Kubernetes Executor failes with bigger input size

The first task of my DAG is downloading a file, does some easy calculations and then uploads a file to google cloud storage. I have two different input files: one is small (contains 200 tweets, 48KB) and one is bigger (contains 20000 tweets, 4700KB). Using the Kuberntetes Executor running the DAG with the small input file works completely fine. But with the large input file, it fails.
So what is the reason for this? The only error message in the log is this one:

Task exited with return code Negsignal.SIGKILL