Strategic Priority Program on Space Science III

The Space Weather Service for Chinese Space Science Satellites

Liu Siqing, Luo Bingxian, Zhong Qiuzhen, Gong Jiancun, Shi Liqin, Chen Dong, Miao Juan, Cai Yanxia

National Space Science Center, Chinese Academy of Sciences Outline

• Space environment service begun in 1960s in China, undertaken by scientists led by Mr. Chao Jiuzhang of the former director of NSSC. • They calculated the energetic particle environment of radiation belt for the first China space mission – DongFangHong 1. • In 1970s, a book called “Manual of Space Environment for Satellites” written by them was published. I. History

• Later on, to support China space programs, especially the China Manned Space program, Space Environment Prediction Center was established in 1992 in NSSC. • The first generation of operational space environment system and forecaster team was ready in 1998,  7days/week, and we started to issue space  365days/year environment predictions via the public internet, as well as tailored http://www.sepc.ac.cn services for China Manned Space Missions. China Manned Space missions Tianzhou I Apr 20, 2017 Shenzhou Ⅰ Tiangong Ⅱ ; Shenzhou Ⅺ Nov 20, 1999 Sep 15, 2016 Oct 17,2016

Shenzhou Ⅱ Shenzhou Ⅹ Jan 10 , 2001 June 11, 2013

Shenzhou Ⅲ Shenzhou Ⅸ Mar 25, 2002 June 16, 2012

Tiangong Ⅰ Shenzhou Ⅳ Sep 29, 2011 Dec 30, 2002 Shenzhou Ⅵ Shenzhou Ⅷ Oct 12, 2005 Nov 1, 2011

Shenzou Ⅴ Shenzhou Ⅶ Oct 15, 2003 Sep 25, 2008

Since then, SEPC acted as one subsystem of the space application system, and supplied space weather service in each step of the China Manned Space missions. Outline

Hard X-ray Modulation Quantum Experiments Telescope (HXMT) at Space Scale (QUESS)

Shijian X Dark Matter

2017-6-15 2016-8-16 2016-4-6 2015-12-17

11 Jan. 2011, Priority Program on Space Science was approved and initiated by CAS. From 2015 to 2017, four missions were implemented: Dark Matter Particle Explorer, Shijian-10, Quantum Experiments at Space Scale, and Hard X-ray Modulation Telescope. Space weather service requirements

 As you may see on the graph, the missions were carried out during the declining phase of solar cycle 24, when solar activity has been at the lowest level in the space era.  However, space environment effects can not be neglected, due to permanent radiations in the space, as well as occasional severe solar eruptions. Space weather service requirements

Polar region

SAA

Radiation hazard in space  South Atlantic Anomaly: all satellites move in orbit height of several hundred kilometers, and will pass through the SAA periodically.  Solar proton events: when SEP events occur, Polar orbital satellites (DAMP and QUESS) will encounter enhanced solar protons. Outline

I. History of Space Weather Services in China II. CAS Strategic Priority Program on Space Science III. Space Weather Service for CAS Strategic Priority Program IV. Future Chinese Space Science Satellites plans In general, space environment services for CAS strategic Priority Program cover each stage of every mission, including Design phase, launch, on-orbit experiment.

Provided the space radiation In order to avoid the impact of major Provided space radiation environment prediction for space environmental events in 2017, impact support for orbital control strategy of the dark provided space environment adjustment of Quantum matter satellite Hard X-ray information support for satellite Experiment Satellite satellite passing through the control and program development SAA.

Design phase Launch On-Orbit experiment

Orbit Design Launch Windows selection; Control Strategy; Radiation Protection Basis for Confirmation. Hazard Avoidance; Fault Diagnosis. Design phase

(1) Orbit Design Evaluation

• For satellites in LEO, we provided orbital decay estimation under different space environment conditions (e.g., Shijian-10). Solar and Orbital Orbital decay rate (km/3 h) geomagnetic inclination conditions 350 km 250 km 0° 0.134 1.985 Ap=10 45° 0.148 2.314 F =70 10.7 90° 0.171 2.856 0° 0.653 4.855 Ap=48 45° 0.715 5.557 F =150 10.7 90° 0.833 6.828 0° 2.861 11.980 Ap=300 45° 3.117 13.001 F =260 10.7 90° 3.877 16.830 Design phase

(2) Radiation Protection

• For the Quantum Experiments at Space Scale (QUESS), the key payload of QUESS, Single Photon Avalanche Diode, is sensitive to proton irradiation and requires special protective measures. Design phase

(2) Radiation Protection

• We carried out high-energy proton environment analysis for different orbit altitudes and evaluated the cumulative proton fluence during the mission life. We also evaluated the shielding abilities under different thicknesses, and calculated the transmitting proton spectrum as well as the proton-induced displacement damage effect for different shielding materials. These analyses helped to build an important basis for the final orbit altitude adjustment.

