ESA Science & Technology - Publications Archive

The SAR has been tasked by the JWST Mission Office to investigate what science cases will be of relevance for the general community in the timeframe 2012-2015, uniquely exploiting the JWST capabilities. These science cases are in addition to, and not a repetition of, the science drivers developed in the JWST Science Requirements Document (SRD). They do not necessarily represent 'drivers', but are a representative sample of science that the 'community' considers important to pursue with JWST in the indicated timeframe, and in addition to the fundamental science described in the SRD.

The JamesWebb Space Telescope (JWST) is a large (6.6 m), cold (<50 K), infrared (IR)- optimized space observatory that will be launched early in the next decade into orbit around the second Earth-Sun Lagrange point. The observatory will have four instruments: a near-IR camera, a near-IR multiobject spectrograph, and a tunable filter imager will cover the wavelength range, 0.6 < l < 5.0 microns, while the mid-IR instrument will do both imaging and spectroscopy from 5.0 < l < 29 microns.

The James Webb Space Telescope (Gardner et al. 2006) will be capable of characterizing extrasolar planets to significantly greater sensitivity than the current Spitzer detections (Charbonneau et al. 2005, Deming et al. 2005, 2006). In combination with ground-based transit surveys and scientific results from the Kepler and Corot missions, JWST will be able to address the detailed physical characterization of up to 250 exosolar planets (Mountain et al. 2006; Beichman et al. 2006). Transit studies of exosolar planets are currently unique in providing measurements that permit comparative exoplanetology.

The James Webb Space Telescope (JWST) will be an exciting, highly capable tool, able to make important contributions to studies of stellar populations in nearby galaxies, including our own. JWST observations will contribute to: (1) the study of the star formation histories of nearby galaxies, exploiting the large lever arm provided by visibleinfrared colors; (2) the derivation of the properties of stellar populations from the study of the bright red stellar component out to the Virgo cluster and beyond; and (3) the derivation of the white dwarf cooling sequence age of globular clusters in the Milky Way from the study of deep visible red color magnitude diagrams.

The James Webb Space Telescope is a large (25 m²), cold (<50 K), infrared (IR)-optimized space observatory that will be launched during 2013. It is the successor to the Hubble and Spitzer Space Telescopes. The observatory has four instruments: a near-IR camera, a near-IR multi-object spectrograph, and a tunable filter imager will operate within the wavelength range, 0.6 < l < 5.0 microns, while the mid-IR instrument will provide both imaging and spectroscopy over the 5.0 < l < 28.5 microns spectrum.

We discuss the recent progress on stellar populations provided by the influx of high sensitivity infrared photometry measurements using the Spitzer SAGE survey of the Large Magellanic Cloud as an example. We discuss the important role JWST will play in expanding such studies out to the local volume of galaxies (~10 Mpc) and its synergy with concurrent missions. In addition to observational capabilities, we will need theoretical tools to further this field in the next decade.

JWST provides capabilities unmatched by other telescopic facilities in the near to mid infrared part of the electromagnetic spectrum. Its combination of broad wavelength range, high sensitivity and near diffraction-limited imaging around two microns wavelength make it a high value facility for a variety of Solar System targets. Beyond Neptune, a class of cold, large bodies that include Pluto, Triton and Eris exhibits surface deposits of nitrogen, methane, and other molecules that are poorly observed from the ground, but for which JWST might provide spectral mapping at high sensitivity and spatial resolution difficult to match with the current generation of ground-based observatories. The observatory will also provide unique sensitivity in a variety of near and mid infrared windows for observing relatively deep into the atmospheres of Uranus and Neptune, searching there for minor species. It will examine the Jovian aurora in a wavelength regime where the background atmosphere is dark. Special provision of a subarray observing strategy may allow observation of Jupiter and Saturn over a larger wavelength range despite their large surface brightnesses, allowing for detailed observation of transient phenomena including large scale storms and impact-generation disturbances. JWSTs observations of Saturns moon Titan will overlap with and go beyond the 2017 end-of-mission for Cassini, providing an important extension to the time-series of meteorological studies for much of northern hemisphere summer. It will overlap with a number of other planetary missions to targets for which JWST can make unique types of observations. JWST provides a platform for linking solar system and extrasolar planet studies through its unique observational capabilities in both arenas.

