Old satellite images

Annotation

The article emphasizes the importance of using old satellite images as tools for historical and scientific research, as well as for making informed decisions in the fields of geopolitics and ecology. The article also describes various methods used for processing and interpreting satellite images, such as analysis of long-term variability, comparison of satellite images from different years, and interpretation of data using geographic information systems (GIS). Readers can learn about the tools and technologies used for processing and interpreting satellite images, and how this information can be used for various purposes including scientific research, urban planning, assessment of natural disaster consequences, and more. Overall, the article can be valuable for professionals in the fields of science, geopolitics, ecology, geography, as well as for those interested in history and the development of our planet.

History of the Creation of Old Satellite Images

The first-ever space photograph was taken on 24.10.1946, and the first satellite under the corresponding name "Sputnik-1" was launched into space on 04.10.1957. The first photos of Earth were taken using the V-2 rocket. These were the world's first long-range ballistic missiles, produced in Germany during World War II. However, after the defeat, they were confiscated, and more than 100 units in disassembled form were sent to the United States, where they began to be re-equipped with instruments for studying the atmosphere.

Fig.1. Photograph of the planet taken by the V-2 rocket. 24.10.1946

 

The rocket launched in October 1946 was equipped with a black-and-white 35-millimeter movie camera. The rocket reached an altitude of approximately 105 kilometers and took a picture every one and a half seconds. 

From 1946 to 1950, over a thousand images of Earth were obtained from space, some of which were taken at altitudes exceeding 160 km. During this time, the USA launched 63 V-2 rockets for research purposes. The first photographs of our planet published in newspapers and magazines were described as "How Earth will look to visitors from another planet arriving on a spaceship".

Fig.2. First space panorama of Earth, created from photos taken by the V-2. 26.07.1948

The history of creating old satellite images dates back to the 1950s when the USA and the USSR began launching the first artificial Earth satellites. One of the first satellites launched into space was the USSR's "Sputnik-1", launched in 1957. This satellite used radar equipment to measure the height and distance to the Earth's surface.

Fig.3. Image of satellite "Sputnik - 1"

The next step in satellite imaging was taken in 1960 when the first satellite equipped with a camera was launched - the "CORONA" satellite, publicly known as "Discoverer". The satellites had the code names KH - KeyHole It had to conduct reconnaissance primarily over the USSR and China. The camera was specially developed to take pictures of the Earth from space and had a high resolution, allowing to see objects the size of 12 meters. Later missions significantly improved on this parameter, reducing it to only 1.5m. One launch was performed with a resolution capability of up to 0.30m, but the limited field of view was deemed ineffective. However, the first photographs taken with this camera were unsuccessful, and only a few years later were high-quality satellite images obtained.

Fig.4. Image of the Soviet "lunar" rocket N-1, obtained by the KN-8 device 19.09.1968

The last launch of the satellite under the Corona program was made on 25.05.1972.

The project was suspended due to the detection of a Soviet submarine waiting in the area of capsule landing in the Pacific Ocean.

The most successful period of filming was 1966—1971, when 32 successful launches returned usable photofilm.

Fig.5. Diagram showing the process of separating the descent vehicle from the satellite, entering the atmosphere, and catching the parachute capsule with a special aircraft.

In 1972, the first Landsat satellite system was launched for monitoring the Earth and collecting environmental data. The Landsat system used a special multispectral camera capable of registering various spectral characteristics of objects on Earth. This improved the quality of satellite images and expanded their range of applications.

Fig. 6. Image of Landsat 1 satellite

In subsequent years, other satellite systems were launched, such as the NOAA satellite system for weather monitoring and the Terra satellite system used for studying climate and the environment.

Today, satellite images are widely used in various fields such as geography, ecology, agriculture, forestry, geology, archaeology, and many others. Furthermore, old satellite images obtained decades ago can also be used to study changes in Earth's environment and climate, as well as the history of land use.

Until 2000, a number of satellites with different characteristics were launched by various countries:

