# How possible would a manned base be on the moons of Mars? [closed]

Planning on writing a story that features a manned scientific base (like the International Space Station) on both moons of Mars, Phobos and Deimos. I had some questions concerning the possibility of such bases:

1. Gravity - Is the gravity of each moon high enough to battle to adverse effects on humans in microgravity environments?
2. Radiation - Does Mars have similar radiation belts as Earth, and do the orbits of either Phobos or Deimos enter those belts?
3. Surface Density - How dense is the surface of each moon, and is it possible to refine that material into buildable structures underneath the surface?

Thank you all!

• Your question seems very broad. I recommend splitting it into several parts Or reformatting the question to be more focussed. – Mormacil Mar 27 '17 at 18:31
• I think the first three questions are fine together as they are all environmental and local but the fourth question should definitely be dropped. – James Mar 27 '17 at 19:17
• Someone already did that ;-) – frarugi87 Mar 28 '17 at 13:10

# Is the gravity of each moon high enough to battle to adverse effects on humans in micro-gravity environments?

No. See calculations here, there is essentially no gravity of the moons of Mars.

# Does Mars have similar radiation belts as Earth, and do the orbits of either Phobos or Deimos enter those belts?

No. Mars does not have Van Allen Belts like Earth (or Jupiter) because does not have a magnetic field. The radiation you would get on the surface of those moons is the same solar wind you would see in deep space.

Most of the danger would be from protons in the solar wind, and periodic x-ray bursts from the sun which would not be mitigated by any sort of atmosphere. There would also be electrons and alpha particles in the solar wind, and various other EM radiation from the sun to be concerned with.

# How dense is the surface of each moon, and is it possible to refine that material into buildable structures underneath the surface?

Phobos has a density of 1876 kg/m$^3$ and is spectroscopically similar to a D-type asteroid, likely composed of organic silicates and carbonates. Deimos is 1471 kg/m$^3$ and is spectroscopically similar to a D or C-type asteroid with a similar composition to Phobos.

Since water has a density of 1000 kg/m$^3$, Earth's crust about 2500 kg/m$^3$, and iron 7870 kg/m$^3$, you can see that there is relatively low metal content in these moons. In fact, both are probably not solid rock, they are significantly porous, perhaps like heap of gravel mixed with ice. Deimos is much smoother than Phobos, indicating presence of regolith, which makes it more like a ball of gravel and ice, coated with fine sand.

Given the porosity and lack of gravity, these moons are probably pretty fragile. One missile strike could conceivably blow them into a ring around Mars. Even if there were useful materials (which there probably aren't) I wouldn't mine something so fragile, unless I didn't mind destroying it.

# What kind of orbits would communication satellites need to hold a constant (or almost constant) connection back to Earth?

Three 'geo'stationary satellites around Mars would be able to ensure constant communication back to Earth. The satellites would orbit at points 120 degrees opposite each other, in the plane of whichever moon's orbit you chose. Then, at least one of the three would always have direct line of sight to Earth, unless the Sun is in the way. The moon would always be in line of sight of at least two of the three. The three satellites would always be in line of sight of each other, so they could relay from moon to Earth as needed.

To get around the problem of the Sun being between the Earth and Mars, you would need some sort of deep space communication relay.

• "at least one of the three would always have direct line of sight to Earth" - unless the Sun is in the way, of course. But no orbit will help with that. – Mołot Mar 27 '17 at 18:54
• @Molot Good point. – kingledion Mar 27 '17 at 19:16
• So would you say that having bases on Phobos and Deimos wouldn't be worthwhile, due to the low density and high hazards? – Berziky Mar 27 '17 at 19:41
• @Berziky I don't see a great reason to have a base there. If you decided the materials were valuable, you could mine from the asteroid without building a base, by basically blowing the moon up and collecting the pieces. – kingledion Mar 27 '17 at 20:10
• @kingledion "by basically blowing up the moon", i have an issue with this, as i think we either cant do this with current technology, or we would need a lot of nukes, which would ultimately bombard earth with radiation – Alex Robinson Mar 27 '17 at 20:37

Given current technology: getting to mars is difficult enough with the complication of getting humans there alive and well, but I'm going to leave "how do we get there" out of it, or maybe address it later.

Now time to address each matter in turn:

1) Gravity

There was a similar question asked a few days ago, to summarise the answers: if you're staying on Mars for a few years, as long as you have dietary supplements, and do regular exercise (every day) you can probably get by for a decade(estimate), but beyond that we don't have any real data so we can't say for sure

Earth has a magnetic field, which helps us survive by blocking out a lot of the radiation (also the ozone layer helps by absorbing UV) Mars, however does not have this, because Earth has a hot Iron core, whereas because mars has a higher surface area to volume ratio, its own core has cooled, which allowed radiation to strip away the atmosphere, and means that lots more radiation compared to earth can hit the surface.

However, Mars does have a thin atmosphere, which will stop all of the alpha radiation, and probably a good 99+% of the beta radiation, which leaves gamma and you don't really have to worry about it, maybe do a monthly checkup for exposure to long term low level radiation and then keep them inside the base if they show signs of radiation poisoning. But this shouldn't be an issue, the film The Martian is very scientifically accurate (apart from the storms) and the suits shown in that : would block out any remaining beta radiation, and you can't worry too much about gamma, there is gamma radiation passing through you RIGHT NOW, but most of it is so low energy it passes clean through you.

3) Surface density

now, for drilling and refinement lets have some context: The average density of continental crust is about 2.7 g/cm3, but the mean density of Mars is 3.9 g/cm However, given how advanced mining technology is, this probably isn't an issue, just bear in mind that Earth equipment will have to be adapted slightly to account for low gravity: if you take a sledgehammer and hit it on the ground, you don't move, however on Mars or the Moon, if you hit a sledgehammer hard enough, you will move off the ground due to conservation of momentum. As for the moons... let's just start off with Mars and see where we get to. Mars contains a lot of useful minerals and metals, as long as you can send spaceships (like the one seen in The Martian) back and forth, you can set up the exact refinery equipment you need (this will be very expensive).

4) Communication

With a permanent base on Mars, communication will always be an issue, until you have the time to set up an extensive satellite network with a 0.75 second delay for the electromagnetic spectrum to actually reach Earth, the same delay to get back, then probably a few seconds of processing and satellite linkage at either end. Before this point, there will be large period of time ( a Mars day is 1 day and 40 mins, so about half this) where no communication will be possible.