6th IAASS International Space Safety Conference Proposal of New Triggered Lightning Launch Commit Criteria for Japan's safety rocket launch Japan Aerospace Exploration Agency (JAXA) Space Transportation Mission Directorate Y.Saito, T. Saito and K.Okita 1
Outline Motivation -Triggered lightning risk -Modern rule and suspension rate Research scenario Organization Observation campaign Analytical results Proposal of New criteria Summary 2
Motivation 1 : Triggered lightning and safety rocket launch What is triggered lightning? -Caused by concentrated E-field with rocket and plume -Happen at the E-field which don t cause the natural lightning 3000kV/m 500kV/m A few hundred times The incidents Apollo12 @ 1969 Nov Atlas Centaur67 @ 1987 Mar Change the computer and could continue Command Destruct To avoid it is very important for safety launch
Motivation 2 : Modern criteria and and suspension rate(1/2) Wind Thick -surface / aloft Cloud Precipitation Rule Lightning -natural / triggered Temperature Cloud base height Earthquake wave height etc. Temperature -20 Thickness over 1800 m 0 No go Go No go Fig. 3 Thick Cloud Rule to prevent triggered lightning Go Do not fly through a non-transparent cloud layer that is thicker than 1.8 km and contains temperatures between 0 and -20 degrees Celsius. (Thick Cloud Rule of Lightning Launch Commit Criteria (LLCC) ) 4
Motivation 2 : Modern criteria and and suspension rate(2/2) Suspension rate: 60% over 70 % in winter Only by Thick Cloud Rule There are strong demands for increasing launch opportunities by improving Thick Cloud Rule while enhancing safety. Before roll out After filling of the fuel Before roll out Before roll out Before roll out Winter Dec. to Feb. F11 F12 F14 F15 F16 After filling of the fuel BF2 F20 Summer Spring Autumn F10 Lightning F13 Typhoon BF1 F17 F18 F19 Typhoon F21 BF3 2006 2007 2008 2009 2010 2011 2012 Fig.4 Launch record in recent 15 launches in 7 years
Research scenario (1/3) Temperature -20 0 Thickness over 1800 m Thickness of cloud layers and temperature Research started based on the idea,,, [Even if a cloud layer violates current regulation, if there were no process of electric charge inside, a launch vehicle can fly through.] We need to evaluate clouds not by thickness but by following parameters. Particle spatial density, Convection, Particle charge, Electric field. Process of Lightning Emergence of Particle Generation of electric charge Evolution of the electric field Ice crystal D=0.02~0.2mm Convection + + + + Updraft + + ++ + + E V/m Graupel D=2mm~ Ground + + + + + + + Downward 6
Research scenario (2/3) -Acquire the necessary data, analyze the correlation with the triggered lightning risk (3kV/m) and development of the technique to forecast simulation -Based on the process of electrification inside cloud, achieve the appropriate criteria and operation matched to each time frame. Rocket launch judgement Launch to 2 days:inform related party Launch to 1 day:go/nogo Launch to 12h:Vehcle move Launch to 6h:Load fuel Compliance New criteria image Criteria of a few hour to launch Numerical prediction and.. -Weather and Cloud pattern -Updraft Inference Triggered lightning risk ABFM 3kV/m * Updraft 5m/s(TBD) Graupel number1/l(tbd) *)Agreed value in NASA relevant, with few analysis and experiment data and Russian paper Launch to 1 hour:go/nogo Compliance Criteria at launch Step1 Step2 霰氷晶例 : 直径 2mm~ 例 : 直径 0.02~0.2mm Concentration of E-field with rocket and plume Estimation Launch to 0.25 hour:go/nogo Estimate cloud water and ice Reflectivity: dbz km Estimate Graupel number density Dual polarization parameter Launch Ground field: kv/m 7
Research scenario (3/3) FY 2011 FY 2012 FY 2013 Weather rules and operation Current / Amended Mile stone Intensive observation 1. Airplane observation Modification Modification Modification Observation Observation Observation 2. Videosonde observation Observation Observation Observation 3. X-band Doppler radar Tuning Observation Tuning Observation Observation 4. Filed mill Observation (through a year) 5. Data analysis 8
Organization R & D center for launch vehicle Tanegashima Space Range Task Force Advisory Panel for Lightning Research (JAXA) M.ISHII (Chairman), Y.FUJIYOSHI, Z.KAWASAKI, K.MICHIMOTO, T.TAKAHASHI, T.USHIO Dr. James Dye(LAP) Dr. Rich Blakeslee Dr. Hugh Christian and his group. 9
OBSERVATION CAMPAIGN@ Tanegashima Space Range Types of particles Degree of convection Particle spatial density Types of particles Particle charge Electric field intensity 6 Airborne field mills UAH/NASA X-band Radar Videosonde 20 launches in 3 weeks Airplane 7 flights in 3 weeks 4 Field mills Process of Lightning Emergence of Particle Generation of electric charge Evolution of the electric field Ice crystal D=0.02~0.2mm Convection + + + + Updraft + + ++ + + E V/m Graupel D=2mm~ Ground + + + + + + + Downward 10
