When the first astronauts land on Mars, maybe in a couple of decades, they’ll need some way to communicate. They’ll need to talk with each other — and mission control back on Earth — using equipment on and around Mars.
Plus, they’ll no doubt want to email loved ones, keep their playlists up-to-date or stream new episodes of their favorite shows. And setting up a Wi-Fi connection to Earth’s internet won’t be an option. Earth is simply too far from Mars.
The distance between the two planets depends on where they are in their orbits around the sun. In fact, it can range from around 55 million to 400 million kilometers (34 million to 250 million miles). So even data traveling at the speed of light would take four to 24 minutes to make a one-way trip.
That means a quick ping from Mars to mission control on Earth is out of the question. And a WhatsApp call home? Forget about it.
There’s also the problem of “solar conjunction.” This is when Earth and Mars are on opposite sides of the sun, which happens every two years or so. During solar conjunction, the sun blocks all signals between the two planets.
No known strategy can overcome the time lag in signals traveling between Earth and Mars. Or make it possible to send messages through the sun.
But researchers are working on ways to make communication on the Red Planet more like it is on Earth. And at least one team has wondered: What if Mars had its own internet?
A good communications setup is crucial for human missions to Mars, says Claire Parfitt. She’s a systems engineer with the European Space Agency, or ESA, in Noordwijk, Netherlands. Basically, people on Mars will need some way to get online, she says.
“At the moment,” she adds, “we’re in the early stages of working out what that means.”
How Mars ‘chats’ work today
Several space agencies have spacecraft on or near Mars. There are landers and rovers on the planet’s surface. (Landers sit still, rovers move around.) Satellites also orbit the Red Planet. All of these machines have to communicate with Earth.
Consider NASA’s Perseverance rover — Percy, for short. It sends and receives two types of data. One is called “command and telemetry.” That’s where operators on Earth tell a rover what to do, receive responses from it and then decide what to do next. Percy typically gets more than 1,000 commands from Earth every day.
Percy and Earth also share science data. Percy takes pictures of Martian rocks and collects other kinds of data about its surroundings. It then sends those findings back to Earth.
The helicopter Ingenuity, which ended its mission earlier this year, used to ping Percy too. Percy relayed data and commands between Ingenuity and Earth.
Orbiters circling Mars likewise send science data back home. These robotic scouts include NASA’s Mars Odyssey and Mars Reconnaissance Orbiter or MRO. There’s also ESA’s Trace Gas Orbiter, or TGO.
Mars orbiters don’t just send their own observations back to Earth. They also help send home data collected by other machines on the planet’s surface.
A lot of messages to and from Mars are routed through the Mars Relay Network. It’s made up of five orbiters around Mars: the three mentioned above, plus NASA’s MAVEN and ESA’s Mars Express orbiters. All five have antennas pointed toward Earth to send data home. It’s “a tightly choreographed dance,” NASA says.
Say a rover needs to send its latest observations home. It first passes those data to one of the orbiters in the Mars Relay Network using radio waves. That orbiter may or may not have a clear view of Earth at the time. If it does, it can beam the data home straight away, also using radio waves. If not, the orbiter can hold on to the rover’s data until Earth is in its line of sight.
Once an orbiter broadcasts its data, powerful radio antennas on Earth can pick those signals up. A global network of radio receivers, such as NASA’s Deep Space Network, is always listening for pings from deep space.
This whole setup works pretty well for robots on Mars. But once a human crew lands there, this system will not be good enough.
Mars communication renovations
Vincent Chan studies fiber-optic and satellite communications at the Massachusetts Institute of Technology in Cambridge. He doesn’t foresee local, on-the-ground communication as a challenge for future Mars explorers.
A crew could interact using existing wireless tech that sends messages through radio waves, Chan says. Two mini cell towers would be enough when the astronauts are close together. When they’re far apart, some device that picks up radio waves and passes them along could help bridge the gap between astronauts. People living in remote places on Earth already connect in a similar way.
“Those services are already in play,” Chan says. What’s more, he adds, they’re “very economical.”
A big antenna on the crew’s landing vehicle could point toward Earth. That antenna would probably be the very first thing Martian explorers would set up, Chan says. It would route all communications to and from Earth.
But what about when that antenna doesn’t have a direct line of sight to Earth? Orbiters similar to the Mars Relay Network could step in. The crew’s ground-based antenna could send messages to an orbiter. That spacecraft would then relay the data between other orbiters to reach one with a clear view of Earth. But several orbiters would be needed for round-the-clock coverage. They’d also need to be equipped to handle a lot of data.
ESA is looking for ways to make today’s Mars Relay Network better. The agency is considering a concept called MARCONI. That’s short for the Mars Communication and Navigation Infrastructure. If this project moves forward, it will develop a set of communication and navigation spacecraft. Those devices could piggyback on any future mission to the Red Planet.
Once orbiting Mars, these spacecraft would handle radio communication on and with Mars, Parfitt explains. They could then stick around for use on future missions.
The more stuff you send to Mars, the more expensive it is, Parfitt says. “So you wouldn’t necessarily want to land massive communication systems on Mars every time [you go there].”