Accumulated proton fluence of Comparison of shielded proton flux in radiation belt in different altitude orbits 500km orbit Launch

(1) Launch window environmental evaluation

• Provided safety period forecast and possible impact analyses for the launch windows 1 year, 6 months, 1 month, and finally 3 days in advance.  solar activity  geomagnetic activity  high-energy radiation, etc On-orbit operation

(1) Control Strategy

• Dark Matter satellite and the Hard X-ray satellite, carrying radiation-sensitive devices, need to take some special mitigation operations (closing the lens protective cover) when encountering severe radiation.

• SEPC provided SAA contours, daily proton and electron energy spectra along the orbit, and hazardous areas during proton events, to help ensure the safety of sensitive devices. On-orbit operation

(2) Hazard Avoidance Routine services  Daily space weather forecast  Developed a real-time  Solar index mid-term forecast satellite orbital radiation  Geomagnetic index mid-term forecast environment calculation  Space environment effect analysis and 3D visualization system. On-orbit operation

(2) Hazard Avoidance Chinese Ghost Festival solar storm  Space weather events warning

Solar active region AR2673 SDO AIA 0193 image(X9.3 flare)

• 27 M-class and four X-class flares and releasing several powerful Coronal Mass Ejections (CMEs) • Two solar proton events with > 10MeV solar proton flux peaked at 1490PFU measured by GOES 15 satellite • Geomagnetic storm On-orbit operation

(2) Hazard Avoidance Chinese Ghost Festival solar storm

• SEPC timely issued space weather alarms, nowcasts and forecasts through the web, Email, SMS, microblog, Wechat and App for the event. On-orbit operation

(2) Hazard Avoidance Chinese Ghost Festival solar storm

GOES 13 solar proton fluxes at energies >1 MeV, >5 MeV, >10 MeV, >30 MeV, >50 MeV and >100 MeV

The proton fluxes of different channels possess an enhancement during the secondary solar proton event.

Events Start time Peak Intensity End time 1 2017.9.5 00:40 844PFU 2017.9.9 00:05 2 2017.9.10 11:45 1490PFU 2017.9.14 17:25 On-orbit operation

(2) Hazard Avoidance Chinese Ghost Festival solar storm Impacts Analysis for the Satellites The proton fluxes for Quantum Experiments at Space Scale and Dark Matter Particle Explore satellites increased significantly in the polar regions. For the Hard X-ray Modulation Telescope the orbital proton fluxes increased only in the vicinity of the magnetic poles due to the low inclination angle of 43°

>10 MeV protons in orbit of Dark Solar proton arrival area in the Hard Matter satellite (Sept. 11, 2017) X-ray satellite orbits under Kp=8. On-orbit operation

(2) Hazard Avoidance Chinese Ghost Festival solar storm Impacts Analysis for the Satellites

The entire spectrum during the CGF solar storm was higher than that in SAA central region, and lower than that of the SPE occurred on January 20th, 2005. The solar proton flux at energies >200MeV of the CGF solar storm was higher than that of the SPE occurred on October 28th, 2003 . Integral spectra at 500km altitude On-orbit operation

(2) Hazard Avoidance Chinese Ghost Festival solar storm

Reactions of satellite operations to the solar storm

• The TT&C (Telemetry, tracking, and command) team increased the tracking number to monitor the space science satellites. • Quantum Experiments at Space Scale satellite suspended scientific experiments, and the experiment control payload was shut down. • Hard X-ray Modulation Telescope was also shut down. • The two satellites returned to normal operation on September 13, 2017. On-orbit operation

(3) Anomaly diagnosis • Occasional anomalies of onboard equipment : star-sensitive resets, on-board large-capacity memory abnormalities, and hardware CPU resets • Analyzed the state of the space environment at the time of the anomaly and provided support for further anomaly diagnosis.

Soft errors detected by EDAC on satellite Outline

Advanced Space-based Solar Einstein Probe (EP) Observatory (ASO-S)

Gravitational Wave High-energy ESA-CAS Solar Wind Magnetosphere Electromagnetic Counterpart All-sky Ionosphere Link Explorer (SMILE) Monitor (GECAM) IV. CAS Strategic Priority Program – Phase II

These space science satellites may experience the peak phase of solar cycle 25. SEPC will continue to monitor the space weather 24 hours per day, providing space weather forecasts, environment analysis, and feasible mitigation strategies for Chinese space missions. Thanks for your attention！