import datetime

def time_stamp(df,time_col):
    df[time_col] = pd.to_datetime(df[time_col])
    df["year"] = df[time_col].dt.year
    df["month"] =  df[time_col].dt.month
    df["day"] = df[time_col].dt.day
    df['day_of_yr']=df[time_col].dt.strftime('%j').astype(int)
time_stamp(df,"Latest Launch")