So far, spacecraft on and around Mars have mostly communicated using radio waves. This has been fine for non-human explorers. They don’t need to send or receive tons of data super fast. But if future astronauts do want to move lots of data, they will need far higher rates of data transfer. For this, they might turn to lasers.
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Laser communication in space
Laser light is made up of optical waves. These have much higher frequencies than radio waves. That is, the crests and troughs of optical waves are much closer together in space than those of radio waves. As a result, optical waves can densely pack in a lot more data than radio waves can. In fact, lasers could carry 10 to 100 times as much data in the same time as radio waves.
But laser-based messaging in deep space must be tested first.
NASA’s Psyche mission is helping here. The spacecraft launched last October. Its main job is to explore an asteroid between Mars and Jupiter. But the spacecraft also carries NASA’s Deep Space Optical Communications tech. This is letting it test long-distance laser communications through space.
Laser signaling had never been tested from distances farther than the moon. But last November, Psyche beamed data to Earth from a distance of 16 million kilometers (10 million miles). That’s 40 times farther from Earth than the moon is. A month later, it sent a video of a cat named Taters from 31 million kilometers (19 million miles) away.
ESA is also exploring long-distance laser communication. One of its programs is called ScyLight (pronounced “skylight”). That’s short for Secure and Laser Communication Technology. This program supports the development of optical and quantum tech for secure and fast messaging from space.
Despite its benefits, laser communication has its drawbacks. For one thing, it requires super-precise aim. Radio waves fan out as they travel through space. This allows radio receivers to net these signals easily from multiple locations. But laser signals travel in narrow beams. That means a laser has to point exactly at the receiver. Miss it and the message is gone.
What’s more, clouds and atmospheric effects also mess with laser signals. And using lasers would require upgrading existing radio antennas in the Deep Space Network. Or building new receivers to listen for laser signals from deep space.
An internet on Mars
Future Mars residents will likely want to do more than send messages back and forth. They’ll want to set up something like Earth’s internet. This might be something they could use to share photos or look things up.
In June 2023, two computing experts proposed how to achieve such a thing. A fleet of satellites orbiting Mars, they said, could provide the Red Planet with its own offshoot internet. Those researchers, Tobias Pfandzelter and David Bermbach, both work at Technische Universität Berlin. That’s in Germany.
Most of us here on Earth access the internet through our phones using radio waves. This happens on either 4G or 5G wireless networks. Or it happens through Wi-Fi routers. These connections are linked by fiber-optic cables. Such cables are buried underground, hang from poles and snake across seafloors around the world.
The proposed Mars “internet” would instead be similar to Starlink. That’s a fleet of satellites in low Earth orbit run by the company SpaceX. On Earth, connecting to the internet by satellite is expensive. But on Mars, such a system might be cheaper and easier to build than a fiber-optic cable network on the ground.
Pfandzelter and Bermbach calculate that a swarm of 81 satellites around Mars could provide planet-wide coverage. This local communications system would essentially be an extension of Earth’s internet.
Imagine that an astronaut on Mars is trying to catch up on a Netflix show. “If you were to stream it from Earth, you would have to first wait 10, 15 or even 40 minutes,” Pfandzelter says. That’s just to connect. It would be a frustrating stop-and-start affair to get through an episode. If another astronaut on Mars wanted to watch the same show, they would have to go through the same process all over.
The 81 satellites around Mars could instead offer local data storage. A movie could be slowly uploaded from Earth to the satellite system once, and then stored there. When astronauts on Mars want to stream that flick, they could then retrieve that data instantly from the Mars satellite fleet.
“You could just have the same experience that you have on Earth, because all your data is locally copied,” Pfandzelter says. Meanwhile, other uploads and downloads to and from Earth, such as science data, could continue in the background.
Putting internet satellites into orbit around Mars wouldn’t require landing a lot of stuff on the surface. That’s a good thing. Landing things on another world can be very costly. “It would be much cheaper to just send a bunch of networking satellites to Mars,” says Pfandzelter. Those satellites could use radio waves — or optical waves, if laser tech is ready.
Learning from the moon
Missions to the moon could offer lessons for setting up an internet on Mars. NASA’s Artemis program, for instance, aims to return humans to the moon. As part of that effort, NASA has arranged for private companies to set up a 4G network for the moon — one based on radio waves. It would include installing antennas and base stations that can withstand the harsh lunar landscape. They’d relay transmissions on the moon.
ESA has a related program called Moonlight. It invites private space companies to set up satellites around the moon. These spacecraft would allow people on the far side of the moon, which never faces Earth, to reach people at home. The first phase of the program includes the launch of the Lunar Pathfinder orbiter in 2026.
“Everything that is being done for the moon, it’s got the objective of taking humans and missions to Mars,” explains Tomas Navarro. He’s a future projects engineer with ESA in London, England.
Even if human missions to Mars are decades away, Parfitt says, it’s not too soon to start planning. Live video-chats between planets not physically possible. But other challenges can be overcome. And tackling those may not only benefit future astronauts on Mars. They also may help convince space agencies that human crews are ready to take on the Red Planet.