Caitlin Hughes
November 27, 2011
Astronomy 105-01
M. Darby Dyar
Planetary Protection
Introduction
As defined by NASA, planetary protection is the practice of protecting solar system
bodies (i.e., planets, moons, comets, and asteroids) from contamination by Earth life, and
protecting Earth from possible life forms that may be returned from other solar system bodies.
This program is essential to our exploration of space, and our cultivation, and eventually,
colonization, of other planets as well as preserving our environment on Earth. “The potential
effects that are of concern about biohazards can be divided into three broad categories:

Large-scale negative pathogenic effects on humans

Destructive impacts on Earth’s ecological systems or environments

Toxic and other effects attributable to microbes, their cellular, or extracellular products”
(Committee on the Review of Planetary Protection Requirements for Mars Sample
Return Missions, and the National Research Council 45).
Planetary protection measures, which have been effectively used for over 50 years, can
limit these threats and allow us to continue the exploration to which we as humans have become
so accustomed. Without these measures, our universe could be in great danger. As a race looking
to expand, it is important that we preserve the integrity of all planets in the solar system.
Origin, Objective, and Goals
1
Caitlin Hughes
Astronomy 105-01
The planetary protection program that exists today was created out of demand by the
Committee on Space Research (COSPAR). COSPAR was created in 1958, at almost exactly the
same time as NASA, and was meant to be an organization independent from politics and
government. Their main concerns included the biological aspects of interplanetary exploration,
such as spacecraft sterilization and planetary quarantine. COSPAR, which was an international
committee, asked the United States early on to examine ways to avoid the transfer of terrestrial
organisms to other planets. In response, NASA implemented the planetary quarantine program.
The objectives of this program were to “protect planets of biological interest so that 1) life
detection experiments would not be invalidated by contamination and 2) a planet would not get
overgrown by terrestrial life with consequent irreversible changes in its environment” (Meltzer
26). From the very beginning of the development of these organizations, it was clear a planetary
protection program was in the making. As early as 1959, prominent scientists such as Carl Sagan
ad Joshua Lederberg advocated priority be placed on the issue of planetary protection. That same
year, NASA began following a planetary protection program that would develop and adapt over
decades into the one we know today.
As outlined in the attached 2008 letter from NASA to Dr. Lennard Fisk, Chair of the
Space Studies Board, In accordance with international treaty obligations, NASA maintains a
planetary protection policy to avoid biological contamination of other worlds, as well as avoid
the potential for harmful effects on Earth due to the return of extraterrestrial materials by
spaceflight missions.
Forward Contamination and Back Contamination
The term forward contamination in regards to Mars refers to contamination of the
Martian environment by other terrestrial organisms, specifically from Earth.
2
Caitlin Hughes
Astronomy 105-01
The term back contamination refers to bringing other terrestrial organisms back to Earth.
In the beginning of the planetary protection program, there was some skepticism about the
necessity of preventing against back contamination, based on things that could not yet be
validated. These concerns are illustrated by three points raised by Norman Horowitz of the West
Coast Committee on Extraterrestrial Life (WESTEX), which he believed to be irrelevant
assumptions:

