The LANDSAT program consists of a series of optical/infrared remote sensing satellites for land observation. The program was first started by The National Aeronautics and Space Administration (NASA) in 1972, then turned over to the National Oceanic and Atmospheric Administration (NOAA) after it became operational. Since 1984, satellite operation and data handling were managed by a commercial company EOSAT. However, all data older than 2 years return to "public domain" and are distributed by the Earth Resource Observation System (EROS) Data Center of the US Geological Servey (USGS).
The first satellite in the series, LANDSAT-1 (initially named as the Earth Resource Technology Satellite ERTS-1) was launched on 23 July 1972. The satellite had a designed life expectancy of 1 year but it ceased operation only on January 1978. LANDSAT-2 was launched on 22 January 1975 and three additional LANDSAT satellites were launched in 1978, 1982, and 1984 (LANDSAT-3, 4, and 5 respectively). LANDSAT-6 was launched on October 1993 but the satellite failed to obtain orbit. A new satellite LANDSAT-7 was launched in 15 April 1999. Currently, only LANDSAT-5 and 7 are operational .
|Repeat Cycle||16 days|
|Band||Wavelength (µm)||Resolution (m)|
|Green||1||0.5 - 0.6||82|
|Red||2||0.6 - 0.7||82|
|Near IR||3||0.7 - 0.8||82|
|Near IR||4||0.8 - 1.1||82|
TM (Thematic Mapper), first operational on LANDSAT-4. TM sensors primarily detect reflected radiation from the Earth surface in the visible and near-infrared (IR) wavelengths, but the TM sensor provides more radiometric information than the MSS sensor. The wavelength range for the TM sensor is from the visible (blue), through the mid-IR, into the thermal-IR portion of the electromagnetic spectrum. Sixteen detectors for the visible and mid-IR wavelength bands in the TM sensor provide 16 scan lines on each active scan. Four detectors for the thermal-IR band provide four scan lines on each active scan. The TM sensor has a spatial resolution of 30 m for the visible, near-IR, and mid-IR wavelengths and a spatial resolution of 120 m for the thermal-IR band.
|Band||Wavelength (µm)||Resolution (m)|
|Blue||1||0.45 - 0.52||30|
|Green||2||0.52 - 0.60||30|
|Red||3||0.63 - 0.69||30|
|Near IR||4||0.76 - 0.90||30|
|SWIR||5||1.55 - 1.75||30|
|Thermal IR||6||10.40 - 12.50||120 (TM) 60 (ETM+)|
|SWIR||7||2.08 - 2.35||30|
|Panchromatic||0.5 - 0.9||15|
The SPOT program consists of a series of optical remote sensing satellites with the primary mission of obtaining Earth imagery for landuse, agriculture, forestry, geology, cartography, regional planning, water resources and GIS applications. it is committed to commercial remote sensing on an international scale and has established a global network of control centres, receiving stations, processing centres and data distributors. The SPOT satellites are operated by the French Space Agency, Centre National d'Etudes Spatiales (CNES). Worldwide commercial operations are anchored by SPOT IMAGE in France with the following subsidiaries: SPOT Image Corp. in the US, SPOT Imaging Services in Australia and SPOT Asia in Singapore.
SPOT 1 was launched on 22 February 1986, and withdrawn from active service on 31 December 1990. SPOT 2 was launched on 22 January 1990 and is still operational. SPOT 3 was launched on 26 September 1993. An incident occured on SPOT 3 on November 14, 1996. After 3 years in orbit the satellite has stopped functioning. SPOT 4 was launched on 24 Mar 1998. Engineering work for SPOT 5 has began so that the satellite can be launched in 2002 to ensure service continuity. To meet the increasing demand for SPOT imagery, notably during the northern hemisphere growing season, SPOT 1 is reactivated in 1997 for routine operation. Currently, three SPOT satellites (SPOT 1, 2, 4) are operational.
