spacecraft enters and exits the Earths shadow each orbit. However, an additional motion of the telescope field of view was discovered during observatory commissioning that is associated with the spacecraft attitude control system and an additional flexing of the mast correlated with the Solar aspect angle for the observation. We present the methodology developed to predict where any particular target coordinate will fall on the NuSTAR detectors based on the Solar aspect angle at the scheduled time of an observation. This may be applicable to future observatories that employ optics deployed on extendable masts. The automation of the prediction system has greatly improved observatory operations efficiency and the reliability of observation planning.

NASA small explorer↗
NASA NTRS2022

The Warm Neptune GJ 3470b Has a Polar Orbit

The warm Neptune GJ 3470b transits a nearby (d = 29 pc) bright slowly rotating M1.5-dwarf star. Using spectroscopic observations during two transits with the newly commissioned NEID spectrometer on the WIYN 3.5 m Telescope at Kitt Peak Observatory, we model the classical Rossiter–McLaughlin effect, yielding a sky-projected obliquity of λ=98 +15 −12 ˚and a v sin i = 0.85 +0.27 −0.33 kms -1 . Leveraging information about the rotation period and size of the host star, our analysis yields a true obliquity of ψ=95 +9 −8 ◦ , revealing that GJ 3470b is on a polar orbit. Using radial velocities from HIRES, HARPS, and the Habitable-zone Planet Finder, we show that the data are compatible with a long-term radial velocity (RV) slope of 𝛾̀=-0.0022±0.0011 ms -1 day -1 over a baseline of 12.9 yr. If the RV slope is due to acceleration from another companion in the system, we show that such a companion is capable of explaining the polar and mildly eccentric orbit of GJ 3470b using two different secular excitation models. The existence of an outer companion can be further constrained with additional RV observations, Gaia astrometry, and future high-contrast imaging observations. Lastly, we show that tidal heating from GJ 3470b’s mild eccentricity has most likely inflated the radius of GJ 3470b by a factor of ∼1.5–1.7, which could help account for its evaporating atmosphere.

Exoplanet astronomy↗
NASA NTRS1991

Operation of the University of Hawaii 2.2M telescope on Mauna Kea

NASA's planetary astronomy program provides part of the funding for the 2.2 meter telescope. The parameters for time on the telescope are laid out. A major instrumental highlight has been the commissioning of a 256 x 256 near infrared camera which uses a Rockwell NICMOS-3 array. At the f/10 focus, image scales of 0.37 and 0.75 arcsec/pixel are available. A new, high quantum efficiency Tektronix 1024 x 1024 CCD saw first light on the telescope in 1991, and was available regularly from April 1991. Data from both of these detectors are transmitted directly to the Sun workstation for immediate analysis by the observers. The autoguider software was enhanced to permit guided tracking on objects have nonsideral motions (i.e., solar system objects).

Hall, Donald N. B.↗
DOE OSTI2024

LSST Commissioning Camera

The LSST Commissioning Camera (LSSTComCam) was mounted on the Simonyi Survey Telescope in August 2022 and observed for seven weeks in late 2024 until it was removed from the telescope in December 2024. It is a smaller, fully functional version of LSSTCam, with only the central raft of 9 4k x 4k CCDs (all ITL sensors) and comprising 144 megapixels. Every CCD has 16 amplifiers, each reading 1 million pixels. LSSTComCam was designed to enable end-to-end testing of the observatory’s systems, including data acquisition, image processing, and observatory operations.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS2002

