Expert Voices

NASA wants to send humans to Mars in the 2030s − a crewed mission could unlock some of the red planet’s geologic mysteries

a rocky, rust colored barren, hilly landscape littered with various rocks and brown dust.
(Image credit: NASA)

NASA plans to send humans on a scientific round trip to Mars potentially as early as 2035. The trip will take about six to seven months each way and will cover up to 250 million miles (402 million kilometers) each way. The astronauts may spend as many as 500 days on the planet’s surface before returning to Earth.

NASA’s Artemis program plans to return humans to the Moon this decade to practice and prepare for a Mars mission as early as the 2030s. While NASA has several reasons for pursuing such an ambitious mission, the biggest is scientific exploration and discovery.

I’m an atmospheric scientist and former NASA researcher involved in establishing the scientific questions a Mars mission would investigate. There are lots of mysteries to investigate on the red planet, including why Mars looks the way it does today, and whether it has ever hosted life, past or present. 

Mars geology 

Mars is an intriguing planet from a geological and atmospheric perspective. It formed with the rest of the solar system about 4.6 billion years ago. Around 3.8 billion years ago, the same time that life formed on Earth, early Mars was very Earth-like. It had abundant liquid water on its surface in the form of oceans, lakes and rivers and possessed a denser atmosphere.

While Mars’ surface is totally devoid of liquid water today, scientists have spotted evidence of those past lakes, rivers and even an ocean coastline on its surface. Its north and south poles are covered in frozen water, with a thin veneer of frozen carbon dioxide. At the south pole during the summer, the carbon dioxide veneer disappears, leaving the frozen water exposed.

Today, Mars’ atmosphere is very thin and about 95% carbon dioxide. It’s filled with atmospheric dust from the surface, which gives the atmosphere of Mars its characteristic reddish color.

Scientists know quite a bit about the planet’s surface from sending robotic missions, but there are still many interesting geologic features to investigate more closely. These features could tell researchers more about the solar system’s formation.

The northern and southern hemispheres of Mars look very different. About one-third of the surface of Mars – mostly in its northern hemisphere – is 2 to 4 miles (3.2-6.4 kilometers) lower in elevation, called the northern lowlands. The northern lowlands have a few large craters but are relatively smooth. The southern two-thirds of the planet, called the southern highlands, has lots of very old craters.

Mars also has the largest volcanoes that scientists have observed in the solar system. Its surface is peppered with deep craters from asteroid and meteor impacts that occurred during the early history of Mars. Sending astronauts to study these features can help researchers understand how and when major events happened during the early history of Mars. 

Mars in a Minute: How Did Mars Get Such Enormous Mountains? - YouTube Mars in a Minute: How Did Mars Get Such Enormous Mountains? - YouTube
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Asking the right questions 

NASA formed a panel called the Human Exploration of Mars Science Analysis Group to plan the future mission. I co-chaired the panel, with NASA scientist James B. Garvin, to develop and assess the key scientific questions about Mars. We wanted to figure out which research questions required a human mission to address, rather than cheaper robotic missions.

The panel came up with recommendations for several important scientific questions for human investigation on Mars.

One question asks whether there’s life on the planet today. Remember, life on Earth formed about 3.8 billion years ago, when Earth and Mars were similar-looking planets that both had abundant liquid water and Mars had a denser atmosphere.

Another question asks what sort of environmental changes led Mars to lose the widespread, plentiful liquid water on its surface, as well as some of its atmosphere.

These questions, alongside other recommendations from the panel, made it into NASA’s architectural plan for sending humans to Mars

How do you get to Mars? 

To send people to Mars and return them safely to Earth, NASA has developed a new, very powerful launch vehicle called the Space Launch System and a new human carrier spacecraft called Orion.

To prepare and train astronauts for living on and exploring Mars, NASA established a new program to return humans to the Moon, called the Artemis program.

In mythology, Artemis was Apollo’s twin sister. The Artemis astronauts will live and work on the Moon for months at a time to prepare for living and working on Mars. 

How We Are Going to the Moon - 4K - YouTube How We Are Going to the Moon - 4K - YouTube
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The Space Launch System and Orion successfully launched on Nov. 16, 2022, as part of the Artemis I mission. It made the Artemis program’s first uncrewed flight to the Moon, and once there, Orion orbited the Moon for six days, getting as close as 80 miles (129 kilometers) above the surface.

Artemis I splashed back down to Earth on Dec. 11, 2022, after its 1.4 million-mile (2.2 million-kilometer) maiden journey.

Artemis III, the first mission to return humans to the lunar surface, is scheduled for 2026. The Artemis astronauts will land at the Moon’s south pole, where scientists believe there may be large deposits of subsurface water in the form of ice that astronauts could mine, melt, purify and drink. The Artemis astronauts will set up habitats on the surface of the Moon and spend several months exploring the lunar surface.

