function OpenParachute() {
    rigidbody.drag = 20;
}

function Update() {
    if (Input.GetButton ("Space")) {
        OpenParachute();
    }
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    void OpenParachute() {
        rigidbody.drag = 20;
    }
    void Update() {
        if (Input.GetButton("Space"))
            OpenParachute();
        
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    def OpenParachute():
        rigidbody.drag = 20

    def Update():
        if Input.GetButton('Space'):
            OpenParachute()