Artificial Satellites

The requirement is to place the satellite in such a way that it appears motionless in the sky, as seen from the surface of the earth. This is a great advantage in satellite communication, because if the satellite appears stationary, then the dish antenna on the ground doesn't have to move to follow the satellite ... the dish can be aimed once, and can stay in the same position permanently. In order to have the satellite appear motionless, it has to follow the 24-hour rotation of the earth. The orbital period of any satellite's revolution (around a much larger body) depends only on the average orbital distance. For the earth, the period of a 238,000-mile orbit (where the moon is) is about 27 days, and the period of an orbit that averages about 22,400 miles is 24 hours. So a communications satellite in an orbit with this average distance will complete one revolution around the earth in 24 hours. Wherever it is right now, it will appear in the same exact place 24 hours from now. This is a "geosynchronous" orbit. But that's not good enough yet. The orbit may have the right average distance, but it may still be very eccentric, ranging from close-in to way-out in the course of 24 hours. If that's the case, then it will move faster when it's closer in, and slower when it's farther out. Watching it from the earth, it'll appear to move back and forth like a pendulum, returning to the same position every 24 hours but making a complete left-right swing every day. This still wouldn't be useful for stationary ground-based dish antennas. So another restriction on the orbit is that it must not only be at the correct average distance, but it must also be very close to a circular shape, so that the satellite's speed in the orbit is nearly constant. And there's yet one more requirement that the orbit has to satisfy. Consider this in your imagination: There can't be an orbit where the satellite circulates over, say, a little 20-mile circle around the North Pole. A satellite orbit has to revolve around the "whole earth", which is a clunky way of saying that the center of the earth has to be in the plane of the orbit. The orbit can "incline" as much as you want ... the satellite can stay over the equator all the time, or swing from North pole to South pole and back again, but the center of the orbit always has to be at the center of the earth. Now you can see the final requirement for a communications satellite: If the orbit is inclined to the equator, then the satellite will appear to swing above and below its average location in the sky every 24 hours, which also makes it hard for a stationary antenna on the ground. The orbit has to be oriented at 'zero inclination', meaning it lies directly above the equator at every point. Now, finally, with a nearly circular, equatorial orbit, of exactly the right size, the satellite appears motionless in the sky, and all those little 18-inch TV dishes on the neighborhood rooftops can be pointed once at the satellite and never need to move. A satellite in this orbit is not only "geosynchronous" (24-hour orbital period), but also "geostationary" ... motionless relative to a point on the earth.

Satellite data provide crucial information on various aspects of the Earth's environment, such as weather patterns, climate change, land cover changes, and natural disasters. This information helps scientists monitor and predict environmental changes more effectively, leading to better resource management and mitigation strategies.

At 5km up the Satellite would still be in the earths atmosphere and would also be subject to gravity. Put simply it would just fall back down. Space starts at about 100km up or 62 miles. The moon also has 1/6ths of Earths gravity and at 5km up there would be little if any pull from the moon.

there once was a boy called john. He was not the usual boy, he liked satellites. One day he designed a satellite and threw it up into the sky.

therefore the satellite's orbit is called Destroyer 556.

Earth observation satellites collect data about a strip of Earth's surface by taking high-resolution images and capturing various types of data such as vegetation health, land use, and weather patterns. These satellites orbit the Earth and use sensors to collect information about specific regions on the planet.

A planet's gravity affects the trajectory of a space probe by pulling it towards the planet, causing the probe to alter its course. The probe's speed and direction can be influenced by the planet's gravity, leading to changes in its orbit or flight path. Scientists must account for the planet's gravitational pull when planning the probe's trajectory to ensure it reaches its intended destination.

Not very much, I would say. There is no work being done in this situation so there's no change in kinetic energy. So the satellite's speed remains constant.

But we already knew the speed was constant. Perhaps I'm missing something.

LANDSAT is a series of satellites that photograph the Earth.

The Landsat program is the longest running enterprise for acquisition of imagery of Earth from space. The first Landsat satellite was launched in 1972; the most recent, Landsat 7, was launched on April 15, 1999. The millions of images images, archived in the United States and at Landsat receiving stations around the world, are a unique resource for global change research and applications in agriculture, cartography, geology, forestry, regional planning, surveillance, education and national security. Landsat 7 data has eight spectral bands with spatial resolutions ranging from 15 to 60 meters; the temporal resolution is 16 days.

Sailors and pilots use Global Navigation Satellite Systems (GNSS) such as GPS (Global Positioning System) to determine their exact location. These systems rely on a network of satellites to provide accurate positioning data anywhere on Earth.

