Answer:
The Cassini Mission do you by chance mean the Cayo Perico Heist/mission
Step-by-step explanation
Can you beat the Cayo Perico heist solo?
It's possible to rake in upwards of a million dollars in GTA fun bucks by completing it and it can be done multiple times, which means there's a lot of money to be made. While many of the heists require you to bring along a gang of friends, this one can be done all by yourself.