the inception of a multi-planetary society

The Inception of a Multi-Planetary Society

Undergraduate Honors Thesis

Maximilian Y Plavcan

University of Florida

Fall 2019

2 Fall 2019

Faculty Advisors:

Dr. Anil Rao MAE

Dr. Steven Miller MAE

Dr. Oscar Crisalle ChE

3 Fall 2019

Abstract

With the technological advances currently being made to return humankind back to the Moon by

the year 2024 with NASA’s Artemis program, the goal of exploring and creating permanent

outposts on Mars has been postponed in the hopes that lessons are learned while colonizing Earth’s

nearest celestial body. In order to effectively colonize any celestial body outside Earth’s sphere of

influence, major challenges must be addressed to protect explorers from hazardous environments

and allow for sustainable living conditions. The report outlines a few of the key milestones that

must be accomplished in order to advance the human species to another planet and proposes

solutions to complex engineering challenges that the space agencies of the world could potentially

utilize when leaping into the vast expanses of space.

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Table of Contents

1 Introduction ........................................................................................................................................... 5

1.1 Reasoning for Human Exploration ............................................................................................... 5

2 Exploration Challenges ......................................................................................................................... 8

3 In-Situ Resource Utilization.................................................................................................................. 8

3.1 Regolith Utilization ....................................................................................................................... 8

3.2 Water Extraction and Utilization .................................................................................................. 9

4 Environment Overview ......................................................................................................................... 9

4.1 Martian Environment .................................................................................................................. 10

4.2 Potential Martian Habitation Sites .............................................................................................. 11

4.2.1 Habitation Site I - Planum Australe .................................................................................... 12

4.2.2 Habitation Site II - Pavonis Mons ....................................................................................... 14

4.2.3 Habitation Site III – Gale Crater ........................................................................................ 16

5 Oxyhydrogen Generation .................................................................................................................... 19

5.1 Chemistry Overview ................................................................................................................... 19

5.2 Engineering Prototype of Oxyhydrogen Generator .................................................................... 21

5.3 Experimental Setup and Prototype Results ................................................................................. 23

5.4 Prototype Improvements and Further Work ............................................................................... 24

5.5 Oxyhydrogen Generator Utilization ............................................................................................ 25

6 Orbital Dynamics ................................................................................................................................ 26

6.1 Characteristics of Simulated Orbit Transfers .............................................................................. 26

6.2 Approximations in Simulation .................................................................................................... 27

6.3 Orbit Fractioning ......................................................................................................................... 27

6.4 Transfer Orbit Simulation Results .............................................................................................. 28

6.4.1 Results Interpretation .......................................................................................................... 34

7 Additional Future Establishment- Sky Cities on Venus ..................................................................... 36

8 Afterthoughts ...................................................................................................................................... 38

9 Acknowledgments ............................................................................................................................... 39

10 Works Cited ......................................................................................................................................... 40

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1 Introduction Fifty years ago, Humanity committed itself to performing a great leap into the unknown by

successfully leaving Earth to set foot on another celestial object. From July 20th, 1969 to December

14th, 1972 twelve humans explored the face of the Moon, returning with Lunar samples effectively

giving humankind a glimpse into the formation of the Moon, Earth and Solar System. At the

conclusion of each mission many of the life support systems and other ground support equipment

that aided the astronauts heavily during their short visits were simply left behind, never to be used

again. With the successful return of Apollo 17 and its crew of three came the hopes of the Space

Shuttle Program as well as orbiting laboratories such as SkyLab and the International Space Station

(ISS). With the historic accomplishments that all successor programs achieved after the Apollo

program all had a single feature in common, each program confirmed human spaceflight again to

Low Earth Orbit (LEO) rather than look outward toward crewed interplanetary missions.

With upcoming human rated launch vehicles such as NASA’s Space Launch System (SLS) rocket

as well as SpaceX’s BFR and Blue Origin’s New Glenn rocket to name a few, the excitement of

the 1960’s space program is again a possibility for humankind to experience. This thesis is meant

to convey a broad overview of how humanity could potentially leave the confines of the Earth and

colonize, expand, and grow a civilization on the surface of Mars. Several celestial bodies within

the Solar system share features with Mars so the outcomes of the report do not exclusively apply

to a singular geological system. Additionally, the report is not all inclusive and does not address

all major challenges but rather outlines a select few. An artist representation of the SLS rocket that

will return humans back to the face of the Moon is displayed in Figure 1.1.

Figure 1.1 Artist Representation of the SLS Rocket During SRB Separation [1]

1.1 Reasoning for Human Exploration With the many hardships and struggles that humanity faces on Earth already it is a valid

question to ask why human exploration and expansion to other celestial bodies is necessary. With

space programs costing on the order of billions of dollars and with the constant risk of mid-flight

anomalies and unsuccessful missions, NASA and its contractors are constantly required to justify

mission purpose, priority and budget.

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Along with various others, there are three underlying reasons why humanity has an obligation to

strive towards becoming a multi-planetary society.

I. The first reason being the technological advancements that are a byproduct of the push to

expand humankind away from Earth. From the development of miniature electronics that

were initially driven by the need for mass reduction in spacecraft to advancements in

medical instrumentation that were driven by life support systems inside confined

spacecraft, the exploration of humankind to LEO and beyond creates constraints and

extenuating circumstances that would otherwise be nonexistent on Earth, thus facilitating

ingenuity and technological advancements in areas that would otherwise be unmodified

and be recognized as “good enough”.

II. The second reason is for the promotion of the longevity of the human species. With the

potential of nuclear warfare and fatal asteroid impacts, one option that could provide safety

to the existence of the human species is to occupy more than a single celestial object. In

the case of a global threat, human-induced or naturally occurring, humans will have the

ability to either escape or completely avoid global tragedies that are unavoidable.

III. The third and final reason is less tangible than the first two previous reasons but equally as

vital. Exploration from Earth inspires future generations as well as provides a means of

self-reflection for humans living on Earth. Within the short span of 13 years, starting in

1959 with NASA’s initial announcement of the Mercury 7 astronauts to 1972 when Apollo

17 and humans departed from the Moon, an entire generation of future explorers, and

dreamers were generated. As Apollo 11’s Lunar Module Pilot Edwin “Buzz” Aldrin said

“The biggest benefit of Apollo was the inspiration it gave to a growing generation to get

into science and aerospace” [2]. Heroes and legends were generated by these various space

missions, effectively providing subsequent generations with role models and liaisons to the

STEM field.

The act of self-reflection driven by leaving the Earth can best be illustrated by the aftermath

of the Earthrise image taken by Apollo 8’s Lunar Module Pilot Bill Anders in 1968. The

impact is best summarized through the words of astrophysicist Neil DeGrasse Tyson:

“In this image, which is one of the most recognizable images ever obtained, we see Earth as nature intended

it to be viewed: the ocean, land, clouds. There are no countries in that image. There are no national

boundaries or state borders. By 1970, the Environmental Protection Agency was founded under a Republican

president. Leaded gas was banned. The catalytic converter was introduced. The Comprehensive Clear Air

Act was passed. The Comprehensive Clean Water Act was passed. The Endangered Species Act was updated.