Microorganisms will be found on other planets

They will prove dangerous to humans

We would be unable to cope with them if they were brought back to Earth and escaped
from quarantine.
Already there was an assured optimism and confidence in the potential for space exploration
internationally, and Horowitz’s claims were dismissed. Back contamination was viewed as
equally important as forward contamination, and scientists Richard Wagner and Robert Zubrin
argue that “if microbes are discovered on Mars, they should be treated no differently than similar
life on Earth, which we do not hesitate to kill” (Zubrin 12).
Processes and Methods
The planetary protection program has many ways of being utilized-in housing,
sterilization, and the usage of quarantine. With the more recent advancements in sterilization
methods, it has been discovered that much of the probability of contamination can be reduced in
the manufacturing process. Ships could be designed to have better microbial barriers, and special
storage for samples collected from other planets. They could also be designed to withstand the
high levels of dry heat used in the sterilization process. Ships would be sterilized before launch
to another planet, and again upon return during an allotted quarantine time. The ship and all
3
Caitlin Hughes
Astronomy 105-01
cargo (including human passengers) need to be kept in quarantine immediately upon their arrival
back to Earth until it is determined that they are not harboring any sort of microorganism.
Sterilization is done by baking the spaceship at temperatures of upwards of 100˚F for
about 30 hours. However, several modern spaceships contain cameras that cannot withstand that
sort of exposure to dry heat, so NASA is developing chemical based sterilization methods to be
used as well.
The probability of contamination is constantly being revised, but it is generally agreed
upon that taking these steps and proceeding with caution in interplanetary transport will be the
best way to uphold the intent of the planetary protection program.
Ethics
The ethical debate of our planetary protection program is still very lively today. Scientists
and civilians alike question out responsibility to protect and preserve not only our own planet,
but others in our solar system as well, and where to draw the line between responsibility and
intrusion. The questions posed by the United Nations Education, Scientific, and Cultural
Organization (UNESCO) illustrate the base of the ethical debate:
1. Do we have an ethical obligation to preserve a planetary environment to the same degree
that we seek to protect our Earth’s environment?
2. Does this obligation hold, even if there is no life on the planet?
3. Or, since environmental ethics seek to benefit and enhance life, do we have an obligation
to see that terrestrial like expands onto lifeless planets?
These questions are ones that may need to be answered for the sake of the integrity of the
program, but deeper, more philosophical questions may remain-questions such as who owns
extraterrestrial bodies? And what gives us the right to contaminate?
4
Caitlin Hughes
Astronomy 105-01
There are several different subsets of ethics relevant to the planetary protection program
that are debated and upheld by different bodies. The main two divisions are:

Preservation ethic: human action in nature should be minimized (leave extraterrestrial
bodies unaltered)

Stewardship: resource management (alter extraterrestrial bodies only if it is scientifically
and economically advantageous)
Stewardship in particular has been difficult for scientists to uphold. As seen in previous missions
to Mars, it is sometimes hard to maintain a balance between contaminating Mars and conducting
rigorous scientific exploration.
Geoethics
Geoethics is a term highly relevant to space travel and the planetary protection program.
The term was coined in 1991 to describe the ethics related specifically to geology. Geoethics are
typically what restrict space missions- regarding damage to the environment of planets.
Major Players
Planetary protection is a program that crosses atmospheres, but it also crosses countries
on Earth. The European Space Agency (ESA), National Aeronautics and Space Administration
(NASA), COSPAR, the UN, and beyond all have put in their two cents on the matter of the
program, and all adhere to it. The issue of space travel is one that is internationally considered,
and the provisions for which have been generally agreed upon. There have been many national
and international legal pursuits to ensure that planetary protection is upheld, including:

Outer Space Treaty (1967): nations will explore planets so as to avoid their harmful
contamination

COSPAR Planetary Protection Policy: upholds the planetary protection program directly
5
Caitlin Hughes
Astronomy 105-01

Specific US legal requirements: to guard the Earth against contamination, to give NASA
the right to determine quarantine periods for missions (people, equipment, cargo, etc.)