Determination of the physical and chemical properties of planetary systems is the main objective of the planetary systems and the origins of life scientific theme of the James Webb Space Telescope (JWST). This white paper summarizes the missions capabilities for direct detection and study of exoplanets and circumstellar material (>0.1" from parent star), planets and other objects in our own Solar System, and corresponding scientific advances expected from JWST in the next decade.

The James Webb Space Telescope (JWST; Gardner et al. 2006) will be a large, cold, infrared- optimized space telescope designed to enable fundamental breakthroughs in our understanding of the formation and evolution of galaxies, stars, and planetary systems (see Astro 2010 white papers by Gardner et al., Stiavelli et al., Meixner et al., G. Rieke et al., & Sonneborn et al.). In the current white paper, we describe the great potential of JWST in the theme of Galaxy Assembly.

The study of transiting exoplanets has provided most of the key data to date on the properties of exoplanets, such as direct estimates of their mass and radius (e.g.Charbonneau 2007), and spectral diagnostics of their atmospheres (e.g. Swain et al. 2008). The Hubble Space Telescope (HST) and Spitzer Space Telescope (SST) have both played lead roles in making the demanding, high S/N observations of light curves, and spectra of transiting exoplanets. Ground-based surveys have so far provided the candidate targets for space-based characterization studies. The study of transiting exoplanets requires the extraction of a differential signal from high S/N observations so the James Webb Space Telescope (JWST), by virtue of its 25 m² collecting area (~50x SST), will open up a new discovery space for transiting exoplanet science. Specifically, it will enable the characterization of intermediate and low mass exoplanets. The goal of this white paper is to provide an informational briefing for the panel on the expected capabilities of JWST for observations of exoplanet transits, in particular the characterization of transiting lower mass planets (d M_Nep).

Before addressing how JWST can detect "First Light" we need to define what we mean by such term. First light is the appearance of the first stars (Population III) or mini-AGNs in the Universe. JWST is incapable of detecting individual Population III stars directly but could detected them as SNae, thought to be ultra-bright pair instability SNae or, even, Gamma Ray Bursts. The recent detection of the superluminous SN2006gy of absolute magnitude -22 (Smith et al. 2007, astro-ph/0612617) and detectable to z=20 and beyond highlights the appeal of this approach as a very effective way to identify the location of very high-z objects.

The aim of this paper is to outline the expected JWST performance in addressing first light and reionization science questions that are found to be of interest today. These are some of the most challenging and interesting questions in modern astronomy, and are key drivers for the design of the JWST. Nevertheless, because these early epochs are difficult to observe, even JWST is unlikely to provide complete answers.

The Hubble Space Telescope (HST) has contributed significantly to studies of dark energy. It was used to find the first evidence of deceleration at z=1.8 (Riess et al. 2001) through the serendipitous discovery of a type 1a supernova (SNIa) in the Hubble Deep Field. The discovery of deceleration at z>1 was confirmation that the apparent acceleration at low redshift (Riess et al. 1998; Perlmutter et al. 1999) was due to dark energy rather than observational or astrophysical effects such as systematic errors, evolution in the SNIa population or intergalactic dust. The GOODS project and associated follow-up discovered 21 SNIa, expanding on this result (Riess et al. 2007). HST has also been used to constrain cosmological parameters and dark energy through weak lensing measurements in the COSMOS survey (Massey et al 2007; Schrabback et al 2009) and strong gravitational lensing with measured time delays (Suyu et al 2010).

The James Webb Space Telescope (Gardner et al. 2006} will have the capability to make significant, early progress in extrasolar planet studies. The JWST instrument complement features several coronagraphs that will be able to conduct programs imaging debris disks, and conduct searches to directly detect gas giant exoplanets.

A report to NASA recommending addition or optimization of the James Webb Space Telescope capabilities to maximize astrobiology science return.

JWST has many 'nascent capabilities' that could be developed to optimize their value for astrobiology at little cost or detriment to other JWST science. Here we summarize recommendations to the JWST project to ensure a wide variety of key astrobiological contributions.