Earth Day was founded. Suddenly, we were thinking of Earth as a system; Earth as a collective home for all

of humanity. That happened while we were going to the Moon, and it was birthed by that photo. That photo

became part of our culture. We were different because of that photo.” [3]

The image of Earthrise is presented in Figure 1.2.

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Figure 1.2 Earthrise Taken by LMP Bill Anders in Lunar Orbit on Apollo 8 [3]

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2 Exploration Challenges

With the push to colonize Mars comes a collection of unique challenges that humanity has

never confronted at such scales. With the many challenges that must be accounted for, three critical

areas that are expanded upon within this report include Mars resource utilization, environmental

conditions and orbital mechanics of planetary arrival.

3 In-Situ Resource Utilization

With limited launch vehicle payload volume and high launch costs, materials and

instrumentation brought to initial interplanetary colonies must be minimal as well as self-

sustainable. Common habitation operations as basic as waste disposal must be calculated and must

focus on minimal resource waste to promote colony longevity. Due to launch constraints, In-Situ

resource utilization will play a key role in the success of future colonies on foreign bodies. In-Situ

Resource Utilization (ISRU) relates to the use and manipulating of local materials in order to

support mission exploration [32]. With the seemingly desolate environment that a planet such as

Mars may portray comes a multitude of hidden resources that can be uncovered through careful

planning and exact science. The two major resources that can be utilized on a planet such as Mars

are the surface regolith and water found within regolith and subsurface lakes/glaciers.

3.1 Regolith Utilization The first mentioned resource, and possibly the most abundant on Mars is the regolith present

on the surface and subsurface level of Mars’ environment. Martian regolith is rich in silica and

metallic oxides which would in turn provide a useful material in which to build infrastructure [18].

Utilizing granular body forming processes such as sintering through thermal treatments would

allow for the forming and hardening of the copious amount of soil found on the planet into useful

resources and infrastructure. One such use of Martian regolith is the sintering of the soil to provide

environmental shielding on habitations, effectively providing protective roofing used to help

hinder cosmic radiation exposure within habitation sites and protect against micrometeorite

impacts. Examples of such a habitation site can be found in Figure 3.1.

Figure 3.1 An Artist's Representation of a Possible Habitation Igloo on Mars. Note the habitat striations present due to

manufacturing [33]

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Through initial interplanetary colonization missions, either an autonomous system or astronaut can

build up the igloo-type habitation mounds simply through heat treatment processes applied to the

local soil in the habitation region. The build-up process would include overlaying soil onto a

habitation module and applying heat to sinter the overlaid granular material into a coherent layer

of material. Repeating this process of heating and building up layer-by-layer will mimic the

additive manufacturing techniques typically used with plastics on Earth.

3.2 Water Extraction and Utilization Water is a vital resource for any colony and will be the most valuable resource for human

exploration when leaving Earth. As a result of this necessity, the extraction and utilization of the

resource is of upmost priority in a mission. Within a system such as Mars, water is primarily

located in polar regions, subsurface cavities or dissolved within salts in the soil. The utilization of

water in the form of ice and liquid found in polar and subsurface regions on Mars is somewhat

straightforward and would require plumbing and filtration systems to extract and utilize the

resource. Due to the likelihood of colonization within Martian equatorial regions, the extraction of

water from soil will likely be the primary method of obtaining water from a planet like Mars. In

regions such as Gale Crater within the Martian equatorial region it has been proven through

spectral analysis by the Mars Science Laboratory (MSL) Curiosity that the soil contains 2% water

by weight [13]. Such a finding results in the ability to extract approximately 1 liter of water from

every 0.03 cubic meters of Martian soil [13]. Through thermal heating of the regolith, water vapor

will be synthesized and thus will be able to be stored and used for various purposes. Furthermore,

water extraction from soil can be coupled with the regolith utilization methods mentioned

previously. As regolith is heated in preparation for sintering of habitation construction, water vapor

can concurrently be extracted, providing two resources simultaneously.

As stated previously, the access to water is essential for the success of remote colonies on celestial

bodies. Not only is water essential for the biological sustainability of exploration crews but can

also be utilized in more non-traditional methods. The electrolysis of water into its elemental forms

of hydrogen and oxygen provides a means of utilizing water as a fuel and heat source. Hydrogen

and oxygen are a typical fuel-oxidizer combination used for propulsion systems on liquid rocket

engines. Thus, by separating water into its basic elements, fuel and oxidizer generation for rocket

propulsion systems on Mars will be possible. Along with uses as rocket fuel, electrolysis of water

can be used for habitations. Through the combustion of the hydrogen, heat produced by the

reaction can be used for environmental control systems within habitations. Additionally, the main

product of the combustion of hydrogen is water vapor so hydrogen combustion can also be used

as a tool to humidify greenhouses within habitation modules to promote plant and crop growth.

The electrolysis of water and its potential are expanded upon in section 5.

4 Environment Overview

The first consideration that must be determined when deciding to colonize the face of another

body in our Solar System is deciding on landing and habitation locations for the explorers arriving.

A compromise is required between the landing and habitation sites because spacecraft landing

locations typically require flat, desolate expanses that allow for unobstructed lander descent and

ascent while habitation locations can often be beneficial near craters and subsurface caves. This

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section explores three geological locations on the Martian surface and details the available

resources at each justifying the feasibility of habitation at each location.

4.1 Martian Environment Mars is the fourth planet from the Sun and the second smallest in size in the Solar System.

Mars orbits the Sun at an orbit with an eccentricity of 0.0934, resulting in a difference of aphelion

and perihelion of 0.285 AU [19]. One Martian sidereal year is the equivalent to 687 days on Earth

[19]. The difference between aphelion and perihelion contributes to the seasonal heating and

cooling of Mars as a result of the cyclic distance fluctuation from the Sun. The surface temperature

on Mars varies greatly by geological location and orbit location. The average temperature on Mars

is -60 ⁰C (-80 ⁰F). Near the equator, during a Martian summer the temperature can range from 20⁰C

(70⁰F) to -73⁰C (-100⁰F) while in polar regions during the winter can see temperatures as low as -

125⁰C (-195⁰F) [9]. Mars has an average surface gravity that is 38% of that experienced on Earth

with an average gravitational acceleration constant of 3.72 m/s2 [36].

The frigid temperatures experienced on the Martian surface are due partly to the atmospheric

conditions. The atmospheric density on the Martian surface is approximately 0.020 kg/m3 making

it approximately two orders of magnitude thinner than Earth’s atmosphere [20]. At the Martian

surface the average atmospheric pressure is approximately 0.00627 atm or 0.63% that of Earth’s

pressure at sea level. Even though Mars’ atmosphere is comprised up of 95% carbon dioxide (per

volume) the low density of the atmosphere does not allow the planet to retain the thermal

irradiation received from the Sun which results in a tundra-like environment.

