From the Bungie Weekley Update
This weekend, for every game you complete in the Defiant Map Pack playlist you will have a chance to win an extra 7,000 credits from a Super Jackpot! You can win the Super Jackpot once a day, so you have the next 3 days to win up to 21,000 in extra credits. The Super Jackpot Weekend will end on Sunday at midnight (Pacific Standard Time). Super Jackpot rewards do not count against your daily credit limit.