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Manned missions to mars will only ever be achieved in science fiction- discuss

Abstract
This report presents all facts on the realities of a manned mission to mars. It reviews robotic
missions that have been successfully sent to mars, looks at the effects a trip would have on a crew
and then looks at existing plans for manned missions. The political viewpoint is also expressed. The
paper concludes by reviewing the information presented. It is found that a mars mission is entirely
conceivable given our present technology. However it also finds that due to the risks involved and
the public opinion of this that it would be difficult to launch a mission at this time. A manned
mission to mars will occur but in order to do so the public view of such a mission has to change.

1 Introduction
Mars is the most likely candidate for future manned missions, as it is the most hospitable
planet in our solar system after earth. People have long been fascinated by the red planet and its
habitation has been a continuing theme in science fiction. However science fiction rarely becomes
fact as the laws of physics govern our reality. Science fiction does give us new ideas and creates
dreams of what could be achieved. To quote a science fiction writer“It is part of the nature of man
to start with romance and build to a reality.” -Ray Bradbury. Through science and engineering the
dream of sending humans to mars is being heavily investigated.

This paper looks at how scientists are tackling the problem of sending a manned mission to
mars. Specifically our present knowledge and plans of what a trip to mars would entail. The paper
begins with an overview of the space environment and its effects on a crew during a trip to mars.
Many robotic missions have already been to mars, the history of these missions is considered before
a look at how manned missions could be undertaken. The political and public situation on manned
space missions is then summarized. Finally conclusions based on the material covered are given on
the reality of manned missions to mars and the likelihood of a mission in the near future.

1.1 Why Go to mars
Mars is the focus of many science fiction novels and fascinates scientists, but why send
humans to mars. The question of why send humans to mars was looked at in detail during August of
1992 when a workshop was held at the lunar and planetary institute in Houston Texas addressing
the whys of mars exploration [1]. Six major points were drawn up about the motivation for human
exploration of mars. The team who thought up these points consisted of 16 professionals from
throughout the space industry.

1) Human Evolution - Mars is the most accessible planet in the solar system where a long term
human settlement could be possible.
2) Comparative Planetology – Understanding the history of Mars we will gain a greater understanding of Earth.
3) International cooperation – A manned mission would provide a focus for international
cooperation.
4) Technological advancement - New technology developed to achieve the mission will help
advance our knowledge and improve the lives of people on earth.
5) Inspiration – A manned mission to mars will inspire the populace and future generations. It will
provide a focus motivating and uniting people towards a common goal.
6) Investment – Compared with other expenditures throughout society, the cost of a mars mission is
not too high.
The "Why Mars" workshop defined 2 primary mission objectives: To gain a greater
understanding of Mars and demonstrate the suitability of Mars as a future human colony.
Now that the reasons for wanting to send a manned mission to Mars have been established
the implications of traveling to Mars can be considered.

1.2 Getting to Mars
At its closest approach Mars is 55 million kilometers from the Earth. If the mission launched
at this time the distance to travel would be 400 million kilometers with a duration of 200-300 days.
This is not the quickest route but gives an idea of the times involved in traveling to Mars. The
human crew would have to live inside the spacecraft for the entire trip providing problems. Humans
have evolved to life on earth. We are not suitably adapted to life outside of the Earths atmosphere.
On Earth there is an atmosphere providing us with oxygen, plenty of water, night and day cycles and
gravity. Space however is an inhospitable environment with none of the essentials allowing humans
to survive. To travel to mars we will have to take with us earths environment. Traveling to Mars is
only part of the problem. Surviving on the surface of Mars and making a safe return trip must also
be considered. It is an extreme challenge to get a human to mars, the challenge is not to unlike the
challenge faced by the early explorers of earth. It will take a huge amount of planning and
preparation before we are ready.