Martian soil, or regolith is composed up of mainly silicon dioxide, iron oxide and various metal

alloys. Due to the thin atmosphere, much of the water found on Mars is in the form of frozen

glaciers that exist in subsurface layers under regolith. There have been discoveries of subsurface

liquid water currently present on Mars near the polar regions of the planet, but these discoveries

have been rare [7]. Along with water, traces of perchlorates have been discovered by various Mars

landers in weight percentages ranging from 0.5%-1% [22]. Perchlorates are significant due to their

potential as a source of fuel but pose a hazard to humans due to their toxicity to the human thyroid

gland system [23].

Mars lacks an interior dynamo that would otherwise generate a powerful protective magnetic field

to protect its surface from harmful radiation. The lack of convection of molten iron within Mars’

outer core is the primary theory of why Mars has a weak and almost non-existent magnetosphere

[25]. Mars is bombarded primarily with two types of radiation, low-energy protons from solar

flares and high-energy atomic nuclei known as Galactic Cosmic Rays (GCR) [24]. Solar flares are

low-energy, intermittent and can easily be shielded using conventional metals or organic polymers.

Conversely, GCRs are high energy nuclei that can damage DNA and can penetrate many

conventional radiation shields.

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4.2 Potential Martian Habitation Sites With the help of satellites such as NASA’s Mars Reconnaissance Orbiter and ESA’s Mars

Express Orbiter, topographic and detailed imagery of the Martian surface have been obtained and

made available to the public. Realistically, there are on the order of hundreds to thousands of sites

on Mars that have the potential to be suitable habitation zones but for all intense and purposes

three of the most promising and potentially scientifically rich locations were identified and

analyzed in this report. Along with geological landmarks and historical lander locations the

locations of the three potential “Habitation Sites” are marked in red on Figure 4.1.

Figure 4.1 Potential Martian Landing Sites [4] [6]

OLYMPUS MONS

NORTHERN LOWLANDS

SOUTHERN HIGHLANDS

HABITATION SITE II

HABITATION SITE I

HELLAS BASIN

ELYSIUM MONS

HABITATION SITE III

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4.2.1 Habitation Site I - Planum Australe (Coordinates: 81° S, 193° E)

Figure 4.2 Location of Subsurface Liquid Water Found at Planum Australe [8]. The subsurface liquid waterbed is shown as the

blue triangle in the image.

The first of the habitation sites is situated in the Southern Highlands of Mars near the

Southern Pole. The area of interest within Planum Australe is roughly 12 miles in width. The

region gained interest in 2018 when Italian physicists announced evidence of subsurface liquid

water in the region found using radar data produced by MARSIS, a low-frequency radar instrument

flown on the European Space Agency’s Mars Express orbiter mission [7]. The 12-mile wide patch

of Martian land is a flat plain with few topographical variations, making descent and ascent to and

from the location ideal. Due to the minimal topographical features, the location provides little

naturally occurring shelter and protection from micrometeorites and radiation. Due to the

subsurface lake location near a polar region, sunlight is limited to the area during a portion of the

Martian sidereal year. Partly as a result of the limited sunlight, temperatures in the polar region

can plummet to -195⁰F (-125⁰C) making living conditions harsh and frigid [9]. Due to the limited

sunlight in the region, alternatives to solar energy must be provided if habitation is considered.

Energy alternatives in the region could include thermonuclear or geothermal. One way to provide

shelter and insulation for habitats within the region is to burrow into the Martian regolith,

effectively creating subsurface habitats. A proposed habitation layout is presented in Figure 4.3.

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Figure 4.3 Habitation Site I With Habitation Details Outlined [6]

Situating the liquid waterbed in between the ascent/descent region and habituation area would

allow astronauts access to ample pre-liquified water for applications such as biological

consumption, fuel for energy utilization and launch vehicle fuel and oxidizer. The ascent/descent

region is an ellipse that is situated in an orientation that aligns with the orbital mechanics analysis

performed in a subsequent section. In order to arrive at the habitation site from cis-Martian space,

a terminal polar orbit would be required with an orbital inclination aligned with the latitude that

passes through the habituation site. To provide landing tolerance, the ascent/ descent region is an

ellipse of approximately 25 miles in major axis.

Habitation Site

Perimeter

Living Region

Ascent/ Descent

Region

Liquid Water

Source

50 miles

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4.2.2 Habitation Site II - Pavonis Mons (Coordinates: 4.70°N, 247°E)

Figure 4.4 Artist Representation of Pavonis Mons [10]. Habitation Zone II is Highlighted in Red.

The second habitation site is located in the Tharsis Montes region near the Martian equator

within Pavonis Mons. Pavonis Mons is one of three inactive volcanic mountains in the Tharsis

Montes region. The habitation zone selected is situated directly above a region of subsurface

glaciers within Pavonis Mons. The region was once home to volcanic activity so subsurface lava

tubes are inevitable. With pre-existing caves and lava tubes, astronauts can use the natural

phenomenon as protection from micrometeorite collisions and cosmic radiation. The location is

situated near Mars’ equator so sunlight is available to the region throughout the entire Martian

sidereal year. The region experiences a warmer climate when compared to polar regions with a

temperature upper and lower bound of 20⁰C to -73⁰C [9]. Due to the constant sunlight, solar energy

could be the primary source of energy production in the region. Due to the seasonal dust storms

that block sunlight exposure on Mars, secondary energy sources such as radioisotope

thermoelectric generators (RTG) should also be considered. The water glaciers that exist within

the volcano would provide astronauts with consumable water, a fuel source and rocket fuel and

oxidizer. The habitation zone’s location near the Martian equator is beneficial because it will allow

spacecraft rendezvous to Low Mars Orbit to use less fuel due to the effective “delta V” provided

by the larger rotational speeds achieved at the equator. The proposed habitation location within

Pavonis Mons along with landing zone is presented in Figure 4.5.

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Figure 4.5 Habitation Site II on Pavonis Mons [11] [6].

Figure 4.5 depicts the proposed habitation site at Pavonis Mons. Both the living and the

ascent/descent regions are situated directly above the subsurface glacier, allowing both regions

direct access to frozen water. The ascent/ descent elliptic region is situated in a way that is aligned

with the orbital mechanics analysis preformed in a subsequent section. When arriving to the

habitation site a craft would be in an orbit with minimal inclination, so having a landing site aligned

with the velocity vector direction of the craft would allow landing location tolerancing. The

location of the subsurface glacier found within Pavonis Mons is shown in the top right region of

Figure 4.6.

Figure 4.6 Elevation Map of Pavonis Mons and Arsia Mons Along with Predicted Glacier Sites [17]

30 Miles

Ascent/Descent

Region

Mountain

Perimeter

Living Region

Habitation Site

Perimeter

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4.2.3 Habitation Site III – Gale Crater (Coordinates: 4.58°S, 137.44°E)

Figure 4.7 Gale Crater with Proposed Habitation Site Identified in Red [15].

