Answer. when the distance between the 2 objects is halved, the gravitational force between the 2 objects is doubled. when the distance between the 2 objects is doubled then the gravitational force doubles.

This means that greater the mass of the bodies, greater is the gravitational force between the two bodies and if we increase the distance between the two bodies, then the gravitational force between them will also decrease and vice-versa.

The gravitational force between two objects becomes weaker if the two objects are moved apart and stronger if they are brought closer together; that is, the force depends on the distance between the objects. The amount of this acceleration is inversely proportional to the mass of the object.

Distance is inversely proportional (as one goes up, the other goes down) to the strength o gravity. In other words, the greater the distance between two objects, the lower the strength of gravity is between them. However, because Earth is larger (has a greater mass), its gravitational pull is greater on a person.

A satellite maintains its orbit by balancing two factors: its velocity (the speed it takes to travel in a straight line) and the gravitational pull that Earth has on it.

The Two Forces That Keep the Planets in Motion Around the Sun

• Gravity. Gravity is the primary force that controls the orbit of the planets around the sun.
• Inertia.
• Gravity Working with Inertia.
• Velocity and Gravity.

Gravity

There have been no observed collisions between natural satellites of any Solar System planet or moon. Collision candidates for past events are: The objects making up the Rings of Saturn are believed to continually collide and aggregate with each other, leading to debris with limited size constrained to a thin plane.

Objects in orbit are moving very fast — many times the speed of a bullet — and even a small piece of debris hitting a critical weather satellite or spacecraft could be catastrophic. The long-term risk, according to NASA, is that as debris accumulates in orbit, collisions that produce more debris become more likely.

As of 2014, there were about 2,000 commercial and government satellites orbiting the earth. It is estimated that there are 600,000 pieces of space junk ranging from 1 to 10 cm (1⁄2 to 4 in), and on average one satellite is destroyed by collision with space junk each year.

They usually fly at altitudes around 200 miles above Earth. Rarely, they fly near 400 miles altitude. Russia’s orbiting space station Mir is another manned satellite.

In celestial mechanics, the term stationary orbit refers to an orbit around a planet or moon where the orbiting satellite or spacecraft remains orbiting over the same spot on the surface. From the ground, the satellite would appear to be standing still, hovering above the surface in the same spot, day after day.

the United States

6,000 satellites

While there are about 2,000 active satellites orbiting Earth at the moment, there are also 3,000 dead ones littering space. What’s more, there are around 34,000 pieces of space junk bigger than 10 centimetres in size and millions of smaller pieces that could nonetheless prove disastrous if they hit something else.

20 satellites

As of May 2020, GPS.gov confirms there are 29 operational satellites. The satellites circle the Earth two times a day at 20,200 km (12,550 miles) up. The U.S. Air Force monitors and manages the system, and has committed to having at least 24 satellites available for 95% of the time.

You need four satellites because each data from one satellite put you in a sphere around the satellite. By computing the intersections you can narrow the possibilities to a single point. Three satellites intersection places you on two possible points. The last satellite give you the exact location.

There continues to be improvement, and you’ll see indoor accuracy of better than 10 meters, but round-trip time (RTT) is the technology that will take us to the one-meter level. If you’re outside and can see the open sky, the GPS accuracy from your phone is about five meters, and that’s been constant for a while.

As of June 15, 2021, there were a total of 31 operational satellites in the GPS constellation, not including the decommissioned, on-orbit spares.

The locations of the satellites are determined using tracking from ground stations. The ground stations use mechanisms such as radar, signal doppler, and laser reflectors to pinpoint the position of a satellite and to maintain an understanding of its orbital elements.

According to the Pentagon, military GPS receivers are accurate to within about 20 metres, even without this refinement, known as differential GPS.

Aryabhata

Types of Satellites and Applications

• Communications Satellite.
• Remote Sensing Satellite.
• Navigation Satellite.
• Geocentric Orbit type staellies – LEO, MEO, HEO.
• Global Positioning System (GPS)
• Geostationary Satellites (GEOs)
• Drone Satellite.
• Ground Satellite.

Vikram Sarabhai

India’s 1st Rocket: ISRO Scientist Shares Stories of Working With Sarabhai, Kalam! “I was in a comfortable and prestigious central government scientific position in the Department of Atomic Energy,” informs Aravamudan.

China

The first ballistic missile was the V-2 rocket, which was created in Nazi Germany during World War II. It was invented by Walter Dornberger and Wernher von Braun, and was first used in 1944, to attack London, England.