There's somewhere else that is a better contender for a base than Mars - and it's even closer.
The Moon has fuel and manufacturing opportunities. It can provide nuclear power to enable mission to not only Mars, but ideally Titan. Solar panels can be manufactured for local power, geothermal energy opportunities are present, and much more.
The concept of a Space Elevator on the Moon is possible with present day technology according to the ESA. For more detailed infomation on space elevators please watch the talk below.
Relying on rockets to build and maintain a base is not sustainable. A space elevator is vital for cost-effective infrastructure on the Moon and on Mars. Since the Moon does not have a very thick atmosphere rockets are not quite as effective, although lower gravity helps.
With a space elevator on earth, and a space elevator on the Moon, connections between Lagrangian points can be made without propellant. This would safely deliver goods to and from the Moon, and other bodies within our solar system like Titan or Mars.
Having a lunar space elevator set up at the lunar equator and polar area(s) is advantageous. It stablizes the tether and allows transport of equatorial resources like helium-3 to a polar base exposed to eternal light. Helium-3 is rare isotope for nuclear fuel on Earth, but the same is not necessarily true for the Moon. Nuclear energy is essential for a long-term base due to eclipses ocassionally disrupting solar power. Battery storage can be used instead of commonly suggested fuel cells, to ensure hydrogen availabilty for future missions.
(Image Credit: Star Technology and Research, Inc./Jerome Pearson)
A north pole base would work well on the rim of Peary crater. The ridges of the crater are exposed to eternal light due to the Moon's axis. This would make for an uninterrupted power source, along with regions of eternal darkness for cryogenic fuel storage. Peary crater receives the most constant light on the Moon. It also has stable temperatures of around -50 C, which are comparable to places on Earth.
A south pole base would also work well, although colder. Shackleton crater is near peaks of eternal light such as Malapert Mountain, which could provide solar power 90% of the time. Shackleton crater also has extremely cold regions which could house an infrared telescope. The crater is located within the South Pole-Aitken basin which lies 13km deep and could provide access to deeper layers of the Moon's crust.
Polar areas, particularly the South Pole, experience magnetic anomalies on the Moon. During Solar Flares or when passing through the Earth's magnetotail, levitating errosive moondust and 200-1000v negative charges are present. Unprotected equipment could suffer damages. This obstacle can possibly be mitigated by electron capture and/or manufacturing processes.
Since the Lunar surface experiences extreme high and low temperatures, geothermal power is also possible via heat engines. A vapor compression loop can be powered by gases cycling through hot and cold areas. Lunar craters can also be used to store cyrogenic fuels more effectively than on Earth. Temperatures rarely rise above the 100K in the eternal darkness, below the boiling points of liquid methane/ethane. Hydrocarbon fuels from places like Mars and Titan could be stored on the Moon for return trips.
The surface of the Moon is harsh. A surface base would be pelted with micrometeorites and exposed to hash radiation. The reflected infrared radiation along with solar radiation caused the ISRO Lunar probe Chandrayaan-1's power supplies to overheat, ending 1000 days sooner than was expected. Prior to it's mission ending, Chandrayaan-1 picked up signals during a solar flare that caused an X-ray fluorescence phenomenon. A base must go underground to avoid dangerous radiation.
Fortunately, the Lunar surface is covered with craters that open up ancient lava tubes from the Moon's volcanically active days. A few of these caves have been detected thanks to NASA'sLunar Reconnaissance Orbiter. Several of the caves opened up go deep into the surface of the Moon, and would provide adequate radiation sheilding. It would make sense to survey these caves first with robotics.
Chandrayaan-1 also detected surface water/ice on the Moon in small quantites. While this could potentially be exploited, the amounts are marginal. The water resources are best left untouched by early settlement.
The real resources the Moon offers are oxygen and metals such as aluminium, magnesium, and titanium. At least twenty different methods have been proposed for lunar oxygen extraction. With hydrocarbon fuels plus oxygen, propulsion is accomplished without relying as many of Earth's resources.
The glass created on the Moon could be optically superior to glass created on Earth. Lunar silicates are mostly anhydrous and carry superior material properties for glass. Glass made on earth typically has more hydrogen bonds which can result in increased brittleness.
With high concentrations of silicon, aluminium, glass, plus the hard vacuum of space - Solar Cells can be constructed layer by layer. The environment is excellent for photovoltaic manufacturing, perhaps even better than earth.
The time for data transmissions between Earth and the Moon is approximately 3 seconds back and forth. This is a major benefit for the safety of astronauts to create infrastructure for further places with more lag.
Many activists are not keen on launching nuclear powered spacecraft into space because of the very realistic threat of rocket failure causing fallout. Their concerns are not misguided. However nuclear power is a very viable long term energy source in the darkness of deep space, where the sun shines exponentially dimmer. There are few alternatives.
The compromise is to harness Helium-3 on the Moon for radioactive material. Initially it would be beneficial to have a nuclear power supply to enable construction of a space elevator and manufacturing facilities. Once Helium-3 can be extracted from the Moon, no more rockets will need to jeopardize Earth. Nuclear energy enables solar cell manafucturing on the Moon, and could also supply cells to Earth and spacecraft. Having access to nuclear fuel in space also benefits missions into deeper space like Mars or Titan.
The Moon has low gravity which isnt good for human anatomy. Superconductive mag-lev loops can generate the centrifugal force needed for artificial gravity pods. Sleeping inside these pods will lower the effects of low gravity sickness. With cryogenic gas and cold temperatures, mag-lev is more practical than in Earth atmosphere. Identical Mag-Lev Loops (and space elevators) can also be used on Titan since its gravity is about the same.
This log will continuely be updated as I am able to elaborate with more information.