Jacques Giroux

Design of the Atmospheric Chemsitry Experiment instrument

The Atmospheric Chemistry Experiment is the mission selected by the Canadian Space Agency for its new science satellite, SCISAT-1. Dr. Peter Bernatch of the University of Waterloo is the ACE Principal Investigator, and ABB Bomem is the prime contractor for the development of the ACE main instrument, a Fourier-Transform Spectrometer. The principal goal of the ACE mission is to measure and understand the chemical and dynamical processes that control the distribution of ozone in the upper troposphere and stratosphere. A comprehensive set of simultaneous measurements of trace gases, thin clouds, aerosols and temperature will be made by solar occultation from a satellite in a low Earth orbit.

Technological evolutions on the FTS instrument for follow-on missions to SCISAT Atmospheric Chemistry Experiment

The Canadian satellite SCISAT-1 developed for the Canadian Space Agency in the context of the ACE mission (Atmospheric Chemistry Experiment) was launched in August 2003. The mission has been a tremendous technical and scientific success. The main instrument of the ACE mission is a high-resolution Fourier Transform Spectrometer (FTS) designed and built by ABB Bomem. Several new missions are currently considered as follow-on to the ACE mission to ensure continuity of the extensive high-quality data set of the Earths atmosphere that was started with the ACE mission, but also possibly to bring new improvements and enhance the utilization of these data. A solar-occultation FTS based on the optical design for ACE-FTS, has been selected for a planetary exploration mission to measure the atmospheric composition of Mars that will launch in 2016. An overview of these different missions will be presented. The need for technological evolutions will be examined for each mission. Some evolutions imply only minor changes, for example, to cope with some parts obsolescence. Others will require increasing instrument capabilities compared to those of the ACE instrument. These different technological evolutions will be presented.

Recent developments on the ACE-FTS instrument

The Atmospheric Chemistry Experiment (ACE) is the mission selected by the Canadian Space Agency for its new science satellite, SCISAT-1. Dr. Peter Bernath of the University of Waterloo is the ACE Mission Scientist, and ABB Bomem is the industrial contractor for the development of the ACE primary instrument. The principal goal of the ACE mission is to measure and to understand the chemical and dynamical processes that control the distribution of ozone in the upper troposphere and stratosphere. A comprehensive set of simultaneous measurements of trace gases, thin clouds, aerosols and temperature will be made by solar occultation from a satellite in a low earth orbit. A high inclination, low earth orbit will allow coverage of tropical, mid-latitude and polar regions. The ACE primary instrument is an infrared Fourier Transform Spectrometer (FTS) coupled with an auxiliary 2-channel visible and near infrared imager. The FTS, operating from 2.4 to 13.3 microns, will measure at high resolution (0.02 cm-1) the infrared absorption signals that contain information on different atmospheric layers to provide vertical profiles of atmospheric constituents. Its highly folded design results in a very high performance instrument with a compact size. The imager will monitor aerosols based on the extinction of solar radiation using two filtered detectors at 1.02 and 0.525 microns. The instrument also includes a suntracker, which provides the sun radiance to both the FTS and the imager during solar occultation of the earths atmosphere. This paper will describe the recent developments on the ACE instrument. Results obtained with the engineering model will be given and the latest status of the flight model will be presented.

Development activities for interferometer-based hyperspectral sounder instrument

A development program was conducted to further improve the technology readiness level of the Generic Flight Interferometer (GFI), a candidate technology for the future hyperspectral sounder on MTG. Interferometer-based sounders have already demonstrated their performance and reliability in conducting advanced sounding tasks in recent missions (METOP-A, IBUKI, SCISAT). The transition from previous single-pixel (or few) to large-format array detectors offering strong hyperspectral capabilities adds technical challenges to the interferometer design. Some of the improvements required to address those challenges have already been implemented in recent deployment of hyperspectral commercial products but must be adapted to the space environment and constraints. Other improvements are dictated by mission specifics but still tend to be recurrent in recent opportunities. The GFI design intent is to regroup these innovations in a generic modular interferometer platform in order to address a variety of missions with minor modifications and hence lower development costs and risks.

Optical performance results for the polar communication and weather mission space technology development program

Current fleet of geostationary Earth orbit (GEO) satellites are used to provide communication in remote areas and to acquire meteorological data that are fed to Numerical Weather Predictions models.

