 How on Earth does NASA keep track of all the spacecraft in the solar system? Deep space communication is what we're looking at today on Vintage Space. This is actually a pretty common question. How does NASA actually talk to all the spacecraft currently on missions throughout the solar system? The answer is radio waves. Messages travel through space on radio waves. Every spacecraft has a transmitter and a receiver that can send downlinked information to the Earth and receive uplinks from the teams monitoring the spacecraft. Radio waves come in different frequencies and wavelengths. The frequency here means the number of waves that pass a fixed point in space in a given amount of time. A higher frequency means shorter waves and a lower frequency means longer. There are two waves that information can be passed on radio waves and you know both of them. AM and FM radio. AM stands for Amplitude Modulation where an information is put into radio waves by verifying the amplitude of the wave. FM stands for Frequency Modulation. The amplitude is kept constant but the frequency of the wave varies. Because radio waves by themselves are quite regular, moderating the amplitude or the frequency allows for information to be carried on those regular waves. So how does NASA actually get the information from these spacecraft? Through very large satellite dishes and this is where the Deep Space Network comes in. The Deep Space Network or DSN began in the 1950s as the Army's Deep Space Instrument Facility and it had three stations. One in Goldstone, California, one in Womera, Australia and one in Johannesburg, South Africa. These stations received information on massive satellite dishes and then they passed that information among themselves and to the center monitoring everything at what was then Caltech's Jet Propulsion Laboratory just by simple telephone and teletype conversations. This was the system that monitored some of the first deep space missions, the Ranger missions to the Moon and the Mariner missions to Mars and Venus and it was only ever meant to be a temporary solution. This telephone and teletype method of coordinating deep space navigation was only ever meant to be a temporary thing. It was actually so basic that at the time technicians were putting out mission updates on the wall on pieces of paper with fun tax. So it was a very good thing that the entire system got a massive upgrade beginning in 1963. The transformation improved and expanded the network and it also changed the radio frequency. Previously the network had been using 960 MHz L-band communications which the early spacecraft used but the new network switched to a higher frequency 2200 MHz which lies on the S-band and allows for far more data to be transferred at a time. Other improvements included replacing the crystal controlled oscillators with atomic clocks for increased accuracy and navigation as well as overall changes to NASA's own ground communication system essentially creating a much stronger link between all the centers monitoring the spacecraft on the ground. As the deep space network has grown in the last 50 years more stations have been added including one in Spain and another one in Australia but they still all filter into what is now NASA's Jet Propulsion Laboratory in Pasadena. There's actually a really great sign in the floor of the DSN because all the information from all the spacecraft we have in the solar system and in the case of the Voyager spacecraft outside the solar system filters through that one room at JPL. So does that clear up how we talk to all the spacecraft we have exploring the solar system on our behalf? Let me know if you have any other questions in the comments below and of course anything you want to see covered on a future episode let me know as well in the comment section. If you want space content every single day of the week be sure to follow me on Twitter as AST Vintage Space and with new episodes every single Tuesday and Friday. Subscribe right here so you never miss an episode.