Introduction

    Studying the Earth from space has evolved from the realm of pure research to that of worldwide, day-to-day applications. We depend on satellite sensors to assist in tasks ranging, for example, from weather prediction, crop forecasting, mineral exploration, pollution detection, and rangeland monitoring. The development of remote sensing and its use have occurred in a very short period of time and continues to change as new and/or improved satellite sensors are placed into the earth's orbit.

    The most important outcome of development of spaceborne remote sensing has been the role this science and technology has played in conceiving the earth as a system. They fundamentally changed our perception of the Earth from a set of distant, isolated continents to an integrated system of land, ocean, atmosphere, and living things. Satellite remote sensing has brought a new dimension of understanding of the processes that govern our earth atmosphere system and also the impacts of man.

    This lecture focuses on the historical development of remote sensing.
 

History of Satellite Remote Sensing

    Prior to Launch of First Satellite

Satellite remote sensing predates the launch of the satellite.

As early as 1860s, Jules Verne wrote about "Lunanauts" observing cloud systems.

Mid 19th century early cameras were first sent aloft in balloons.

At the beginning of 20th century, a passenger in an airplane piloted by Wilbur Wright made the first photographs from an airplane over Centocelli, Italy.

By the late 1940s, rockets carrying cameras were being launched into sub-orbital flights. The photographs that they returned gave rise by the early 1950s to serious scientific discussion of the possibility of observing the weather from space. Several groups pursued the idea of launching a weather satellite -

- U.S. Army Evans Signal Laboratory
- University of Wisconsin

Efforts were intensified after the launch by the Soviet Union on Oct 4, 1957 of the first successful Earth Satellite, Sputnik 1.
- era of remote sensing began
- provided first space views of our planet's surface and atmosphere


First successful U.S. satellite, Explorer 1, was launched on Jan 31, 1958 (123 days later).

These early days are chronicled in proceedings volumes edited by Vaughan (1982) and Vonder Haar et al. (1982).

Of particular importance to space flight, in general, was the formation of the National Aeronautics and Space Administration (NASA) on Oct 1, 1958.

- for more than 30 yrs, NASA has lead the development of all types of scientific satellites used for civilian purposes
- involved from the beginning in satellite meteorology/climatology were agencies that now are components of U.S. National Oceanic and Atmospheric Administration (NOAA), particularly the U.S. Weather Bureau

U.S. launched (April 1, 1960) the 1st generation of polar-orbiting meteorological satellites, the Television and Infrared Observation Satellite (TIROS-1), which provided the first systematic cloud cover photography and observations of Earth with broad-band visible and infrared imagery.

     TIROS-1 22nd successfully launched satellite

- imaging-making instrument on TIROS 1 was a vidicon camera (adaptation of a standard television camera)
- 1st image returned by TIROS 1
-- although crude by today standards, TIROS 1 image generated immense excitement
-- for the 1st time we could view the Earth and its weather systems as a whole
-- not only have satellite observations become essential for meteorology/climatology; they have fundamentally changed our perception of the Earth from a set of distant, isolated continents to an integrated, inseparable system of land, ocean, atmosphere, and living things
-- nearly 23,000 images were returned in the 79-day lifetime of TIROS 1
1961: A manned Mercury satellite successfully took the first photographs of the Earth's surface from space.

TIROS series
- TIROS 8 launched on Dec 21, 1963 introduced Automatic Picture Transmission (APT). A new camera with 800-line resolution was scanned at slow rate of 4 lines/s and data were immediately broadcast to the Earth at very high frequency (VHF). Slow transmission rate meant that inexpensive equipment could be used to receive and display the images. Thus anyone w/ proper equipment could directly receive weather satellite images as the satellite passed by 2/day. APT is still an important function on today's polar-orbiting weather satellites.


1964:  NASA initiated the Nimbus series of experimental satellites.  These were primarily experimental platforms to test instrument concepts and to make measurements on a global basis. Nimbus Series

1965:  First complete view of the world's weather was taken by the TIROS-9, the first to be in sun-synchronous orbit (passing over any point on Earth at approx. the same time each day)

1966:  A new era in meteorological observations opened with the launch of the first geostationary spacecraft, Applications Technology Satellite-1 (ATS-1) by NASA.  The ATS carried the spin-scan radiometer, which provided the first continuous observations of cloud and severe weather tracking from a stationary platform.    ATS Series

1967:  The first full-disk image of the Earth was produced by the U.S. ATS-3 satellite.  The U.S. also put into orbit the first infrared sounder for global temperature soundings.  3 ATS satellites were flown in the next 10 years.

1968:  U.S. launched its first Geodetic Earth Orbiting Satellite (GEOS)

1969:  U.S. Nimbus-3 provided the 1st global vertical temperature profiles of the atmosphere.  Nimbus 3

-- carried two instruments - satellite infrared spectrometer (SIRS) (measurements in 15um portion of spectrum and forerunner to today's operational sounding instruments) and infrared interferometer spectrometer (IRIS) (measured spectra in infrared from 6 to 25um)
-- designed to provide atmospheric soundings from space
-- for first time, satellite data used quantitatively in numerical weather-prediction models

1970: The decade began with Nimbus-4, which provided the first global ozone profiles.

1972:  U.S. launched the first Earth Resources Technology Satellite (ERTS), which provided the first multispectral map of the surface of the Earth.  In 1975, satellite was renamed to Landsat, the first in an ongoing series that now totals 6.