Concept and technology development for the multispectral imager of the Canadian Polar Communications and Weather mission

The Polar Communications and Weather (PCW) mission is proposed by the Canadian Space Agency (CSA), in partnership with Environment Canada, the Department of National Defence, and several other Canadian government departments. The objectives of the PCW mission are to offer meteorological observations and telecommunication services for the Canadian North. These capabilities are particularly important because of increasing interest in the Arctic and the desire to maintain Canadian sovereignty in this region. The PCW mission has completed its Phase A in 2011. The PCW Meteorological Payload is a Multi-Spectral Imager (MSI) that will provide near-real time weather imagery for the entire circumpolar region with a refresh period of 15 to 30 minutes. Two satellites on a Highly Elliptical Orbit (HEO) will carry the instrument so as to observe the high latitudes 24 hours per day from a point of view that is almost geostationary. The data from the imagers are expected to greatly enhance accuracy of numerical weather prediction models for North America and globally. The mission will also produce useful information on environment and climate in the North. During Phase A, a certain number of critical technologies were identified. The CSA has initiated an effort to develop some of these so that their Technology Readiness Level (TRL) will be suitable for the follow-on phases of the program. An industrial team lead by ABB has been selected to perform technology development activities for the Meteorological Payload. The goal of the project is to enhance the TRL of the telescope, the spectral separation optics, and the infrared multispectral cameras of the PCW Meteorological Payload by fabricating and testing breadboards for these items. We will describe the Meteorological Payload concept and report on the status of the development activities.

Development of a micro-satellite compatible FTS sounder for sun-occultation measurements

The SciSat/ACE mission provided, and still provides, high quality and high spectral resolution measurements of the atmosphere with a FTS sounder in sun-occultation configuration. Based on the comprehensive results and models of SciSat/ACE it is foreseen that most of the desired information can also be retrieved from lower spectral resolution measurements with higher signal-to-noise ratio (SNR) and appropriate data treatment. With the Canadian Space Agency under the Space Technologies Development Program, ABB Analytical developed a small size sun-occultation sounder compatible with a micro-satellite platform that has identical throughput, spectral bandwidth and vertical resolution as ACE. The spectral resolution is decreased by a factor 25 (0.6 cm-1 instead of 0.024 cm-1 for ACE) whereas the SNR performance is highly increased with an equal factor (target of 2500 instead of 100 for ACE over most of the spectral bandwidth between 750 and 4000 cm-1).A prototype of the sun-occultation sounder was built, tested under various thermal conditions and subjected to vibrations similar to those expected at launch. An outdoor experiment was also conducted to test the instrument in sun-occultation conditions. The good behavior of the instrument indicates interesting opportunities for such small footprint sounder on a low-cost micro-satellite mission and potentially good earth coverage if several of such instruments are used in coordination. Depending on the scientific needs, it is possible to adapt the proposed instrument to increase the vertical resolution and/or to extend the measurements on lower altitudes due to the higher SNR performances.

A Generic Flight Interferometer for Hyperspectral Atmospheric Sounding from GEO Orbit

A new generation of sensors with hyperspectral capabilities is being considered for future Geostationary Earth Orbiting weather satellite. The World Meteorological Organization now officially considers hyperspectral sounding as a vital part of future geostationary platforms to be deployed beyond 2015. This choice is dictated by the scientific interest for more vertical resolution in the sounder data product which suggests that multi-bandpass filter approaches be replaced by those providing true spectral capabilities. Interferometer based sounders were recently selected in Europe and Japan to fulfill this requirement. They offer the possibility to efficiently combine large format 2D imaging and high spectral resolution into a single instrument. The Generic Flight Interferometer presented in this paper incorporates ABBs latest flight heritage from three recent missions using FTSs. It aims at showing the community that this key sounder module can meet science requirements with low development risk and offer the high reliability required on operational programs. Dedicated risk mitigation activities results conducted on a demonstration interferometer coupled with an imaging detector are discussed.

Engineering model testing activities for ACE

This presentation is an overview of the current engineering model activities around the ACE Fourier transform spectrometer. ACE is a Canadian space mission that will make measurements of the upper atmosphere to support ozone studies.