The third habitation site is Gale Crater. The habitation region highlighted in Figure 4.7 is

located within an region of flat, semi-uniform land within Gale Crater. The flatness of the region

is advantageous and would allow for habitation and launch locations to be in the vicinity of one

another. The crater is best known as the location of the 2012 landing of the Mars Science

Laboratory (MSL) Curiosity rover. The crater is located near Mars’ equator and is approximately

96 miles in diameter and encircles the 3.4-mile-high Aeolis Mons [12]. Due to the crater’s location,

it will experience temperature fluctuations like those of Habitation Site II. The primary sources of

energy would likely be solar due to the areas ample sun exposure year-round but would require

contingency energy production methods such as RTGs or geothermal utilization. The location does

not have an abundance of subsurface caves and lava tubes so protection and shelter from natural

elements would likely require human manipulation of the region. Gale Crater is of interest due to

its soil surface composition which was confirmed in 2013 to contain 2% water by weight [14]. As

a result of the soil composition it would be feasible to extract approximately 1 liter of water from

every 0.03 cubic meters of Martian soil [13]. The soil analysis performed by the Sample Analysis

at Mars (SAM) instrument on the MSL is presented in Figure 4.8. From the analysis, the four most

prevalent chemical components (by an order of magnitude of 2) were water, carbon dioxide,

oxygen and sulfur dioxide, with water being the most abundant of the four. The highest counts per

second for water was obtained when each sample was heated to a temperature of approximately

250 degrees Celsius (Figure 4.8).

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Figure 4.8 Soil Analysis Conducted by SAM Within the MSL Curiosity Rover [14]

The proposed habitation site layout is presented in Figure 4.9. The habitation region is in the same

area in which the water observed by the Curiosity rover was found, giving future habitants access

to water through a heating process similar to that performed by SAM. The ascent/ descent elliptic

region is situated in a way that the semi major axis is parallel to Mars’ lines of latitude. When

arriving to the habitation site a craft would be in an orbit with minimal inclination so having a

landing site aligned with the velocity vector direction of the craft would allow landing tolerances

as previously described in habitation site II.

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Figure 4.9 Gale Crater Habitation Site III [16]

Habitation Site

Perimeter

Ascent/Descent

Region

Living Region

15 Miles

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5 Oxyhydrogen Generation

With the need for energy production on Mars, one form can be found within the subsurface

lakebeds and permafrost entrenched in the Martian regolith. The reminisces of water on Mars has

become a known fact within the scientific community, which in turn has created a discussion on

its potential utilization by future explorers to the planet. As stated in previous sections, water has

the potential to be utilized not only as a biological consumable but also as a source of energy. For

example, cryogenic hydrogen is often used as a fuel for liquid rocket engines while standard

gaseous hydrogen can be used as a heat source for astronaut living quarters and green houses.

Furthermore, if hydrogen is used for biological sustainability purposes, when hydrogen undergoes

a combustion reaction, the main byproduct of the reaction is liquid water which then has the

potential to either be recycled within a system or be used as a biological consumable.

Water is composed up of hydrogen and oxygen molecules, two elements that prove highly useful

in human spaceflight and sustainability. In order to utilize both elements, the electrolysis of water

can be utilized to split the water molecules into their respective elemental states. To split water

molecules within an electrolytic cell, an electrical current can be run through electrolyzed liquid

water and as a result hydrogen gas will be produced at the cathode and oxygen gas at the anode.

An electrolyte is mixed within the water to promote water conductivity and thus the flow of

electricity through the system.

Figure 5.1 Example of Electrolysis Process of Hydrogen and Oxygen Separation from Water [28]

5.1 Chemistry Overview The electrolysis of water as described within the report occurs within an electrolytic cell. An

electrolytic cell utilizes electrical current in order to drive a nonspontaneous reduction-oxidation

(redox) reaction, as opposed to a galvanic cell which generates energy through a spontaneous redox

reaction [34]. The ideal half reactions that occur within the electrolytic cell for the electrolysis of

water are presented within equations 1 and 2.

Equation 1 represents the half reaction that occurs at the anode of the electrolytic cell. Water within

the cell is stripped of electrons due to the electric potential difference driven by the application of

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an external power source. The positive terminal of the power source is connected directly with the

anode, allowing for the transfer of electrons from the anode. The process of electron stripping is

known as oxidation. As water molecules oxidize, they produce oxygen gas and hydrogen cations.

2𝐻2𝑂(𝑙) → 𝑂2(𝑔) + 4𝐻+(𝑎𝑞) + 4𝑒− (1)

As oxidation occurs, electrons transfer from the anode to the opposite end of the cell at a location

known as the cathode. The cathode is opposite to the anode and receives electrons driven from the

anode by the power supply. The cathode is the site where the cell receives electrons or where

reduction occurs. As hydrogen cations combine with electrons, hydrogen gas is produced as shown

in equation 2.

4𝐻+(𝑎𝑞) + 4𝑒− → 2𝐻2(𝑔) (2)

Combining the two half reactions produces the overall chemical reaction accounting for both

reduction and oxidation. The overall equation is presented in equation 3.

2𝐻2𝑂(𝑙) → 2𝐻2(𝑔) + 𝑂2(𝑔) (3)

The cell potential of the electrolytic cell is -1.23 Volts, which represents that the cell utilizes a

non-spontaneous chemical process, requiring applied potential. The cell potential is an idealization

and does not account for losses such as contact resistance and undesired side reaction so an

overpotential was required to drive the reaction within the experimental setup.

The selection of the electrolyte used within the cell is of importance due to the various competing

side reactions that occur as a result of the driven chemical process. With the use of sodium chloride

as an electrolyte within distilled water, the danger of producing chlorine gas was identified and

thus the salt should not be considered if the generator is located within a confined space or within

a “manned” area. More suitable electrolytes such as sodium hydroxide are often used due to their

ability to conduct well as well as produce relatively benign byproducts if side reactions do occur.

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5.2 Engineering Prototype of Oxyhydrogen Generator To aid with the previous discussion of the potential that hydrogen production has on the

development and sustainability of a colony located on a foreign body, an oxyhydrogen generator

was designed built and manufactured to demonstrate a proof of concept of the mentioned chemical

process. Solidworks Computer Aided Design software was utilized to create a 3D model of the cell

to aid in manufacturing and clearance verifications. A side-by-side comparison of the CAD model

to the actual manufactured cell is presented within Figure 5.2.

Figure 5.2 Side-by-side comparison of the oxyhydrogen generator CAD model to the actual engineering proof of concept.

The oxyhydrogen generator is composed up of three major subcomponents: the main reservoir, the

anode & cathode plate arrays and the bubbler. An image detailing the physical representation of

each subassembly is presented within Figure 5.3.

Figure 5.3 Overview of the subcomponents of the oxyhydrogen generator built for the report

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The oxyhydrogen reservoir is the location in which distilled water and electrolyte were stored

during testing. Ionized water could have also been utilized for testing, but distilled water was used

to hinder undesired side reactions as well as reduce corrosion buildup on anode and cathode plate

arrays. Sodium hydroxide was utilized as the cell electrolyte due to its desirable conductivity

properties within water as well as its tendency to not produce toxic gases when oxidized.

The anode and cathode arrays were composed up of alloy aluminum flashing used for housing roof

applications. When aluminum is exposed to a solution of sodium hydroxide, hydrogen gas and

aqueous sodium aluminate forms causing metal dissolving. Due to this undesired phenomenon,

low molarity solutions of sodium hydroxide were utilized during testing to reduce plate corrosion.

