using UnityEngine;
using System.Collections;
using System.Collections.Generic;

public class Planet : MonoBehaviour {
private float alpha; //will use for cos & sin (as angle)
private float distance;//distance from center
private float Rotation;//rotation angle
private float currentTime;//Time start when Instantiated
//input values
public float speed;
public Vector2 RotationValues;
public Vector2 distanceValues;
public Vector2 sizeValues;


void Start () {
    //Initialize with Random rotation & distance & size

    //Random Rotation between -2 & 2
    Rotation = Random.Range(RotationValues.x, RotationValues.y);
    //Random distance  between -1 & 2
    distance = Random.Range(distanceValues.x, distanceValues.y);
    //Random Size between 0.2f & 0.7f
    var Size = Random.Range(sizeValues.x, sizeValues.y);
    //Set localScale with random size
    transform.localScale = new Vector3(Size, Size, Size);

    //calculating current time by subtraction Time.time and lastTime
    currentTime = Time.time - Generator.lastTime;

    //GetComponent<MeshRenderer>().material.color = new Color(Random.value, Random.value, Random.value); //Random Color
}

void Update () {
    //Timer
    currentTime += Time.deltaTime;

    var X =  (distance * Mathf.Cos(currentTime)); //X
    var Y =  (distance * Mathf.Sin(currentTime)); //Y
    var R = (Rotation * Mathf.Cos(currentTime)); //Rotation
    //give earth from generator class
    var Earth = Generator.Earth;
    transform.position = Earth.transform.position + (new Vector3(X, R, Y));// RotateAround Earth

}
}

using UnityEngine;
using System.Collections;

public class Generator : MonoBehaviour {
public GameObject prefab;
public static GameObject Earth;
public static float lastTime;
public int numerOfSatellites;


void Start() {
    Earth = GameObject.FindGameObjectWithTag("MainPlanet");//Find Earth
    for (int i = 1; i <= numerOfSatellites; i++) {
        lastTime = Time.time;
        GameObject sat = Instantiate(prefab, Earth.transform.position, Quaternion.identity);
        Physics2D.IgnoreCollision(sat.GetComponent<CircleCollider2D>(), Earth.GetComponent<CircleCollider2D>());
    } }
}

void Update () {

    //Timer
    currentTime += Time.deltaTime;

    var X =  (distance * Mathf.Cos(currentTime)); //X
    var Y =  (distance * Mathf.Sin(currentTime)); //Y
    var R = (Rotation * Mathf.Cos(currentTime)); //Rotation

    //give earth from generator class
    var Earth = Generator.Earth;
    transform.position = Earth.transform.position + (new Vector3(X, R, Y));// RotateAround Earth

}