Elon Musk is sure there will be Life on Mars.

On 2nd February Starship number 9 (SN9) exploded on landing.  This is a small setback for the Mars colonisation program but Starship SN10 is already on the launch pad awaiting the next test.

Why go to Mars?  Mars has a third of Earth's gravity and plentiful frozen water and carbon dioxide for fuel and oxygen so it is the ideal location for a space base.  Starships can take off directly from Mars and visit the solar system but Earth's stronger gravity means they need a massive, re-usable booster to leave Earth for other planets.

Impression of Starship plus booster

Mars is also commercially attractive.  Metals extracted from Mars and the relatively nearby asteroid belt could be returned to Earth automatically and fairly cheaply with the use of dedicated re-entry pods and parachutes.  They would literally be "dropped off".   

However Elon Musk is not devoting his enormous fortune to a project to colonise Mars for purely commercial reasons. He is mainly motivated by the need for humanity to have a planet 'B' just in case we make Earth uninhabitable with nuclear war etc.  The Martians would be able to return to Earth and colonise it once the apocalypse had passed.  How likely is he to succeed?

The first step in this project is to create a fleet of relatively inexpensive launch vehicles.  There are two ways to lower the cost of launching spacecraft.  The first is to build massive re-usable rockets because the fuel costs per payload kilo decrease with size, the second is to develop a new power source such as fusion power.  Musk wants to colonise Mars by 2050 so only the first option is available.  Musk's objective is to create a fleet of thousands of low cost, giant, re-usable rockets called "Starship".

It looks like Starship will be a success.   A by-product of Starship meeting the parameters for Mars colonisation is that each launch is very inexpensive, costing only about $2m, and up to 100 tonnes of cargo can be put into orbit at a time.  A hundred one tonne satellites can be put into Earth orbit at around $40,000 launch cost each.  This means it is probable that Starship will benefit from its own success by cornering the global space transport market. At present each Starship prototype probably costs £200m but as mass production gets under way this figure will be drastically reduced - SpaceX must be expecting a target price of around $20m to $50m per vehicle if each is to be re-used only 10-20 times at $2m per launch. This means that within a year or two SpaceX will be building 20 Starships a year for every $billion pa profit from space activities.  

Ships will be queued up for launches every two years because the distance between Mars and the Earth varies between about 60m and 400m miles over a 2 year synodic period:

Mars colonisation will need a fleet of over 200 starships to provide 200 flights to Mars every two years.  200 flights will be able to transport at least 10,000 colonists. 

The starships will, in total, cost about $10bn and each flight will be $2m-$3m.  It will cost £10 to 20bn to set up the infrastructure of the colony so for $25 bn - $45 bn a sustainable colony on Mars will be created. This is only 25% of Elon Musk's fortune although he would expect much of the cost to be met by paying passengers.

The likely colonisation program will at first involve the transport of large solar panel arrays and possibly a nuclear fission reactor or two.  The first use of this energy will be to produce methane fuel by generating hydrogen and oxygen from the electrolysis of water and then reacting the hydrogen with martian atmospheric CO2 to make methane via the Sebatier process.

Source: CleanTechnica

Fuel production will need very approximately 10GWh of energy per Starship (depends on efficiency).  Modern marine nuclear reactors can produce a GWh of energy every day so could refuel a Starship in 10 days.  Solar panels on Mars would take ten days or so to generate enough fuel from a km2 of panels  Solar panels can be made as light as 6W per gram, if we assume 2W/g on Mars, a km2 of solar panels would weigh about 50 tons and could be transported on one or two Starships.  These are only very rough calculations but they show that Starships will be able to refuel on Mars.

The availability of water will determine the site of the first colony.  It is possible that one of the large ice patches such as Elysium Planitia will be chosen because it seems to host a slab of ice 800km x 900km in area and 45m deep and is sufficiently equatorial for solar energy generation. Elysium Mons, a 46,000 ft high volcano, is also nearby and may be a source for metal ores etc.  However, others have identified Deuteronilus Mensae, Phlegra Montes and Utopia Planitia as more likely sites.

Having established a sustainable fuel production industry large greenhouses will be installed to provide food and initially, stainless steel tubes covered in Martian soil will provide accommodation.  Carbonate rocks have been found on Mars which means that concrete can be made, however, concrete substitutes using Martian soil are also possible.

Mars is likely to have extensive mineral reserves that can be used to supply metals.  The more valuable of these metals may be the first Martian exports and should finance the supplies required from Earth in the early years of the Martian colony  (1 tonne of gold is worth about $40m and could finance 20 Starship launches).  Although the goal of the colony would be to attain sustainability and independence from Earth in the long run.

SpaceX imagines that by around 2050 the Martian colony will look like this:

Sunrise on Mars SpaceX

Politics will look very different in 2050.  The Martian Corporations such as SpaceX will be the most powerful in the solar system.  They will ensure that Mars-Earth trade continues.  It will be easy for Martian manufactures to be dropped off on Earth but expensive to send goods in the other direction so there will be pressure for people to migrate.  

The likely development of fusion propulsion in the latter half of the century will result in truly cheap travel around the solar system from orbital spaceport to orbital spaceport.  When that happens Elon Musk's dream of humanity as a truly interplanetary species will have been realised.  He will go down in history as the greatest man in the Galaxy (at least for humans).

2/2/2021