Planetary Protection: Technology Development and Prospects for Space Exploration

1. Technology Development and Prospects of Planetary Protection PENG Jing, CAST, China Oct. 2018, Beijing

2. Contents • Requirements and understanding of Planetary Protection • Current status of Planetary Protection in China • Prospects of Planetary Protection technology in the future

3. Requirements and understanding of PP One of the ultimate goals of space exploration is to answer the question of the origin of life on Earth and the existence of life on other celestial bodies. So the space exploration shall follow the rules including: • To prevent the Earth`s life forms from polluting other celestial bodies. (Forward Contamination) • Avoid the biological samples polluting Earth and its biosphere. (Backward Contamination) Forward Back

4. Requirements and understanding of PP Planetary Protection Mission Categories (COSPAR, 2017)

5. Requirements and understanding of PP Category IV missions to Mars are subdivided into IVa, IVb, and IVc. • Category IVa missions—those not carrying instruments designed to investigate extant martian life—are restricted to a surface bioburden of ≤300,000 spores, and an average of ≤300 spores/m2. • Category IVb missions—those carrying instruments designed to investigate extant martian life—restricted to a surface bioburden of ≤30 spores. • Category IVc missions—if the landing site is within the special region, the entire landed system is restricted to a surface bioburden level of ≤30 spores.

6. Requirements and understanding of PP • PP is necessary to ensure the success of an extraterrestrial space mission, inherent requirements of the mandate itself. To some extent, PP enhances the reliability of the extraterrestrial space mission. • PP shall be considered from the very beginning of mission proposal, and appropriate measures shall be taken during development, launch and operation after launch in order to ensure its effectiveness. • The requirements of PP shall be consistent with the international policies published by the COSPAR.

7. Requirements and understanding of PP Good practice in past Mars exploration: • DHMR: Viking, MSL, MER • Hydrogen peroxide vapor: Phoenix,MSL • Others: Restriction of RPS, nuclear source • Mars Special regions: water or ice under the soil, subsurface

8. Current status of PP in China Implementation of China`s deep space exploration missions

9. Current status of PP in China Ongoing China’s lunar exploration: • In the 3rd phase of Chinese Lunar Exploration Program, the robotic lunar sample and return spacecraft – CE-5 will be launched in 2019. • As a category V unrestricted return mission defined in COSPAR PP policy, the samplers, drill, sealing devices onboard CE-5 spacecraft which will contact with lunar samples will be cleaned and recorded before shipping to launch center and integrated with launch vehicle, in order to ensure that the returned samples are consistent with the original status. • After return, the lunar samples with sealing devices will be carefully protected and dealt within a special device which is isolated from Earth air.

10. Current status of PP in China Ongoing China`s Mars Exploration Mission: For China’s first Mars mission, the corresponding requirements for PP shall be determined, in order to prevent forward contamination to Mars. The ongoing PP implementation includes following aspects: • Make a series of PP strategies for the spacecraft; • Train workers for PP requirements and implementation; • Detect microbes on the spacecraft and sterilize.

11. Current status of PP in China Make a series of PP strategies for the spacecraft: • Analyze the characteristics of the mission profile; • Classified the mission type and PP requirements; • Determine the methods of detection and sterilization; • Define the timing of PP implementation.

12. Current status of PP in China Train workers for PP requirements and implementation: • Choose the proper time to train the workers, responsible for AIT of the spacecraft. • It requires strengthening the personal hygiene of the workers before entering the AIT facility and operate on the spacecraft hardware, such as washing hands. • In addition, all the worker’s suits, caps and shoes shall be disinfected regularly, and the clothes needs unified management.

13. Current status of PP in China Detect microbes on the spacecraft and sterilize • Bioburden assessment: AIT environment, workers, parachutes, wheels, etc. • Sterilization: wiping by disinfectants, radiation for textile, dry heat for some key parts.

14. Prospects of PP technology in the future

15. Prospects of PP technology in the future The key technologies for future PP technology development: • Develop a broader range of sterilization methods • Establish the database of aerospace material properties • Adopt aseptic assembly procedure • Contamination control of transportation • Contamination control after Launching • Contamination control of sample after returning

16. Prospects of PP technology in the future Develop a broader range of sterilization methods: • Disinfecting: Develop new type of disinfectants to kill extremophiles. Regular wiping of spacecraft to lower the bioburden. • Radiation method: Apply for textile, e.g. the parachute. • Hydrogen peroxide vapor: High sterilization efficiency, wide scope of application, high safety, validated on spacecraft. • Others:Plasma sterilization technology.

17. Prospects of PP technology in the future Establish the database of aerospace material properties: • It is possible to make statistics on the sterilization methods that suitable to different material. Then materials with same sterilization methods can be selected as far as possible during design, which can reduce the repetition of the process. • It is possible to select the anti-bacterial and anti-mold material, which can lower the bioburden level to a large extent.

18. Prospects of PP technology in the future Adopt aseptic assembly procedure: • Parts and products shall be sterilized by specific methods, and the processed parts shall be preserved aseptically before general assembly. The package shall be open in the high cleanliness environment. • The workers shall strictly control the contamination of themselves. Make a standard operation protocol of the clean assembly, and conduct periodic training and supervision of the assembly to ensure the implementary effects. • The spacecraft shall be assessed regularly and the results shall be archived.

19. Prospects of PP technology in the future Contamination control of transportation: • The package case needs to be designed sealed, to maintain the positive pressure inside, so that it can prevent the air outside entering the case. • Before putting the spacecraft in, the package case shall be cleaned at first, and then pump into the high cleanliness gas. During the transportation, the case is forbidden to be open without permission. • After transportation, the package shall be stored in ISO-8 Level environment.

20. Prospects of PP technology in the future Contamination control after Launching: • Before launching ,the important sampler and the lander shall be treated aseptically, and the outer layer shall be covered with a bio-shield. After the spacecraft separation with launch vehicle in space, the bio-shield can be discarded. • Carefully designed trajectory can avoid unexpected impact on celestial bodies. • UV radiation may help to lower bioburden to some extent on surface after landing. • Strict restrictions on dumping waste on the surface of the planet.

21. Prospects of PP technology in the future Contamination control of sample after returning: • To avoid the release of the space substance to Earth’s biosphere, the return sample must be sealed before dealt with. • The sample which is brought back shall be carefully disposed. It shall be put in a sealed box, and then transport to the highest bio-safety class laboratory-class 4. The sample shall be totally disposed after the analysis in order to avoid some severe consequences.

22. Prospects of PP technology in the future Future consensus of PP: • As an international responsibility, every space actor in the world shall strictly follow and keep compliance with COSPAR PP policy. • Only three planetary bodies are paid higher attention as Category III and IV to date. The COPSAR PP policy shall be updated with the latest knowledge about life in space beyond Earth. • Along with robotic deep space mission, future human mission in deep space will require more research and development on manned mission PP. • More new technologies would be applied be the PP, which can make the PP much more easier and efficient.

23. Thanks for your attention!