My camera is moving away from the object it's rotating around, how do I fix this?

For some reason the distance between my camera and the object it's rotating around is getting larger.

 using UnityEngine;
 
 public class PlanetControls : MonoBehaviour {
 
     public Transform cameraTransform;
     public GameObject body;
     public float speed = 10f;
 
     void Start () {
         cameraTransform.LookAt(body.transform.position);
     }
 
     void Update () {
         Debug.Log(Vector3.Distance(cameraTransform.position, body.transform.position)); //Distance grows as time goes on
         cameraTransform.position += (cameraTransform.right * speed * Time.deltaTime);
         cameraTransform.LookAt(body.transform.position);
     }
 }