1. Planetary Protection Category V Restricted Earth Return
Non-Case Study
Planetary Protection Category V
Restricted Earth Return
Presented by Dr. Gerhard Kminek, COSPAR

2. Table of Content
Planetary protection category V, restr. Earth return description
Driving requirements
Probabilistic risk assessment
Failure tolerance
Sample safety assessment
Things to remember

3. Category V, restricted Earth return
Sample return from solar system bodies deemed by scientific opinion to have the potential for indigenous life forms
Credit: ESA/Mars Express
Credit: NASA/JPL/Galileo
Credit: NASA/JPL/Cassini
The concern is the possibility that a putative martian organism inadvertently released from containment could produce large-scale negative pathogenic effects in humans, or could have a destructive impact on Earth’s ecological systems or environments (NRC, 2009)
The potential risks of large-scale effects arising from the intentional return of martian materials to Earth are primarily those associated with replicating biological entities
The potential for large-scale negative effects on Earth’s inhabitants or environments by a returned martian life form appears to be low, but is not demonstrably zero
Consistent advice from various scientific advisory bodies (NRC 1997, NRC 2009, ESF 2012)
Samples returned from Mars should be contained and treated as though potentially hazardous
No uncontained martian materials, including spacecraft surfaces that have been exposed to the martian environment, should be returned to the Earth-Moon system unless sterilized
Ensure independent oversight, including regulatory authorities

4. Campaign outline

5. Driving requirements WORK
Use of the Best Available Technique (BAT) optimisation concept as a benchmark and adapted to the specificities of an MSR mission in order to guarantee that the probability of an unintended release and also the magnitude of this release is minimised
Optimisation approach aimed at limiting the release of pollutants into the environment
Use science, technology and economics to optimise protection of people & environment
Focused on methods that will eliminate or reduce the input of hazardous waste into the environment rather than determining its assimilative capacity's
Recommendations
The probability that a single unsterilized particle of 0.01 μm diameter or greater is released into the Earth’s environment shall be less than 1x10-6
If the size requirement cannot be met without decreasing the overall level of assurance, a size limit of 0.05 μm can be considered
The release of a single unsterilized particle larger than 0,05 μm is not acceptable under any circumstance
The Best Available Technique (BAT) optimization concept provides a framework for the overall approach to protect the terrestrial biosphere
It is planned to use the size limit of 0.5 m, pending additional review result (see later)
The probability value will be evaluated during the system engineering activities
WORK
IN PROGRESS

6. Probabilistic Risk Assessment (PRA)
Safety (planetary protection) requirement is stated in probabilistic terms “…probability shall be less than…”
Verification of probabilistic requirement using a PRA at system level
“A PRA is a structured, logical analysis methodology that is used for identifying and assessing risks in a variety of applications including complex technological systems. In general, a PRA provides a modelling framework that interfaces with or includes the various disciplines used to conduct health, safety, and mission assurance analyses including hazard analysis, failure mode and effects analysis, and reliability analysis. A PRA draws upon the relevant collection of qualitative and quantitative information and models that are developed as part of design and assurance activities.” NPR

7. Failure tolerance WORK
European space safety standard requires two failure tolerance against generating catastrophic effects (loss of life or sever detrimental environmental effects)
In line with US NRC-SSB and ESF-ESSC recommendations, uncontrolled release of unsterilized material from Mars is treated as potential hazardous not because of expected consequences but as precautionary approach due to the large number of uncertainties
Applicable only to safety critical functions that could lead to an uncontrolled release
Affected systems: Flight containment system, Earth return orbiter, Earth entry vehicle, safety critical software, safety critical flight operations
MPCV approach but with 2 FT to start with because the consequences affect risk to the public and not occupational risk
ISS
MPCV†
MSR (TBC)
Failure tolerance
2 FT
1 FT
Probabilistic limit NA
LOC
CNA
WORK
IN PROGRESS
Using this approach would allow to reduce levels of FT for some functions as long as the probabilistic requirement is still met, there is knowledge about the redundancy level, and a chance to stop (avoid Earth impact)
†FT level can be reduced for certain functions as long as the probabilistic requirement is met; this approach requires knowledge (monitoring) of the redundancy level and the chance to stop (i.e. mission phase abort)

8. Sample safety assessment
Post-mission, there is a need to conduct timely analyses of any unsterilized sample collected and returned to Earth, under strict containment, and using the most sensitive techniques
A Planetary Protection Protocol should be produced as soon as it is feasible by an international working group under the authority of COSPAR or other international body
COSPAR is acting on this recommendation in setting up an international working group to formulate a sample safety assessment protocol (SSAP)
Starting point: Draft test protocol (2001)
Input from life detection conference and workshop reports:
Employing a hypothesis driven approach
The same types of scientific measurements would inform the science and planetary protection elements
A Planetary Protection Test Protocol should be data driven, i.e., responsive to the measurements
A clear decision making framework, with well identified decision points is necessary

9. Things to remember Requirements not fully consolidated yet
Probabilistic risk assessment will play an important role in the mission and spacecraft design
Failure tolerance, more similar to human spaceflight, will have an impact on hardware and software qualification
Space agencies will not have the authority to decide what is good enough and what is not
All activities necessary to perform the PRA are interdisciplinary and require the interactions between different engineering disciplines from the very begin!