Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_73 ( launch_failures INTEGER, launched VARCHAR, not_usable VARCHAR )

### Question ###
What is the total launch failures when there are 4 launches, and the not usable is greater than 0?

### Accurate SQL ###

SELECT SUM(launch_failures) FROM table_name_73 WHERE launched = 4 AND not_usable > 0