The Herschel SPIRE On-Board Software (OBS) is presented. This real time operational software controls the scientific
data transmission and keeps a control layer between the SPIRE Mission Timeline (MTL) and the real instruments status.
It embeds a multithreaded engine that interprets control procedures for the detector and mechanism subsystems. An
autonomous monitoring agent keeps control of subsystems status, and takes local decisions based on pre-loaded reaction
maps. The behaviour of low level system functions is configurable remotely via the reactions maps and control
We describe the current state of the ground segment of Herschel-SPIRE photometer data processing, approximately
one year into the mission. The SPIRE photometer operates in two modes: scan mapping and chopped
point source photometry. For each mode, the basic analysis pipeline - which follows in reverse the effects from
the incidence of light on the telescope to the storage of samples from the detector electronics - is essentially
the same as described pre-launch. However, the calibration parameters and detailed numerical algorithms have
advanced due to the availability of commissioning and early science observations, resulting in reliable pipelines
which produce accurate and sensitive photometry and maps at 250, 350, and 500 μm with minimal residual
artifacts. We discuss some detailed aspects of the pipelines on the topics of: detection of cosmic ray glitches,
linearization of detector response, correction for focal plane temperature drift, subtraction of detector baselines
(offsets), absolute calibration, and basic map making. Several of these topics are still under study with the
promise of future enhancements to the pipelines.
The Spectral and Photometric Imaging Receiver (SPIRE) is one of three scientific instruments onboard the European
Space Agency's Herschel Space Observatory launched on 14 May 2009. The low to medium resolution spectroscopic
capability of SPIRE is provided by an imaging Fourier transform spectrometer of the Mach-Zehnder configuration.
Results from the in flight performance verification phase of the SPIRE spectrometer are presented and conformance with
the instrument design specifications is reviewed.
SPIRE, the Spectral and Photometric Imaging Receiver, is a submillimetre camera and spectrometer for Herschel. It
comprises a three-band camera operating at 250, 350 and 500 µm, and an imaging Fourier Transform Spectrometer
covering 194-672 μm. The photometer field of view is 4x8 arcmin., viewed simultaneously in the three bands. The FTS
has an approximately circular field of view of 2.6 arcmin. diameter and spectral resolution adjustable between 0.04 and 2
cm<sup>-1</sup> ( λ/▵λ=20-1000 at 250 μm). Following successful testing in a dedicated facility designed to simulate the in-flight
operational conditions, SPIRE has been integrated in the Herschel spacecraft and is now undergoing system-level testing
prior to launch. The main design features of SPIRE are reviewed, the key results of instrument testing are outlined, and
a summary of the predicted in-flight performance is given.
We describe the on-board electronics chain and the on-ground data processing pipeline that will operate on data from the
Herschel-SPIRE photometer to produce calibrated astronomical products. Data from the three photometer arrays will be
conditioned and digitised by on-board electronics and sent to the ground with no further on-board data processing. On
the ground, the data pipeline will process the data from point source, jiggle-map, and scan-map observations in a fully
automatic manner, producing measured flux densities (for point source observations) or maps. It includes calculation of
the bolometer voltages from the raw telemetry, glitch removal, and corrections for various effects including time
constants associated with the detectors and electronics, electrical and optical crosstalk, detector temperature drifts, flatfielding,
and non-linear response of the bolometers to strong sources. Flux density calibration will be with respect to
standard astronomical sources with the planets Uranus and Neptune being adopted as the baseline primary standards.
The pipeline will compute estimated values of in-beam flux density for a standard flat <i>νS(ν) </i>source spectrum.
SPIRE, the Spectral and Photometric Imaging Receiver, is a submillimetre camera and spectrometer for the European Space Agency's Herschel Space Observatory. It comprises a three-band imaging photometer operating at 250, 360 and 520 μm, and an imaging Fourier Transform Spectrometer (FTS) covering 200-670 μm. The detectors are arrays of feedhorn-coupled NTD spider-web bolometers cooled to 0.3 K. The photometer field of view of is 4 x 8 arcmin.,
observed simultaneously in the three spectral bands. The FTS has an approximately circular field of view with a diameter of 2.6 arcmin., and employs a dual-beam configuration with broad-band intensity beam dividers to provide high efficiency and separated output and input ports. The spectral resolution can be adjusted between 0.04 and 2 cm-1 (resolving power of 20-1000 at 250 μm). The flight instrument is currently undergoing integration and test. The design of SPIRE is described, and the expected scientific performance is summarised, based on modelling and flight instrument test results.