1973:  The first active microwave sensor, operating as an altimeter, scatterometer and radiometer was flown on NASA's Skylab.

1974:   First generation of semioperational geostationary meteorological satellites began with the launch of the Synchronous Meteorological Satellite 1 (SMS 1) on May 17, 1974 (forerunner of the Geostationary Operational Environmental Satellite (GOES) system).

- these SMS satellites carried the first Data Collection Platform (DCP) repeater. Data from meteorological or other platforms on the surface could be relayed by the satellite to a central receiving site.
- since Jun 27, 1974, when SMS 1 became operational, we have had continuous, uninterrupted, 24 hr/day monitoring of most of the Western Hemisphere from space

Astronauts abroad Skylab used multcamera systems to provide Earth images in several bands.

NASA's Nimbus-5 carried the 1st  Electronically Scanned Microwave Radiometer.

- First microwave sounding device, Nimbus Experimental Microwave Spectrometer (NEMS) was onboard Nimbus-5
-- nadir viewing 5-channel instrument
-- demonstrated the capability to probe through clouds, even dense overcast
-- good comparisons of ITPR, NEMS, and radiosonde data were achieved
-- found that best results were achieved from an amalgamation of infrared and microwave radiance data in the temperature profile inversion process thereby proving maximum available thermal information, regardless of cloud condition

1975: The first truly operational geostationary meteorological satellite, the Geostationary Operational Satellite 1 (GOES 1), was launched on Oct 16, 1975.
- GOES Program
- U.S. has generally maintained 2 geostationary satellites in orbit, 1 at 75 degrees W and another at 135 degrees W longitude

Nimbus-6 provided the 1st atmospheric limb scanner and the 1st global Earth radiation budget measurements.

1976:  U.S. launched the 1st satellite in its Defense Meteorological Satellite Program (DMSP).

1977:  1st of the U.S. large-scale agricultural studies by satellite, the Large Area Crop Inventory Experiment (LACIE)

1st microwave sounder with all-weather sounding capability.

1978:  A "vintage" year for remote sensing.  NASA launched 2 satellites using new microwave techniques that have had a major impact on subsequent systems.

- Seasat, a satellite devoted to measurements of the oceans, which provided global measurements of winds at the ocean surface, sea surface topography, surface and internal waves and bathymetry in shallow regions
- Nimbus-7, last of the Nimbus series, which provided a number of firsts including global ocean color measurements and daily mapping of ozone concentration (the Nimubs-7 is still flying, although many of the instruments are not operating)

NASA also launched the Heat Capacity Mapping Mission with a scanning visible and infrared radiometer for geological and vegetation mapping.

Third generation of U.S. polar-orbiting metsats began on Oct 13, 1978 with launch of TIROS N. This series continues today.

U.S. Solar Maximum Mission began to provide the 1st continuous measurements of the radiation from the sun.

 
1980:  Era of Geostationary sounding began in Sept. 1980 with launch of Visible Infrared Spin Scan Radiometer (VISSR) Atmospheric Sounding (VAS).  GOES Sounder
- time continuous 3-D probing of atmosphere is accomplished using 12 infrared spectral bands in imaging or a sounding mode
- filter wheel in front of the detector package is used to achieve spectral selection
- central wavelengths of spectral bands lie between 3.9 and 15um
- VAS radiometer observes upwelling radiation in 2 windows (4.0 and 11um), 3 water vapor channels, and 7 regions of 4.3 and 15um CO2 bands
- housed in GOES satellite, VAS spins in west to east direction at 100 rpm and achieves spatial coverage at resolutions of 1km in visible and 7 or 14 km in infrared
  - spatial coverage, time of observation, and spectral bands are programmed into an onboard processor from the ground

GOES 4 launched on Sept. 9, 1980 was first of the second generation GOES satellites. Discuss in more detail when cover Satellite Systems later in semester
Launch of Meteor-3 1 on July 26, 1988 by Soviet Union

1981:  First study by NASA of the Earth's aurora from space and the beginning of the U.S. Space Shuttle program, which provided many opportunities for orbiting cameras and imaging instruments over the next 5 years.

The first Shuttle Imaging Radar (SIR-A) was flown on the Space Shuttle.

Satellites Explorer 1 and 2 measured the impact of solar radiation on the atmosphere, auroral displays, and climate and weather.

1982:  U.S. Thematic Mapper on Landsat provided the 1st high-resolution multi-wavelength images of Earth.

Landsat Program designed for land remote sensing with extremely high resolution with 80m in first satellite and up to 30m in the lasted (Landsat 7). Landsat 1 was called Earth Resources Technology Satellite (ERTS) launched on July 23, 1972.

1984:  U.S. launched the Earth Radiation Budget Satellite (ERBS)
Earth Radiation Budget Satellite
- carried two instruments
Earth Radiation Budget Experiment (ERBE)
Stratospheric Aerosol and Gas Experiment II
- nonsunsynchronous orbit so that its measurements will sample all local times

1986:  France successfully launched the Satellite Pour l'Observation de al Terra (SPOT) satellite.  This was 1st in a series of satellites for the commercial production of images of the Earth.
Spot System

In U.S., EOSAT company began operating the Landsat system on a commercial basis.

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Last revised September 7, 1999.