The Mikulski Archive for Space Telescopesb (MAST), a multi-mission archive that hosts science data products for several NASA missions, has since 2003 solicited collections of processed data, termed High-Level Science Products (HLSPs), from investigators with observing and archive science programs. As of early 2018 there were nearly 130 contributed collections, and the growth rate is expected to accelerate with the start of the TESSc and JWSTd missions. While the data volume of all HLSP collections is only about 1% of the total volume hosted by MAST, they have an outsized impact on science. The aggregate downloaded volume for a given HLSP collection is typically about 40 times the collection size, and the citation rates for HLSP collections are significantly higher than that for typical observing programs. Yet hosting HLSPs presents special challenges for long-term archives. It is often problematic to obtain sufficient metadata to specify fully the data products without requiring work from potential contributors that may discourage them from sharing their collections. Historically, preparing an HLSP collection for distribution via MAST has been quite time-consuming and often required substantial interaction with the collection contributors. We are creating a more automated workflow and using new technologies for HLSP collection management to improve collection discoverability, simplify the process for the investigator, ease the burden for MAST staff, and shorten the timeframe for publishing HLSPs. This work will also help MAST staff better assess the impact of HLSP collections on science outcomes for hosted mission data.
In this paper we present the envisaged setup and changes to the current Mikulski Archive for Space Telescopes (MAST) configuration at the beginning of operations for the James Webb Space Telescope mission. The placing of the observatory at L2 and long periods of autonomous operations mean that observations can be split over several time periods or ‘visits’. Data are processed through standard science data reduction pipelines after arriving at the Space Telescope Science Institute (STScI). We describe how data from visits and pipeline processing lead to the data products that are to be stored in the archives. Most observations will require a number of exposures; we discuss the data associations that will formulate the highest level of pipeline products that will be available in the MAST archive for JWST. The JWST observatory has numerous spectroscopic modes, including integral field units and multiple object spectra which will distinguish it from the Hubble Space Telescope archive. We describe the expected data products and services. Finally, we discuss the links to data analysis software and archive products available for user reprocessing.
The Near-Infrared Spectrograph (NIRSpec) is one of the four science instruments onboard the James Webb Space Telescope (JWST). The instrument features a focal plane array (FPA) consisting of two 2048 × 2048 HAWAII-2RG sensor chip assemblies (SCAs) with a cutoff wavelength of approximately 5.3 μm. The detectors are read out via a pair of SIDECAR ASICs. To ensure a stable operating environment and best performance, the FPA is temperature controlled via a dedicated control loop by the NIRSpec focal plane electronics. The targeted in-orbit operating temperature of the NIRSpec FPA is close to 42.8 K. Due to the low background levels that the JWST will provide, most NIRSpec observations of very faint targets will be detector noise limited. Therefore, stringent noise requirements on the detector system were put in place. In order to meet these requirements, NIRSpec offers a dedicated readout mode for its detectors that is called improved reference sampling and subtraction (IRS2 ). In this paper we present the noise performance of the NIRSpec detectors as a function of readout mode and exposure parameters. We find that the NIRSpec detector system meets its stringent noise requirement of 6 electrons total noise in a ∼ 1000 second exposure. We also highlight the types and effects of different kinds of bad pixels that are present in the detectors in small numbers.
The James Webb Space Telescope (JWST) is frequently referred to as the follow-on mission to the Hubble Space Telescope (HST). The “Webb”, as it is often called, will be the biggest space telescope ever built and it will lead to astounding scientific breakthroughs. The observatory is currently scheduled for launch in 2020 from Kourou, French Guyana by an ESA provided Ariane 5 rocket. The Observatory houses four scientific instruments. One of them is NIRSpec, the multi-object Near Infrared Spectrograph, built for ESA by Airbus Defence and Space in Germany. After the JWST Optical telescope Element (OTE) integration and testing was completed in early 2016, the Integrated Science Instruments Module (ISIM) was integrated to the OTE in May 2016. The complete system of OTE and ISIM, now called OTIS, then successfully went through an acoustic and vibration test campaign at NASA Goddard Space Flight Center (GSFC). After this, the OTIS system was shipped to the Johnson Space Center (JSC) in Houston, TX, where a final 100+ days lasting cryogenic vacuum test was conducted inside the famous Thermal Chamber A. This paper presents NIRSpec’s hardware status and some preliminary test results from the OTIS test campaign.
The Near-Infrared Spectrograph (NIRSpec) is one of the four instruments on the James Webb Space Telescope (JWST) which is scheduled for launch in 2018. NIRSpec is developed by the European Space Agency (ESA) with Airbus Defense and Space Germany as prime contractor. The instrument offers seven dispersers covering the wavelength range from 0.6 to 5.3 micron with resolutions from R ∼ 100 to R ∼ 2700. NIRSpec will be capable of obtaining spectra for more than 100 objects simultaneously using an array of micro-shutters. It also features an integral field unit with 3” x 3” field of view and a range of slits for high contrast spectroscopy of individual objects and time series observations of e.g. transiting exoplanets. NIRSpec is in its final flight configuration and underwent cryogenic performance testing at the Goddard Space Flight Center in Winter 2015/16 as part of the Integrated Science Instrument Module (ISIM). We present the current status of the instrument and also provide an update on NIRSpec performances based on results from the ISIM level test campaign.
The James Webb Space Telescope (JWST), scheduled for launch in 2018, promises to revolutionize observational
astronomy, due to its unprecedented sensitivity at near and mid-infrared wavelengths. Following launch, a ~6 month
long commissioning campaign aims to verify the observatory performance. A key element in this campaign is the
verification and early calibration of the four JWST science instruments, one of which is the Near-Infrared Spectrograph
(NIRSpec). This paper summarizes the objectives of the NIRSpec commissioning campaign, and outlines the sequence
of activities needed to achieve these objectives.
This paper describes the Heterodyne Instrument for the Far-Infrared (HIFI), to be launched onboard of ESA's Herschel Space Observatory, by 2008. It includes the first results from the instrument level tests. The instrument is designed to be electronically tuneable over a wide and continuous frequency range in the Far Infrared, with velocity resolutions better than 0.1 km/s with a high sensitivity. This will enable detailed investigations of a wide variety of astronomical sources, ranging from solar system objects, star formation regions to nuclei of galaxies.
The instrument comprises 5 frequency bands covering 480-1150 GHz with SIS mixers and a sixth dual frequency band, for the 1410-1910 GHz range, with Hot Electron Bolometer Mixers (HEB). The Local Oscillator (LO) subsystem consists of a dedicated Ka-band synthesizer followed by 7 times 2 chains of frequency multipliers, 2 chains for each frequency band. A pair of Auto-Correlators and a pair of Acousto-Optic spectrometers process the two IF signals from the dual-polarization front-ends to provide instantaneous frequency coverage of 4 GHz, with a set of resolutions (140 kHz to 1 MHz), better than < 0.1 km/s. After a successful qualification program, the flight instrument was delivered and entered the testing phase at satellite level. We will also report on the pre-flight test and calibration results together with the expected in-flight performance.