JWST Project Scientist Jonathan Gardner presents an overview of JWST commissioning activities, highlighting observatory performance, followed by more detailed discussion of the individual science instruments.
KEYWORDS: Telescopes, James Webb Space Telescope, Image segmentation, Observatories, Mirrors, Space operations, Space telescopes, Galactic astronomy, Wavefronts, Stars
The James Webb Space Telescope (Webb) is a large, infrared space telescope that recently completed its on-orbit commissioning activities and has now embarked on its 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 at the 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.
The James Webb Space Telescope (JWST) is a large (6.5 m) near- and mid-infrared telescope scheduled for launch in 2021. JWST will be used to explore fundamental questions in astrophysics and planetary science, including the evolution of galaxies, the first light of stars, the formation of stars and planets as well as the characterization of exoplanets. To achieve these scientific goals, NASA and its international partners, the Canadian Space Agency (CSA) and the European Space Agency (ESA), have developed four science instruments for JWST and have prepared detailed commissioning plans for each. The NASA Project Science team has also outlined activities to characterize the performance of the Observatory as a whole. These activities include: 1) monitoring of the instrument and telescope cooldown for contamination mitigation; 2) measurements of straylight and other backgrounds for validation of the JWST stray light models as well as instrument background subtraction algorithms; 3) characterization of optical thermal distortion between its hot and cold telescope pointings within the observable field of regard and 4) trending of observatory performance parameters. Each of these activities has been planned in close collaboration with the observatory wavefront, commissioning planning, and science instrument teams. Here we present the plans for these activities, the expected results and how they will impact future guest observer (GO) proposals and JWST science community.
Establishing improved spectrophotometric standards is important for a broad range of missions and is relevant to many astrophysical problems. ACCESS, “Absolute Color Calibration Experiment for Standard Stars”, is a series of rocket-borne sub-orbital missions and ground-based experiments designed to enable improvements in the precision of the astrophysical flux scale through the transfer of absolute laboratory detector standards from the National Institute of Standards and Technology (NIST) to a network of stellar standards with a calibration accuracy of 1% and a spectral resolving power of 500 across the 0.35 − 1.7μm bandpass. This paper describes the sub-system testing, payload integration, avionics operations, and data transfer for the ACCESS instrument.
Establishing improved spectrophotometric standards is important for a broad range of missions and is relevant to many astrophysical problems. ACCESS, Absolute Color Calibration Experiment for Standard Stars", is a series of rocket-borne sub-orbital missions and ground-based experiments designed to enable improvements in the precision of the astrophysical flux scale through the transfer of absolute laboratory detector standards from the National Institute of Standards and Technology (NIST) to a network of stellar standards with a calibration accuracy of 1% and a spectral resolving power of 500 across the 0.35 - 1.7μm bandpass. This paper describes the payload status, sub-system testing, and data transfer for the ACCESS instrument.
KEYWORDS: Astrophysics, Space telescopes, Astronomy, Observatories, James Webb Space Telescope, Space operations, Telecommunications, Mars, Telescopes, Asteroids
We describe how availability of new solar electric propulsion (SEP) technology can substantially increase the science capability of space astronomy missions working within the near-UV to far-infrared (UVOIR) spectrum by making dark sky orbits accessible for the first time. We present two case studies in which SEP is used to enable a 700 kg Explorer-class and 7000 kg flagship-class observatory payload to reach an orbit beyond where the zodiacal dust limits observatory sensitivity. The resulting scientific performance advantage relative to a Sun-Earth L2 point (SEL2) orbit is presented and discussed. We find that making SEP available to astrophysics Explorers can enable this small payload program to rival the science performance of much larger long development-time systems. Similarly, we find that astrophysics utilization of high power SEP being developed for the Asteroid Redirect Robotics Mission (ARRM) can have a substantial impact on the sensitivity performance of heavier flagship-class astrophysics payloads such as the UVOIR successor to the James Webb Space Telescope.
Establishing improved spectrophotometric standards is important for a broad range of missions and is relevant
to many astrophysical problems. ACCESS, “Absolute Color Calibration Experiment for Standard Stars”, is a
series of rocket-borne sub-orbital missions and ground-based experiments designed to enable improvements in
the precision of the astrophysical flux scale through the transfer of absolute laboratory detector standards from
the National Institute of Standards and Technology (NIST) to a network of stellar standards with a calibration
accuracy of 1% and a spectral resolving power of 500 across the 0.35−1.7μm bandpass. Achieving a calibration
accuracy of 1% not only requires an accurate calibration transfer from the detector standards to the instrument,
but it also requires characterization and stability of the detector as well as a thermal background that contributes
less than 1% to the flux per resolution element in the near-infrared (1.7μm) spectral region of the ACCESS
bandpass. This paper describes the thermal mechanical design for achieving a low thermal background across
the ACCESS spectral bandpass.