2 The space environment
The space environment is a harsh and hostile environment not well suited for humans.
During a mission to mars people will have to be kept alive healthy and comfortable while living in
the space environment. Traveling to mars is very risky for humans. There are three main
environments in space. The active space environment is a high risk environment[12]. This
environment includes launch, landing and all maneuvers. The most likely place for a space mission
to go fatally wrong is during the launch and landing phases of a mission this has been sadly
demonstrated during the challenger and more recent Columbia missions which were lost on launch
and earth reentry respectively. During a mars mission the astronauts will not only have to lift off
from earth and subsequently reenter the atmosphere on there return but they will also have to enter
the Martian atmosphere and lift off from mars at the end of there stay. At the earth end of the
mission then in the event of an accident then there is still the possibility of rescuing the astronauts
however at when the astronauts reach mars the risk increases because even a small accident could
escalate with no chance of help from earth. The active space environment is considered the most
dangerous as it includes the highest energies and therefore the greatest risk of fatal accidents. once
the mission is underway the astronauts will have to complete the trip to mars and back so in the
event of an accident during maneuvers there will be no chance of help until the ship returns to earth.

In the event of a misfire of a motor during an orbit maneuver there is the possibility the ship will be
sent onto an unintended orbit. The second and most obvious environment to consider is the in space
environment. The in space environment is an intermediate risk environment. This includes
radiation, vacuum and weightlessness. These risks are usually long term and would have an effect
on the astronauts after the mission. The in space environment is unlikely to be fatal unless there is a
total catastrophic system failure to the life sustaining systems of a spacecraft. a brief explanation of
the effects of the in space environment on the human body is given below.

There are two types of space radiation, solar particle events (SPEs), otherwise known as
solar flares and galactic cosmic rays (GRCs). SPEs are irregular difficult to predict primarily emit
photons making them easy to shield. GRCs are the constant background tradition occurring
throughout space. The Martian environment provides a fair amount of shielding against SPEs but
little against GRCs. The effect of this radiation on astronauts can be fatal if they are exposed to to
much radiation lower doses can cause radiation sickness. In order to protect astronauts from the
dangers of radiation shield can be used. cosmic radiation cascades through heavy element shielding
making the radiation situation up to 50% worse. Radiation. cosmic radiation shielding requires high
electron densities per unit volume. a material that can absorb cosmic radiation without cascading is
ideal, liquid hydrogen is very good shield against cosmic radiation. tests at NASA Langley have
verified that liquid hydrogen is the best radiation shield due to its high electron density and small
nucleus size.

The effects of the zero g environment. Because the human body is built to live in a 1g
environment on earth and also due to the way the human body adapts to new environments the
effect of zero g causes changes in the human body which build up as the mission proceeds. As the
muscles are not being used as much in zero g they begin to break down and muscle atrophy can
occur. Also because the the strain of 1g has been removed from our skeletal structure the bones also
begin to atrophy and calcium is released into the blood stream. This has two effects it cause the
muscles to be weakened making breakage easier which is unwanted for an astronaut in space and it
causes the deposition of the free calcium in other parts of the body for example astronauts can suffer
from kidney stones. In order to combat these effects on the body calcium supplements can be taken
to replace the lost calcium and exercise can be undertaken by the astronauts to slow down the
muscle loss. Other effects include cardiovascular deconditioning and suppression of the immune
system. All of these things are unwanted as they effect an astronauts ability to carry out the mission
which is especially important on a long duration mars trip. However on there return to earth the
effects of the zero g environment can be reversed. However this is a cumulative effect which builds
up over time it is not known what the effect of an extended stay in space might be. Astronauts at the
present time spend a maximum of 6 months on board the international space station.

A final effect to be mentioned is the psychological effect on the astronauts this is not directly
due to the space environment but is due to the type of craft the astronauts will most likely travel in.
the astronauts will have to make the trip in a small cramped ship sharing there space with each other
for an extended period of time. It has been shown in studies on earth that this can have a significant
effect on some people causing increased stress levels and emotional reactions. During a mars
mission the astronauts will not only have to cope with this but also with heightened stress levels due
to the high work load and being away from earth. Only the fittest and most highly trained people
would be able to cope mentally with such stresses. Another effect not usually looked at has been
looked into by Researchers at the University of Virginia who have begun looking for ways to help
the human body adapt to months, perhaps years, of space travel during a Mars mission. Once
astronauts leave Earth, there will be no day/night cycles. And on the Martian surface, the days are
slightly longer than the 24-hour day on Earth, which likely will skew the natural rhythms of the
astronauts’ biological clocks. This alteration in circadian rhythm is apparent on earth and known as
jet lag. Disrupting the bodies natural cycle can have wide ranging effects especially on an astronauts
ability to concentrate and remain fully alert.