The Spectral and Photometric Imaging REceiver (SPIRE) is one of the three scientific instruments to fly on the
European Space Agency's Herschel Space Observatory, and contains a three-band imaging submillimetre photometer
and an imaging Fourier transform spectrometer. The flight model of the SPIRE cold focal plane unit has been built up
in stages with a cold test campaign associated with each stage. The first campaign focusing on the spectrometer took
place in early 2005 and the second campaign focusing on the photometer was in Autumn 2005. SPIRE is currently
undergoing its third cold test campaign following cryogenic vibration testing. Test results to date show that the
instrument is performing very well and in general meets not only its requirements but also most of its performance
goals. We present an overview of the instrument tests performed to date, and the preliminary results.
The Spectral and Photometric Imaging REceiver (SPIRE) is one of the three scientific instruments on the European Space Agency's Herschel mission. At the start of 2004 the Cryogenic Qualification Model (CQM) of SPIRE was tested with the aim of verifying the instrument system design and evaluating key performance parameters. We present a description of the test facility, an overview of the instrument tests carried out on the CQM, and the first results from the analysis of the test data. Instrument optical efficiency and detector noise levels are close to the values expected from unit-level tests, and the SPIRE instrument system works well, with no degradation in performance from stray light, electromagnetic interference or microphonically induced noise. Some anomalies and imperfections in the instrument performance, test set-up, and test procedures have been identified and will be addressed in the next test campaign.
The Far InfraRed and Submillimeter Telescope (FIRST) is the last of the four Cornerstone Missions in the 'Horizon 2000' long term science plan of the European Space Agency (ESA) and as an observatory type mission it will be open to the international astronomical community. Its launch is presently foreseen for the end of 2005. The nominal mission duration will be 4.5 years and the active archive phase 3 years. Taking into account the experience from other ESA missions and in order to minimize costs, the ground segment for FIRST scientific operations will be structured in a novel 'decentralized' way, creating centers of competence.
For successful, continued, operation of space-based instruments over the lifetime of a satellite it is common practice to put into place procedures to identify, investigate and monitor long term trends in the characteristic parameters of an instrument in order to be able to take action before a failure of the instrument or a subsystem occurs. With the advent of more sophisticated instrumentation and the need for efficient utilization of ground-based telescopes, there is an increasing need to carry out this function as part of the routine operations of ground based observatories. This paper characterizes the types of trend data that may be obtained during the lifetime of an instrument and presents examples of such data taken from the long wavelength spectrometer instrument on-board the IR space observatory. The resulting actions taken to minimize the possibility of failure of subsystems and to maximize the scientific output from the instrument will be discussed.
The Infrared Space Observatory (ISO) has a complement of four focal plane instruments for making a range of astronomical observations at infrared wavelengths. The telescope and instruments are operated at cryogenic temperature. Spectroscopy is shared between two of these instruments, with the Long Wavelength Spectrometer (LWS) providing for spectroscopic observation over the wavelength range 43 micrometers to 198 micrometers at two resolving powers. The flight model of the LWS has been completed, following an extensive program of performance testing and calibration at the Rutherford Appleton Laboratory. For this, a test facility has been developed to provide the necessary operating and environmental conditions, including a very low thermal background. The design and operational details of the test facility are given, followed by examples of the LWS performance values obtained. The data from these measurements will provide the initial calibration of the LWS in-orbit.
The Infrared Space Observatory (ISO) is essentially a cooled 60cm diameter telescope with four flocal plane instruments operating at cryogenic temperature. One of these instruments, the Long Wavelength Spectrometer (LWS), offers spectroscopic capability over the wavelength range 43 micrometers to 198 micrometers , with a choice of either a mid-resolving power mode (R approximately equals 200) or a higher resolution mode (R approximately equals 10000). For testing the Flight Model of the LWS, it is necessary to establish many of the operating conditions which will apply when it is operating in space, using a specially constructed calibration facility. These tests have enabled the operating modes of the LWS to be refined, as well as measuring its operational performance and establishing a calibration database. This data will provide the initial calibration for the LWS when operating in-orbit.