Following Landsat and SPOT, other earth-observing satellite programs proliferated. Several are sponsoreded by international governments while others are now operated by private industry. Some spacecraft supported exclusively, or primarily, radar sensors. (These are considered again on page I-25 (two pages hence) and in more detail on page 8-7.)
The European Space Agency (ESA) sent two missions, ERS-1 in March, 1991 and ERS-2 in April, 1995 with radar systems. Here is the ERS-1 spacecraft and a scene (southern coast of Finland) it acquired:
Envisat is an ESA satellite that has both wide and medium angle viewing sensors as well as radar. The satellite looks like this and has these instruments: Envisat home page
The ASAR radar on Envisat imaged the east coast of Sri Lanka shortly after the massive tsunami struck in December, 2004 (see second page of Overview):
Starting in the mid 1980s, the Soviet Union (and now Russia) entered the world arena with an Earth-observing satellite program available on the open market. Prior to that, the USSR had the largest 'competitive' space program next to the U.S.'s. Most of its unmanned satellite programs had primarily military surveillance and support objectives. The first surveillance system was Zenit-2, launched in 1961. Some data were released but the bulk were kept secret, with the data used internally within the Soviet Union. The earth-observing programs evolved from some of these earlier satellite missions. A simplified chain of missions leading to these programs begins with the Meteor Series (meteorological) --> Okean Series (oceanographic) --> Salyut/Almaz series --> ResursF1 and F2 series --> Resurs-O --> Resurs-F (these are not progressive but overlap). We will only consider a few of these in the next paragraphs. To get more insight, log on to these websites:Soviet/Russian space systems and Soviet and Russian earth observation systems. We will not show any results from the Meteor, Okean and Almaz series here. Consult these sites for descriptions and a few images.
The Resurs (also presented as RESURS) program has a long history. We will simplify it, mentioning only a few aspects. The Resurs F series has operated for more than 40 years - most of this time for military purposes. These spacecraft were about 7 meters long, as shown here
This group containing high resolution photo-cameras and after a few weeks released the camera package in a capsule for return to Earth by parachute (this retrieval method is discussed on page I-26e. Cameras used include those designated KATE-200, KVA-1000, and KVR-1200. Here is a view into one such capsule, showing the cameras in place:
This is a Resurs-F photo of the Vatican and adjacent Rome (you will see high resolution images of the Vatican again in Section 6):
The camera retrieval program, which utilizes low cost equipment, continues with a 2006 launch of the first Resurs-DK spacecraft, shown below:
The Russian film retrieval technique is at the heart of its SPIN-2 series. Resolution of 2 meters is achieved in the film products. This quality enticed the TerraServer Corp. into partnership to distribute the imagery to a worldwide market. This scene of downtown Manhattan (pre-mid2001; can you tell how this is known?) shows the sharpness of this photography (compare this scene to the one shown on page 2 of the Overview and another on page 4-3 of Section 4).
The RESURS-01 series (4 so far) provided a multispectral system (3 Vis-NIR bands; 2 thermal) whose resolution (160 m, and 600 m for thermal) is intermediate between that of Landsat/SPOT and the AVHRR on meteorological satellites. Like Landsat RESURS are placed in near-polar, sun-synchronous orbits. A drawing of the Resurs01-3 spacecraft appears here:
Two images from this RESURS system appear below: the first is a false color composite Moscow and its surroundings.
The second RESURS (Resources) image is part of a mosaic of Europe which here includes all of Norway, Sweden, and Denmark, and part of Finland and several Baltic nations.
The National Space Agency of the Ukraine begn its own program of space observations in 1992; it works in cooperation with the Russian Federation in using certain facilities. Its OKEAN series includes multispectral scanners, thermal sensors, and radar. Two MSU-V images (50 m resolution) show a standard false color composite (left) of the southern Crimea (Sebastapol in lower left) and a different color combination (right) of the Dnieper River in the Ukraine Lowlands, with Kiev just below the upper "lake" (caused by river damming).
