You can land an advanced spacecraft on Mars, but if you can’t keep in touch with it, it might as well be so much scrap. To prevent that from happening, NASA has issued a Request for Information to investigate the feasibility of using private satellites to provide communications into the 2020s between Earth and the fleet of exploration probes operating on and around Mars.
Though the US and European orbiters and rovers are state-of-the-art hardware, they still rely on radio-link communications systems from the 1960s. The rovers are able to communicate directly with Earth, but they only have limited power and during the Martian night they’re often out of the necessary line of sight, so they use the orbiters with their more powerful transmitters as relays.
This arrangement works, but it has a couple of problems. For one, using radio, even the orbiter links have very limited bandwidth, so only so much information can be transmitted at any time. But the other big problem is that this relay system depends on NASA’s Mars Odyssey and Mars Reconnaissance Orbiter (MRO), and ESA’s Mars Express orbiter.
These will soon be joined by NASA’s Mars Atmosphere and Volatile EvolutioN (MAVEN) and ESA’s ExoMars/Trace Gas Orbiter, but after that, no more Mars orbital missions are currently planned. According to NASA, this means that by the next decade gaps could appear in the relay network as older orbiters fall out of service.