Which of the following are essential conditions for a satellite to be geostationary?

Options

A. It should be at a height of 36000 km above the surface of earth.
B. Its orbit may be circular or elliptical.
C. It should rotate from west to east.
D. Its orbital speed should be 3.1 km//s.

Answer

To determine the essential conditions for a satellite to be geostationary, we need to understand the characteristics that define such a satellite. A geostationary satellite appears to remain fixed over a specific point on the Earth's surface, which means it must meet certain criteria. Here’s a step-by-step solution to identify these conditions:

### Step 1: Understand the Concept of a Geostationary Satellite
A geostationary satellite is one that orbits the Earth at the same rotational speed as the Earth itself. This means that as the Earth rotates on its axis, the satellite remains above the same point on the Earth's surface.

**Hint:** Remember that the satellite must match the Earth's rotation period.

### Step 2: Determine the Required Orbital Period
For a satellite to be geostationary, its orbital period must be equal to the Earth's rotational period, which is approximately 24 hours. This ensures that the satellite completes one orbit in the same time that the Earth completes one rotation.

**Hint:** Think about the relationship between the orbital period and the rotation of the Earth.

### Step 3: Calculate the Required Altitude
The altitude of a geostationary satellite is approximately 36,000 kilometers above the Earth's surface. This specific height allows the gravitational pull of the Earth to balance the centrifugal force experienced by the satellite, keeping it in a stable orbit.

**Hint:** Consider how gravitational force and centrifugal force interact at this altitude.

### Step 4: Identify the Orbit Shape
The orbit of a geostationary satellite must be circular. This is because a circular orbit allows for a constant distance from the Earth, which is necessary for maintaining a fixed position relative to the surface.

**Hint:** Recall that elliptical orbits would cause the satellite to move closer and farther from the Earth, making it impossible to remain stationary over one point.

### Step 5: Direction of Orbit
The satellite must orbit in the same direction as the Earth's rotation, which is from west to east. This alignment ensures that as the Earth rotates, the satellite remains above the same point on the surface.

**Hint:** Visualize the Earth's rotation to understand the required direction of the satellite's orbit.

### Step 6: Orbital Speed
The orbital speed of a geostationary satellite is approximately 3.1 kilometers per second. This speed is necessary to maintain the balance between gravitational pull and the inertia of the satellite's motion.

**Hint:** Think about how speed affects the satellite's ability to stay in orbit.

### Conclusion
In summary, the essential conditions for a satellite to be geostationary are:
1. It must have an orbital period of 24 hours.
2. It must be at an altitude of approximately 36,000 kilometers above the Earth's surface.
3. Its orbit must be circular.
4. It must orbit in the same direction as the Earth's rotation (west to east).
5. Its orbital speed must be around 3.1 kilometers per second.