Planetary Protection

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  Planetary Protection Ushers in Discipline's Future With New Logo

  January 27, 2025

  NASA’s Office of Planetary Protection is looking toward the future of solar system exploration and now has a new logo to represent its mission effectively.

  The updated logo, designed in partnership with the NASA Safety Center, embodies exploration of the solar system while emphasizing the importance of Planetary Protection (PP) and its connection to enabling science with safety at the forefront.

  The logo also highlights the focus on Earth’s biosphere while embracing and supplementing the traditional spore assay with metagenomics methods. Additionally, it captures both a robotic and crew mission portfolio through its design.

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  Setting Her Own Path Led Amy Baker to a Meaningful Career in Planetary Protection

  June 24, 2024

  Amy Baker, Planetary Protection project manager for the SETI Institute, is set to retire at the end of June 2024. In recognition of her contributions to the Office of Planetary Protection and NASA’s mission, the Office of Safety and Mission Assurance would like to honor her achievements and acknowledge her important work in support of the agency.

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Planetary Protection Handbook

This handbook provides guidance to mission providers and Planetary Protection (PP) practitioners on implementing PP measures for both robotic and crewed space missions. This handbook represents major updates to PP practices since a previously drafted handbook from 2010.

In 2017, NASA reorganized the Office of Planetary Protection (OPP) from the Science Mission Directorate (SMD) to a Technical Authority (TA) within the Office of Safety and Mission Assurance (OSMA). With this organizational change came a complete overhaul of NASA’s PP policy and technical standards.

This handbook reflects the latest NASA PP policy updates in NPR 8715.24, Planetary Protection Provisions for Robotic Extraterrestrial Missions and technical requirements of NASA-STD-8719.27, Implementing Planetary Protection Requirements for Space Flight. This handbook is a companion document to the NPR and technical standard and provides guidance, best practices, background information, and advice for practitioners to consider when implementing PP on NASA missions and NASA-partnered missions.

National Academies Reports

• What is Planetary Protection?

  Planetary Protection is the practice of protecting solar system bodies from harmful contamination by Earth life to enable scientific exploration (forward contamination) and protecting the Earth-Moon system from possible harmful contamination that may be returned from other solar system bodies (backward contamination). Recognizing the Outer Space Treaty, which has been signed and ratified by 110 countries, the goals of Planetary Protection are to

  • Protect solar system bodies from biological contamination from Earth
  • Prevent harm to Earth’s environment from possible harmful extraterrestrial contamination
  • Support safe, sustainable exploration of chemical evolution and the origins of life

  NASA’s Office of Planetary Protection works with mission teams to ensure compliance with NASA policy and international agreements by assisting with

  • Construction of biologically managed (or low biological burden) spacecraft
  • Development of flight plans that protect planetary bodies of interest to the search for life
  • Development of plans to protect the Earth-Moon system from samples returned from extraterrestrial bodies
  • Formulation and application of space policy as it pertains to Planetary Protection
• Why is Planetary Protection important?

  Planetary Protection makes it possible for scientists to study extraterrestrial environments without interfering with any extant or existing life that may have developed there. It also preserves the integrity of scientific research conducted in those environments. Finally, Planetary Protection preserves Earth’s biosphere from possible contamination by harmful extraterrestrial material.

• How long has NASA been involved with Planetary Protection?

  The first mission to use Planetary Protection recommendations from the United Nations Committee on Space Research (COSPAR) was the Ranger project, a series of unmanned spacecraft in the 1960s whose objective was to take close-up images of the Moon. In 1967, the United States, the Soviet Union and the United Kingdom were the first nations to sign the Outer Space Treaty, which is the legal framework for space exploration. The first article of the Outer Space Treaty reads,

  “The exploration and use of outer space, including the moon and other celestial bodies, shall be carried out for the benefit and in the interests of all countries, irrespective of their degree of economic or scientific development, and shall be the province of all mankind.”