Force limited vibration was used during the sine and random qualification tests of the NIRSpec instrument, to limit stresses in the brittle structure while demonstrating adequate qualification with regard to the environmental flight conditions. First, NASA provided a force limit curve based on their internal 'Semi-Empirical Method'. Then, strain gages were mounted on the legs of the kinematic mounts to recover interface forces during the vibration test. Two different methods were then used to determine the notches: one called the 'Apparent Mass' method that is based on sine sweep signatures and another one based on direct force measurement in the time domain during random test. The second method resulted in the most effective notch determination, allowing the justification of the notches in real time with high accuracy. The resulting RMS forces are well below the forces corresponding to static design loads that is a more conventional method.

In "Optical System Alignment, Tolerancing, and Verification III", edited by José Sasian, Richard N. Youngworth, Proc. of SPIE Vol. 7433, 74330P, (2009), doi: 10.1117/12.826286

The Mid Infrared Instrument (MIRI), one of the four instruments on the Integrated Science Instrument Module (ISIM) of the James Webb Space Telescope (JWST), supports all of the science objectives of the observatory. MIRI optical alignment is an important step in the verification process, directly affecting mission success. The MIRI optical alignment is verified on the ground at the integrated ISIM level using an element in the MIRI Filter Wheel, the pupil alignment reference (PAR), developed by NASA GSFC and provided to MIRI. It is a ~2.3g aluminum piece that has a flat, specularly reflective, 3mm diameter surface in its center, with laser-etched fiducials within its aperture. The PAR is illuminated via an optical stimulus (ground support equipment) and imaged using a pupil imaging camera, during the ISIM test program in order to determine absolute and relative changes in the alignment that impact pupil shear and roll. Here we describe the MIRI PAR; its physical properties and challenges during its design, manufacturing, and testing.

Infrared Systems and Photoelectronic Technology IV. Edited by Dereniak, Eustace L.; Hartke, John P.; Levan, Paul D.; Longshore, Randolph E.; Sood, Ashok K. Proceedings of the SPIE, Volume 7419, pp. 741907-741907-10 (2009)

The James Webb Space Telescope, an infrared-optimized space telescope being developed by NASA for launch in 2014, will utilize cutting-edge detector technology in its investigation of fundamental questions in astrophysics. JWST's near infrared spectrograph, NIRSpec utilizes two 2048 × 2048 HdCdTe arrays with Sidecar ASIC readout electronics developed by Teledyne to provide spectral coverage from 0.6 microns to 5 microns. We present recent test and calibration results for the "pathfinder NIRSpec detector subsystem" as well as data processing routines for noise reduction and cosmic ray rejection.

Presented at the "International Conference On Environmental Systems", July 2009, Savannah, GA, USA, Session: Thermal Testing (Part 1 of 2), ID: 2009-01-2410

The Mid-Infrared Instrument (MIRI) is one of four scientific instruments on the James Webb Space Telescope (JWST) observatory, scheduled for launch in 2014. It will provide unique capabilities to probe the deeply dust-enshrouded regions of the Universe, investigating the history of star formation both near and far. The MIRI is the coldest instrument on the observatory. Its thermal design is driven by requirements to cool an Optics Module (OM) to below 15.5 K and detectors within this to below 6.7 K with a stability of \ml10 mK over 1000 seconds. The OM is accommodated within the JWST Integrated Science Instrument Module (ISIM) which is cooled passively to between 32 and 40 K. The instrument temperatures are achieved by a combination of thermal isolation of the OM and the ISIM supplemented with active cooling of the OM by a dedicated cryo-cooler. A flight representative "verification model" underwent two cryogenic thermal test campaigns at the UK's STFC Rutherford Appleton Laboratory between December 2007 and September 2008. This paper begins by summarizing the thermal design of the MIRI OM and describing the design of the cryogenic test facility. It goes on to describe the two test campaigns and the correlation of the MIRI OM thermal model to the thermal balance test measurements, concluding with the predicted in-flight thermal performance of the instrument based on this testing.

MIRI is the Mid InfraRed Instrument for the James Webb Space Telescope (JWST) and will provide imaging, coronography and integral field spectroscopy in the range between 4.9 and 28.6 micron. We summarise solar system observations which may be possible with this instrument, drawing on examples of observations made with previous space missions such as IRAS, ISO and Spitzer.

Presented at the conference "Future Ground Based Solar System Research, Isola d'Elba, 8-12 September 2008"