World Library  
Flag as Inappropriate
Email this Article


Article Id: WHEBN0000664649
Reproduction Date:

Title: Scisat-1  
Author: World Heritage Encyclopedia
Language: English
Subject: Bristol Aerospace, MOST (satellite), Reaction wheel, Atmospheric chemistry observational databases, ISIS (satellite)
Publisher: World Heritage Encyclopedia


Mission type Remote sensing
Operator Canadian Space Agency
COSPAR ID 2003-036A
Website .asp/default/scisat/satellites/
Mission duration 2 years (minimum)[1]
Spacecraft properties
Manufacturer Bristol Aerospace[1]
Launch mass 260 kilograms (570 lb)[1]
Start of mission
Launch date 13 August 2003, 02:09:33 (2003-08-13T02:09:33Z) UTC[2]
Rocket Pegasus-XL F35
Launch site Vandenberg Runway 12/30
Contractor Orbital
Orbital parameters
Reference system Geocentric
Regime Low Earth
Perigee 642 kilometres (399 mi)[1]
Apogee 654 kilometres (406 mi)[1]
Inclination 73.9 degrees[1]

SCISAT-1 is a Canadian satellite designed to make observations of the Earth's atmosphere. Its main instruments are an optical Fourier transform infrared spectrometer, the ACE-FTS Instrument, and an ultraviolet spectrophotometer, MAESTRO. These devices record spectra of the Sun, as sunlight passes through the Earth's atmosphere, making analyses of the chemical elements of the atmosphere possible.

SCISAT is a relatively small satellite weighing 150 kg (~330 pounds). It is partly drum shaped with a diameter of about five feet and a depth of about five feet. The Canadian Space Agency coordinated its design, launch and use. The main contractors were Bristol Aerospace of Winnipeg, Manitoba, who were prime contractor for the bus, and ABB Bomem Inc. of Quebec City, Quebec who developed the ACE-FTS instrument. The total development cost of SCISAT, as estimated [3] by the CSA in 2003, was about CDN$60M. As of 10 years after launch, the satellite and its instruments are still operating.

SCISAT passes through the Earth's shadow 15 times per day, profiting from the occultation of the Sun to make a spectrographic analysis of the structure and chemistry of those parts of the upper atmosphere that are too high to be reached by balloons and airplanes and too low to be visited by orbiting satellites. This kind of analysis can help understand the depletion of the ozone layer and other upper atmosphere phenomena.

SCISAT was placed in low Earth orbit, or LEO, by a Pegasus rocket launched from a NASA Lockheed L-1011 carrier aircraft on August 12, 2003 from Vandenberg Air Force Base. Expected to operate for two to five years, it was still operational in 2014. Current information may be obtained from the ACE Mission Information for Public Data Release report.[4]

The University of Waterloo, York University, the University of Toronto, and several other Canadian universities collaborated in the design of the experiments, and in several aspects of the testing of the satellite.


  • ACE-FTS 1
  • References 3
  • External links 4


The ACE-FTS instrument is the main payload of the SCISAT-1 spacecraft. The primary scientific goal of the Atmospheric Chemistry Experiment (ACE) is to measure and understand the chemical and dynamical processes that control the distribution of ozone in the upper troposphere and stratosphere. The principle of ACE measurement is the solar occultation technique. A high inclination (74 degrees), low Earth orbit (650 km/400 miles) will provide ACE coverage of tropical, mid-latitudes and polar regions.

The spectrometer is an adapted version of the classical Michelson interferometer using an optimized optical layout. Its highly folded double-pass optical design results in a very high performance instrument with a compact size. A signal-to-noise ratio (SNR) better than 100 is achieved, with a field-of-view (FOV) of 1.25 mrad and an aperture diameter of 100 mm (4"). A semiconductor laser is used as the metrology source of the interferometer sub-system.

The auxiliary Visible/Near-infrared Imager (VNI) monitors aerosols based on the extinction of solar radiation using two filtered detectors at 0.525 and 1.02 micrometres. The instrument also includes a Suntracker mechanism providing fine pointing toward the radiometric center of the Sun with stability better than 3 μrad. The ACE-FTS instrument was launched on August 12, 2003.

ABB was the prime contractor for the design and manufacturing of the ACE-FTS instrument.


The Measurements of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation (MAESTRO) instrument aboard SCISAT-1 measures the vertical distribution of ozone, nitrogen dioxide, water vapour, and aerosols in the Earth's atmosphere.[5] MAESTRO consists of a UV-VIS-NIR spectrophotometer that measures the 285-1030 nm spectral region.[6]


  1. ^ a b c d e f "SCISAT". Encyclopedia Astronautica. Retrieved 13 November 2012. 
  2. ^ McDowell, Jonathan. "Launch Log". Jonathan's Space Report. Retrieved 13 November 2012. 
  3. ^ Emerson, David. "Canadian Space Agency Departmental Performance Report For the Period Ending March 31, 2004". Treasury Board of Canada Secretariat.  Table entry "Current Estimated Total Cost" in Section 8.1.8.
  4. ^ "Atmospheric Chemistry Experiment : ACE Mission Information for Public Date Release" (PDF). Retrieved 2013-10-01. 
  5. ^ [2]
  6. ^ "MAESTRO - Atmospheric Chemistry Experiment". Retrieved 2013-10-01. 

External links

  • The Atmospheric Chemistry Experiment (ACE)
  • ABB Bomem, Inc.
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.