The final environment to be dealt with is the mars surface environment this is a low risk
environment. At this point mars itself will be looked at in ore detail. Mars is slightly more than half
as large as Earth, and about double as large as the Earth's Moon in diameter. It is about 1.5 times
more remote from the Sun so that it receives less than 1/2 the radiation as planet Earth.
Surface gravity (m/s^2) 3.71
Escape velocity (km/s) 5.03
Number of natural satellites 2
Mars orbits the Sun on an elliptical orbit, which is considerably more eccentric than the nearly-
circular orbit of Earth, and larger (i.e. outside, or farther away from the Sun).
Like Earth and most other planets, Mars rotates, with a siderial period of 24h 37m 22.65s, only
slightly more than Earth's 23h 56m 4.09s. Synodical rotation periods, or day lengths, are 24h 39m
35s and 24h 00m 00s (by definition), respectively. A Mars day is often referred to as "Sol" (Latin
for Sun).

The planet experiences seasons similar to that of Earth, but due to its higher orbital eccentricity,
their length is quite different:
Northern spring / southern fall: 199.6 (Earth) days
Northern summer / southern winter: 181.7
Northern fall / southern spring: 145.6
Northern winter / southern summer: 160.1
The effects on a human during the trip to Mars are drastic, so why send humans when robots can
carry out all the science we need. The next section reviews the history of robotic missions to Mars
and considers just how much modern robotic missions can achieve.

3 Robotic missions
Since the mid 20th century humans have been sending robots to Mars. These emissaries have
provided scientists with data about the planet and provided pictures of its surface to stir the publics
imagination.

3.1 History of robotic missions [2]
The first robotic mission to travel to Mars was a Nasa probe know as Mariner 4. This probe
was a fly by mission that passed within 9845km of the planets surface. It returned 22 pictures of the
surface on 14th of July 1965. The first probe to land on the surface was Mars 2, it took up an
elliptical orbit of 1380 by 25000 km on November 27th 1971 and hit the surface the same day. It
returned pictures with little detail. Mariner 9 became the first artificial satellite around mars on the
14 of November 1971, returning 7,329 pictures of the surface. Out of all the missions sent to Mars
not mentioned here are the significant number of missions that have been lost. These early Mars
missions returned limited data. Two later missions which returned a large quantity of good data
were viking 1 and 2. Each viking had a lander on board. The orbiters collected 52,000 images and
cartographed 97 percent of the Martian surface. The landers returned 4,500 pictures and conducted
experiments on the surface.

3.2 Missions currently underway

Currently there are three orbiters around Mars The mars global surveyor and mars odyssey
are Nasa missions. The Mars express is an ESA mission. The Orbiter inserted into orbit on the 25th
December 2003. The Mars express carried a British lander,Beagle 2, this lander crashed during its
descent and was lost. The twin landers, Spirit and Opportunity launched on June 10th and July 7th
2003.After a 6 month 303 million km Journey they both landed on the surface. The missions were
scheduled to last 90 days but both rovers have far outperformed there primary missions. These
robotic landers have been very successful and demonstrate the limits of present robotic lander
technology.

3.3 Future Robotic missions
For the time after 2016, a continuation of the research missions is planned. NASA would
like these missions to be precursors to an eventual human mission. Precursor missions would be
used to gather more information about mars and determine the science that a future crew could
undertake on the surface. Other missions could be used to develop surface infrastructure prior to a
human crew arriving. Robotic missions could specifically be used to determine a safe and
scientifically interesting landing site with remote sensing orbiters to map the surface and rovers to
determine surface conditions.

4 Reports on manned missions
Many Papers have been written on manned missions to mars [3]. One of the major reports on
manned missions written for NASA has become a major benchmark for other scientists to look too
when considering Manned missions to mars. The Reference mission of the NASA Mars exploration
Study Team[4] is a 230 page report looking at every aspect of carrying out a manned mars mission.
To get to mars there are three mission blueprints that can be used. [5]

Short stay mission - this mission has a Mars stay time of 30 to 90 days and a total transit
time to mars and back of 400 to 650 days. A large amount of energy is required during transit to
obtain the short transit period. This mission has a good transit time keeping the astronauts out of the
dangerous space environment however the time spent on the surface of mars is short.