Stainless steel washers, nuts and bolts were utilized to constrain both the anode and cathode plate

arrays. During testing the bolts housing each plate array were the regions in which the power

source was interfaced directly with. As mentioned previously, the cathode is the region in which

reduction occurs and hydrogen forms while the anode is the region where oxidation occurs and

oxygen forms.

The third subassembly within the oxyhydrogen generator is the bubbler assembly. It was

anticipated prior to manufacturing that match tests would be performed. A match test consists of

holding a match to the outlet hose of the cell in order to verify hydrogen production through

combustion. The bubbler was installed into the cell as a safety measure, to hinder the phenomenon

of “flashback” during testing. Flashback is the propagation of a combustion reaction in a reverse

direction as intended, effectively causing a flame to creep into the main reservoir of a fuel cell. Of

course, this phenomenon is highly undesirable and dangerous so adding a bubbler adds an

additional inert barrier between the ignition source and the main reservoir such that if flashback

occurred it would only occur in a small volume in comparison to the main reservoir.

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5.3 Experimental Setup and Prototype Results Experimental performance testing of the manufactured engineering prototype was

completed in order to characterize and quantify the capabilities of the electrolytic cell. Distilled

water mixed with sodium hydroxide to produce a low molarity solution was poured into the main

reservoir of the oxyhydrogen generator in preparation of testing. Additionally, untreated tap water

was poured into the bubbler since no chemical processes occur within its reservoir. Utilizing an

Eventek KPS3010D Variable Switching Regulated Digital Power Supply, alligator clip leads were

attached directly to the anode and cathode of the electrolytic cell, with the positive terminal

interfacing with the anode plate array and the negative terminal interfacing with the cathode plate

array. A depiction of the experimental setup is presented within Figure 5.4.

Figure 5.4 Depiction of the experiential setup used to characterize the engineering prototype performance.

While operating the power supply at approximately 3.8 Volts and 9.6 Amps, experimental tests

were performed for 3-minute intervals. The short interval duration was chosen due to the formation

of undesired side reactions as a result of prolonged plate oxidation. Due to the limitations of the

experimental setup hydrogen production was quantified through visual inspection of the bubble

formation rate of the cell. As the cell was operated, approximations of bubble formation average

size as well as rate at which bubbles formed within the bubbler were documented and extrapolated

for longer time periods. It was calculated that the engineering prototype had the ability to produce

approximate 1.45 L/hr of hydrogen and oxygen when supplied with the aforementioned power

from a DC power supply. A depiction of hydrogen and oxygen formation within the cell during

testing is presented within Figure 5.5.

24 Fall 2019

Figure 5.5 Depiction of hydrogen and oxygen bubble production within the oxyhydrogen generator

As mentioned previously, a match test was performed to verify the formation of hydrogen and

oxygen within the oxyhydrogen generator. The test was performed in a well-ventilated

environment to mitigate the buildup of explosive gases. Images of the match test are presented

within Figure 5.6

Figure 5.6 Images of a match test performed during testing to verify hydrogen and oxygen production within the electrolytic cell

5.4 Prototype Improvements and Further Work Due to the fast-paced design, manufacturing and testing phases performed for the

oxyhydrogen generator, several areas of improvement can be performed to advance further

versions of the hydrogen generator. During testing it was observed that local regions of electrolysis

formed as a result of the overlapping anode and cathode plate arrays. Localized electrolysis greatly

hindered the bubble production of the hydrogen and oxygen because only a fraction of each plate

area was utilized as a result (see Figure 5.5). Additionally, alternative plate materials should be

utilized in further iterations of the design to allow for higher molarity solutions of sodium

hydroxide to be utilized. Materials such as stainless steel and platinum could be considered within

25 Fall 2019

this material selection process. The number of contacts within each plate array should also be

minimized in further iterations to lower losses associated with contact resistance between surfaces.

It was also observed that bubble trapping occurred due to the orientation of the cell, future

iterations should orient the arrays of the cathode and anode to mitigate such phenomenon.

5.5 Oxyhydrogen Generator Utilization The potential uses of a hydrogen-oxygen generator were discussed briefly in previous

sections and included uses such as: fuel production for spacecraft, a biological consumable for

explorers and fuel for habitations. A key concept that is required in order to promote sustainable

living on another celestial body is the ability of a species to produce food for biological

consumption. A hydrogen-oxygen generator has the ability to be utilized as a humidifier used to

promote the growth of planet life grown on Mars. An overview of one method in which explores

could efficiently farm on another celestial body is presented within Figure 5.7.

Figure 5.7 Concept of space farming utilizing an oxyhydrogen generator as a central humidifier and heat source.

As hydrogen and oxygen are produced by a generator, the produced gas can be combusted to

produce water vapor as well as heat, due to the exothermic nature of the reaction. Situating the

humidifying hydrogen generator within the center of a farming unit could allow humidification as

well as warming of the surrounding environment, effectively promoting plant growth. To “close

the system” of the farming technique a polymer lining can be applied to the walls of the farming

unit to allow for water vapor condensation to form. With condensation forming, water can be

recycled by forcing the condensed water to settle within a water collection reservoir underneath

the system. The water in the reservoir can then be recirculated into the hydrogen generator to be

separated and combusted again.

26 Fall 2019

6 Orbital Dynamics

In section 4.2 of the report three potential habitation sites on Mars were proposed: Planum

Australe, Pavonis Mons and Gale Crater. The first mentioned is situated in the southern region of

Mars in the vicinity of the South pole while the second two are situated within 5 degrees north and

south of the Martian equator. To further investigate the feasibility of arriving to each habitation

site, on-orbit dynamics scenarios were simulated using MATLAB computer software. The purpose

of the simulation was to generate estimates of required spacecraft impulse maneuvers that would

be performed to transfer a vehicle from an inclined large circular orbit to a smaller circular orbit

of different inclination and longitude of ascending node. The final orbital inclination of each

simulation is directly dependent on habitation site location.

For the orbit transfers within the simulations, two-impulse Hohmann transfers of non-coplanar

circular orbits were performed. For simplification, within the simulation all orbit circularizations

were performed at the periapsis of each elliptic transfer orbits while all plane changes were

performed at the apoapsis of each transfer orbit.

Figure 6.1 Two-impulse Hohmann transfer of two non-coplanar circular orbits, transferring from a small circular orbit to a larger

circular orbit [37]

6.1 Characteristics of Simulated Orbit Transfers The initial orbit for all scenarios simulated a spacecraft within a circular orbit (e =0), 1000

kilometers from the surface of Mars with an orbital inclination of 25.19⁰ and longitude of

ascending node of 0⁰. The initial orbit inclination was chosen because Mars has an orbital tilt of

approximately 25.19⁰ [20] so any spacecraft arriving to Mars from a transfer orbit within the

ecliptic plane would appear to have an inclination equal to the planetary tilt when viewed within a

27 Fall 2019

Mars Centered Mars Fixed coordinate system (MCMF). The initial and final longitudes of

ascending nodes were 0⁰ and 90⁰. The values of the initial and final longitude of ascending nodes

were chosen arbitrarily and kept constant for all scenarios. The longitude of ascending node was

varied from initial to final orbit to simulate the variation in impulse maneuver locations that could

occur within a “real-life” orbit transfer scenario.

