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570 miles above you, an electronic eye is scanning the earth. It’s focus is on the land – the geological make-up of the earth we live on. It is called Landsat. How can Landsat help you?
There are currently two Landsats. Each one passes directly overhead once every 18 days. It is constantly taking pictures from it’s polar orbit. For Landsat to be of value each of its orbits must be over a different area. By having a polar orbit this is made possible. As the satellite travels from north to south, the earth is slowly turning beneath it. Over time, Landsat’s two satellites are able to cover every place on Earth. Positioning the Satellites at the Poles also allows for a constant angle of the Sun in pictures, which is a great help in map making.
So what does Landsat actually do to benefit mankind? Well, in the week after it was launched it identified more than 30 previously unknown geological features in just one part of California. It was also busy identifying new oil reserves that were worth over 1 billion dollars by 1977. Landsat was also proving very valuable in identifying crop types and predicting harvest times. In a study with wheat, harvest yields were predicted well in advance with a 90 percent accuracy rate. Before long private companies were utilising such information and selling it to private buyers. Crop and harvest forecasts are especially useful in developing countries. It allows them to accurately forecast possible famines and put emergency measures into place well in advance.
Landsat provides high resolution pictures by means of a device called a multispectral scanner. The satellite has a mirror which scans back and forth looking at a strip of ground below. Light from the ground bounces off the mirror and goes into a telescope where it is focused on four sets of light detectors. Each of these sets of detectors is sensitive to a different kind of light. The resulting image is in the form of pixels, each of which has a corresponding number indicating how strong it appears in each wavelength in which it is viewed. The four numbers, then, are like a fingerprint telling the analyst exactly what is being viewed.
With regard to developing countries, however, there is a problem with Landsat. To turn the data generated from Landsat into useable information, computer technology and trained experts are needed. This of course takes money. Unfortunately many less developed countries cannot afford this technology. However it is often the case that multi national oil and mineral companies operating within such countries do have such technology and are, in fact, routinely analysing Landsat data for their own commercial ends. These companies are then able to lease the information to the Government. This has, however, created an atmosphere of mistrust between the Governments of these less developed countries and the big oil and mineral companies, who have better information about the country than the Government. Some Governments have actually nationalised the oil and mineral industries in order to secure control over Landsat data.
Another problem with Landsat arises with regard to the level of resolution used in analysing Landsat photographs. Countries are now developing technology to allow them to greatly improve the resolution of such images. If such information is used, not by farmers or oil companies, but by intelligence gathering bodies of hostile nations real security problems emerge. In fact, the subject of what level of resolution civil survey satellites should be allowed to have has been heatedly debated in the United Nations.
So, like many other of man’s technological achievements Landsat offers great potential for good. But it also has much potential for bad. Speculators could, for example, use crop forecasts to manipulate commodities markets. Mineral and oil information could lead to widespread plunder by greedy multi national companies. Countries could use Landsat information to find out vital security information about their neighboring countries.
With the success of Landsat the United States launched an ambitious satellite in June of 1978 called Seasat-A. Unlike the light waves used by Landsat, Seasat incorporated high resolution radar which allowed it to observe ocean conditions. After just four months of operation, however, Seasat went dead. This was due to a massive short circuit onboard Seasat. The multi-million dollar satellite was now useless. What had caused the problem? A NASA inquiry concluded that human error was to blame. According to that report, “a test was waived without proper approval, important component failures were not reported to project management , compliance with specifications was weak and flight controllers were inadequately prepared for their task.”
All of which goes to show that no matter how clever man’s technology becomes, it is always dependant for it’s success on a less than perfect operating device – man himself.
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