The Tricky Logistics of Putting Human Explorers on Mars
15 mins read

The Tricky Logistics of Putting Human Explorers on Mars

For as long as humans have looked to the stars, we’ve dreamed of venturing out and visiting these distant places. And no place has been the target of more speculation than Mars. Now, we’re finally at a place where the dream of human beings setting foot on another planet could become a reality within our lifetimes.

We understand the technology we need to send humans to Mars, and we have the experience of sending robotic missions there as well. So when are we going to take that next giant leap and send a crewed mission to another planet for the first time? And what will it take to make that happen?

We spoke to space expert Michael Hecht of the Massachusetts Institute of Technology, veteran of the Jet Propulsion Laboratory and principal investigator of the MOXIE oxygen-making instrument on the Perseverance rover, to understand how we get from Earth to Mars — and how we’ll get boots on the ground for the first time.

humans on mars nasa conceptNASA

Always 15 years away

With the recent flurry of interest in Mars exploration, it feels like we’re closer than ever before to actually getting people on the surface of the planet. And yet, it’s also a goal that constantly seems to be just out of reach.

We have the technology to make a crewed Mars mission happen now, and there is increasing interest in the topic.

After the Apollo missions of the 1960s and 1970s, many space enthusiasts assumed we would keep reaching and exploring, and move on to the next target for exploration: Mars. But public interest waned, support for Apollo dried up, and humans haven’t left Earth orbit since.

In the intervening decades, many have speculated that humans would set foot on Mars in only 15 years; that inevitably we’ll end up on the red planet soon. But a concrete, serious mission plan to put people on Mars has yet to materialize.

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We have the technology to make a crewed Mars mission happen now, and there is increasing interest in the topic. But Hecht argues that the space community, and we as a species as a whole, have yet to make a serious financial and practical commitment to really make a mission happen. If we decided to do this, we could. But we need to make that commitment.

“We could have gone after Apollo,” Hecht said. “It would have been hard, and it would have been dangerous. But we can do it more safely now. We could have gone then, and we can go now.”

One magic spot in the cycle

When trying to picture what a crewed Mars mission might look like, there’s really only one practical way to get from here to there. Due to Mars’s orbit around the sun, a year there lasts just under two Earth years. Allowing for travel time, that means if you want to travel from Earth to Mars, there’s one period in a 26-month cycle when that journey is easiest: When the two planets are close and a rocket can be sent into what is called a Hohmann transfer orbit.

mars earth oppositionsNASA

“There’s one magic spot in that 26-month cycle,” Hecht explained. When a rocket launches from Earth at just the right time, it can intersect Mars’s orbit at the same time Mars does. “It’s like changing lanes on the highway.”

Although it is possible to send craft to Mars using other orbits, it’s more difficult and dangerous, and a lot more expensive. So this 26-month cycle puts a practical limit on when we can send missions to Mars. It’s why Mars missions often launch around the same time, like the three spacecraft which launched in summer 2020 — NASA’s Perseverance rover, China’s Tianwen-1 mission, and UAE’s Hope mission.

And there’s an equivalent opportunity to come back in the other direction. This puts a pragmatic frame around what a crewed Mars mission will look like: A six- or seven-month journey from Earth to Mars, a bit over a year and a half on the surface, and another six or seven months coming back. That’s around a three-year mission in total.

A longer mission than we’re used to

3D Sculptor/Shutterstock

That three-year mission length poses challenges, as it’s a longer mission than we’re used to sending people on. The missions to the moon lasted just a few days, and crew rotations on the International Space Station typically last between six months and one year.

Having people on the Martian surface for around 18 months gives them the opportunity to do some serious science and exploration, but it also carries much more risk. If there’s a problem on a Mars mission, it will be extremely difficult — if not impossible — to send help or supplies from Earth. If something goes wrong, the astronauts will be on their own.

“Nobody who is close to this is under any illusions that it is safe,” Hecht said. From the health threat of radiation exposure to risks during launch and landing to the problems which arise which you spend a year and a half in cramped conditions where you can’t go outside without a spacesuit: “It is a risky venture.”

That’s why the focus of planning for a crewed mission is getting as much essential equipment as possible in place before anyone leaves Earth. To minimize risks to astronauts, you would send machines and equipment to the planet during the previous window in the 26-month cycle so it’s ready for the astronauts’ arrival. You need to make sure that the most basic needs of the astronauts, like oxygen and water, are already met.

Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE)Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) NASA

Hecht’s MOXIE project is one example of the kind of technology that would enable a crewed Mars mission and reduce its risks. It is a way to produce oxygen from the abundant carbon dioxide in the Martian atmosphere, and a small version of the technology is currently inside the Perseverance rover and has had several successful runs already. A larger version of this technology could be sent to Mars along with a large oxygen tank, which could be filled with oxygen ready for the arrival of a Mars crew.

Moon to Mars?


NASA is planning to return to human space exploration with the upcoming Artemis missions to the moon, and the agency has consistently stated that one of the reasons to travel to the moon is to prepare for a crewed mission to Mars.

As former NASA Administrator Jim Bridenstine put it in a recent report, “NASA has always set its sights on human exploration of Mars. Now with humans returning to the Moon in four years to establish sustainable lunar exploration by the end of the decade, we are able to clearly see the Moon is a critical stepping stone to the red planet. Learning to live and work on the Moon will bring us closer and closer to our next giant leap as we search for life farther in the solar system.”

