yee@ames.arc.nasa.gov (Peter E. Yee) (01/25/89)
Paula Cleggett Headquarters, Washington, D.C. January 23, 1989 Jim Wilson Jet Propulsion Laboratory, Pasadena, Calif. RELEASE: 89-9 NASA SELECTS ATMOSPHERIC SOUNDER FOR EOS SPACE PLATFORM NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif., has established a new scientific instrument project office to develop and design a major new system for observing Earth's atmosphere. Scientists expect it to support a quantum leap in weather forecasting and in understanding our climate. The instrument, called the Atmospheric Infrared Sounder (AIRS), was selected by NASA in late November 1988 to ride aboard the Earth Observing System (EOS) polar orbiting platform, as a facility instrument, beginning in the 1990s. This platform is an element of NASA's Space Station Freedom and proposed "Mission to Planet Earth" programs. EOS also is one of several Earth- orbiting scientific platforms planned by the U.S. and other nations. The AIRS system will provide global, three-dimensional information on the temperature and composition distributions in the atmosphere (including humidity and clouds) as well as climate-related properties of the sea and land. It also will measure and help map ozone and various other "greenhouse" gases. AIRS will observe both day and night. The instrument is designed to scan 45 degrees East and West from the North-South suborbital track aboard the EOS platform. It is being planned to operate 435 miles above the Earth in a 100- minute, circular orbit. AIRS will observe the atmosphere and surface in elements about 10 square miles and perceive the atmosphere in mile-thick vertical layers. It will be designed to read the temperature in each of these elements to an accuracy of approximately 1 degree Celsius (about 2 degrees Fahrenheit). The value of AIRS will be the continuous long-term record it compiles of climate change. "We can see and measure changes in global temperature over periods of one or more solar cycles," says Dr. Moustafa Chahine, JPL's chief scientist and an atmospheric physicist. "We will have records of trends in the greenhouse effect, both in the composition and movement of gases which cause it and in regional patterns of moisture and air circulation which may result from it. These are long-term changes, in contrast to weather patterns and are very subtle." These measurements will be derived from infrared radiation data. The Earth emits electro-magnetic radiation which peaks in the infrared wavelength region. Some of this radiation is absorbed by gases in the atmosphere. The atmospheric gases themselves also radiate in the infrared. Determining wavelength bands the gases absorb and radiate and how intense the radiation is in the various bands will help determine such things as composition and temperature. AIRS will be able to make measurements in 256 spectral channels in the infrared spectrum (from 3 to 17 microns in wavelength). Accurate temperature mapping may require the use of 50 to 100 of these channels. Data processing will be the key to AIRS. Scientists have been developing the algorithms (the complex of formulas used by scientists and their computers to turn the measurements into useful parameters) needed to process, use and understand AIRS data. These include computer models of the atmosphere which AIRS will help to refine as well as use in generating maps of the parameters retrieved after the use of the algorithms. It is anticipated that processing and interpreting the large constellation of AIRS measurements will call for large-scale computers in the "super" class, possibly parallel-processor designs. AIRS is similar in some respects to the ATMOS experiment flown aboard a Shuttle flight in the spring of 1985 and planned for another Shuttle mission as part of the Atlas 1 mission. There are substantial differences in the two systems in their resolutions (how small an element of atmosphere each can pick out) and in the length of their observing periods. "ATMOS can observe the makeup of the upper atmosphere better than AIRS for a short period, but only AIRS can stay at its post observing changes year in and year out," says project manager Fred O'Callaghan, who is in charge of both efforts at JPL. "With refurbishments, we hope to get 15 years or more out of the AIRS instrument". AIRS will be a "facility" instrument aboard the EOS platform. That is, it will function more like a laboratory or observatory than an instrument designed and operated by a single scientist or single team. A scientific committee to be selected by NASA will oversee its use and data records will be archived for later research as well as for immediate use. The AIRS project is part of JPL's Office of Space Science and Instruments. The EOS scientific program is administered by Dr. Shelby Tilford of NASA's Office of Space Science and Applications, Washington, D.C. and the first orbiting platform will be managed by NASA's Goddard Space Flight Center, Greenbelt, Md.
tneff@well.UUCP (Tom Neff) (01/30/89)
How can something like EOS - in polar orbit - be "part of" the Space Station? Is that just the budget cubbyhole? Also, how does NASA plan to "refurbish" AIRS if it's in polar orbit? Is this dependent on a working OMV? Surely a polar Shuttle mission would be too expensive for a purpose like this. -- Tom Neff tneff@well.UUCP or tneff@dasys1.UUCP
henry@utzoo.uucp (Henry Spencer) (02/09/89)
In article <10522@well.UUCP> tneff@well.UUCP (Tom Neff) writes: >How can something like EOS - in polar orbit - be "part of" the Space >Station? ... As both the NRC and me -- two illustrious authorities :-) -- have pointed out, nothing in polar orbit has any rational connection with the space station whatsoever. -- Allegedly heard aboard Mir: "A | Henry Spencer at U of Toronto Zoology toast to comrade Van Allen!!" | uunet!attcan!utzoo!henry henry@zoo.toronto.edu