Marc-André Soucy

Atmospheric Chemistry Experiment (ACE): Mission overview

SCISAT-1, also known as the Atmospheric Chemistry Experiment (ACE), is a Canadian satellite mission for remote sensing of the Earths atmosphere. It was launched into low Earth circular orbit (altitude 650 km, inclination 74°) on 12 Aug. 2003. The primary ACE instrument is a high spectral resolution (0.02 cm-1) Fourier Transform Spectrometer (FTS) operating from 2.2 to 13.3 μm (750-4400 cm-1). The satellite also features a dual spectrophotometer known as MAESTRO with wavelength coverage of 285-1030 nm and spectral resolution of 1-2 nm. A pair of filtered CMOS detector arrays records images of the Sun at 0.525 and 1.02 μm. Working primarily in solar occultation, the satellite provides altitude profile information (typically 10-100 km) for temperature, pressure, and the volume mixing ratios for several dozen molecules of atmospheric interest, as well as atmospheric extinction profiles over the latitudes 85°N to 85°S. This paper presents a mission overview and some of the first scientific results. Copyright 2005 by the American Geophysical Union.

On-orbit commissioning of the ACE-FTS instrument

The Atmospheric Chemistry Experiment (ACE) is the mission selected by the Canadian Space Agency for its science satellite, SCISAT-1. ACE consists of a suite of instruments in which the primary element is an infrared Fourier Transform Spectrometer (FTS) coupled with an auxiliary 2-channel visible (525 nm) and near infrared imager (1020 nm). A secondary instrument, MAESTRO, provides spectrographic data from the near ultra-violet to the near infrared, including the visible spectral range. In combination the instrument payload covers the spectral range from 0.25 to 13.3 micron. A comprehensive set of simultaneous measurements of trace gases, thin clouds, aerosols and temperature will be made by solar occultation from a satellite in low earth orbit. The ACE mission will measure and analyze the chemical and dynamical processes that control the distribution of ozone in the upper troposphere and stratosphere. A high inclination (74 degrees), low earth orbit (650 km) allows coverage of tropical, mid-latitude and polar regions. The ACE/SciSat-1 spacecraft was launched by NASA on August 12th, 2003. This paper presents the on-orbit commissioning of the ACE-FTS instrument. Various steps were required to safely and progressively activate each module and sub-system of the instrument. This paper describes each step and its relation with the health and safety of the instrument. The overall strategy and sequence of the commissioning activity is presented. Commissioning results are presented in terms of validation of instrument functionality from an engineering perspective. The characterization of the detector contamination is described as well as methods that were developed to mitigate this issue.

ACE-FTS instrument: after five years on-orbit

The Atmospheric Chemistry Experiment (ACE) is the mission on-board Canadian Space Agencys science satellite, SCISAT-1. ACE consists of a suite of instruments in which the primary element is an infrared Fourier Transform Spectrometer (FTS) coupled with an auxiliary 2-channel visible (525 nm) and near infrared imager (1020 nm). A secondary instrument, a grating spectrometer named MAESTRO, provides spectrographic data from the near ultra-violet to the near infrared, including the visible spectral range. With all instruments combined, the payload covers the spectral range from 0.25 to 13.3 micron. A comprehensive set of simultaneous measurements of trace gases, thin clouds, aerosols and temperature are being made by solar occultation from this satellite in low earth orbit. The ACE mission measures and analyses the chemical and dynamical processes that control the distribution of ozone in the upper troposphere and stratosphere. A high inclination (74°), low earth orbit (650 km) allows coverage of tropical, mid-latitude and polar regions. The ACE/SciSat-1 spacecraft was launched by NASA on August 12th, 2003. This paper presents the status of the ACE-FTS instrument, after nearly five years on-orbit. On-orbit SNR and some telemetry signals are presented. The health status of the instrument is discussed.

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.

A new imaging FTIR spectroradiometer

ABB Bomem is expanding its line of infrared remote sensing products with the addition of a new imaging spectroradiometer. That hyperspectral instrument is based on the proven MR FTIR spectroradiometers. This field instrument, called the MR-i, is a fast imaging Fourier Transform spectroradiometer. It generates spectral data cubes in the MWIR and LWIR. It is designed to be sufficiently fast to acquire the spectral signatures of rapid events. The design is modular. The two output ports of the instrument can be populated with different combinations of detectors (imaging or not). For instance to measure over a broad spectral range, one output port can be equipped with a LWIR camera while the other port is equipped with a MWIR camera. No dichroics are used to split the bands, hence enhancing the sensitivity. Both ports can be equipped with cameras serving the same spectral range but set at different sensitivity levels in order to increase the measurement dynamic range and avoid saturation of bright parts of the scene while simultaneously obtaining good measurement of the faintest parts of the scene. Various telescope options are available for the input port. This is a presentation of the current state of the development.

On-orbit performance of the ACE-FTS instrument

The Atmospheric Chemistry Experiment (ACE) is the mission selected by the Canadian Space Agency (CSA) for its science satellite, SCISAT-1. ACE consists of a suite of instruments in which the primary element is an infrared Fourier Transform Spectrometer (FTS) coupled with an auxiliary 2-channel visible (525 nm) and near infrared imager (1020 nm). A secondary instrument, MAESTRO, provides spectrographic data from the near ultra-violet to the near infrared, including the visible spectral range. In combination the instrument payload covers the spectral range from 0.25 to 13.3 micron. A comprehensive set of simultaneous measurements of trace gases, thin clouds, aerosols and temperature are made by solar occultation from a satellite in low earth orbit. The ACE mission measures and analyses the chemical and dynamical processes that control the distribution of ozone in the upper troposphere and stratosphere. A high inclination (74 degrees), low earth orbit (650 km) allows coverage of tropical, mid-latitude and polar regions. The ACE/SciSat-1 spacecraft was launched by NASA on August 12th, 2003. This paper presents the on-orbit performance of the ACE-FTS instrument. The commissioning activities allowed the activation of the various elements of the instrument and the optimization of several parameters such as gains, integration times, pointing offsets, etc. The performance validation was the last phase of the instrument hardware commissioning activities. The results of the performance validation are presented in terms of on-orbit instrument performance with respect to instrument requirements such as signal-to-noise ratio, transmittance accuracy, and spectral resolution. Results are also compared to ground validation tests performed during the thermal-vacuum campaigns. Performance is presented in terms of validation of instrument from an engineering perspective.

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.

Range image integration for direct replication of objects

Laser range sensors measure the 3D coordinates of points on the surface of objects. Range images taken from different points of view can provide a more or less complete coverage of an objects surface. The geometric information carried by the set of range images can be integrated into a unified, non-redundant triangular mesh describing the object. This model can then be used as the input to rapid prototyping or machining systems in order to produce a replica. Direct replication proves particularly useful for complex sculptured surfaces. The paper will describe the proposed approach and relevant algorithms, and discuss tow test cases.

Design and Qualification of the TANSO Interferometer

The Greenhouse gases Observing SATellite will monitor global distributions of CO2. This paper presents the interferometer designed for the Thermal And Near infrared Sensor for carbon Observation FTS along with qualification and performance verification activities.