One_Button_Game/OneButtonGame/Assets/Scripts/Thruster.cs

using UnityEngine;
using System.Collections;

public class Thruster : MonoBehaviour {

    public float speed;
    public float thrustDuration;

    public bool shot = false;
    public bool attached = false;

    private ParticleSystem particles;

    [HideInInspector]
    public Rigidbody2D rigid;
	// Use this for initialization
	void Start () {
        rigid = GetComponent<Rigidbody2D>();
        particles =  GetComponentInChildren<ParticleSystem>();

        particles.enableEmission = false;
    }
	
	// Update is called once per frame
	void FixedUpdate () {
        if (Input.anyKeyDown && attached) {
            StartCoroutine(fireEngines());
        }

            /*
            rigid.AddForceAtPosition(transform.right * speed, transform.position, ForceMode2D.Impulse);
            particles.enableEmission = true;
            shot = true;

        } else if (shot) {
            
            Destroy(gameObject);
        } else {
            particles.enableEmission = false;
        }
        */


    }

   private IEnumerator fireEngines() {
        Debug.Log("firing Engines");
        float startTime = Time.time;
        particles.enableEmission = true;

        while (Time.time - startTime < thrustDuration) {
            rigid.AddForceAtPosition(transform.right * speed, transform.position, ForceMode2D.Impulse);
            yield return new WaitForSeconds(0.01f);
        }

        Destroy(gameObject);
        yield return null;

    } 
}