Should We Go to Mars or Back to the Moon?

When humans finally blast off for another world, where will we be going? Will we return to the Moon, and take over where the Apollo astronauts left off, or will we press onto Mars, and set foot on a whole new planet?

Humanity is going to need to make a difficult choice in the next few years. One that will have implications for the very future of space exploration: classic Star Wars or the new Trilogy? Star Trek fans feel your pain.

But also, we’ll need to figure out whether we should push on with the human exploration of Mars, so that Mark Watney can fulfill his potato destiny, or return to the Moon and build Moonbase Alpha. It’s surprisingly difficult to choose.

First, the case for the Moon. Obviously, the Moon is close. It’s just a few hundred thousand kilometers away, and it only takes astronauts a few days to get there, land on the surface and continue our scientific exploration of this world – which we still know very little about.

Why is the far side so different from the near side? Are there lava tubes and even vast underground caverns that future colonists could live in? It would be great to get more geologist boots on the regolith to find out.

Although it’s expensive, going to the Moon could eventually pay for itself. There are vast reserves of Helium-3 just sitting on the surface of the Moon. This material is rare on Earth, and could be used for future fusion energy planets. Not to mention other valuable minerals and elements that might just be lying around, ready for collection and used for space-based manufacturing.

The Moon makes sense as a testing ground, for humanity to perfect the techniques of surviving and thriving off planet Earth. If we can make it there, then we stand a chance of going the distance as a true interplanetary species.

The big problem with the Moon is that it’s completely inhospitable to human life. There’s no atmosphere, no protection from the Sun’s radiation, enormous temperature variations and a gravity so low it could be lethal over the long term.

The lunar regolith is like tiny shards of glass that would get everywhere, into everything, and be a constant danger to anyone living on the Moon.You couldn’t imagine a worse place to live.

The Moon is close but it sucks, what about Mars? Mars is much much farther than the Moon; the average distance to Mars is about 225 million kilometers.

Mars, as photographed with the Mars Global Surveyor, is identified with the Roman god of war. Credit: NASA
Mars, as photographed with the Mars Global Surveyor, is identified with the Roman god of war. Credit: NASA

This means that a journey to Mars with even a short visit to the surface will take the better part of 2 years. Astronauts will be beyond any kind of rescue and completely reliant on their spacecraft and supplies for that entire journey.

During their voyage, they’ll be bombarded with radiation from the Sun and there’ll be no protection on the surface on the planet either, because Mars doesn’t have a global magnetosphere like Earth.

But once they do get to Mars, they’ll have a world that’s much more earthlike. The temperatures are extreme, but can be reasonable at the equator, in the middle of the day. There’s a slight atmosphere, and stronger gravity – maybe your bones won’t waste away if you spend too long there.

To say there’s science to be done on Mars is an understatement. There are so many different terrains, with different geologic features. There’s the outstanding question of whether there was ever life on Mars, and if it’s there now. We’d really like to know the answer.

The Martian regolith is smoother and safer than the lunar version, having been weathered down by wind over millennia. It would still get everywhere, but it wouldn’t give you lung disease.

We now know there are vast reserves of water under the surface of Mars, and astronauts will be able to use this for all kinds of projects, like growing plants, drinking water, breathable atmosphere and even rocket fuel.

Venus imaged by Magellan Image Credit: NASA/JPL
Venus imaged by Magellan Image Credit: NASA/JPL

Sending humans to Mars is much more complicated and expensive than sending them to the Moon, and the level of space-based infrastructure would be much greater. Assuming we did this right, we’d have much more technology and a stronger presence in space.

Both Mars and the Moon have their pros and cons, but there’s another world that you might want to consider: Venus.

Although Venus is mostly a terrible hellscape, completely worthless down on the surface, where it’s hot enough to melt lead, and the atmospheric pressure is as bad as being a kilometer under the ocean. Did I mention it rains sulphuric acid?

But high up in the cloud tops of Venus, around 50 km altitude, the evil planet becomes downright habitable. You wouldn’t need to wear a spacesuit to regulate the delightful room temperature atmosphere. And you wouldn’t need a pressure suit, because it’s already perfect Earth pressure. You would, however, still need to worry about the sulphuric acid rain. And unless you’ve evolved to breathe carbon dioxide, you’ll need to keep a supply of oxygen handy.

