user: Question: What was the ceased operation with a launch date of August 8, 1968?
Columns: ['Name', 'Launched', 'Vehicle', 'Ceased operation', 'Notes']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Injun 1', 'June 29, 1961', 'Thor-Able', 'March 6, 1963', 'Failed to separate from Solrad 3; still in orbit']
SQL:

assistant: SELECT "Ceased operation" FROM "Table" WHERE "Launched" = 'August 8, 1968';