The SPOT system provides global coverage between 87 degrees north latitude and 87 degrees south latitude.
|Repeat Cycle||26 days|
|Off-Nadir Revisit||1 to 3 days|
SPOT 1, 2 Twin HRV (SPOT 4 Twin HRVIR) Imaging System
Each SPOT 1 and SPOT 2 satellite carries two HRV sensors, constructed with multilinear array detectors, operating in a cross-track direction. The SPOT 4 satellite carries two HRVIR detectors. The HRVIR is similar to the HRV, except that HRVIR has an additional short wave infrared (SWIR) band, and the wavelength bandwidth of the panchromatic mode for HRVIR is narrower than that for HRV. The position of each HRV or HRVIR entrance mirror can be commanded by ground control to observe a region of interest not necessarily vertically beneath the satellite. Thus, each HRV or HRVIR offers an oblique viewing capability, the viewing angle being adjustable through ±27º relative to the vertical. This off-nadir viewing enables the acquisition of stereoscopic imagery and provides a short revisit interval of 1 to 3 days.
Off-nadir viewing capability of SPOT HRV, HRVIR enables a short revisit interval of 1 to 3 days.
Two imaging modes are employed, panchromatic (P) and multispectral (XS). Both HRVs on the SPOT 1, 2 satellites (HRVIRs on the SPOT 4 satellite) can operate in either mode, either simultaneously or individually.
Panchromatic (P) mode
Imaging is performed in a single spectral band, corresponding to the visible part of the electromagnetic spectrum. The panchromatic band in SPOT 1, 2 HRV covers 0.51 to 0.73 µm. For SPOT 4 HRVIR, the panchromatic band is has a narrower bandwidth centered at the red band (0.61 to 0.68 µm). The panchromatic mode of the SPOT 4 HRVIR is named as the Monospectral (M) mode, to differentiate it from the Panchromatic mode of the SPOT 1,2 HRV. The single channel imaging mode (P or M mode) supplies only black and white images with a pixel width of 10 m. This band is intended primarily for applications calling for fine geometrical detail.
Multispectral (XS) mode
Multispectral imaging is performed in three spectral bands in SPOT 1, 2 HRV. The bands used are band XS1 covering 0.50 to 0.59 µm (green), band XS2 covering 0.61 to 0.68 µ m (red) and band XS3 covering 0.79 to 0.89 µm (near infrared). There is a fourth band in SPOT 4 HRVIR covering 1.53 to 1.75 µm (short-wave infrared). The four multispectral bands of the HRVIR are denoted by XI1, XI2, XI3 and XI4). By combining the data recorded in these channels, colour composite images can be produced with a pixel size of 20 meters.
|Multispectral Mode (XS)||Panchromatic Mode (P)|
|Instrument Field of View||4.13 deg||4.13 deg|
|Ground Sampling Interval (Nadir Viewing)||20 m by 20 m||10 m by 10 m|
|Pixel per Line||3000||6000|
|Ground Swath (Nadir Viewing)||60 km||60 km|
|Mode||Band||Wavelength (µm)||Resolution (m)|
|Multispectral||XS1||0.50 - 0.59 (Green)||20|
|Multispectral||XS2||0.61 - 0.68 (Red)||20|
|multispectral||XS3||0.79 - 0.89 (Near IR)||20|
|Panchromatic||P||0.51 - 0.73 (Visible)||10|
|Mode||Band||Wavelength (µm)||Resolution (m)|
|Multispectral||XI1||0.50 - 0.59 (Green)||20|
|Multispectral||XI2||0.61 - 0.68 (Red)||20|
|Multispectral||XI3||0.79 - 0.89 (Near IR)||20|
|Multispectral||XI4||1.53 - 1.75 (SWIR)||20|
|Monospectral||M||0.61 - 0.68 (Red)||10|
The VEGETATION program is being co-funded by the European Union, Belgium, France, Italy and Sweden and led by French space agency CNES.
|Blue||0.43 to 0.47|
|Red||0.61 to 0.68|
|Near-infrared||0.78 to 0.89|
|Short-wave infrared||1.58 to 1.75|
The MOS program consists of a series of satellites for observation of ocean surface, vegetation, land ecology and measurement of stratospheric water vapour and surface temperature. MOS-1 ("Momo-1"), launched in 19 February 1987, was Japan's first experimental Earth observation mission. The follow-up mission is MOS-1b, launched in 7 February 1990. It also carries a microwave radiometer, besides optical sensors.