Long-Stay Mission (slow transfer) - this mission has a Mars stay times up to 500 days with
a round trip total time of about 900 days. The energy requirements for this mission are the lowest of
the three considered profiles. The energy is lowest as this mission has the longest transit time. It is
more suited to transfer of robotic missions or cargo missions sent before the manned mission.

Long-Stay Mission (fast transfer) - similar to the minimum energy Long-Stay profile.
Increasing the propulsive energy allows for a shorter transit time, minimizing the astronauts
exposure while still maintaining the long stay on the Martian surface. Due to the risk of the space
environment it is necessary to reduce the transit time thereby reducing the time the astronauts have
to spend in the space environment also to get a good return from the mission the surface time will
have to be maximized. These two mission requirements are satisfied by the long stay fast transit
mission design making this an ideal design for a manned mission to mars.

As gaining a fast transit time requires a large amount of energy it could be appropriate to
utilize a split mission design in which the manned vehicle uses a fast transit and a second cargo
vehicle uses a slow lower energy transit. In this way a maximum amount of cargo could be
transported for minimum energy expenditure while also minimizing the crews exposure to the space
environment.

The proposed missions looked at here only consider the journey and don't look into the
actual vehicles or technology used. The NASA reference mission designs its mission with present
technology in mind demonstrating that a manned mission is feasible with the technology and
knowledge we have now.

4.1 A closer look at two mission plans
During the 1950's the available technology was a lot more basic, rockets for sending objects
into orbit were only just being developed. It was during this period that German scientist W. von
Braun, who was working on American rockets, wrote a book about an expedition to mars. [6] This
was an imaginative look at sending humans to mars. The book describes how 10 400 ton spacecraft
will be assembled in obit, 70 crew will make the trip and then descend to mars on gliders before
trekking to the equator to set up a base camp. This was a science fiction account of how von Braun
imagined we could travel to mars in the future. However von Braun did prove the feasibility of the
science behind the trip using calculations. This was one of the first scientific mission plans to be
written.

More recently a group of Caltech students wrote a paper on a mars mission improving on the
NASA reference mission. [7] This mission plan uses existing technologies, minimizes the risk
factor by increasing the crew survival options and maximizes the science return. It also tries to be
politically sensitive by reducing the cost and use of unfavorable technologies such as nuclear power.
This mission looks closely at safety factors and adds an amount of redundancy to improve the
overall safety. For example the crew transport vehicle will travel wit an identical “ghost” vehicle
providing a backup should the primary transport fail. The mission also proposes a split mission
design with the supplies and infrastructure being sent to mars and verified on the surface before the
manned mission launches.

5 Public and political issues
On the 25th of May 1961 John F Kennedy revealed his vision for landing man on the moon
this became the Apollo missions. Between 1969 and 1772 numerous missions were made to the
moon. On the 14th January 2004 President George W. Bush set two goals for the nation’s space
program[8]: humans will return to the moon by 2020, and land on Mars by 2030. the visions of
these too political leaders is very similar in many respects. However the political reasons for the
Kennedy proposal was to demonstrate Americas power to the Russians. The reasons for Presidents
Bush's Could have been to gain public favor prior to the elections in 2004. However the public is
very wary of missions in space.

We live in a very risk averse society, each time NASA suffers a lose of life during one of its
missions there is a public backlash against the government. People expect space to be 100% safe as
otherwise it is believed to be an unnecessary risk. If a mission was to go ahead and then fail the
effect of the space industry would be huge. It would set the industry back decades. If a mission was
successful it would be a globally celebrated event. However this would soon pass as people turned
there attention back to issues on earth. A mission would have to have a long term plan in order to
keep momentum and be a worthwhile future investment. I f the public were to loose interest in the
mission the setbacks could be as far reaching as those of a mission failure. A mission would also
have to be planned in the short term as spending money without results would soon make the public
wonder if there money was going to good use. In other words for a ,mission to be successful in the
public mind it would have to have a quick planning and implementation phase with the first landing
within at most 10 years from the beginning of the mission and a long duration after the first landing
with the establishment of a Martian infrastructure and continuing missions. Also to keep the publics
interest the mission itself would have to be made into as much an entertainment spectacle as a
scientific endeavor.