Formation of Brown Dwarfs LTSA 2001

The goals of the work funded by this grant are: (1) The measurement of the mass function and minimum mass of free-floating brown dwarfs down to the mass of Jupiter; (2) The measurement of the frequency of wide brown dwarf and planetary companions down to the mass of Jupiter as function of primary mass (0.02-2 Msun), age (1-10 Myr), and environment (clusters vs. dispersed regions). For the first objective, we have completed the design of guaranteed SIRTF observations of nearby star-forming regions and now await the launch of the mission in April 2003. In support of these upcoming observations, in the fall of 2002 we obtained optical spectroscopy at the MMT and the 1.5-meter telescope at Fred Lawrence Whipple Observatory for candidate young low-mass stars and brown dwarfs in the IC348 and Taurus star-forming regions. Two papers that include these data in new measurements of the mass functions in these regions are near completion and will be submitted for publication to the Astrophysical Journal in January. We have also proposed deep optical and near-IR imaging of the SIRTF fields in the IC348, Chamaeleon, and Ophiuchus star-forming regions with the MMT, Magellan, and Gemini North telescopes in early 2003. For the second objective, we have used deep HST WFPC2 images to search for young giant planets and brown dwarfs around approximately 100 low-mass stars and brown dwarfs in the nearby cluster IC 348. We have completed all data reduction and have checked these data for candidate companions. We are in the process of writing a paper that describes these candidate companions and presents the companion detection limits that were achieved with HST. We will attempt followup spectroscopy of the most promising candidate companions to confirm their nature as cool companions rather than background field stars during the commissioning of the facility adaptive optics system for the Gemini North telescope early in 2003. In addition, in SIRTF guaranteed time observations we plan to search for wide substellar companions (greater than 10 inches) around the youngest nearby field stars (ages of 30-100 Myr, d less than 30 pc). We have proposed to use Keck adaptive optics imaging to search these same stars for close-in planets and brown dwarfs at 0.1-l0 inches, which will perfectly complement our SIRTF observations.

Luhman, Kevin L.↗
NASA NTRS2014

The Outer Disks of Herbig Stars From the UV to NIR

Spatially-resolved imaging of Herbig stars and related objects began with HST, but intensified with commissioning of high-contrast imagers on 8-m class telescopes. The bulk of the data taken from the ground have been polarized intensity imagery at H-band, with the majority of the sources observed as part of the Strategic Exploration of Exoplanets and Disks with Subaru (SEEDS) survey. Sufficiently many systems have been imaged that we discuss disk properties in scattered, polarized light in terms of groups defined by the IR spectral energy distribution. We find novel phenomena in many of the disks, including spiral density waves, and discuss the disks in terms of clearing mechanisms. Some of the disks have sufficient data to map the dust and gas components, including water ice dissociation products.

H-band↗
NASA NTRS1991

New 1982-1990 photometry of Lambda Andromedae and its 11-year cycle

The paper presents photoelectric photometry of Lambda And never before published, obtained between February 1982 and December 1990 at 29 different observatories. Then it is combined with all other photometry available (previously published, contained in the I.A.U. Commission 27 Archives, and obtained with the Vanderbilt 16-inch automatic telescope but not yet published), to yield a 14.8-year data base. Analysis reveals a long-term cycle in mean brightness, with a full range of 0.15 m and a period of 11.4 +/- 0.4 years. Because most of the new photometry was concentrated in the 1983-1984 observing season, this one well-defined light curve is analyzed with a two-spot model. Spot A keeps a 0.04 m amplitude throughout four rotation cycles whereas the amplitude of spot B diminishes from 0.09 m down almost to 0.03 m. The spot rotation periods were 55.9 d +/- 0.6 d and 52.8 d +/- 1.0 d, respectively.

Hall, Douglas S.↗
NASA NTRS2007

TRL-6 for JWST Wavefront Sensing and Control

NASA's Technology Readiness Level (TRL)-6 is documented for the James Webb Space Telescope (JWST) Wavefront Sensing and Control (WFSC) subsystem. The WFSC subsystem is needed to align the Optical Telescope Element (OTE) after all deployments have occurred, and achieves that requirement through a robust commissioning sequence consisting of unique commissioning algorithms, all of which are part of the WFSC algorithm suite. This paper identifies the technology need, algorithm heritage, describes the finished TRL-6 design platform, and summarizes the TRL-6 test results and compliance. Additionally, the performance requirements needed to satisfy JWST science goals as well as the criterion that relate to the TRL-6 Testbed Telescope (TBT) performance requirements are discussed

Feinberg, Lee↗