It was very strange and unexplained .
I was sending a probe to jool when i had to quit from the game.
To make the things more realistic i switched off the fuel valves of the probe , save and quit.
When i reloaded kerbal and the career, i had to make a course correction, and in the moment to switch on the fuel valves again, the whole spacecraft blow up in pieces in a huge explosion, and a big cloud of debris .