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NPR 8020.12D
Effective Date: April 20, 2011
Expiration Date: January 20, 2022
Printable Format (PDF)

Subject: Planetary Protection Provisions for Robotic Extraterrestrial Missions

Responsible Office: Office of Safety and Mission Assurance

| TOC | Preface | Chapter1 | Chapter2 | Chapter3 | Chapter4 | Chapter5 | AppdendixA | AppendixB | AppendixC | AppendixD | ALL |

Chapter 3. Planetary Protection Constraints

3.1 General

3.1.1 Planetary protection constraints shall be imposed according to the contents of this document, as may be applicable to each mission.

3.1.2 Specific deviations from individual constraints may be requested by a flight project in accordance with the provisions of section 2.6, Deviations.

3.2 Specification of Parameters

3.2.1 In order for a flight project to plan for compliance with planetary protection requirements, appropriate mission specific parameters and specifications (such as the microbial burden requirement for a mission type to a given target planet) shall be obtained from the PPO during Phase A. Each major parameter and specification shall be defined and its value specified on a "Parameter Specification Sheet" which is valid when dated and signed by the PPO. Flight projects may use applicable values specified therein without further authorization. Approved planetary protection parameter specifications are included in Appendix D. Deviations from specified values shall be handled per section 2.6.

3.2.2 The values adopted by a project for undesignated parameters and specifications shall be subject to the approval of the PPO. These project-developed parameters and specifications must be included in the "Planetary Protection Plan" with later changes reflected in the "Pre-Launch Planetary Protection Report." Approval of these documents will constitute approval of the parameters and specifications contained therein. Alternatively, a project manager may request that the PPO issue appropriate Parameter Specification Sheets based on submitted new information and data.

3.2.3 In addition to the primary purpose of designating parameters and specifications used in mission planning, Parameter Specification Sheets also may be used for other purposes, such as defining contamination-related process parameters (e.g., minimum temperature for microbial reduction processes, etc.).

3.3 Microbiology Related Determinations

3.3.1 Missions with bioburden constraints shall monitor and document bioburden carried on spacecraft hardware using approved methods.

a. Approved protocols for the microbiological assay of spacecraft hardware and their associated environments are provided in the current version of NASA HDBK 6022, "NASA Standard Procedures for the Microbiological Examination of Space Hardware," as supplemented by the project's "Microbiological Assay Plan."

b. Alternative assay procedures consistent with mission and life detection objectives may be proposed to the PPO for review and approval prior to use.

3.3.2 In addition to those microbiological assays which a flight project organization or its contractors may wish to conduct, various verification assays (see section 2.4) shall be conducted for the PPO by an organization designated by the PPO. Collection of samples for verification assays from flight hardware may be delegated to involved flight project and contractor organizations, under supervision. Microbial samples taken from spacecraft hardware, the assembly facility environment, etc. shall be furnished to the PPO by the flight project (or contractors) in accordance with the quantity and locations identified in the Microbiological Assay Plan. Collection of microbiological samples may, at the option of the PPO, be subject to observation by the PPO or his/her designated representative. Microbiological samples will be processed by the organization designated by the PPO to obtain pertinent data (e.g., microorganism types and numbers).

3.3.3 In the event of significant discrepancies between project assays and verification assays due to possible laboratory contamination, the PPO shall take appropriate action to review the suspect data and resolve the discrepancies. An Assay Review Board may be formed to review the suspect data and their causes.

3.4 Microbial Reduction

3.4.1 Microbial reduction for planetary spacecraft (including planetary entry probes and planetary landing capsules) shall be accomplished by an approved process.

a. Alternate methods of microbial reduction may be proposed, such as by chemical or radiation techniques or various combinations of these techniques with heat. Approval of alternative methods shall be based on a rigorous examination of supplied data which must demonstrate conclusively the biological effectiveness and reproducibility of the alternate method for the specific application under consideration. It may be desirable to subject either all or certain elements of the spacecraft hardware to a microbial reduction process prior to their assembly. Approval from the PPO shall be obtained for use of methods other than those approved for an entire spacecraft, according to the following criteria:

a. A statement shall be made in the Planetary Protection Plan that unique microbial reduction techniques or processes different from those applied to hardware during the microbial reduction of the entire spacecraft are proposed for use.

b. Each unique microbial reduction technique or process cycle shall be described in a process specification in the Microbial Reduction Plan that provides documentation regarding the biological qualification and quality assurance requirements applicable to the process.

c. The microbial reduction process specification to be used on an individual item of hardware shall be cited in its detailed engineering specification, as an applicable document.

d. The unique microbial reduction techniques or process cycles employed shall not degrade the ability of the spacecraft to withstand the standard "dry heat" or other approved process cycles to be applied to the entire spacecraft.