The final orbits in each simulation have altitudes of 230 kilometers, which was chosen due to the

altitude being the theoretical beginning of the Martian exosphere [36]. It was assumed that landing

to all three locations would endure similar reentry/descent regimes once in a low orbit, 230

kilometers about their targets so energy required for orbital transfer to each final orbit was only

considered when comparing habitation sites.

6.2 Approximations in Simulation As stated previously, the simulation performed in MATLAB approximated the impulses

required to perform an orbital transfer from an initial circular orbit with altitude of 1000 km ,

inclination of 25.19⁰ and longitude of ascending node of 0⁰ to three different orbits that correlated

with the three previously mentioned proposed habitation sites. In order to simplify calculations for

the simulations performed, various approximations were implemented. The largest simplification

made was the modeling of on-orbit maneuvers as scaled Dirac delta functions, or better known as

impulsive thrust approximation [37]. The approximation assumes that that an infinite thrust force

is applied instantaneously due to the thrust’s magnitude being extremely large in comparison to its

application duration. In reality, burn durations associated with on-orbit plane changes and

circularization maneuvers would likely not be negligible in comparison to the thrust produced by

vacuum optimized engines so the approximation was performed purely for simplicity. The

simulation also assumed uniform gravity distribution within Cis-Martian space.

6.3 Orbit Fractioning Within the simulation, a method of orbit fractioning was employed. Orbit fractioning is a

method of splitting up an orbit transfer into a series of thrust maneuvers that would otherwise be

performed as singular events. For example, in the case of a two-impulse Hohmann transfer

simulated within the report, orbit fractioning would allow for N number of apoapsis-periapsis on-

orbit maneuvers effectively allowing for splitting of large orbit circularization and plane change

burns into smaller achievable maneuvers. The mathematical representation of orbit fractioning is

represented within equation (4).

[

𝑟𝑛

𝛺𝑛

𝑖𝑛

] = [

𝑟0

𝛺0

𝑖0

] +𝑛

𝑁[

𝑟𝑓 − 𝑟0

𝛺𝑓 − 𝛺0

𝑖𝑓 − 𝑖0

] , (𝑛 = 1,2,3 … 𝑁) [38] (4)

Where rn is the incremental radius of each transfer orbit, Ωn is the incremental longitude of

ascending node and in is the incremental inclination of each transfer orbit.

28 Fall 2019

6.4 Transfer Orbit Simulation Results As stated previously, MATLAB simulations were performed for all three habitation sites.

Each simulation produced plots of incremental “delta V” for impulse maneuvers performed at the

transfer orbit apoapsis and periapsis as well total “delta V” and total time required.

Planum Australe

Maneuver Number (n) vs Impulse Maneuvers Performed at

Transfer Orbit Apoapsis


Transfer Orbit Periapsis

Total Orbit Fraction Number (N) vs Total Delta V Required

Total Orbit Fraction Number (N) vs Total Transfer Time

Required

Table 1 Planum Austale simulation results

29 Fall 2019

The instance in which the total orbit fraction number was equal to four was analyzed to provide

additional orbit transfer analysis. For N=4, the total impulse required to transfer from the ecliptic

plane to Planum Australe was found to be 5.1 km/s. The 3D simulation results are presented in

Table 2.

Table 2 Planum Austale 3D simulation results. The top image depicts an isometric view of the entire orbit transfer, where the light

blue orbit represents the initial orbit and the orange orbit, with approximately 90 degrees of inclination, represents the final orbit.

The bottom image highlights the final orbit’s placement over Habitation Site I, Planum Australe.

30 Fall 2019

Pavonis Mons







Required

Table 3 Pavonis Mons simulation results

31 Fall 2019



plane to Pavonis Mons was found to be 1.9 km/s. The 3D simulation results are presented in Table

4.

Table 4 Pavonis Mons 3D simulation results. The top image depicts an isometric view of the entire orbit transfer, where the light

blue orbit represents the initial orbit and the orange orbit represents the final orbit. The bottom image highlights the final orbit’s

placement over Habitation Site II, Pavonis Mons.

32 Fall 2019

Gale Crater







Required

Table 5 Gale Crater simulation results

33 Fall 2019



plane to Gale Crater was found to be 2.1 km/s. The 3D simulation results are presented in Table

6.

Table 6 Gale Crater 3D simulation results. The top image depicts an isometric view of the entire orbit transfer, where the light blue

orbit represents the initial orbit and the orange orbit represents the final orbit. The bottom image highlights the final orbit’s

placement over Habitation Site III, Gale Crater.

34 Fall 2019

6.4.1 Results Interpretation Presented in the results section above are various key outcomes that were obtained for each

habitation site using the orbit transfer simulation within the report. The results show that the total energy

required when transferring to each location was directly related to the magnitude of cranking angle required

to perform each orbit transfer. As a result of this relation, it was found that performing an orbit transfer to

Planum Austale, located within the Mars southern pole, required the largest amount of energy (delta V) of

the three locations and exhibited asymptotic behavior approaching 5.2 km/s when factoring number was

incrementally increased. This key finding intuitively makes sense since transferring to a polar orbit from

the plane of the ecliptic would require more than 50⁰ of cranking angle, while the other two equatorial

locations would require cranking angles of approximately 20⁰-30⁰. The habitation site that required the least

total energy to arrive to from the plane of the ecliptic was Pavonis Mons with asymptotic behavior with

incremental fractioning increase towards 1.95 km/s. Gale Crater required slightly more total energy with

asymptotic behavior towards 2.2 km/s. It is also valuable to note that the plane change impulse maneuvers

performed at the apoapsis of each transfer orbit were all an order of magnitude larger than their transfer

orbit periapsis impulse maneuver pair. This phenomenon is largely due to the direction of impulse

application and extent of the maneuver. The impulse maneuver performed at the apoapsis of each elliptic

transfer orbit provided an orbital plane change and also produced an elliptic transfer orbit from an initially

circular orbit while the periapsis maneuvers simply circularized each orbit. Due to the nature of the

simulation performed, all habitation site transfers followed similar linear time requirements with increased

total transfers. This phenomenon can be explained due to each simulation trajectory following similar

overall trajectories but differing in orientation.

When analyzing the three habitation sites, an apoapsis impulse reduction phenomenon was observed when

cranking to habitation sites of low overall required cranking angle (e.g. Pavonis Mons & Gale Crater). A

depiction of the phenomenon is presented within Table 7.

Table 7 Visualization of apoapsis energy reduction phenomenon observed for low inclination change orbit transfers. if represents

the angle of inclination of the terminal orbit with respect to the initial inclination of 25.19°. For example, if represents an inclination

of 19.19° within MCMF. Longitude of ascending node was held constant for each simulation.

