Space, Spaceflight

Moon or Mars?

This past week, there has been quite a lot of attention on space travel, due to the fact that July 20th marked 50 years since the Apollo moon landing! And what makes this even more exciting is that recently, NASA announced its accelerated plans to put people on the moon again… by 2024! 

The main problem NASA faces is political: during the Obama administration, the focus for 8 years was on going to Mars, but now, the Trump administration are pushing for a focus on the moon (although Trump seems to think he has decided Mars is better?). This isn’t an uncommon occurrence- with nearly every new president comes a new target for NASA, and this is incredibly annoying for the scientists who work there, with projects being dropped and revived, and budgets shrinking or swelling from year to year. This has prevented the progression of many projects and missions, but luckily although the logistics of going to the moon or Mars are very different, the technology needed is relatively similar! Which means that although progress is slowed, it isn’t completely halted! What makes it so difficult to decide is that both places offer so much, for science and industry!

NASA budget over the years (via SpaceNews)

So, out of curiosity, I conducted a *very* scientific study of the public’s opinions… amongst a group of 50 of my friends! Although hardly a reliable source, I found that quite a lot of them thought we should go to Mars, not the moon, with ~80% preferring Mars! Overwhelmingly, the most common reason was simply: “We have already been there”. My immediate response was that we haven’t seen it all yet- the moon has so much more to offer! But how does it weight up against Mars? How is a mission to Mars different to that of going to the moon?…

Artemis Logo with white background,
NASA Artemis Logo (via Wikipedia)

In order for any life to survive, it needs water. And it is very difficult to carry large amounts of water into space, simply because it is so heavy! This meant that the ISS was built with an incredibly efficient water purification system, recycling 93% of the water. This reduces the amount of water that needs to be sent up each year drastically, down to less than 500 litres a year (I think, I couldn’t find an exact figure so I just used information from some news stories, as well as the NASA website). This costs quite a lot, and the further away from the earth we go, the more costly it will be to send up water. So ideally crews should make use of water on the moon/mars. This is why NASA’s mission -Artemis- will make use of the new SLS rocket, Orion Module and the proposed Lunar Orbital Platform Gateway, to land crews at the Lunar South Pole. This is because it has near constant sunlight (useful for solar power) but has quite a lot of craters. These craters are key, as there is water ice hidden in the shadows, that can be used in a semi-permanent/permanent moon base. It isn’t just NASA that wants to take advantage of the Lunar South Pole: on July 22nd, India’s Chandrayaan-2 launched, with its goal to land there!

Location of ice at the Lunar poles (via

Like the moon, water can also be found frozen in the shadows of Mars’ craters, but it also has other supplies that the moon does not. At the equator, water only exists trapped within mineral compounds, and could be extracted with a chemical reaction, but further towards the poles, the astronauts would simply have to dig under the surface to find sheets of ice! So water won’t be a big problem on either landing, but it will require some ingenuity!

Mars’ North Pole

Going back to power, using solar panels for energy on mars is slightly problematic: frequent dust storms would cover any solar panels, so they would have to be put in an accessible place, as it would likely be a weekly, if not daily, chore for the astronauts to clean them off. Well, if you could call doing a spacewalk a ‘chore’! In addition to this, Mars gets less insolation (amount of solar radiation hitting a given area) than Earth, because it is further away! Earth gets a maximum 1000 Watts per metre squared, whereas Mars gets 590 W/m^2, only just over half! So it is likely that astronauts would, in the long run, switch to an alternative source, which could have benefits for life back here on Earth!

Radiation will be another big problem for missions that venture out of the earth’s protective magnetic field. Mars has its own atmosphere- albeit thin- so you would be more protected from solar radiation there than on the moon, which has an atmosphere so thin that it is basically considered a vacuum! This would not protect you at all, if there was a solar flare! Whether we land on the moon or mars, any base will need substantially thick walls in order to protect the astronauts for an extended period of time. This is feasible, with solutions such as building into caves/lava tubes, or using the surrounding rock to cover walls. So although Mars has an atmosphere, in the long run, it is the journey that makes the difference: it takes less than a week to reach the moon (Apollo 11 took 8 days for its round trip), and depending on where the moon is in its orbit, the journey could be partly shielded by the Earth’s magnetic field. Going to Mars however, will take at least 8 months just to get there, so the radiation dosage would be a lot higher. 

Apollo Module above the moon (via WIkipedia)

Not only is the journey to Mars more dangerous, it will also require a lot more precautions, astrobiologically speaking! Put simply, astrobiology is the study of aliens (well the possibility of them). The moon is considered to be lifeless- it lacks everything that life needs (link to life post), Mars however, has slightly higher chances of alien life. This is because in the past, Mars was incredibly Earth-like, and probably habitable! If life did exist there, we could find fossils there, and there is a very small chance of microbiotic life still living there today, deep beneath the surface! This means that all of the suits and base would have to be as sterile as possible, to reduce potential contamination, if there was any microbial life left there. It would be quite difficult, so we would have to weigh up the benefits! Do you think we should prioritise getting settled or preserving potential life?

Olympus Mons

Regardless of whether going to Mars could contaminate potential subsurface life, Mars has lots else to offer for science! With towering volcanoes, carefully preserved craters, long evaporated waterways and CO2 ice caps, it would be an awesome place to explore! I think Mars is so interesting because it actually started off relatively Earth-like, so could portray what Earth’s future may hold…

The moon however, is thought to be barren of all life, due to the fact that it has never had habitable conditions. Then again, the Moon, as it used to be part of Earth, could reveal valuable secrets about our planet’s past! It also holds vast reserves of natural resources, such as magnesium, titanium, aluminium, silicon and iron- used in modern technology- and Helium-3, which has potential applications for Nuclear Fusion! So it definitely shouldn’t be cast aside.

Looking into the future, having a permanent moon base is more achievable, and would probably result in a whole new trade market due to its richness in resources and proximity to Earth. I think that NASA will pioneer this mission, and be followed by many companies. Mars, however, is a more exciting place to go, both for science, and the future of humanity. This is because it would be easier to build a sustainable, independent colony, partly out of necessity, partly because it is far more Earth-like, with a more similar gravity and surface than the moon has. I suspect that although NASA will continue to send robotic missions with scientific aims, it will be private agencies that set foot on the red planet for the first time! But, this is purely speculation on my behalf, and I can’t wait to see what the future *actually* holds!

So, moon or mars? Both offer awesome scientific possibilities, but whatever is decided, it is scientists, not politicians, who should get the final say, and that decision should last, because science is a long old process! There is so much I could talk about here, so perhaps a follow up post is needed! Have I missed anything out? Let me know your thoughts in the comments! If you were an astronaut, where would you want to go? Why?

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