We describe a mission architecture designed to substantially increase the science capability of the NASA Science
Mission Directorate (SMD) Astrophysics Explorer Program for all AO proposers working within the near-UV to far-infrared
spectrum. We have demonstrated that augmentation of Falcon 9 Explorer launch services with a 13 kW Solar
Electric Propulsion (SEP) stage can deliver a 700 kg science observatory payload to extra-Zodiacal orbit. This new
capability enables up to ~13X increased photometric sensitivity and ~160X increased observing speed relative to a Sun-
Earth L2, Earth-trailing, or Earth orbit with no increase in telescope aperture. All enabling SEP stage technologies for
this launch service augmentation have reached sufficient readiness (TRL-6) for Explorer Program application in
conjunction with the Falcon 9. We demonstrate that enabling Astrophysics Explorers to reach extra-zodiacal orbit will
allow this small payload program to rival the science performance of much larger long development time systems; thus,
providing a means to realize major science objectives while increasing the SMD Astrophysics portfolio diversity and
resiliency to external budget pressure. The SEP technology employed in this study has strong applicability to SMD
Planetary Science community-proposed missions. SEP is a stated flight demonstration priority for NASA's Office of the
Chief Technologist (OCT). This new mission architecture for astrophysics Explorers enables an attractive realization of
joint goals for OCT and SMD with wide applicability across SMD science disciplines.
Establishing improved spectrophotometric standards is important for a broad range of missions and is relevant
to many astrophysical problems. ACCESS, “Absolute Color Calibration Experiment for Standard Stars”, is a
series of rocket-borne sub-orbital missions and ground-based experiments designed to enable improvements in
the precision of the astrophysical flux scale through the transfer of absolute laboratory detector standards from
the National Institute of Standards and Technology (NIST) to a network of stellar standards with a calibration
accuracy of 1% and a spectral resolving power of 500 across the 0.35-1.7µm bandpass.
KEYWORDS: James Webb Space Telescope, Stars, Galactic astronomy, Spectroscopy, Planets, Solar system, Planetary systems, Exoplanets, Hubble Space Telescope, Infrared radiation
The science objectives of the James Webb Space Telescope fall into four themes. The End of the Dark Ages: First Light
and Reionization theme seeks to identify the first luminous sources to form and to determine the ionization history of the
universe. The Assembly of Galaxies theme seeks to determine how galaxies and the dark matter, gas, stars, metals,
morphological structures, and black holes within them evolved from the epoch of reionization to the present. The Birth
of Stars and Protoplanetary Systems theme seeks to unravel the birth and early evolution of stars, from infall onto dust-enshrouded
protostars, to the genesis of planetary systems. The Planetary Systems and the Origins of Life theme seeks to
determine the physical and chemical properties of planetary systems around nearby stars and of our own, and to
investigate the potential for life in those systems. These four science themes were used to establish the design
requirements for the observatory and instrumentation. Since Webb’s capabilities are unique, those science themes will
remain relevant through launch and operations and goals contained within these themes will continue to guide the design
and implementation choices for the mission. More recently, it has also become clear that Webb will make major
contributions to other areas of research, including dark energy, dark matter, exoplanet characterization and Solar System
objects. In this paper, I review the original four science themes and discuss how the scientific output of Webb will
extend to these new areas of research.
ACCESS, Absolute Color Calibration Experiment for Standard Stars, is a series of rocket-borne sub-orbital
missions and ground-based experiments designed to enable improvements in the precision of the astrophysical
flux scale through the transfer of absolute laboratory detector standards from the National Institute of Standards
and Technology (NIST) to a network of stellar standards with a calibration accuracy of 1% and a spectral resolving
power of 500 across the 0.35.1.7μm bandpass.
Establishing improved spectrophotometric standards is important for a broad range of missions and is relevant
to many astrophysical problems. Systematic errors associated with problems such as dark energy now compete
with the statistical errors and thus limit our ability to answer fundamental questions in astrophysics.
The ACCESS design, calibration strategy, and an updated preliminary performance estimate are discussed.
