Example Solar Proton Event Data

Example Solar Proton Event Data NASA JSC August 30, 2006

Times of Occurrence of Large SPE s GCR Deceleration Potential 1800 1600 1400 1200 Φ, MV 1000 800 600 400 200 + + + + - - - 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020 Year F(>30 MeV), Protons/cm 2 10 10 F>10 8 solar proton events only 10 9 10 8 1/1/1950 1/1/1960 1/1/1970 1/1/1980 1/1/1990 1/1/2000 1/1/2010 1/1/2020 Modern Era (1956-2005) Recent Era (1550-2000) McKracken et al.

Projections of Cycles and Mean Occurrence Frequency of SPE 200 Cycle 23 Cycle 24 14 Sunspot number 180 160 140 120 100 80 Population distribution level, percent 90 70 50 30 Measured sunspot number Smoothed sunspot number Projected smoothed sunspot number at level, percent 80 75 70 <ν(t)> : Φ 30 >=10 5 Φ 30 >=10 6 12 10 8 6 <ν(t)>, Events/year 60 10 4 40 2 20 0 1996 2001 2006 2011 2016 Year 0

Large Solar Proton Events during Solar Cycles 19-23 with Φ 30 > 10 9 protons/cm 2 Cycle Onset Time Φ 30, protons/cm 2 Time to Peak Flux, hr Comment 19 11/12/1960 9.00 x 10 9 14 (a), note 1 20 8/2/1972 5.00 x 10 9 69 (a) 22 10/19/1989 13:05 4.23 x 10 9 26.9 (b) 23 7/14/2000 10:45 3.74 x 10 9 25.8 (b) 23 10/26/2003 18:25 3.25 x 10 9 4.2 (b), note 2 23 11/4/2001 17:05 2.92 x 10 9 33.2 (b) 19 7/10/1959 2.30 x 10 9 note 3 (a) 23 11/8/2000 23:50 2.27 x 10 9 16.1 (b) 22 3/23/1991 8:20 1.74 x 10 9 19.5 (b) 22 8/12/1989 16:00 1.51 x 10 9 15.2 (b) 22 9/29/1989 12:05 1.35 x 10 9 14.1 (b) 23 1/16/2005 2:10 1.04 x 10 9 39.7 (b) 19 2/23/1956 1.00 x 10 9 note 4 (a) (a) Φ 30 for solar cycle 19-21: data taken from Shea and Smart. (b) Φ 30 for solar cycle 22 and 23: calculated using corrected 5-min average proton flux of GOES measurements. Note 1: There are large differences in the estimate of fluence in November 1960 SPE. Data given by others are significantly smaller than this value (1.3 x 109 protons/cm2 by Freier and Webber). Note 2: Φ 30 for the combined 3 major peaks occurred during 10/26-11/6/2003: 3.42 x 10 9 protons/cm 2. Note 3: one day later on July 11, 1959 Note 4: in the same day on February 23, 1956

1,000,000 Proton Integral Flux August 2-11, 1972 SPE 100,000 E > 10 MeV Flux, Protons/cm 2 -s 10,000 1,000 E > 30 MeV E > 60 MeV 100 10 0 50 100 150 200 250 Time, h

BFO Dose Rate August 2-11, 1972 SPE 1.E+02 1.E+01 Dose Rate, cgy-eq/h 1.E+00 1.E-01 1.E-02 1.E-03 AL(0) AL(1) AL(3) AL(5) AL(10) AL(15) AL(20) AL(30) 1 cgy/h 1.E-04 1.E-05 0 40 80 120 160 200 240 Time, hr

BFO Cumulative Dose August 2-11, 1972 SPE 1.E+03 1.E+02 Cumulative Dose Equivalent, csv 1.E+01 1.E+00 1.E-01 1.E-02 Current 30-day limit Al thickness, g/cm 2 : 0 1 3 5 10 15 20 30 1.E-03 0 40 80 120 160 200 240 Time, h

82 BFO Locations 32 location set 50 location set

August 1972 SPE (1 g/cm 2 Al shield) 500 BFO Dose Eq, cgy-eq 400 300 200 100 Marrow location, j Head and Neck Upper Torso Middle Torso Thighs Average 0 0 5 10 15 20 25 30 35 40 45 50 BFO Location

100000 Hourly-Averaged Proton Integral Flux during Oct 26 - Nov 6, 2003 SPE Flux, protons/cm 2 -s 10000 1000 100 10 E 30 MeV E 60 MeV E 100 MeV 1 0.1 0 50 100 150 200 250 300 Time, h