NASA has already proposed sending dirigibles to Venus, filled with our breathable atmosphere for buoyancy, to explore. So maybe the next planet we set foot on, will be the one that we can never set foot on. Hmm, that sounded better in my brain.

You know what, I can’t choose. We should go back to the Moon, we should send humans to Mars, and we should explore Venus too. No matter where we go in the Solar System, it’s going to be an enormous undertaking. We’re going to need to develop new technologies, and risk the lives of everyone involved. But the rewards will be great, moving us one huge leap towards becoming a true interplanetary species.

So now it’s time for you to decide. The fate of humanity rests on your shoulders. Should we press on to Mars, or focus our energy on the Moon or even Venus? Give us your suggestions in the comments below.

18 Replies to “Should We Go to Mars or Back to the Moon?”

  1. I suspect the development of 3D printing in space factories, turning asteroids into parts for spaceships, etc, will have to precede any broader human exploration as just getting stuff off the surface of Earth is a colossal task.

  2. I, too, see the advantages of both approaches. However, in my opinion, the combination of scientific value of a return to the Moon plus the ability to use the Moon as a test bed and proving ground for technologies to go to Mars, tip the scales in favor of the Moon. Depending upon how large a presence we are able to establish on the Moon, we might even be able to use it to fabricate and launch planetary spacecraft; however, our ability to do so is both so speculative and so (probably) far in the future, that is not really a strong argument in favor of returning to the Moon in the next decade or so.

  3. So we can use H3 to build “fusion energy planets”? (5th paragraph)
    They sound like small stars, let’s hope they don’t end up that way. LOL
    I vote Moon first, followed shortly by Mars. G’day!

  4. My bet is that it is going to boil down to economic feasibility and profitability, meaning the Moon wins. The Moon would take less time to terraform, has a much lower escape velocity, meaning it would make a much better jump-off point to other worlds, and, while living above-ground may not be immediately feasible, living below-ground would. That leaves us with the gravity problem . . . . which, in my opinion, could be solved by medical means . . . . finding a way to stop the process of bone deterioration. My bet is that we could get a pretty good slingshot effect (3,683 kilometers per hour) by launching off of the Moon at specific times, given that it is rotating around the earth . . . . . it would give us that effect in nearly any direction we would want to go. Didn’t think if that one did you?

    1. Frankly, we don’t even know if there is a “gravity problem”. It may turn out that needing to support our bodies – sitting, standing and walking – even in very low gravity is much less deleterious to human health than microgravity. The only way to find out for sure is to do what we’ve been doing with microgravity aboard the ISS – send people to the Moon for long periods of time and see what effect it has.

      And, no, I didn’t “think if that one”.

  5. The idealistic answer of course is both. The realistic and practical answer is the moon. The primary limiting factor will be cost, especially in the short run. Anything that lowers the cost of space travel makes sustaining outposts and manned missions to both more feasible. At some point the cost of going to Mars will be low enough for the advantages of going there to outweigh the disadvantages (which is primarily cost.) The shorter distance also makes the moon much safer and easier to get to if extraction is needed urgently. In all honesty we should not be considering a sustained manned presence on the moon until we have urgent extraction infrastructure already in place if something goes terribly wrong. Lava tubes would make for an ideal location for a base as it has pre-built protection from radiation and micro meteors . Once we have vetted maintenance technologies on the moon, Mars by comparison will be easy.

  6. I expect that until adequate radiation shielding is developed for manned spacecraft, it will be found necessary that when our species takes its next number of forays into the full force of the solar wind, flying during the years of solar max will be avoided, and missions will be conducted during periods of minimal solar activity.
    This will tend to group the flights into short episodes of activity in manned space flight, followed by a number of years of primarily robotic missions.
    A pattern may develop occurring approximately on eleven year cycles.

    1. The peak of solar activity for Cycle 20 was November of 1968, just a month before Apollo 8. Apollos 8, 10, 11, 12, 13, 14, 15, 16 and 17 were all successful in terms of survival of solar radiation. (As I recall, there was one solar flare between Apollo 16 and Apollo 17 which, had it occurred during a mission, would have been fatal to the crew.)

