Cannot figure out what is wrong

[sparkz_alot]

You should avoid globals whenever possible. In your case, they are not needed. You are just not using functions correctly. For instance, in order for 'planet_call' to work, you need two pieces of information: the planet and the calculation for that planet (which we will call 'pounds' for now). Now we know our function is

def planet_call(planet, pounds):

You get the value of 'planet' by calling function 'ask_planet()', you get the value from the input(), so you just need to 'return' that value.

def ask_planet():
    planet = input("Which planet would you like to know your weight for? ")
    return planet

The same holds true for the function 'calculation()', in which you need to know the value of 'planet', so:

def calculation(planet):
    # Do calculation. Note you need your 'if/elif/else' here
    return pound

To use them, you need to call them:

user_planet = get_planet()
user_pounds = calculation(user_planet)
user_final = planet_call(user_planet, user_pounds)

Your 'planet_call()' only needs one print statement, the pythonic way would be:

print("Your weight on {} would be {} pounds".format(planet, pounds))

For now, forget about asking for new planets. See if you can get the 'base' working correctly. As was also pointed out, Python is case sensitive so make sure your variables are of the same case.