  NASA formed its Office of Planetary Protection in 1976, however, it was already shaping mission policy based on COSPAR recommendations before that time.

• Can you explain the idea behind forward and backward contamination?

  Forward contamination: The transfer of viable organisms, including microorganisms, from Earth to another celestial body.

  Planetary Protection requirements to control forward contamination begin on Earth and are accomplished by understanding mission science, operational requirements and goals based upon the environmental characteristics of each planetary destination. Forward Planetary Protection requirements protect the integrity of science exploration, including the search for and study of potential extraterrestrial life. 

  All missions leaving Earth are evaluated for impact from forward contamination.

  Backward contamination: The transfer of extraterrestrial organisms, if they exist, to Earth’s biosphere.

  Spacecraft carrying samples back to Earth pose a risk of unintended transfer of extraterrestrial life. Backward Planetary Protection requirements are needed to assure safety for Earth’s environment and responsible scientific study once extraterrestrial samples are landed on Earth and transferred to a receiving facility. 

  Extraterrestrial materials from planetary destinations with the possibility of supporting life are considered potentially harmful to humans and Earth’s biosphere until scientific study in a biologically secure laboratory can establish that there is no evidence of extraterrestrial life in the samples. 

  Only missions bringing material back to Earth are evaluated for harm to Earth from backward contamination.

• How does NASA ensure spacecraft are clean before launch?

  All spacecraft such as orbiters, landers and rovers must be built in cleanrooms that meet International Organization for Standardization specifications for particulate control and air flow as well as gowning protocols for protective clothing. 

  Planetary Protection requires workers to wear full cleanroom garments. These include head coverings, coveralls and shoe covers. Workers wear these garments over their street clothes to prevent contaminants such as clothing fibers and hair and skin particles from entering the cleanroom and potentially transferring to sensitive spaceflight hardware. 

  Planetary Protection also requires clean assembly practices, as well as preventing recontamination on flight hardware up to the last time of access prior to launch.

  NASA uses multiple cleaning methods to reduce the number of viable organisms on a spacecraft and vaporize chemical remnants of terrestrial biology. Dry Heat Microbial Reduction is a process that heats hardware under controlled humidity, temperature and time conditions. This method not only kills microbes on the surface or encapsulated within hardware, but the heating process can bake off organic molecules from hardware surface. 

  If spacecraft parts or scientific instruments are susceptible to damage from heating, then there are other methods for microbial reduction, such as exposure to vapor hydrogen peroxide or ultraviolet light. Each cleaning method has benefits and drawbacks to be considered when deciding on the best approach. 

  Exposed hardware surfaces are cleaned during the assemble process by alcohol wiping. Alcohol does not destroy bacterial spores in general, rather, they are removed by the mechanical action of physical cleaning. Hardware is wiped clean before final assembly and installation. Workers routinely wipe down flight hardware surfaces that remain accessible to maintain cleanliness. 

  Finally, ground support equipment is subject to rigorous cleaning and testing for biological cleanliness throughout the assembly process.

• How does NASA keep a cleanroom clean?

  Cleanrooms are cleaned every day using several chemical solvents. It is a continuous practice. Once the room has been cleaned, the team goes back to begin cleaning again. In addition, cleanrooms have robust air filtration systems that filter air multiple times before returning to the room, with filters changed on a regular basis. The air flow changes in NASA’s cleanrooms for biologically sensitive hardware can be up to 350 per hour using an industrial Ultra-Low Particulate or High-Efficiency Particulate Air filtration system as per ISO 14644-1 Cleanroom Standards. This is compared to a house where the air flow changes only four to eight times per hour using a residential HVAC system with a variety of filter ratings removing large particles, allergens and bacteria based on the homeowners’ filter selection.

• Do different space missions have different Planetary Protection concerns?

  There are different mission categories that determine the Planetary Protection requirements for each mission. Based upon Committee on Space Research recommendations, Planetary Protection categorizes each planetary body reflecting its importance in the search for evidence of fossil life, present-day life or prebiotic chemical evolution.