      Our technology for shielding against radiation is much better than it was in the late 60’s and early 70’s. For instance, we now know that, pound for pound, many plastics provide better radiation shielding than aluminum. A polyethylene-based material called RXF1 is particularly good for this purpose. We also have strategies that were not tried in Apollo – for instance, the water supply for a long-duration flight could be stored in a shell around the inhabited part of the spacecraft, which would provide additional shielding using material we had to take with us anyway. There are others as well. Honestly, I do not think solar radiation is going to be a major factor dictating when flights can take place.

      Once we reach the Moon or Mars, any long-term habitat should either be built underground or covered with regolith. We know, from the soil brought back from the Apollo missions, that a couple of feet of regolith provides excellent radiation shielding, and there is no real reason to expect that things will be different on Mars.

  7. I think we ought to stay on Earth and develop a new technology for space travel that will allow us to go anywhere in the solar system in just a few hours.

    A recent discovery in physics may facilitate this. As one physicist noted:
    “The physics of the Weyl fermion are so strange, there could be many things that arise from this particle that we’re just not capable of imagining now,”

  8. We need to go back to the Moon first and make a permanent base there and get the experience from the low gravity also the Moon dust makes a perfect building material which can be used to build domes over inflated moulds using robotics, just imagine how fantastic it would be to look up to the Moon from Earth and see Man made lights glowing from our new settlements, also it would pay for itself just from mining the minerals there, NASA and the ESA need to get back there before China, Russia and others take the spoils, also going to Mars first is not financialy viable and if there is a problem, a quarter of a million miles to the Moon is a lot closer than the 47.4 million miles (closest orbit) to Mars,

  9. I think the actual plan is to send humans to the moons of Mars in the 2030s. More available in those conjunctions without much further effort than what has or is being done. Clever and affordable, I really think they’ll do it. Attempt it.

  10. Another vote for the Moon, I’m afraid. Let’s try living long-term on some other body, and see whether we can build a self-sustaining colony, bit by bit, but still be within a couple of days travel of home if things go bad.

  11. I think there’s a second question implicit in the first, here. Are we going just to put boots on the ground, or to stay? Mars can go either way, but there’s not much reason to return to the Moon unless it’s “there to stay”, to support further exploration. And while I love the idea of a Moon-based infrastructure using lunar ice to fuel Mars-bound vessels, I think we need to run a one-shot mission to Mars first.

    That’s not just about sticking a flag in something. It’s a proof of concept. If we want to inhabit Mars, we first need to show that we can put human boots there in the first place. The best way to do that is a direct-flight mission on the (relative) cheap. I think it would be foolish to start building the economy to support extended habitation and exploration without testing the waters first.

    We see the same pattern in history; the later Apollo craft were improved based on what NASA learned from the first landings. The lessons learned from that “one small step” will be important to designing the kind of full-scale habitation effort that a moonbase implies.

  12. instead that stoopid ISS eating money for nothing, i`d love a small base on the Moon with a nice telescope like Hubble there near the base. Mars has almost no atmosphere so it wouldn`t be that much difference. I would love to see there some small greenhouses for some fresh vegetables on the spot 🙂 People there wouldn`t feel so alone as they will see the Earth always in the same place shining blue to the Moon, also a continuous radio/video link would be available to them with a very small 2 seconds delay instead 10-40 minutes to Mars…

  13. Lunar or Martian dust might be at least partially mitigated by using solar powered walk-thru de-magnetizing ‘Faraday cages’? Knock off the positive charge(s) then blow the dust into collection filters prior to entering pressurized portions of the habitat?

  14. Send Rovers to the Moon as we’ve done on Mars. Then make a plan for human settlement as were doing on Mars if desired. As for Mars send enough supplies to sustain a colony before actually sending anyone. There are plenty of people willing to make the one way trip and live out there lives on the red planet if they could. Low gravity only becomes a factor if they should return to Earth. Hopefully, we will have technologies to sustain life on mars independent of Earth.

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