There is none. This spacecraft doesn't even have an onboard computer. The only reason people don't routinely hack spacecrafts like this is because you need a worldwide network of huge dish antennas to communicate with it. Right now, outside of the Deep Space Network, only the Aricebo dish is capable of transmitting to it. Once it gets closer to earth (within a few million miles), the 20 meter dish at Moorehead in Kentucky will be used.