1. Landsat - a series of American medium-resolution satellites (30 meters), launched since 1972. They created multispectral images in the visible and infrared spectrum used for mapping, studying forests, agriculture, and geology.
2. SPOT (Satellite Pour l'Observation de la Terre) - a series of French satellites launched in 1986. They had high resolution (up to 2.5 meters) and were used to create detailed images of cities, transportation networks, and other objects.
3. NOAA (National Oceanic and Atmospheric Administration) - an American satellite launched in 1972. It was used to obtain information about cloud cover, ocean currents, and other meteorological data. Image resolution ranged from 1.1 km to 4 km.
4. Kosmos - a Soviet satellite launched in 1985. It was used to create panoramic images of Earth and had a resolution up to 500 meters.
5. ИСЗ "Электрон" - a Russian satellite launched in 1994. It was used to create panoramic images and had a resolution up to 1 km.
6. Landsat-7 - an enhanced version of the American Landsat satellite, launched in 1999. Image resolution was 15 meters.
7. IRS (Indian Remote Sensing) - a series of Indian satellites launched since 1988. They had resolutions ranging from 5.8 to 70 meters and were used for mapping, agriculture, and other applications.
8. Ресурс-Ф - a series of Soviet (Russian) remote sensing spacecraft. Used for national economy and natural resource management from 1973. Multi-spectral data with a resolution of 6–8 meters was collected using the MK-4 sensor.
9. KeyHole satellites — the general name for the American military reconnaissance satellite series of the “Corona” program. The spacecraft in this series were used for detailed optical reconnaissance of the territory of the USSR, China, and other potential adversaries of the USA. A total of 13+ types of KeyHole satellites were developed and launched from 1959.

Technology of Creating Old Satellite Images

The technology used to create old satellite images depended on the specific type of satellite and the era in which they were taken. However, in general, the process of creating satellite images proceeded as follows:

1. Capture: Satellites used cameras to capture images of the Earth's surface. Photos could be taken in different ranges (visible, infrared, radio wave) and had varying resolutions. The early images were captured on film.
2. Delivery: First-generation reconnaissance satellites took photographs and then released containers with exposed photographic film, which descended to Earth. Capsules were retrieved mid-air during descent via parachute. Later spacecraft were equipped with phototelevision systems and transmitted images via encrypted radio signals.
3. Development of Photograph: During the development process using chemical agents, the film was processed to fix and reproduce the images captured by the camera.
4. Scanning or Enlarging: Negatives obtained could either be scanned to obtain a digital version of the image or used to create enlarged prints.
5. Processing: If images were scanned, they could undergo further digital processing to enhance quality, color correction, detail refinement, and more. Image processing software significantly improved the original images.
6. Storage: Images were stored in film capsules, on magnetic media, or electronically on servers.

The technology for creating satellite images has evolved significantly over time, and modern satellites use more advanced cameras and data transmission methods. However, old satellite images still hold great value in scientific and historical research.

Fig. 7. Satellite image from 1965

Processing and Analysis of Old Satellite Images

The methods for processing old satellite images depended on the technological capabilities and data processing methods available at the time the images were created. Let's consider several processing methods used for old satellite images:

1. Mosaic of Images: To create a comprehensive picture of terrain across different study areas, old satellite images were merged into a single image. This method allowed for creating maps and atlases for various regions.
2. Calibration: Old satellite images had varying accuracies that could be improved through calibration. This method established correspondence between pixels in the image and points on the Earth's surface.
3. Noise and Distortion Removal: Methods such as filters were used to improve the quality of images obtained from old satellite photos by removing noise and distortions.
4. Interpolation: To fill gaps in old satellite images caused by cloud cover or other reasons, interpolation methods were used. They allowed filling in missing data using information from neighboring pixels.
5. Information Extraction: Old satellite images could be used to extract information about various objects on the Earth's surface such as buildings, roads, rivers, and other features. Methods used included object detection, machine learning, and other image analysis techniques.

Processing and analyzing old satellite images were significantly constrained by technological capabilities and data processing methods available at the time they were created. However, some processing and analysis methods used for old satellite images included:

1. Rectification: Rectification methods were used to correct errors in geometric accuracy of old satellite images. It aligned images and established correspondence between points on the Earth's surface and pixels in the image.
2. Image Enhancement: Old satellite images often contained noise and distortions that hindered interpretation. Image enhancement techniques, such as filters to remove noise and other artifacts, were used to improve image quality.
3. Object Detection: Various methods for object detection were employed to identify and extract information about objects such as buildings, roads, rivers, etc. These methods involved machine learning, classification, segmentation, and other image analysis techniques.
4. Map and Model Creation: Old satellite images were used to create maps and landscape models, which were useful for studying natural phenomena, landscape changes, and other geospatial research.

Modern data processing and image analysis methods enable obtaining more precise and detailed results compared to what was possible with old satellite images.

Satellite Image Archives

There are numerous archives where old satellite images can be found. Some of these archives offer the ability to search for images by year:

• Google Earth: Provides access to satellite images from 1984 to the present. Select the corresponding option from the menu on the left and navigate the map to view images from different years.
  