35 Fall 2019

Specifically within Table 7 it can be observed that at low overall cranking angles that the required impulses

with increasing fractioning number actually decreases. The phenomenon is counter-intuitive because one

would imagine increased required impulses with subsequent fractioning due to increased orbital speeds

reached within incrementally lower orbits. The apoapsis impulse reduction phenomenon reaches a critical

inflection point at approximately 20° of overall cranking angle where the reduction behavior diminishes,

and the impulses required at the transfer orbit apoapsides increase with increasing fraction increment as

expected. The reduction behavior for low overall cranking angles can be attributed to the geometry of the

impulsive plane changes applied at each elliptic transfer orbit apoapsis. For each plane change maneuver,

a law of cosines relation was applied to obtain the magnitude of the required plane change as presented

within equation (2).

‖∆𝑣‖ = √(𝑣−)2 + (𝑣+)2 − 2𝑣−𝑣+ cos(𝜃) (2)

Where Δv is the required delta V for the burn, v- is the orbital speed before the impulse and v+ is the orbital

speed after the burn and θ is the cranking angle. It can be observed that for transfer orbit maneuvers with

generally low overall cranking angles, that fractioning reduces the crank angle per maneuver even further

such that the small angle approximation can be utilized. Specifically, for a very small angle the

trigonometric function approaches 1 so the first two terms will be reduced increasing amounts as the v+ and

v- terms increase with fractioning. Conversely with large cranking angles the trigonometric term will be

fractioned causing the first two terms to be subtracted by a relatively small number in comparison, thus

causing increased impulse with increased orbit fractioning number. For completeness, equation (3) was

provided to show the implementation of the Vis-Viva equations implemented into the law of cosines

expression within equation (2).

‖∆𝑣‖ = √(√𝜇

𝑟)

2

+ (√2𝜇

𝑟−

𝜇

𝑎)

2

− 2 (√𝜇

𝑟) (√

2𝜇

𝑟−

𝜇

𝑎) cos(𝜃) (3)

Where μ is a gravitational parameter of a planet, r is the location of a spacecraft within an orbit and a is

the semi-major axis of an elliptic transfer orbit.

36 Fall 2019

7 Additional Future Establishment - Sky Cities on Venus As stated in previous sections, the report is not unique to a single celestial body. Many geological

locations within the Solar System share commonalities and thus the approaches to in-situ resource

utilization, human factors and orbital dynamics can be translated to fit differing exploration missions. There

are a few instances of “unique cases” in which the approaches described in the report do not apply and non-

traditional modes of colonization must be applied. One such scenario is the case of colonizing Venus. With

Venus’ surface pressure 96 times that of Earth’ the development of alternative habitations are required.

The planet Venus has an orbit that situates it approximately 40% closer (at closest approach) than the orbit

of Mars, making it the closest planet to Earth in the solar system. With its “close” proximity with Earth one

may wonder why space agencies haven’t announced major plans of Venus colonization. It is not until one

examines the geological environment of Venus that this colonization hesitancy can be realized. Underneath

the seemingly benign façade of Venus’ outer surface lies a hostile wasteland. The surface temperature of

Venus ranges from 461 ⁰C (861 ⁰F) to 701 ⁰C (1293 ⁰F) with an atmospheric pressure of 96 Bar (1300 PSI)

along with an atmosphere composed primarily of carbon dioxide, nitrogen and sulfuric acid [29].

Conversely, if one were to examine the thermodynamic properties of the atmosphere simply 50 kilometers

above the harsh surface, Earth-like conditions are present. This has driven scientists and engineers to

propose potential colonies capable of floating high within Venus’ upper atmosphere, quite literally creating

floating sky cities.

At an attitude of 50 kilometers Venus’ environment mimics that of Earth with 90% of Earth’s gravity and

a temperature range of 0⁰C (32⁰F) to 50⁰C (122⁰F) providing abundant to near constant exposure to solar

energy for energy production. Furthermore, due to the thick Venusian atmosphere “breathing air” of the

nitrogen-oxygen ratio of 80:20 can serve as a lifting gas (0.5 kg/m3) , effectively allowing the full interior

volume of an aerostat, as shown in Figure 7.1, to be utilized as living quarters.

Figure 7.1 Artist Concept of Venus Sky Cities [30]

With the endless possibilities that habitations within the Venusian atmosphere appear to bring come major

challenges that require ingenuity and approaching problems never before seen on Earth. Some of the

37 Fall 2019

challenges that humanity will be faced to address within these type of habitats include examples such as:

the development of lightweight structures for self-sustaining city sized colonies to be structurally sound

within confined thin walled balloons, the ability to resupply the floating habitats with resources, cosmic

ray/micrometeorite shielding of the habitat walls, methods of sulfuric acid contamination prevention within

the habitation and development of contingency evacuation options in the occurrence of worst case

scenarios.

38 Fall 2019

8 Afterthoughts With the excitement of interplanetary travel and the prospect of creating utopia-like

civilizations on other celestial bodies comes a key responsibility by the Earth-based humans

committing themselves to this outward expansion. Colonizing additional celestial bodies in the

Solar system is certainly exciting and vital to the human species but should not be taken as an

excuse to neglect the planet that all of humanity currently resides on. With the extensive research

I completed within the Fall 2019 semester came a realization of how challenging and unforgiving

the process of colonizing another celestial body will be when performed. The Earth is a fragile

system that has the potential to reach a similar demise achieved by planets such as Mars and Venus

if further neglect to the planet is applied. It is in my hopes that with an endeavor to return to the

Moon or exploration to Mars that humanity experiences a unanimous clarity of the magnitude of

our existence similar to the aftermath of Earthrise that sparks increased care and appreciation of

the pale blue dot that our species is currently confined on.

Figure 8.1 Pale Blue Dot image taken of Earth by Voyager 1 on February 14th 1990 from a distance of more than 6 billion kilometers [39].

39 Fall 2019

9 Acknowledgments I would like to thank all three of my faculty advisors for the incredible support that they have

given me throughout the honors thesis process. An abstract and ambitious topic of formulating a

paper that underlines the key requirements of colonizing another celestial body made it difficult to

find interested advisors, so the willingness and knowledge provided to me by all three of them was

greatly appreciated.

40 Fall 2019

10 Works Cited

[1]: Mohon, Lee. “Space Launch System (SLS) Artists' Concepts.” NASA, NASA, 23 Mar. 2015,

www.nasa.gov/exploration/systems/sls/multimedia/gallery/SLS_Concepts.html.

[2]: Anton. “Best Apollo Space Program Quotes - Space Quotations.” Spacequotations.com, 20

July 2019, spacequotations.com/quotes-about-apollo/.

[3]: Tyson, Neil deGrasse. “Neil DeGrasse Tyson: The Photograph That Most Influenced

Civilization.” Time, Time, 17 Nov. 2016, time.com/4543627/neil-degrasse-tyson-

influential-photo/.

[4]: “Landing Site Selection.” NASA, NASA, 27 Nov. 2018,

mars.nasa.gov/insight/timeline/prelaunch/landing-site-selection/.

[5]: Staff, SPACE.com. “Photos: Mars Caves and Lava Tubes.” Space.com, Space, 17 Nov.

2012, www.space.com/18519-mars-caves-lava-tubes-photos.html.