Many other national and international agreements that held varying weight in regards to
planetary protection regulations
As planetary protection is so widely recognized, it should also be upheld based on the UN’s
Declaration of Legal Principles Governing the Activities of States in the Exploration and Use of
Outer Space, 1963:
1. Outer space exploration and use shall be carried out for the benefit and in the interests of
all people.
2. Outer space and celestial bodies are free for exploration by all states and are not subject
to national appropriation or claims of sovereignty.
3. All states will follow international legal principles, including those of the UN, in their use
and exploration of space.
4. States shall conduct all their outer space activities with due regard for the interests of
other states.
5. States are liable for damage to the Earth or air or any other nations due to objects
launched into space.
Costs
Quantitative annual and cumulative costs of the planetary protection program are
impossible to calculate due to inconsistencies. Costs for the program include elements for
cleaning and sterilizing the spaceships, materials obtained for alteration or re-design of
spaceships to meet the guidelines of the program (usually to better withstand sterilization
processes), and provisions used in the quarantine program. However, these costs are constantly
6
Caitlin Hughes
Astronomy 105-01
fluctuating-changes are not always needed, and sometimes are more drastic than others.
Similarly, because costs cannot always be attributed to only the planetary protection program,
there is no record of the costs the program has incurred.
A way to reduce costs would be to streamline the process-to create a system that is the
most efficient combination of cleaning, spacecraft design, and flight system design. This
streamlined process was implemented gently by the Mars Program; the Mars Reconnaissance
Orbiter demonstrated that the heat flux experienced when entering the atmosphere could be used
as part of the sterilization process, effectively limiting the surface cleaning process.
Cost is essentially not a concern of the program, but steps are being taken to improve
efficiency and make the best use of resources.
Limitations on Space Travel and Exploration and What this Means for Habitation of Other
Planets
As mentioned previously, the only real limitation put on space exploration is that a
balance must be maintained between planetary protection and scientific cultivation on other
planets. The planetary protection program must be upheld, but has been for over 50 years
without inhibiting astronomic advancement and exploratory.
It attests to our faith in Mars as an inhabitable planet that we insist on maintaining
planetary protection in Martian contact, “Based on current knowledge of past and present
habitability of Mars, NASA should continue to maintain a strong and conservative program of
planetary protection for Mars sample return. That is, samples returned from Mars should be
contained and treated as though potentially hazardous until proven otherwise. No uncontained
materials, including spacecraft surfaces that have been exposed to the Martian environment,
should be returned to Earth unless sterilized” (Committee on the Review of Planetary Protection
7
Caitlin Hughes
Astronomy 105-01
Requirements for Mars Sample Return Missions, and National Research Council 28). These
rigorous measures indicate that the scientific community maintains that biotic life may be present
on Mars.
The question of our ability to colonize other planets while upholding planetary protection
guidelines can be answered by looking at another field of science-ecology. We must protect
different ecosystems from invasive species, but we are still able to go forth and turn forest into
field or pond into stream successfully.
There are economic and social pros and cons to the idea of unhampered space traffic
(eliminating planetary protection), but it is generally agreed that a system like that would do
more harm than good.
Conclusion
In conclusion, it is necessary to point out the great weight of and need for the planetary
protection program. While the ethics of space exploration and colonization of other planets
remains in debate, the effectiveness of the program in past decades in absolute. In order to
continue our habits of exploration, we must uphold the program. To go forth, we must first fight
to preserve the integrity of our planet and our universe.
8
Caitlin Hughes
Astronomy 105-01
Works Cited
Committee on the Review of Planetary Protection Requirements for Mars Sample Return
Missions, and National Research Council. Assessment of Planetary Protection Requirements for
Mars Sample Return Missions. Washington, D.C.: National Academies, 2009. Print.
Conley, Dr. Catharine. "Planetary Protection." Planetary Protection at NASA. NASA, 24 Nov.
2011. Web. 11 Nov. 2011. <http://planetaryprotection.nasa.gov/>.
Dick, Steven J., and James Edgar Strick. The Living Universe: NASA and the Development of
Astrobiology. New Brunswick: Rutgers UP, 2004. Print.
Martinez-Frias, Jesus, et al. "A Geoethical Approach to the Geological and Astrobiological
Exploration and Rese." The Smithsonian/NASA Astrophysics Data System. Web. 11 Nov. 2011.
<http://adsabs.harvard.edu/abs/2010cosp...38.3961M>.
Meltzer, Michael. When Biospheres Collide: a History of NASA's Planetary Protection
Programs. Washington, D.C.: NASA Aeronautics and Space Administration, 2010. Print.
Nolan, Kevin. Mars, a Cosmic Stepping Stone: Uncovering Humanity's Cosmic Context. New
York: Copernicus in Association with Praxis Pub., 2008. Print.
Task Group on Planetary Protection, Commission on Physical Sciences, Mathematics, and
Applications, and National Research Council. Biological Contamination of Mars Issues and
Recommendations. Washington, D.C.: National Academy, 1992. Print.
Williamson, Mark. Space: the Fragile Frontier. Reston: American Institute of Aeronautics and
Astronautics, 2006. Print.
Zubrin, Robert, and Richard Wagner. The Case for Mars: the Plan to Settle the Red Planet and
Why We Must. New York: Free, 1996. Print.
9