Electric Field [kv/m] Analytical results (1/4) The modern criteria Thick cloud rule was evaluated with the relation of 3kV/m as safety level of E-field threshold. The thickness of cloud has no relation with the triggered lightning risk, which is electric field That means there is the necessity to update the criteria. 100 Relation to be assumed at modern criteria Ground Filed mill (Takesaki) Airborn Field mill data 10 Triggered lightning guide:3kv/m 1 Thickness 1.8km (Modern) 0.1 Value of Fine day 0 1 2 3 4 5 6 7 8 9 10 Obs. Cloud Depth * [km] Every cloud depth contains temperatures between 0 and -20 *)IR Cloud Top - Ceilo meter 11
Analytical results (2/4) For 2 days or 12 hours before launch. Numerical forecast based criteria. -SSI and Updraft Stationary front and winter monsoon was separated into two area. Winter monsoon Cloud thickness < 3km Ground E-field < 3kv/m Stationary front Cloud thickness > 3km Ground E-field > 3kv/m E-Field We may say Go. even if the thickness exceeds 1.8 km Fig.8 SSI vs. Updraft 12 12
Winter monsoon pattern Front pattern High pressure Low pressure front with low pressure
Analytical results (3/4) For 2 days or 12 hours before launch. -In case of 15hrs, we could confirm the possibility to forecast with MesoScale Model of JMA (Japan Metrological Agency). -This is a sample of stability parameter SSI -To develop two days forecast, we have to update the model of simulation 14
Analytical results (4/4) Volume averaged For 1 hour before launch. Height Integrated Remote sensing based criteria. Radar Reflectivity -VAHIRR :Radar reflectivity (indication for airborne E-field ) @NASA When VAHIRR is under 20, E- field will never exceed 3 kv/m, then regardless of thickness of clouds. We may say GO! Fig.9 VAHIRR VAHIRR < 20 never exceeds 3kV/m E-Field [kv/m]
(Side view of left figure) 1km 11km 11km Average of11km 11km 1km region EchoR(t) Cloud thickness h at airplane location (Radar echo>0dbz) = VAHIRR (How to count the cloud thickness) 1. From airplane location, altitude±1km ±2km make evaluate point +2km 2. For each evaluate point if 1km region 0dBZ<Radar echo, we judge as cloud regrion +1km 1km 航空機高度 -1km -2km :t-5 分 ~t+5 分 10minutes Radar echo data :In above data, Radar echo <0dBZ data 3. Length to altitude direction of evaluate point, which includecloud, is cloud thickness
PROPOSAL OF NEW LIGHTNING LAUNCH COMMIT CRITERIA Temperature Thickness over 1800 m Go -20 No go 0 No go Go Don t fly on the following situations -A few hour to launch: Updraft<-6Pa/s and SSI<10 -At launch: VAHIRR(Radar) > +20dBZ km -At launch: Ground E-field > 3kV/m 17
Summary To keep safety of a flight, Go / No Go decisions are determined under certain weather rules. Delay of launch due to Thick Cloud Rule has been about over 70% in winter season. To increase launch opportunities, at the same time enhancing launch safety, research activity for triggered lightning initiated since 2011. The approach of this research is to investigate applicable parameter and their threshold for triggered lightning based on particular process of atmospheric electrification. In this year -Verify the New criteria -Begin to operate it 18
THANK YOU!!! 19 19
(a) (a) (b) (b) Ice (c) Each operation was done by Diamond air service (DAS) under the contract of JAXA A gap between height of 0 deg. C observed by aircraft and sonde. (c) LP Fig. Picture of ice on wings. Observed in the flight for H-IIA/F12 in 2007 20
<L-2 days : 2 days notice for relevant agencies and organizations> Since JAXA have to declare the launch date and the time at least 2 days before the launch, we have main decision point in the morning on L-2 days. Numerical forecast of thick cloud is a major source of concern. In this prediction, we estimate temperature and cloud thickness just above the pad. Thickness of cloud is calculated with the expression of (T - Td) < 3, where T is temperature and Td is dew-point temperature. Area of (T - Td) < 3-20 deg -0 deg Fig. Example of GPV numerical prediction for thick cloud above the launch pad. 21
Model Cloud Depth [km] 10 9 8 7 6 5 4 3 2 1 0 Every cloud depth contains temperatures between 0 and -20 Y=X+0.6 0.6 8 7 9 10 11 2 1 15 12 13 14 3 4 Hyvis2 6 19 5 20 16 17 18 Hyvis1 Regression line (Y=0.72X+0.82) R 2 =0.87 Reliability limit area [Y-X] -Probability = 95% - 0.60±0.58 0 1 2 3 4 5 6 7 8 9 10 Obs. Cloud Depth * [km] *)IR Cloud Top - Ceilo
JAXA Organization and Resources 23
Space Centers and offices Liaison offices 24
Table 1 Overview of Lightning Launch Commit Criteria (LLCC) No. Criteria 1 Do not launch if there is any type of lightning or any cloud which produced it within 10 km from launch pad. 2 Do not launch within 20 km of any type of lightning in the past 30 minutes. 3 Do not fly through a) within 20 km of any type of lightning, cumulonimbus cloud and anvil cloud. b) a non-transparent cloud layer that is thicker than 1.8 km and contains temperatures between 0 degrees Celsius and -20 degrees Celsius. c) cold weather front with cloud whose top is over 3 km or squall line. 4 Do not launch if any electric field mill shows 2kv/m or over in the past 15 minutes.