3.4.2 Following the successful application of a microbial reduction process, appropriate measures shall be taken to prevent recontamination. Preplanned operations involving the use of microbial barriers after microbial reduction processes have been conducted may be proposed as part of the Planetary Protection Plan or Subsidiary Plans. If the use of microbial barriers is proposed, the appropriate plan shall describe the operation and qualification of both the hardware and techniques to be used. Specific constraints applicable to the design and operation of spacecraft microbial barriers are given in the appropriate Specification Sheets (Appendix D).

3.4.3 The specification of basic microbial reduction parameters shall be made in one or more of the Microbial Reduction Plan, Parameter Specification Sheets, or contractor-prepared documents submitted for approval. Approval of these documents by the PPO constitutes approval of the parameters specified therein.

3.4.4 In no case shall basic parameters of microbial reduction processes (e.g., temperature, radiation type, etc.) be made binding in contractual instruments or governing project documents without documented approval of these parameters by the PPO.

3.4.5 Microbial Reduction Calculations shall be performed according to the following procedures: Calculations involving the death rates of populations of microorganisms subjected to sterilizing conditions shall be based on a death rate model (kill curve) approved by the PPO. Parameter values, other than those specified in applicable Parameter Specification Sheet, that are used in calculating microbial reduction process cycles shall be supported by data from reproducible laboratory tests or by suitable technical references. A calculation of the microbial reduction produced by a given process shall demonstrate that the predicted number of microorganisms surviving the process does not exceed the acceptable value given in the "Pre-Launch Planetary Protection Report." For microbial reduction process cycles that use transient lethality effects, the value of parameter used to begin lethality calculations shall be as stated in the appropriate Parameter Specification Sheet or approved documentation. The minimum steady-state value of the parameter used for a microbial reduction treatment cycle shall not be less than that specified in either the approved Microbial Reduction Plan or in a Parameter Specification Sheet.

3.4.6 Verification that a spacecraft has undergone the required degree of microbial reduction shall be provided to the PPO. Microbiological assay of the interior of the spacecraft subsequent to the application of the microbial reduction process may be avoided by providing documentation of the following constraints:

a. Approved microbial reduction processes were used.

b. The microbial burden of the spacecraft prior to the application of the microbial reduction process has been measured or estimated (by a means acceptable to the PPO) to be within limits that will allow the planned microbial reduction process to be adequate.

c. The specified microbial reduction process parameters, such as time, atmospheric composition (including water vapor), and temperature, have been properly imposed on the spacecraft hardware.

3.5 Launch and Post-Launch Operations (PP Categories III-V)

3.5.1 As a part of launch operations, the PPO shall verify that planetary protection requirements have been met and that the mission may be launched. Prior to final launch approval, the PPO shall provide, to the SMD AA, a letter certifying that the project has complied with planetary protection requirements. To assure that planetary protection requirements are met throughout launch operations and until the spacecraft leaves the atmosphere, the PPO (or designated representative) shall be present at the launch site during launch operations. To provide a basis for verification of planetary protection compliance, the project shall make available, to the PPO, pertinent information and documentation generated since the Pre-Launch Planetary Protection Review and the Launch Readiness Review, as well as real-time information relevant to planetary protection aspects of launch operations.

3.5.2 Changes from the original mission plan that become necessary as a result of postlaunch anomalies shall be approved by the PPO before implementation if such changes potentially could affect compliance with planetary protection requirements (also see section 2.6)

| TOC | Preface | Chapter1 | Chapter2 | Chapter3 | Chapter4 | Chapter5 | AppdendixA | AppendixB | AppendixC | AppendixD | ALL |
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