In 1988, astronauts aboard the space shuttle looked down on South America and saw a 1,000-kilometer-long smoke cloud that covered the entire Amazon basin and was only stopped by the towering wall of the Andes mountains. The haze of smoke came from the burning of the Amazon rain forest, a region containing the world’s greatest variety of plants and animals. That vast spread of smoke was clearly visible to the astronauts, who were in a unique position to see how and where humans are altering natural ecosystems on planet Earth.
That is precisely what scientists plan to learn by using space to take an inventory of natural resources and to investigate environmental problems.
Cameras, radar systems, and other remote sensing instruments aboard spacecraft will zoom in on the Earth from high, high above. Remote sensors offer a relatively inexpensive way to monitor the whole planet over long periods of time.
By the end of the ’90s, the National Aeronautics and Space Administration (NASA) will launch a high-tech program called Mission to Planet Earth. It will diagnose the Earth’s condition using remote sensors aboard weather and other satellites, earth probes (small spacecraft used to study specific problems), the space shuttle, and Space Station Freedom. Reports from space will be transmitted to a computerized network that will sort and store huge amounts of information. This database will allow scientists to produce better maps, images, chemical analyses, and models of Earth.
Nature in Action
The space shuttle, orbiting more than 200 kilometers above the earth, will continue to view the spectacle of nature in action. Astronauts will photograph such activities of nature as the Mississippi River dumping its load of sediment into the Gulf of Mexico, hurricanes roaring across the oceans, and blooms of plankton (microscopic organisms that serve as food for larger marine life) drifting at the ocean’s surface near the coasts. During week-long flights, astronauts probably will see at least three erupting volcanoes.
Unmanned spacecraft will also provide a worldwide perspective of the earth’s environment. Weather forecasts will improve as intruments are used that can read air and sea temperatures, follow storm paths, track currents, and measure ice cover. Satellites will also do further studies on “holes” in the ozone layer of the atmosphere. (The ozone layer shields living things from the sun’s ultraviolet radiation.) Sensors that “sniff” the chemical composition of the atmosphere will analyze pollutants. They will also detect increases in carbon dioxide, methane, chlorofluorocarbons, and other gases that retain heat in the atmosphere and contribute to global warming.
Two Landsats–spacecraft that orbit the earth every eight days–will continue to map cities as well as remote regions of the earth. They will be joined by other satellites that will increase the accuracy of records on soil erosion, the size of crops, and the growth of deserts.
“Eyes in the sky” will assist rescue efforts during earthquakes, hurricanes, or volcanic eruptions. Scientists are already using information from space to speed emergency services and guide restoration efforts after natural disasters.
Something for Everyone
During the 15-year Mission to Planet Earth, not only government leaders, but also city planners and ordinary citizens will benefit from studies of the Earth. Spacecraft will take a look at:
* The sun: Satellite instruments will examine how much sunshine is received and how much is reflected by the Earth. Since solar energy drives the winds, the oceans, and photosynthesis (food-making by green plants), sun studies will improve our analysis of weather, crops, and global warming.
* The lithosphere (Earth’s crust): Space-based instruments will report where earthquakes might occur, where volcanoes erupt, and where underground oil, gas, and water may be found.
* The atmosphere (the Earth’s blanket of air): Spacecraft will track paths of pollution and measure winds, clouds, the ozone layer, and gases that contribute to global warming.
* The hydrosphere (water in rivers, lakes, oceans, ice, and clouds): Satellites will record sea surface temperature, ice cover, rainfall, rivers, and sediment distribution. They will determine where currents flow, where nutrients rise from the ocean floor, and where large schools of fish are likely to be found.
* The biosphere (the living world of plants, animals, and microorganisms): Astronauts and instruments will observe how much forest and fertile land is being destroyed, where plankton is concentrated along coasts, and identify crops, trees, and other vegetation.
An International Endeavor
Mission to Planet Earth will be an international endeavor, with space scientists, meteorologists, ocean scientists, biologists, and ecologists working together. Each person will embark on this mission knowing that all the earth’s systems are interdependent; that what happens in the Amazon rain forests influences what happens in The Great Plains and near the poles; and the pollution travels by winds and water to many nations.
These scientists know that cities and wilderness influence one another, and that human beings are intimately connected with all living things. Therefore, by discovering how natural ecosystems interact, the people on Mission to Planet Earth hope to protect every kind of life in the world.