Since the Moon is a mere 240,000 miles (386,000 km) from Earth, it will act as a training ground for the future human exploration of Mars. While a Mars mission is still many years out, the Artemis program will help NASA develop the capabilities it needs to explore the red planet.

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Joel S. Levine
Research Professor, Department of Applied Science, William & Mary

From 1970 to 2011, Dr. Levine was a Senior Research Scientist, Science Directorate, at the NASA Langley Research Center in Hampton, VA. From 2007-2010 he was a Program Scientist for the Mars Scout Program and Mars Exploration Program at the NASA Headquarters in Washington, D.C. From 1990-2011 he was an Adjunct Professor of Atmospheric Science in the Department of Applied Science at William and Mary in Williamsburg, VA. From 2011 to present he has been a Research Professor in the Department of Applied Science at William and Mary in Williamsburg, VA.

  • Unclear Engineer
    While I support the idea of sending humans to Mars for scientific exploration, I am questioning the idea that NASA's SLS is adequate for that task. Even for the Moon missions, the SLS is not even taking a lander - SpaceX (or Blue Origin) has been tasked with getting an orbit-to-surface-and-back taxi waiting in lunar orbit for the Orion capsule to arrive. So, how is the SLS going to get the NASA astronauts from Mars orbit to Mars surface and back? And, how is it going to supply enough consumables for the astronauts to be there for "up to 500 days"? It seems like NASA would need a lot of SLS launches using upper stages that have not yet been even conceptually designed. Will Congress provide the needed funding - this century?

    I am thinking that SpaceX is a much more likely source for an actual crewed trip to Mars. But, NASA is probably going to need to pay for crew seats, and may need to pay for getting its astronauts a return vehicle, if SpaceX/Musk are still thinking one-way trips by then.

    NASA does seem to be thinking about nuclear thermal propulsion for Earth-to-Mars orbit transfer spacecraft, so that needs to be developed, too. Unless somebody comes up with fusion powered thrusters by then.

    Which reminds me, how about a status report on the Pulsar direct fusion drive engine? Their website says "Static tests are to begin in 2024 followed by an In Orbit Demonstration (IOD) of the technology in 2027." Is that still on-track for the tests this year? That could really change the equations for Mars exploration.
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  • billweberx
    No way in hell will NASA use the SLS to go to Mars. Starship is the only viable solution, once it's fully functional. Even then, there's no way to get back with the Starship until a lot of infrastructure is built on Mars. That could take decades of robotic missions.
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  • Ogre
    It seems like every decade some space agency somewhere is planning to send humans to Mars the following decade. Mark my words: there will be no humans on Mars in this century.
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  • Ken Fabian
    On Mars anything astronauts can do robots will do better. Go further, last longer. Cost less. Nothing blows out the difficulties and costs of missions in space than including astronauts.
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  • billslugg
    NASA's rationale for sending humans to Mars.

    "3.1.1 Taking advantage of the unique attributes of humans in scientific exploration

    It is important to consider the unique capabilities that humans bring to the process of exploring Mars. As a result, a common set of human traits emerged that apply to exploration relating to the MEPAG science disciplines, which include geology, geophysics, life, and climate. These characteristics include: speed and efficiency to optimize field work; agility and dexterity to go places that are difficult for robotic access and to exceed currently limited degrees of-freedom robotic manipulation capabilities; and, most importantly, the innate intelligence, ingenuity, and adaptability to evaluate in real time and improvise to overcome surprises while ensuring that the correct sampling strategy is in place to acquire the appropriate sample set. Real-time evaluation and adaptability especially would be a significant new tool that humans on Mars would bring to surface exploration. There are limitations to the autonomous operations that are possible with current robotic systems, with fundamental limitations to direct commanding from Earth being the time difference imposed by the 6- to 20-minute communications transit time and
    the small number of daily uplink and downlink communications passes."

    Boiling it down:
    1) Humans excel at speed and efficiency in field work
    2) Humans have the ability to go places robots can't
    3) Humans are more dexterous than robots
    4) Catch errors in real time
    5) The 20 minute time delay

    My belief is all of these problems will go away very soon with advances in robotics and AI. Adding humans increases cost a hundred fold. The justification is simply not there. Send in the machines until they can't tell us any more.

    https://www.nasa.gov/wp-content/uploads/2015/09/373665main_nasa-sp-2009-566.pdf?emrc=6dfe40
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  • Rob77
    Costs aside - the big benefit in my opinion of sending humans is to get them prepared for interplanetary travel and the technologies that come with it. I think by continually sending robots we aren't pushing for human interaction and technology required to live sustainably on other planets, thus slowing progress in this area.
    I know there are some (even in this community) that accuse Musk of dreaming too big (i.e. ego) - but I believe that is driving some of the success for SpaceX.
    On a personal note - I wasn't alive for any of the moon landings so be nice to be alive to see humans set foot on Mars.
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  • Joexo
    Pretty sure they meant 2130s
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