Operation of MOS-1 ended on March 31,1995 and at the end of April 1996.MOS-1b operation is terminated, after over six years of service, due to degradation of batteries.
|Repeat Cycle||17 days|
Earth Observing-1 (EO-1) is the first satellite in NASA's New Millennium Program Earth Observing series. EO-1 was launched on 21 November 2000.The EO missions will develop and validate instruments and technologies for space-based Earth observations with unique spatial, spectral and temporal characteristics not previously available.
EO-1's primary focus is to develop and test a set of advanced technology land imaging instruments. However, many other key instruments and technologies are part of the mission and will have wide ranging applications to future land imaging missions in particular and future satellites in general. EO-1 is inserted into an orbit flying in formation with the Landsat 7 satellite taking a series of the same images. Comparison of these "paired scene" images will be one means to evaluate EO-1's land imaging instruments.
A unique feature of the EO-1 mission is that it carries an experimental hyperspectral imager (the Hyperion) that can capture high resolution images of the earth surface in 220 contiguous spectral bands.
|Type||Sun-Synchronous, 10:01 am descending node|
|Repeat Cycle||16 days|
The Hyperion is a "push broom" instrument. It has a single telescope and two spectrometers, one visible/near infrared (VNIR) spectrometer (with CCD detector array) and one short-wave infrared (SWIR) spectrometer (HgCdTe detector array).
|Spatial Resolution||30 m|
|Swath Width||7.75 km|
|Spectral Channels||220 unique channels. VNIR (70 channels, 356 nm - 1058 nm), SWIR (172 channels, 852 nm - 2577 nm)|
|Spectral Bandwidth||10 nm (nominal)|
|Signal-to-Noise Ratio (SNR)||161 (550 nm); 147 (700 nm); 110 (1125 nm); 40 (2125 nm)|
IRS-1 is India's dedicated Earth resources satellite system operated by ISRO and the National Remote Sensing Agency (NRSA). The primary objective of the IRS missions is to provide India's National Natural Resources Management System (NNRMS) with remote sensing data.
|Repeat Cycle||24 days|
|Sensor||Band||Wavelength (µm)||Resolution (m)||Swath Width (km)|
|LISS||1||0.52 - 0.59 (Green)||23.5||142|
|LISS||2||0.62 - 0.68 (Red)||23.5||142|
|LISS||3||0.77 - 0.86 (Near IR)||23.5||142|
|LISS||4||1.55 - 1.75 (SWIR)||70||142|
|PAN||0.5 - 0.90||<10||70.5|
|bands||Wavelength (µm)||Resolution (m)||Swath Width (km)|
RESURS-O is a series of satellites for monitoring natural resources, similar in function to the US LANDSAT series. Operation of the RESURS-O1 series was started in 1985 with the launch of the RESURS-O1-1 followed by two other satellites, the latest of which was launch in November 1994. Data is received at the ground stations in Moscow, Novosibirsk and Khabarovsk. Recently, the data is also downlinked straight from the satellite to the Esrange ground station in northern Sweden. It is now possible to obtain RESURS-O imagery from the Swish Space Corporation (SSC) Satellitbild.
|Repeat Cycle||21 days (4 days revisit at Equator)|
|Band||Wavelength (µm)||Pixel Size (m)|
|1||0.5 - 0.6 (green)||160|
|2||0.6 - 0.7 (red)||160|
|3||0.7 - 0.8 (near IR)||160|
|4||0.8 - 1.1 (near IR)||160|
|5||10.4 - 12.6 (thermal IR)||600|
Source : http://www.crisp.nus.edu.sg