  The three worlds that have the highest scientific interest in possible extraterrestrial life carry the strictest exploration requirements for Planetary Protection and are Mars, Europa and Enceladus. A mission to these worlds is either Category III (flyby/orbiter) or Category IV (lander).

  Any spacecraft going beyond Earth orbit and then returning to Earth is classified Category V (Earth Return). If a spacecraft has landed on or near Mars, Europa or Enceladus, then the returning leg of the mission is considered Restricted Earth Return. Restricted Earth Return requirements assure safety for Earth’s environment and responsible scientific study of returned hardware and samples. Sample retrieval missions will be designed to contain the sample prior to return to Earth, where they will be examined under quarantine and confirmed safe or completely sterilized prior to distribution to science laboratories. 

  For most other destinations in the solar system, a returning mission is categorized as Unrestricted Earth Return.

• Do other countries have Planetary Protection offices that NASA coordinates with?

  Planetary Protection is an agreed international practice that is defined by the United Nations and its Committee on Space Research. Space-faring agencies that implement Planetary Protection policies include the European Space Agency, the Japanese Aerospace Exploration Agency and others.

• Are there organizations that discuss best Planetary Protection procedures and policy at the international level?

  The Committee on Space Research (COSPAR) was established October 1958 with the objective of promoting international guidelines for scientific research in space and emphasizing the exchange of results, information and opinions. 

  The Outer Space Treaty (OST) was signed on Jan. 27, 1967, in Washington D.C., London and Moscow. It now has 110 states-parties. It includes 17 Articles that provide the legal framework for space exploration. 

  Based upon new scientific discoveries and exploratory capabilities, COSPAR provides accepted international guidelines and policy standards for compliance with the OST. Overall, there have been over 50 years of international collaboration in space exploration policy.

• Does NASA share its Planetary Protection policies with commercial space companies?

  All commercial space companies that partner with NASA on missions must work in compliance with Planetary Protection requirements. All policies, guidelines and mission requirements are publicly available to commercial space companies.

• Who’s responsible for ensuring commercial space companies follow established Planetary Protection guidelines?

  NASA’s Office of Planetary Protection is responsible for ensuring that all NASA missions, along with their contracted commercial partners, follow Planetary Protection requirements.

  Since NASA is not a regulatory agency, the Federal Aviation Administration (FAA) is responsible for any U.S. payload launch made from a commercial requestor not directly sponsored by NASA. During the FAA pre-application consultation and license application process, if a mission is determined to need a Planetary Protection consultation, NASA’s Office of Planetary Protection is engaged. Technical leads within the Office of Planetary Protection will review any provided material from the commercial requestor. The initial assessment is made based on the payload and additional payload propulsive capabilities to leave the Earth orbit. A more detailed assessment of the payload is then conducted with the specific areas of interest to include

  • Description of the energetic potential of the primary launch vehicle, second stage, cruise stage and additional independent propulsion systems on primary and secondary payloads
  • Description of trajectory including flybys or gravity assists of celestial objects and orbital insertion or landing at the destination
  • Assessment of biological contamination risk and associated mitigation strategy for celestial objects, along the trajectory and at the orbiting or landed destination
  • For missions to the surface of the Moon, an inventory of propulsion products released into the lunar environment; additionally, for missions to Permanently Shadowed Regions or the lunar poles, an inventory of organics

  The initial assessment and detailed areas of interest are then directly used to evaluate the potential impacts for harmful contamination under the Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies (U.N., 1967), Article IX. The technical assessment is then provided to the FAA for further consideration as part of the pre-application consultation and license application process. 
  

• How do you determine how many microbes there are on a given surface?

  The number of microbes on the surface of a spacecraft is called its bioburden. A part of a spacecraft (usually a square meter) is sampled by using a wipe or a swab. The collected sample is then analyzed in a culture dish, and the number of bacterial colonies are measured. This will give an estimate of the number of bacteria per square meter of surface. If the bioburden exceeds the Planetary protection limit, then the spacecraft is recleaned and retested.