  

Fig. 8. Google Earth Image from 1985

• USGS EarthExplorer: This archive offers access to satellite images from 1972 to the present. Here you can select a specific year to view available images.
  
  

  Fig. 9. List of Images from USGS in 1999

• LandsatLook Viewer: Provides access to Landsat satellite images from 1972. Here you can select a year and region to view available images.
• NOAA View: This archive contains NOAA satellite images from 1975. You can select a year and area to view available images.
• NASA Earthdata Search: This archive contains a large number of satellite images from various missions including Landsat, MODIS, ASTER, and others. Here you can select year, region, and mission to find the images you need.
• The European Space Agency (ESA) Sentinel Hub EO Browser: Provides access to Sentinel satellite images from 2014. Here you can select year, region, and product type to find the images you need.
  
  

Fig. 10. Hungary Image from 2015

• DigitalGlobe ImageLibrary: This archive contains a large number of DigitalGlobe satellite images from 2002. Here you can select year, region, and image resolution to find the images you need.
• NOAA Climate Data Online (CDO): This archive contains climate and environmental data, including satellite images from 1974. Here you can select year, data type, and area to find the images you need.
• USGS National Map: This service provides access to a variety of data, including satellite images from 2003. Here you can select year, area, and image type to find the images you need.
• RetroMap Website: An online archive of old satellite images, providing access to over 500,000 Earth images taken by satellites from the 1950s to the 2000s. The site allows you to find images of various regions of the world, taken by different satellites and in different years. Additionally, the site offers the ability to search by coordinates and dates.
  
  

Fig. 11. Example from RetroMap, Satellite Image of Leningrad on 17.07.1966

Currently, there are several other ways, besides the above, to obtain old satellite images. For example, you can contact specialized companies such as LLC "GEO Innovator," which sells old satellite images. Our company can provide access to a wider range of images than free archives and offer data processing and analysis services. Another method is to contact government agencies and scientific organizations. LLC "GEO Innovator" has its own archive of old satellite images.

Fig. 13. Coverage of Iran Territory by satellite images of the KA "Resource-F" with the onboard sensor KFA-1000.

Limitations and Issues of Using Old Satellite Images

Limitations and issues of using old satellite images include:

1. Limited spatial resolution: Old satellite images have low spatial resolution, meaning they cannot provide detailed information about small objects on Earth's surface. This can hinder studies that require high levels of detail.
2. Limited spectral resolution: Old satellite images may have limited spectral resolution, meaning they cannot provide complete information about different types of land surface. Some applications, such as soil type determination or vegetation state assessment, may be hindered by this.
3. Limited availability: Some satellite images may be unavailable for use due to technical issues such as data loss, equipment damage, or simply lack of copies. Additionally, access to some satellite images may be restricted due to political or legal reasons.
4. Inability to obtain current data: Images cannot provide current information about the state of Earth's surface. This can limit their use for applications such as monitoring natural disasters or environmental changes.

Application of Old Satellite Images Today

Old satellite images find application in various fields of remote sensing.

Study of land use changes: These images can be used to analyze changes in land use over many years. They help in studying the impact of human activities on the environment, such as urban expansion, deforestation, and changes in land cover.

Archaeology and history: Old satellite images can be utilized for archaeological research of historical sites. They assist in identifying archaeological features like fortresses, burial mounds, and ancient cities.

Fig. 12. Traces of the layout of the burnt city of Kunya-Urgench in 1968

Study of climate change: Old satellite images can be used to analyze climate changes over many years. This aids in understanding global climate trends and weather pattern changes.

Cartography: Satellite archive images can be used to create maps and terrain models. This is useful in various fields such as geology, environmental conservation, and urban planning.

Reconnaissance: Old satellite images can be used for reconnaissance of military facilities and locations of army bases, as well as for detecting changes in terrain that may indicate potential military actions.

Legal purposes: Archived images provide an objective representation of the terrain on a specific date.

It is worth noting that the use of old satellite images has its limitations and issues, such as low spatial resolution and limited availability of images.

Conclusion

Old satellite images have significant potential for use in modern Earth remote sensing tasks. They can provide valuable information about the state of the natural environment, climate changes, topography, and much more. Additionally, they can be used for comparison and analysis of changes over long periods of time. However, the use of old satellite images also has its limitations and challenges, such as low spatial resolution and limited availability of archives. It is important to remember that to maximize the benefits of these images, they should be carefully selected for specific tasks, undergo necessary data processing and analysis, and consider possible constraints. Despite all the challenges, old satellite images remain a valuable resource for scientific and applied tasks in remote sensing, complementing modern data and enhancing the accuracy and completeness of research.