KEYWORDS: Stars, Galactic astronomy, James Webb Space Telescope, Planets, Clouds, Planetary systems, Hubble Space Telescope, Imaging spectroscopy, Space telescopes, Solar system
The scientific capabilities of the James Webb Space Telescope fall into four themes. The End of the Dark Ages: First
Light and Reionization theme seeks to identify the first luminous sources to form and to determine the ionization history
of the universe. The Assembly of Galaxies theme seeks to determine how galaxies and the dark matter, gas, stars, metals,
morphological structures, and active nuclei within them evolved from the epoch of reionization to the present. The Birth
of Stars and Protoplanetary Systems theme seeks to unravel the birth and early evolution of stars, from infall onto dustenshrouded
protostars, to the genesis of planetary systems. The Planetary Systems and the Origins of Life theme seeks to
determine the physical and chemical properties of planetary systems around nearby stars and of our own, and investigate
the potential for life in those systems.
The On-board Calibration Monitor (OCM) is being developed as an integral component of the ACCESS instrument
and as a pathfinder for other missions. It provides stable full-aperture illumination of the telescope for
tracking the instrument sensitivity as a function of time. The light source is composed of an ensemble of LED
pairs with central wavelengths that span the spectral range of the instrument and illuminate a diffuser that is
observed by the full optical path. Feedback stabilization of the light source intensity is achieved by photodiode
monitoring of each LED. This stable source will provide real time knowledge of the ACCESS sensitivity throughout
the 5-year duration of the program. The present status of the design and laboratory evaluation of the OCM
system will be presented.
ACCESS is a recently approved rocket-borne payload with a ground-based calibration and performance monitoring
program that is designed to transfer the National Institute of Standards and Technology (NIST) absolute
laboratory standards to the stars with a precision and calibration accuracy of 1% across the 0.35-1.7μm bandpass.
This represents a significant improvement in the absolute and relative astrophysical flux calibration system,
particularly at near-infrared (NIR) wavelengths.
Establishing improved spectrophotometric standards is important for a broad range of missions and is relevant
to many astrophysical problems. In particular, the precise calibration of the flux scale across the bandpass
extending from 0.35-1.7 μm is fundamental to the precise determination of dark energy measurements based
on SNeIa photometry.
We report results of a recently-completed pre-Formulation Phase study of SPIRIT, a candidate NASA Origins Probe mission. SPIRIT is a spatial and spectral interferometer with an operating wavelength range 25 - 400 μm. SPIRIT will provide sub-arcsecond resolution images and spectra with resolution R = 3000 in a 1 arcmin field of view to accomplish three primary scientific objectives: (1) Learn how planetary systems form from protostellar disks, and how they acquire their chemical organization; (2) Characterize the family of extrasolar planetary systems by imaging the structure in debris disks to understand how and where planets form, and why some planets are ice giants and others are rocky; and (3) Learn how high-redshift galaxies formed and merged to form the present-day population of galaxies. Observations with SPIRIT will be complementary to those of the James Webb Space Telescope and the ground-based Atacama Large Millimeter Array. All three observatories could be operational contemporaneously.
The scientific capabilities of the James Webb Space Telescope (JWST) fall into four themes. The End of the Dark Ages:
First Light and Reionization theme seeks to identify the first luminous sources to form and to determine the ionization
history of the universe. The Assembly of Galaxies theme seeks to determine how galaxies and the dark matter, gas,
stars, metals, morphological structures, and active nuclei within them evolved from the epoch of reionization to the
present. The Birth of Stars and Protoplanetary Systems theme seeks to unravel the birth and early evolution of stars,
from infall onto dust-enshrouded protostars, to the genesis of planetary systems. Planetary Systems and the Origins of
Life theme seeks to determine the physical and chemical properties of planetary systems around nearby stars and of our
own, and investigate the potential for life in those systems. To enable these for science themes, JWST will be a large
(6.5m) cold (50K) telescope with four instruments, capable of imaging and spectroscopy from 0.6 to 29 microns wavelength.
The scientific requirements of the James Webb Space Telescope fall into four themes. The End of the Dark Ages: First Light and Reionization seeks to identify the first luminous sources to form and to determine the ionization history of the Universe. The Assembly of Galaxies seeks to determine how galaxies and the dark matter, gas, stars, metals, morphological structures, and active nuclei within them evolved from the epoch of reionization to the present. The Birth of Stars and Protoplanetary Systems seeks to unravel the birth and early evolution of stars, from infall onto dust-enshrouded protostars, to the genesis of planetary systems. Planetary Systems and the Origins of Life seeks to determine the physical and chemical properties of planetary systems including our own, and investigate the potential for life in those systems. These themes will guide the design and construction of the observatory.
The STIS instrument was installed into HST in February 1997 during the Servicing Mission 2. It has almost completed checkout and is beginning its science program, and is working well. Several scientific demonstration observations were taken to illustrate some of the range of scientific uses and modes of observation of STIS.
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