However, exactly how analogous moon missions are to Mars missions is a matter of debate in the space community. Some argue that any human space exploration will help build knowledge, technologies, and procedures which will be beneficial in future endeavors — that was what Artemis astronaut Kjell Lindgren told Digital Trends when we interviewed him about the goals of the Artemis missions.

But others, like Hecht, are skeptical about how much you can learn about a Mars mission by going to the moon. “I struggle to find commonalities between the two, to be honest,” Hecht said. He pointed out differences between Mars and the moon in terms of the duration of the trips, the gravity and dust environments that astronauts will encounter, the presence or absence of atmosphere and how that affects landings, and the resources which are available. “I just don’t see it as a stepping stone.”


When it comes to Mars, Hecht said, “I don’t think you practice by going somewhere else. But I do understand the point of view of people who say that going anywhere — doesn’t matter if it’s an asteroid or the moon — is giving us experience in operating off Earth.”

It’s not that people who are in favor of a mission to Mars are against visiting the moon — proponents of space exploration generally support more missions of all kinds — it’s rather that if we want to travel to Mars, we ought to be focusing on Mars and its unique challenges.

A McMurdo station for the red planet

There’s plenty of talk about futuristic cities on Mars, and of sending hundreds or even thousands of people to live there long-term. But the far-fetched ideas are unlikely to happen any time soon. Instead, a more realistic vision would be a scientific research outpost, like the McMurdo base in Antarctica, with a handful of astronauts spending time there in 18-month shifts.

DigitalGlobe/ScapeWare3d via Getty Images

It would be feasible to set up the first crewed mission to Mars within 20 to 25 years and to set up a research outpost there within the next decades.

Although it might be possible for such a mission to be planned and executed by a single country, there could be a more robust mission if different countries were involved. Currently, NASA cooperates closely with other space agencies like the European Space Agency (ESA) and the Japanese Space Agency (JAXA), but there’s a schism between the U.S. and one of the biggest players in space missions: China. Whether or not these different agencies would be willing to work together on a future Mars mission is still unclear.

“Hopefully, that first mission [to Mars] will involve not just NASA and not just the United States,” Hecht said, “Hopefully it will involve China too, so there won’t just be one failure point. It will keep going if one partner decides to go somewhere else.”

It won’t only be government agencies involved in the project either. Companies like SpaceX, Blue Origin, and Boeing are all heavily involved in space missions, and you can expect them to be involved as subcontractors or even project managers in future Mars missions as well.

Why go to Mars?

NASA's Ingenuity Mars Helicopter's fifth flight was captured on May 7, 2021, by one of the navigation cameras aboard the agency's Perseverance rover. This was the first time it flew to a new landing site. NASA's Ingenuity Mars Helicopter's fifth flight was captured on May 7, 2021, by one of the navigation cameras aboard the agency's Perseverance rover. This was the first time it flew to a new landing site.NASA/JPL-Caltech

Whenever the subject of a crewed mission to Mars comes up, there are always people who object to the time and money such an undertaking would require and argue that this money would be better spent solving problems here on Earth. And undeniably, in the last year in particular, we’ve seen the cracks in the systems which are supposed to support the basics needs of many, like housing, education, and healthcare.

But, Hecht points out, we don’t only spend money on meeting the basic requirements of life. He described frantically trying to scrape together $1 million of funding to put a new piece of scientific equipment on Mars, and turning on the TV to see the ads that played during the Super Bowl. The cost of each 30-second spot could have paid for his piece of equipment several times over.

“We spend money on all sorts of silly things like Super Bowl ads,” he said. “And an awful lot of them have to do with our personal enjoyment of life and fulfillment — whether it’s sports, whether it’s libraries, whether it’s art, whether it’s music, whether it’s parks. We’d be a pretty poor excuse for a society if the only thing we would spend money on was food and shelter.”

When it comes to space exploration, we have the opportunity to teach and inspire, and, perhaps most important of all, to understand more about the universe and our place within it. If we want to answer some of the biggest questions in life: Where we came from and whether we are alone in the universe — then we need to venture out beyond our planet and explore.

What we learn from exploration

Many proponents of Mars exploration will argue that we should travel to Mars because there are specific things we can learn there about Earth. From studying some of the oldest rocks in the solar system to learn about the formation of Earth to studying the climate to get insights into the pressing issue of climate change, there are many ways that discoveries made on Mars could improve life here on Earth.

But for Hecht, trying to justify space missions in this way “flies in the face of history. In the sense that yes, there always have been those tangible benefits [to exploration]. But we haven’t been very good at predicting them. That’s what’s wonderful about it. You go and explore somewhere new and you learn something you never expected to learn.”

We simply don’t know what we’ll discover from Mars until we go there. That has always been true of scientific discovery — from the accidental discoveries of penicillin or X-rays to the way that tech developed for the Apollo moon missions lead to better kidney dialysis machines and improved protective equipment for firefighters.

And beyond the pragmatic upsides to developing technologies and scientific knowledge, there’s a deeper impetus to explore. “The pursuit of knowledge is what makes us human,” Hecht said.

“We’ve been doing this since the first time we banged two rocks together. We pursue knowledge. And the exploration of new places — that’s why there isn’t a corner of the globe where human beings haven’t set foot, including the bottom of the ocean. That’s what we do.”

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