text: Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
  ### Context:
  CREATE TABLE table_name_30 (not_usable INTEGER, block VARCHAR, launch_failures VARCHAR, retired VARCHAR)
  ### Question:
  What is the highest number of not usable satellites when there are more than 0 launch failures, less than 30 retired, and the block is I?
  ### Answer:
  SELECT MAX(not_usable) FROM table_name_30 WHERE launch_failures > 0 AND retired < 30 AND block = "block i"