Since April 4th, the Mars rovers Curiosity and Opportunity have "hung up" their phones.

It's a planned disconnect, though. NASA reports that every two years the Earth and Mars end up on opposite sides of the Sun as they roll around the Solar System.

As the Earth slides closer and closer to the Sun, the signals from NASA to the Mars landers can get scrambled. So, to protect the rovers from get the wrong instructions and driving into a sand pit or off a cliff, the scientists don't transmit to Mars for a month. That provides a nice safety zone as the Earth goes behind and emerges on the other side of the Sun.

That silence will end May 1.

Meanwhile, the rovers have been parked where their solar panels get get the most sun as possible - just like vacationers do next to the pool on Earth while they're on vacation.

So, enjoy your time off, rovers. It's back to work May 1.