Any large scale space mission will cost a large sum of money, a mars mission could well
cost into the hundreds of billions which at first seems like a huge amount of money. However
compare this to for example Americas military budgets which at present stands at around $350
billion a year[9] President Bush has proposed increasing this to $500 billion by the end of the
decade[10]. This makes a budget for a mars mission seem like pocket change. NASAs present
annual budget stands at around $16 billion[11] Any mars mission will cost a significant amount but
the return will be much greater than the cost.

6 Conclusions
People have long held a fascination with Mars and it has been a continuing theme in science
fiction that humans will one day inhabit Mars. Numerous robotic missions have been sent as
emissaries, is it now time humans went to experience it for themselves? Do we have the capability
and level of technology required to carry out such a mission? Should we even bother? This report
has presented the facts of manned Martian missions in an attempt to answer these questions. This
report has demonstrated that there are inherent problems and risks concerning a mars trip and our
present climate of minimizing risk makes a mission more difficult, especially for governments. This
report has also demonstrated that in the near future a manned mission is entirely possible, there have
been many conceivable plans drawn up allowing, with little technological advance, a mission to be
carried out. Regardless of the facts this report presents it is in the nature of people to expand there
horizons and push the boundaries of science. Maybe the question shouldn't be if we will travel to
Mars but when will we make the journey. During the 1970's a great leap was made when the Apollo
missions took men to the moon it is my opinion that it is about time we stepped up to the next
challenge and traveled to mars. Due to the current political and public opinion on space I do not
envisage a government funded manned mission in the near future. The Apollo missions occurred
during a time of political turmoil between two super powers, the climate of competition that drove
the Apollo program no longer exists. Governments are now more concerned with issues on earth
and are not willing to risk the money or public opinion to fund a mission. The public are very much
against taking risks when it comes to manned space missions. I find this strange as many more
people are killed on the roads than in space, until more people die in space the risk factor should not
have become part of mission planning, this however is not the public opinion and if a government
was to risk human life for a mission they would soon loose power. In order to go ahead with a
mission public opinion needs to change as the risk of damage to the industry is a much greater
concern than the risk of lose of life. The speech made by President Bush was a well placed political
tool prior to the American elections. However governments do not stay in power for a long enough
duration to mount a manned mission. It may become up to individuals to take up the challenge.
People have previously not had the power or money to carry out such a mission however with the
advent of privately funded space missions such as scaled composites spaceship one and proposed
prizes for people who advance human knowledge and technology this situation may change. A
situation much like the time of the great explorers may arise in which many people compete to be
the first to Mars.

Mars is the next great challenge for humanity to overcome, we now have the technological
know how to undertake this challenge.

7 References
[1] http://nssdc.gsfc.nasa.gov/planetary/mars/marswhy.html
[2] http://www.astrodigital.org/mars/mission_future.html
[3]http://www.marsinstitute.info/rd/facult y/dportree/rtr/rtr-ma.html
7
Peter Oates 11/29/04
[4]The Reference Mission of the NASA Mars Exploration Study Team, Stephen J. Hoffman,
Editor David I. Kaplan, Editor Lyndon B. Johnson Space Center Houston, Texas
July 1997 NASA Special Publication 6107
[5]http://nssdc.gsfc.nasa.gov/planetary/mars/marsprof.html
[6] The Mars Project, Wernher von Braun, University of Illinois Press, 1953.
[7] "A New Plan for Sending Humans to Mars: The Mars Society Mission," Christopher
Hirata, Jane Greenham, Nathan Brown, Derek Shannon ("contributors"), and James
Burke ("advisor"); paper presented at the Human Exploration and Development of
Space - University Partners (HEDS-UP) Exploration Forum, Houston, Texas, May
6-7, 1999.
[8]http://www.nasa.gov/missions/solarsystem/bush_vision.html
[9]http://news.bbc.co.uk/1/hi/world/americas/2167515.stm
[10]http://news.bbc.co.uk/2/hi/americas/2720851.stm
[11]http://home.hamptonroads.com/stories/story.cfm?story=65639&ran=20140
[12]http://nssdc.gsfc.nasa.gov/planetary/mars/marsprof.html