Mars Mission Planning for the Next Decade

 

Planning Early Mars Robotic Infrastructure Development

Jack Brzezinski Ph.D.

 

What do we know now?

Early uncrewed starship missions to Mars will need to establish infrastructure for human exploration. The first successful test of the Starship SN8 makes the planning process much more realistic even though there will be many difficult engineering problems in the future. SpaceX has proven that they can get their engineering correctly. 

 

Figure 1. Starship SN8 high-altitude test was mostly a success. Source: SpaceX 

There is a consensus that a human-crewed mission to Mars will require refueling with liquid methane and oxygen on the surface. The amount of fuel necessary for the launch from the planet’s surface is significant. We are talking about a ballpark figure of 10-ton methane and oxygen mix of propellant for the return trip that needs to be ready on the surface. Bringing that mass from Earth would make the project almost infeasible with the currently available technologies.

The propellant production process will have to be completed using robotics and automation technologies because of two significant reasons:

-Sending humans to Mars without the propellant ready and secure on Mars is a one-way ticket and a possible public relations disaster for the corporations and government agencies involved

- There is a high risk involved if there is a decision to send sending human crew that needs to focus on building the propellant infrastructure.  There may be unknown issues that might not be solvable with the equipment available at that time on Mars. A ruptured pipe or suck valve might not be fixable.

 

Planning the payload for the 2020 – 2030 decade

 

At the time of writing, the most recent launch window has opened in the summer of  2020. To be more specific: The Perseverence rover mission launched July 30, 2020, with the arrival in mid-February 2021.

 

Table 1. Approximate Earth-Mars launch windows for Hohmann Transfer Orbits. Source: Cosmic Train Schedule, http://clowder.net/hop/railroad/sched.html

Departure Dates		Arrival Dates
Month	Year	Month	Year
8	2022	4	2023
9	2024	6	2025
11	2026	7	2027
1	2029	9	2029
2	2031	11	2031
4	2033	12	2033
5	2035	2	2036
7	2037	4	2038
9	2039	5	2040
10	2041	7	2042

 

There is a debate about whether the 2022 window is realistic for a Starship to land on Mars. At the time of this writing in 2020, the launch window in 2024 is a definite possibility. It is also possible that SpaceX will be able to deal with engineering problems by delaying missions by two or four years.  However, the type of payload that needs to be delivered can be discussed with more certainty. SpaceX made it clear that their objective is establishing a self-sustaining city on the surface. Therefore, crewed missions will probably be a priority only when the risk factors are at acceptable levels. The risk factors will be defined by the reliability of the Starship as well as the available infrastructure

 

There are several mission payloads that SpaceX might consider to send without humans on board.

a)      Mars sample return mission:
It is not likely that SpaceX will use their Starship architecture for a sample return mission in the early missions (2022, 2024). It is much easier to send the analytical equipment with the rovers to Mars and transmit the results electronically,

b)      Basic equipment delivery:
SpaceX will probably decide that delivering a relatively inexpensive payload consisting of essential surface logistic equipment, solar panels, power cables, tanks, pipes, etc., makes financial sense. The early high-risk missions probably should not have the payload worth hundreds of million dollars that might be difficult and slow to replace.  

c)      Deep geological testing mission:

Propellant/rocket fuel production is critical for return trips for human-crewed missions.  There is a knowledge gap in terms of the exact geology and around and under the possible landing sites and water availability. Also, the engineering of the water acquisition process depends on the exact geology of the area. There might be a need for deep drilling and underground samples analysis to determine the equipment parameters that will do the mining tasks. All sample analysis can be performed on Mars.

d)      Habitat infrastructure:
Delivering heavier, larger, and simpler equipment that does not require extensive assembly processes like habitats might be advantageous for early missions. However, the ships that already landed might be used as habitats. Therefore, dedicated habitats will be less necessary for the first decade of missions to Mars.

e)      Energy infrastructure development:
Fuel/propellant production will be an energy-intense process requiring electricity for mining and operation, supporting the Sabatier chemical reaction procedure. Therefore electricity production will be the first necessary step towards propellant production. SpaceX might be able to obtain nuclear sources of energy from the government. It will depend on how well SpaceX will cooperate with government agencies. If nuclear reactors are not an option, then a large solar array will have to be constructed using robotic systems. In any case, energy infrastructure development is a top priority.

 

Payload design scenarios will highly depend on the level of funding and success rate of Mars missions. The following table is an optimistic one and assumes an exponential growth of the number of missions within each window. It is probably safe to think that the payload capability per each launch will be increasing and eventually reaching the 100 ton of useful payload goal set by SpaceX. We can safely assume that the early mission will be at around 20% of that payload goal.

 

Table 2: Optimistic payload design scenario for future Mars missions in the next decade

Approximate Launch Window	Main Payload Objectives	Equipment
September 2024	Number of missions: 1 Low-cost tooling and equipment for power generation and surface logistics	Power cables Pipes Solar panels Storage tanks
November 2026	Number of missions: 3 Deep geological analysis Solar array construction	Robotic system/rover for deep drilling and sample analysis Solar panels, power transmission equipment Robotic systems for solar panel assembly
January 2029	Number of missions: 6 Propellant production setup Energy production Component for habitat construction	Mining rovers Water acquisition system from the ground Fuel production equipment Automated vehicles Alternative energy sources: nuclear
February 2031	Number of missions: 12 First crewed mission Components for habitat construction	Rovers, vehicles Habitat construction materials Construction tooling Food production components Robotic systems