  The most important type of microbe to consider is an endospore (or “spore”), which is a type of bacteria that can enter a dormant, protective state and survive even in the vacuum of space. The bioburden limit for a Mars rover is just 300 spores per square meter of the rover’s surface.

• Are there microbes in space that we don’t have here on Earth?

  We have not yet discovered whether there is life beyond Earth. All currently known forms of life, microbial or otherwise, exists on Earth. Any known microbes (so far) that are on Mars have been carried there from Earth by human spacecraft!

• How do you ensure samples that we return from other planets are safe once they arrive?

  Any spacecraft going beyond Earth orbit and then returning to Earth is classified Category V (Earth Return). If a spacecraft has landed on or near Mars, Europa or Enceladus, then the returning leg of the mission is considered Restricted Earth Return. Restricted Earth Return requirements assure safety for Earth’s environment and responsible scientific study of returned hardware and samples. Sample retrieval missions will be designed to contain the sample prior to its return to Earth, where they will be examined under quarantine and confirmed safe or sterilized prior to distribution to science laboratories.

• What Planetary Protection processes have changed for the Moon?

  As the search for life beyond Earth advances, Planetary Protection requirements are modified to reflect new scientific knowledge about the diversity of life on Earth and the detection capabilities of advanced instruments. 

  Historically, Earth’s Moon has not been considered significant from a biological perspective in the search for life. As a result, it was categorized by the Committee on Space Research (COSPAR) as a Category I body with no Planetary Protection requirements warranted.

  Since the time of the Apollo missions, ice deposits located in the Permanently Shadowed Regions (PSRs) of the Moon have been detected. In 2008, COSPAR updated the Moon to a Category II body with significant interest relative to chemical and biological evolution of the solar system but with minimal risk of contamination during exploration.

  More recently, because the existence of water at the lunar poles of the Moon provides a potential resource for future human exploration, COSPAR has called special attention to contamination concerns for PSRs, leading to sub-categorizations for missions that will explore those areas of the Moon.

• What Planetary Protection processes have changed since we returned the Moon rocks during the Apollo missions?

  Planetary Protection requirements and processes evolve based on the current scientific input. The requirements are aligned with the current scientific consensus as established by an independent, international community. Earth return samples from the Moon were originally treated as a Planetary Protection Restricted Earth Return up until Apollo 11. The mission required additional cleaning measures, quarantine of the astronauts for 21 days and sample safety analysis to ensure that the samples would not pose adverse harm to the Earth’s biosphere. Once the samples were deemed safe through sample safety assessments at the curation facility and it was confirmed the astronauts were not experiencing adverse reactions, subsequent missions did not have to adhere to such strict protocols. Thus, since Apollo 15, the Moon has been characterized as an Unrestricted Earth Return mission.  

• Does Planetary Protection also look for signs of life on other planets?

  Missions to search for life beyond Earth include multidisciplinary teams of experts across scientific fields that include planetary science, geology and geoscience, astrobiology, astronomy, astrophysics, biology, microbiology, chemistry, and much more. Planetary Protection is responsible for ensuring that all missions follow Planetary Protection requirements to protect solar system bodies from biological contamination from Earth and to prevent harm to Earth’s environment from possible extraterrestrial life forms. As such, Planetary Protection experts are crucial members of mission teams that search for life beyond Earth.

• What should students study to become a Planetary Protection Officer?

  Given the multidisciplinary nature of topics covered by Planetary Protection, there is not a one-size-fits-all approach. Anyone interested in a career in Planetary Protection needs a strong background in a variety of subjects, including engineering and microbiology. At school, a student should focus on biology, chemistry, physics and mathematics. At university, a degree in astrobiology, engineering, geology, planetary science, microbiology, the biological sciences or chemistry would be ideal. A curiosity about the universe is of course a must. Try to take an introductory astronomy, if possible.