So far, humans have sent 28 robotic missions to Mars. The Martian rovers and satellite observers have together revealed the Red Planet's chemistry, topography, and some of its history. Thanks to these missions, we now know liquid water once flowed across the planet’s surface, suggesting Mars may have been habitable at one time, and may even still be inhabited by subterranean microbes.
But nothing can compare to a human mission to Mars. SpaceX CEO Elon Musk is going one further, pushing to set up a permanent city on Mars. SpaceX's Starship is being created to this end. Others, like NASA, are also working on the technology to take us to Mars.
At this point, it seems like only a matter of time before human reach Mars. But to get there, we need to hit these five milestones first.
Who wants to go to Mars?
To understand how we will get to Mars, it is perhaps helpful to go over who is going to take humans there in the first place. There are four main players in the space (for now):
- NASA: The American space organization plans to send people to Mars in the 2030s. “Our innate human desire to explore cannot be satiated by robotic exploration alone,” reads one NASA report.
- Elon Musk/SpaceX: The billionaire entrepreneur wants to build a city on Mars by 2050, and believes crewed missions will travel to the Red Planet within six years.
- European Space Agency: The agency’s Mars exploration program ExoMars, sent an orbiter to Mars in 2016. It plans to launch a robotic lander in 2022. These missions are explicitly designed to answer scientific questions about Mars, but the ESA has made their overall interest in crewed missions clear. “Mars exploration plans should result in an even greater adventure — a human mission,” according to the agency's website.
- United Arab Emirates: The UAE successfully launched a robotic mission to Mars in July 2020 and announced plans to build a city on Mars by 2117.
What do we need to make the trip to Mars?
A trip to Mars ultimately depends on being able to fly to Mars safely, land and survive on the planet, refuel, and then fly home to Earth again.
To fully understand the scale of such an endeavor, it is important to break those five things down a little bit further. Let's start with the first task: Finding a way to fly there safely.
SpaceX is perhaps the furthest down the line in terms of the rocketry we will need. The Starship, currently in prototype testing, is designed to travel to Mars, refuel, and then blast off again for Earth or another destination. Musk hopes the first Starship mission to Mars will launch in 2026.
NASA is also working on their own rocket system. The agency is developing a nuclear propulsion system and an entry, descent, and landing system specifically tailored to the Martian atmosphere.
Because Mars' atmosphere is so scant, traditional landing techniques like a parachute system are not sufficient to keep vessels from crashing into the Martian surface. NASA has already developed entry, descent, and landing systems for its Mars rover missions, but a rover is a relatively small payload compared to a space shuttle. Curiosity rover weighed a ton, but NASA predicts crewed landers would weigh in at about 20 metric tons, so there will need to be some tweaks before the agency can be sure a crewed lander would make it.
Say we get a ship capable of making the trip. So far, so good. But then there are 5 major dangers to humans to overcome, too. According to NASA, these are:·
- Space radiation: Radiation exposure on Earth is known to damage the central nervous system and can cause cancer. But we still aren't sure what space radiation does to the human body.
- Isolation and confinement: During space travel, sleep loss, work overload, and disrupted circadian rhythms may compromise a crew's ability to do good work.
- Distance from Earth: At some point, the ability to turn back or send a rescue mission from Earth disappears. The farther you get from Earth, the longer it takes to relay messages, and equipment failures or medical problems easily addressed on Earth could quickly become catastrophic in space.
- Gravity fluctuation: Gravity on Mars is less than half of that on Earth. Crew members would have to work under those conditions for potentially lengthy missions. There is also evidence life in microgravity may have long-term health consequences, suggesting life under Martian gravity may have similar ill-effects.
- Hostile environments: Exposure to Mars' ambient conditions would be deadly for a human, so the crew must be able to access everything they need in a contained, small space.
Which brings us to the next test we need to pass: Finding a landing and relaunch site.