A satellite in orbit around the Earth does not fall into the Earth because the force of Gravity between the satellite and Earth is exactly balanced by the centripetal reaction force of the satellite constantly changing direction.

Think of driving in a car in a straight line. Now, think about turning right. You will be pulled towards the left. Well, actually, you are going in a straight line and the car is moving to the right. That causes you to drift towards the left. You encounter the door, and now you are going to the right as well. The door is pushing on you towards the right, and you are pushing towards the left against the door. The force pushing you towards the right is sort of like Gravity, while the force you are pushing on the door to the left is your centripetal reaction force. Since you are going in a constant speed circle, these two forces are balanced. Its the same type of thing as a satellite.

Sphere shaped

Studying space is important as it helps us understand our place in the universe, the origins of life, and the potential for future exploration and colonization. It also leads to technological advances that benefit society in various ways, from communication to medical research.

Monitoring satellites are typically put into polar orbits, allowing them to cover the entire surface of the Earth as it rotates. These orbits are ideal for Earth observation missions because they provide global coverage and revisit the same area at regular intervals.

It uses 66 small satellites in low earth orbit

India's second satellite launched in 1979 was named Bhaskara-I. It was an experimental Earth observation satellite designed for remote sensing applications.

Studying outer space helps us understand the universe, the formation of stars and planets, and the possibility of life beyond Earth. It also contributes to technological advancements and inspires curiosity and wonder about our place in the cosmos.

Satellite channels can contribute to cultural erosion by promoting Western values and consumerism, diluting local traditions, and homogenizing global culture. However, they can also facilitate cultural exchange and provide access to diverse perspectives, so the impact depends on the content and how it is consumed.

They stand for United States Geological Survey. The United States Geological Survey makes maps.

A GPS receiver typically needs signals from at least 3 satellites to calculate a 2D position (latitude and longitude) and 4 or more satellites for a 3D position (latitude, longitude, and altitude). The receiver uses the signals from multiple satellites to triangulate its position on Earth.

The first law states that an object in motion stays in motion unless acted upon by an external force. The meteor impact imparts an external force that changes the satellite's motion.

The second law describes how force equals mass times acceleration, which means the satellite's mass and the force of the meteor impact determine the resulting acceleration.

Finally, the third law states that for every action there is an equal and opposite reaction, so the satellite exerts a force back on the meteor as it is knocked out of orbit.

they use sensors to measure the shallow depths of the ocean and can detect variations in sea surface height caused by the gravitational pull of the seafloor's features. This data is then used to create maps of the seafloor topography and to study ocean currents, tides, and marine habitats.

The earth's orbit around the sun is elliptical, so the earth moves at a constantly varying velocity as it moves closer to the sun (perihelion) or further away (aphelion). The earth's angular velocity (speed of movement) is considerably greater at perihelion than it is at aphelion.

So in that sense, the earth orbits at a constantly varying speed.

But there is a sense in which the earth orbits at constant speed. Similar segments of the elliptical orbit are crossed in similar lengths of time wherever the earth is in its orbital path. The earth gets through 10% of its path in the same length of time whether it is at aphelion (moving slowly) or perihelion (moving fast).

The absolute speed at which the earth moves varies, but the rate at which it orbits is constant.

---- The realisation that the earth's orbit was both speed variant (absolute speed of motion) and speed constant (segment of elliptical orbit covered) was the crucial breakthrough that allowed Johannes Kepler to solve the longstanding problem of the regression of Mercury (why Mercury appears to go backward in its orbit some of the time). Discovering that the earth's orbit is elliptical (astronomers had always assumed orbits were based on perfect circles) was how Kepler showed finally that the earth goes around the sun (and not the other way around).

Satellites are used to study the Earth by collecting data on various factors such as weather patterns, climate change, land use, and natural disasters. They provide valuable information through remote sensing technologies, helping scientists monitor and predict environmental changes on a global scale.

Satellite orbital spacing refers to the distance between different satellites in orbit around the Earth. This spacing is carefully planned to prevent collisions and to optimize coverage, communication, and other functions of the satellite network. Satellite operators coordinate with each other and regulatory bodies to ensure safe and efficient use of orbital space.

There are 24 satellites in the United States GPS system that are active. There are 6 more that are "asleep" and saving power until they are activated to replace one of the 24 satellites that has to be taken off line for maintenance, damage, and so forth.

The Russians also have roughly that number of satellites in their GLONASS system.

Europe is deploying satellites in its Galileo positioning system.

Japan has or will launch its first satellite in its QTZZ positiong system.

There are also about 4 satellites in WAAS, the Wide Area Augmentation System that makes GPS more accurate. Europe's version of this is EGNOS, or European Geostationary Overlay Service. It has 4 or 5 satellites.