India successfully operates several Earth-resources satellites that gather data in the Visible and Near IR bands, beginning with IRS-1A in March of 1988. The latest in the series, IRS-1D, launched on September 29, 1997. Its LISS sensor captures radiation in the blue-green, green, red, and near IR bands at 23 m spatial resolution. The spacecraft also produces 5.8 m panchromatic images, as well as 188 m resolution wide-field (large area) WiFS multispectral imagery. Below are three recent images from this system, the one on the top (WiFS) showing the Grand Canyon of Arizona, in the middle a three-band color composite made by the 23 m LISS, showing mountainous terrain and pediments with alluvium fans in southern Iran, and at the bottom a 5.8 meter panchromatic view of part of the harbor at Tamil Nadu in India.
On December 4, 2003 the IRS program orbited the first in a new series, ResourceSat-1, whose multiple sensors produce multispectral images at 56, 23 and 5 meters. Details on its orbital parameters and instrument capabilities are found at this Internet Site Here are several examples of the imagery its produces; location and resolution is given in the captions (remember, click on lower right of the image).
More information on the Indian remote sensing program is available on this Wikipedia website.
The Japanese, beginning in 1990, have flown JERS-1 and JERS-2 which include optical and radar sensors. Here is an artist's conception of JERS-1 in space:
The optical system is a seven band scanner similar in coverage to the TM. The satellites are operated by the National Space Agency, JAXA Here is a false color JERS-1 image of Tokyo and Tokyo Bay:
NASDA's ALOS (Advanced Land Observation Satellite) was successfully launched on January 23, 2006. The ALOS has three remote-sensing instruments: the Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) for digital elevation mapping, the Advanced Visible and Near Infrared Radiometer type 2 (AVNIR-2) for precise land coverage observation, and the Phased Array type L-band Synthetic Aperture Radar (PALSAR) for day-and-night and all-weather land observation. Here is the spacecraft:
This scene of Naples, Italy and the Bay of Naples is typical of AVNIR inagery:
Using digitized land elevation data convolved with a corresponding AVNIR image, the ALOS can produce a perspective scene, such as this view of the Kujyu mountain range in Japan:
It is increasingly common now for earth-observing satellites to have a radar system working in conjunction with a visible imager. Here is a view of a fjord near Bergen, Norway imaged by ALOS PALSAR radar:
The Peoples Republic of China has joined forces with the Brazilian government to develop a series of earth-observing satellites launched by Long March rockets from China. Their program goes by the name of CBERS (China-Brazil Earth Resources Satellites); in China these satellites are called the Zujuan series. CBERS-1 was orbited on October 14, 1999. It includes three sensors: 1) WFI (300 km swath; 260 m resolution; 4 bands); 2) IR-MSS (20 km swath; 80 m resolution; 4 bands including thermal); and 3) CCD (20 m resolution; 4 bands). The more than 280000 images received are concentrated mainly over Brazil and China and are not generally available to other nations. CBERS-2 (YZ-2) was launched on September 1, 2000; although reputed to be available for earth resources applications, western observers have concluded that its 3-meter resolution sensor is being used primarily for military reconnaissance. Here is a CBERS-1 CCD image of the area in Brazil that includes the capital, Brazilia.:
The British, in cooperation with the various national space agencies, have developed a program that is inserting into (700 km altitude) orbits a series of small (440 kilograms [200 lbs]) but versatile satellites (because of their size, referred to as Microsatellites consisting of a single sensor that can image in the green, red, and near IR wavelength band intervals. This is the DMC (Disaster Monitoring Consortium) program which will (as now planned by the end of 2003) have four similar satellites in staggered orbits that have spacings and repeat cycles which allow any location on Earth to be visited once during a 24 hour period. The sensor can cover an area 600 x 600 km (roughly, 400 miles on a side) in dimension at a resolution of 34 km. Higher resolution - smaller area - coverage is also an option. While capable of many scene monitoring and classification tasks, the prime utilization which is the "selling point" for this system of "formation flying" satellites (see page 16-11) is to obtain images that (if clouds are not a hindrance) can see damage or other consequences of a group of natural or manmade disasters detectable at the resolutions available. The first satellite (AlSat-1) was built at Surrey, England for operation by Algeria. This is AlSat-1 seen in its fabrication room.
An image encompassing part of the U.S. Southwest from ALSat-1 appeared at the bottom of page Overview-2. Below are two more ALSat-1 images, the first including the land adjacent to Colorado River between Arizona and California and the second a smaller area view of Las Vegas, Nevada.
Others in this series are BilSat (Turkey), UK-DMC (England), NigeriaSat (Nigeria), and ThakPaht (Thailand).