Before landing a crewed vessel on Mars, NASA plans to set up surface systems to facilitate landing and relaunching. Pre-placed assets would include a power system used to charge robotic landing scouts that would determine the best touch down site. Due to familiar day and night cycles, as well as Mars' months-long dust storms, solar power wouldn't be reliable on Mars. So NASA and the Department of Energy are attempting to develop a compact fission power system.
Elon Musk plans to use liquid oxygen and methane to fuel the Starship. A landing and relaunch site would need to be able to access these resources easily if he is to pull off his designs.
If we triangulate a suitable site, then we come to our next tests: finding the resources to survive on Mars — and the resources to make it back home.
At least at first, most of the things humans will need to keep them alive on Mars will need to be brought with them from Earth. But Mars hopefuls are already brainstorming ways to transform Martian resources to work for us.
For instance, New York firm Air Company previously told Inverse they are developing technologies to convert carbon dioxide, the most prevalent gas in the Martian atmosphere, into useful products future astronauts can take advantage of, including sugar, hand sanitizer, and even vodka. Elon Musk for his part has also suggested terraforming the planet to establish farms.
While working on the technology to create alcohol from carbon dioxide, Air Company also started investigating the possibility of using similar technology to create fuel.
"We stumbled upon this application of our technology when working on improvements to our existing pilot plant that converts CO2 to alcohols," Air Company co-founder Gregory Constantine told Inverse at the time. "Our goal is to use our CO2 conversion technology and expertise to help groups like NASA, SpaceX, and others enable human colonization throughout the Solar System."
As mentioned above, Musk's plan is to use liquid oxygen and methane, taken from the Martian environment, in order to fuel the Starship.
What will humans do when they get to Mars?
If we meet the five conditions outlined here, then there are a range of ambitions as to what we will do when we get to Mars. NASA's focus is on scientific exploration (although this is not without risk), while Musk seems more concerned with establishing a fully functioning Mars city.
The UAE, meanwhile, has mooted plants to build a city on Mars, too. Architect Bjarke Ingels' design firm BIG envisioned the city as a collection of 3D printed buildings.
The UAE futuristic Martian settlement
Elon Musk's Mars city follows a similar scheme to that of the UAE's vision — a collection of geodesic domes encasing humans and all they need to survive. But ultimately, Musk also hopes to terraform Mars, reengineering the planet to be more inviting to humans. Musk’s terraforming plans range from the extreme “nuking Mars” to creating a giant, mirrored satellite to melt the ice at Mars' poles, releasing carbon dioxide stores and warming the planet via the greenhouse effect.
The UAE is planning to build a prototype of their Martian city on Earth, calling it Mars Science City. The site is both exhibition and research center.
What's next for manned Mars missions?
NASA is practicing for Mars on the Moon. The Artemis mission, which includes a crewed mission to the Moon in 2024, will function as a practice run for Mars.
As NASA states in a recent report:
"On the lunar surface, NASA will build Mars-forward systems whenever possible. Rovers, spacesuits, surface habitation, and small power plants will be built with future Mars applicability in mind so that astronauts can gain experience using them and provide early feedback for improvements. As a result, nearly all of the systems deployed on the lunar surface will serve as prototypes for future Mars surface systems, including advanced life support technologies needed for the long transit to Mars."
Ultimately, there are two ways successful Mars missions could go. One is a situation similar to that already in place in Antarctica, where there are international science outposts. The other is colonization — establishing a city or state in which humans may be born, live, and die on the Martian surface.
In a recent Inverse interview, German director Werner Herzog dubbed the colonization of Mars an “obscenity,” comparing such an endeavor to the behavior of locusts. He suggested humans are better off finding ways to on live better on Earth. But he did recognize the scientific importance of crewed missions to the Red Planet.
For his part, Musk seems excited to move to Mars, and recently suggested he would rather die there than on Earth.
“The window of possibility is open for us to extend life to another planet,” Musk told Werner Herzog in a 2016 interview. “I think it’s important for us to take advantage of that window while it is open."