The idea of calling home is not new for sci-fi enthusiasts. Scientists, on the other hand, have a different version of what it means to call home than the throngs of E.T. fans wanting the alien to finally make contact with its people again.
For scientists, the deeper we explore space, the more we need a secure interplanetary internet connection. How to do this, however, is a question that needs to be answered.
According to DW, if successful, millions of humans in colonies on the Moon or Mars may want to be able to phone home -- if the Earth still exists, at that. However, to phone home, they may want more secure lines and not have the government listen in on the conversations with their loved ones.
In fact, as the web site noted, the deeper humans can explore space, the more important these secure communications networks become. To achieve this, however, there will be a need of cryptography. In space, this is where a field called quantum physics could help, specifically in the area of photon entanglement.
Today, as noted by Discover Magazine, the Curiosity rover can already take selfies on Mars and have the data transported to Earth. However, the arrival of the data depends entirely on the Deep Space Network, which is an overworked collection of radio antennas installed in different remote locations around the globe. DSN dishes are very sensitive, but data transfer rates are very slow. For instance, a 1.5GB video from the Curiosity rover could take up to 6 hours to download via radio DSN.
Photon entanglement, however, is an extremely fragile state, and only one pair out of 6 million beamed per transmission could survive "entanglement" through the Earth's atmosphere. However, a slight interference of the photons in their entangled state could effectively break the pairing.
Here on Earth, photon entanglement is said to be considered for teleporting properties in quantum computers. However, it seems that more studies and collaborations will have to be done before humans can properly call home from Mars -- if there is a way to get to that point.