According to NOAA, a satellite is a moon, planet, or machine that orbits a planet or a star. Usually the word “satellite” refers to a machine that is launched into space and moves around Earth or another body in space, but there are also natural satellites. For example, Earth is a satellite because it orbits the sun, and the moon is a satellite because it orbits the Earth. This blog will look into a variety of man-made satellites that orbit Earth.
Why are Satellites Important?
Some satellites take pictures of Earth that help meteorologists predict weather and track storms such as hurricanes. Satellites provide a unique, birds-eye view that allows them to see large areas of Earth at one time, which means that they can collect more data, more quickly, than instruments that are on the ground. Some satellites take pictures of other plants, the sun, black holes, dark matter, or faraway galaxies. Satellites are better at looking into space than telescopes here on Earth because they fly above the clouds, dust, and molecules in the atmosphere that can block the view from the surface.
Other satellites are used primarily for communications, like beaming TV signals and phone calls around the world. Before satellites, TV signals could only travel in straight lines so they couldn’t go very far – mountains or tall buildings would block them! Making a phone call to a loved one far away was also difficult. Setting up telephone wires over long distances or under water was difficult and proved to be quite costly. Luckily, TV signals and phone calls can now be sent upward to a satellite and the satellite can send the signals back down to Earth almost instantly! It is amazing to think how far technology has come. There is also a group of approximately 20 satellites that make up the Global Positioning System, or GPS. So if you’ve ever used Google Maps – you have a satellite to thank!
How do Satellites Orbit Earth?
Most satellites are launched into space on rockets and then orbit the Earth when their speed is balanced by the pull of gravity. Without this balance, satellites would fly in a straight line into space or fall back to Earth! Satellites orbit the Earth at different heights, speeds, and along different paths. NASA and other U.S. and international organizations keep close track of satellites in space. Collisions between satellites are rare because when a satellite is launched, it is placed into an orbit designed to avoid other satellites.
The two most common types of orbit are “geostationary” and “polar.” Geostationary satellites travel west to east over the equator. It moves in the same direction and at the same rate Earth is spinning. From Earth, a geostationary satellite looks like it is standing still since it is always above the same location. These satellites typically see less of the Earth, but at a higher resolution, than polar-orbiting satellites. Polar-orbiting satellites travel in a north-south direction from pole to pole. As Earth spins underneath, these satellites can scan the entire globe, one strip at a time.
What is the History of Satellites?
The Soviet Union launched Sputnik 1 into space in 1957. The launch, which was kept a secret from much of the world until its success, stunned much of the world. The United States quickly followed suit and launched Explorer 1 in January of 1958. The main instrument aboard was a sensor that measured high-energy particles in space called cosmic rays. NASA has since launched dozens of satellites into space. The first satellite picture of Earth came from NASA’s Explorer 6 in 1959. TIROS-1 followed in 1960 with the first TV picture of Earth from space. Although these pictures showed relatively little detail (especially compared to what we can see now!), they demonstrated the enormous potential that satellites had to change how people view Earth and space.
How is Information from Satellites Used Today?
NASA satellites help scientists study Earth and space in many ways. Satellites that look towards the Earth provide information about clouds, oceans, land and ice. They also measure gases in the atmosphere, such as ozone and carbon dioxide, and the amount of energy that Earth absorbs and emits. Satellites also monitor wildfires, volcanoes, and their smoke. This multitude of information helps scientists predict the weather and climate, but we aren’t the only ones who utilize information from satellites!
Did you know that public health officials use information from satellites to hep track disease and famine? Farmers also utilize satellite images to determine what crops to plant, the best times to irrigate their fields, and when to harvest their crops. Information from satellites is also critical inn aiding emergency workers who are responding to natural disasters (who can forget the people who were rescued in Florida after Hurricane Michael after their message spelling out “HELP” with downed trees was caught via satellite?). Engineers use satellites to monitor ground movement as well as road stability and bridge structure. Have you ever tracked a friend or family members flight in real time? Guess what – satellites are to thank for that too! Satellites have also taken the “search” out of some “search and rescue missions” for people in distress in remote regions. Distress radio beacons linked to a satellite can lead rescuers quickly and accurately to a land, air, or sea emergency location. 39,000 people worldwide have been saved using the Search and Rescue Satellite-Aided Tracking System.
Satellites that look towards space have a variety of jobs. Some of these satellites watch and monitor for dangerous rays coming from the sun. Others explore asteroids and comets, the history of stars, and the origin of planets. Some satellites fly near or orbit other planets. NASA has even launched an interactive app – Eyes on the Solar System – that lets you explore the planets, their moons, asteroids, comets and the spacecraft exploring them from 1950 to 2050. Satellites have learning in this interactive this possible.
While we may not always realize or acknowledge their existence, the important role these systems play in our daily lives cannot be underestimated. They contribute considerably to our well-being and enable us to achieve our objectives in new and innovative ways. Every single day, satellites are meeting the needs of multiple users, providing information and services to support global communications, the economy, security and defense, safety and emergency management, the environment and health.