[6]: “Planetary Names .” Planetary Names: Collis, Colles: Tartarus Colles on Mars,

planetarynames.wr.usgs.gov/Feature/5874.

[7]: Orosei, R., et al. “Radar Evidence of Subglacial Liquid Water on Mars.” Science, 2018,

doi:10.1126/science.aar7268.

[8]: Kaufman, Marc. “Large Reservoir of Liquid Water Found Deep Below the Surface of

Mars.” Many Worlds, 18 Mar. 2019, manyworlds.space/2018/07/25/large-reservoir-of-

liquid-water-found-deep-below-the-surface-of-mars/.

[9]: Sharp, Tim. “What Is the Temperature of Mars?” Space.com, Space, 30 Nov. 2017,

www.space.com/16907-what-is-the-temperature-of-mars.html.

[10]: Lamm, Jay. “The 9 Tallest Mountains In The Solar System.” Irene W. Pennington

Planetarium, 22 Aug. 2018, penningtonplanetarium.wordpress.com/2013/12/21/the-9-

tallest-mountains-in-the-solar-system/.

[11]: Carr, M. H. The Surface of Mars. Cambridge University Press, 2018.

[12]: Dunbar, Brian. “NASA's Next Mars Rover to Land at Gale Crater.” NASA, NASA,

www.nasa.gov/mission_pages/msl/news/msl20110722.html.

[13]: Wall, Mike. “Curiosity Rover Makes Big Water Discovery in Mars Dirt, a 'Wow Moment'.”

Space.com, Space, 26 Sept. 2013, www.space.com/22949-mars-water-discovery-curiosity-

rover.html.

41 Fall 2019

[14]: Shultz, David. “Curiosity Rover Finds Organic Molecules on Martian Surface.” Eos, vol. 96,

2015, doi:10.1029/2015eo037083.

[15]: “Oblique View of Gale Crater from the North.” NASA, NASA,

www.jpl.nasa.gov/spaceimages/details.php?id=PIA14291.

[16]: Administrator, NASA Content. “Destination Gale Crater in August 2012.” NASA, NASA, 4

Aug. 2017, www.nasa.gov/mission_pages/msl/multimedia/pia15687.html.

[17]: Head, James W., and David K. Weiss. “Preservation of Ancient Ice at Pavonis and Arsia

Mons: Tropical Mountain Glacier Deposits on Mars.” Planetary and Space Science, vol.

103, 2014, pp. 331–338., doi:10.1016/j.pss.2014.09.004.

[18]: Karl, David, et al. “Towards the Colonization of Mars by in-Situ Resource Utilization: Slip

Cast Ceramics from Martian Soil Simulant.” PloS One, Public Library of Science, 11 Oct.

2018, www.ncbi.nlm.nih.gov/pmc/articles/PMC6181286/.

[19]: “Orbit of Mars.” Planetary Sciences, Inc., planetary-science.org/mars-research/orbit-of-

mars/.

[20]: “Mars Fact Sheet.” NASA, NASA, nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html.

[21]: Rieder, R., et al. “The Chemical Composition of Martian Soil and Rocks Returned by the

Mobile Alpha Proton X-Ray Spectrometer: Preliminary Results from the X-Ray Mode.”

Science, vol. 278, no. 5344, 1997, doi:10.1126/science.278.5344.1771.

[22]: David, Leonard. “Toxic Mars: Astronauts Must Deal with Perchlorate on the Red Planet.”

Space.com, Space, 13 June 2013, www.space.com/21554-mars-toxic-perchlorate-

chemicals.html.

[23]: Davila, Alfonso F., et al. “Perchlorate on Mars: a Chemical Hazard and a Resource for

Humans.” International Journal of Astrobiology, vol. 12, no. 4, 2013, pp. 321–325.,

doi:10.1017/s1473550413000189.

[24]: “MEPAG.” NASA, NASA, mepag.jpl.nasa.gov/topten.cfm?topten=10.

[25]: Townsend, L W, et al. “Large Solar Flare Radiation Shielding Requirements for Manned

Interplanetary Missions.” Journal of Spacecraft and Rockets, U.S. National Library of

Medicine, 1989, www.ncbi.nlm.nih.gov/pubmed/11537157.

[26]: “Mars' Magnetic Field - DTU Space.” Https://Www.space.dtu.dk,

www.space.dtu.dk/english/Research/Universe_and_Solar_System/magnetic_field.

[27]: “Hydrogen Production: Electrolysis.” Energy.gov,

www.energy.gov/eere/fuelcells/hydrogen-production-electrolysis.

42 Fall 2019

[28]: Libretexts. “23.9: Electrolysis of Water.” Chemistry LibreTexts, Libretexts, 16 Oct. 2019,

chem.libretexts.org/Bookshelves/Introductory_Chemistry/Book%3A_Introductory_Chemis

try_(CK-12)/23%3A_Electrochemistry/23.09%3A_Electrolysis_of_Water.

[29]: Landis, Geoffrey A. “Colonization of Venus.” AIP Conference Proceedings, 2003,

doi:10.1063/1.1541418.

[30]: Shadbolt, Peter. “NASA's Plan for Our next World: a Cloud City over Venus.” CNN, Cable

News Network, 3 Jan. 2015, www.cnn.com/2014/12/23/tech/innovation/tomorrow-

transformed-venus-blimp-city/index.html.

[31]: “In Depth.” NASA, NASA, solarsystem.nasa.gov/moons/saturn-moons/titan/in-depth/.

[32]: “In Situ Resource Utilization.” In Situ Resource Utilization - an Overview | ScienceDirect

Topics, www.sciencedirect.com/topics/earth-and-planetary-sciences/in-situ-resource-

utilization.

[33]: “Hassell + Eckersley O'callaghan Design Martian Habitat Where People Could Really

Thrive.” Designboom, 1 Aug. 2018, www.designboom.com/design/hassell-eckersley-

ocallaghan-martian-habitat-people-thrive-08-01-2018/.

[34]: Libretexts. “Electrolytic Cells.” Chemistry LibreTexts, Libretexts, 5 June 2019,

chem.libretexts.org/Bookshelves/Analytical_Chemistry/Supplemental_Modules_(Analytic

al_Chemistry)/Electrochemistry/Electrolytic_Cells.

[35]: Hirt, C.; Claessens, S.J.; Kuhn, M.; Featherstone, W.E. (2012). "Kilometer-resolution

gravity field of Mars: MGM2011". Planetary and Space Science. 67 (1): 147–154

[36]: Zhang, Fuqing (eds.), "SOLAR SYSTEM/SUN, ATMOSPHERES, EVOLUTION OF

ATMOSPHERES | Planetary Atmospheres: Mars", Encyclopedia of Atmospheric Sciences

(Second Edition), Academic Press, pp. 168–177

[37]: Rao, Anil. Orbital Mechanics: An Introduction. Unpublished, 2019.

[38]: Rao, Anil. Quiz 4. University of Florida, 2019

[39]: “Poster Pale Blue Dot.” Poster Pale Blue Dot, Amazon, www.keyword-suggest-

tool.com/search/poster+pale+blue+dot/.

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