10 BFO Dose Rate during Oct 26 - Nov 6, 2003 SPE 1 1 rem/h 0.1 Dose Rate, csv/h 0.01 0.001 0.0001 0.00001 Al thickness, g/cm 2: 0 1 3 5 10 15 20 30 0.000001 0 50 100 150 200 250 300 Time, h

Hourly-Averaged Proton Integral Flux Oct 26 - Nov 6, 2003 SPE 100000 10000 Flux, protons/cm 2 -s 1000 100 10 E 30 MeV E 60 MeV E 100 MeV 1 0.1 0 50 100 150 200 250 300 Time, h

BFO Dose Rate October 26- November 6, 2003 SPE 10 1 1 cgy/h Dose Rate, cgy-eq/h 0.1 0.01 0.001 0.0001 0.00001 Al thickness, g/cm 2: 0 1 3 5 10 15 20 30 0.000001 0 50 100 150 200 250 300 Time, h

BFO Cumulative Dose October 26- November 6, 2003 SPE Cumulative Dose Equivalent, csv 1.E+02 1.E+01 1.E+00 1.E-01 1.E-02 1.E-03 Current 30-day limit AL(0) AL(1) AL(3) AL(5) AL(10) AL(15) AL(20) AL(30) 1.E-04 1.E-05 0 50 100 150 200 250 300 Time, h

Hourly-Averaged Proton Integral Flux January 16-22, 2005 SPE 1.E+05 1.E+04 E 10 MeV E 30 MeV E 60 MeV E > 100 MeV Flux, protons/cm 2 -s 1.E+03 1.E+02 1.E+01 1.E+00 1.E-01 0 20 40 60 80 100 120 140 160 180 Time, h

BFO Dose Rate January 16-22, 2005 SPE 1.E+01 1.E+00 1 cgy/h Dose Rate, cgy-eq/h 1.E-01 1.E-02 1.E-03 1.E-04 Al thickness, g/cm 2 0 1 3 5 10 15 20 30 1.E-05 0 20 40 60 80 100 120 140 160 180 Time, h

BFO Cumulative Dose January 16-22, 2005 SPE 1.E+02 Current 30-day limit 1.E+01 Cumulative Dose Equivalent, csv 1.E+00 1.E-01 1.E-02 1.E-03 AL(0) AL(1) AL(3) AL(5) AL(10) AL(15) AL(20) AL(30) 1.E-04 1.E-05 0 20 40 60 80 100 120 140 160 180 Time, h

Role of Dose-Rate and Shielding Shielding mitigates most SPE events High-energy component (>100 MeV) often poorly known Proton biological damage is dependent on dose-rate Effects increase above ~5 rad/hr EVA Today (Y/N?) IVA (time to storm shelter)

25 20 15 10 5 0 216 Particle Events (1976-2005) 0 1.5 3 4.5 6 7.5 9 12 13.5 15 10.5 16.5 18 19.5 21 22.5 24 25.5 27 28.5 30 31.5 33 34.5 36 37.5 39 40.5 42 43.5 45 46.5 Time to Max Proton Flux, hr 100.00% 90.00% 80.00% 70.00% 60.00% 50.00% 40.00% 30.00% 20.00% 10.00%.00% Frequency Cumulative % Frequency

Large SPE Integral Fluence Spectra at 1AU 1.E+12 1.E+11 1.E+10 Feb 1956 SPE Aug 1972 SPE Nov 1960 SPE Oct 2003 SPE Φ p(>e), protons/cm 2 1.E+09 1.E+08 1.E+07 1.E+06 1.E+05 1.E+04 1 10 100 1000 Kinetic energy, MeV

Big SPEs (Cycles 22-23) 1.00E+12 Φ (>E), cm -2 1.00E+10 1.00E+08 1.00E+06 1.00E+04 1.00E+02 1.00E+00 1.00E-02 1.00E-04 1.00E-06 10/19/1989 SPE 7/14/2000 SPE 9/29/1989 SPE 11/8/2000 SPE 10/26/2003 SPE 11/4/2001 SPE 1/16/2005 SPE 8/12/1989 SPE 10/30/1992 SPE 6/4/1991 SPE 9/24/2001 SPE 11/6/1997 SPE 6/14/1991 SPE 3/23/1991 SPE 4/21/2002 SPE 11/2/2003 SPE 11/22/2001 SPE 4/20/1998 SPE 11/30/1989 SPE 1.00E-08 1 10 100 1000 E, MeV/amu

From Nymik- COSPAR

The Average BFO Doses of the Regions at 6 DLOCs from 1972 SPE 140 120 100 BFO Dose, cgy-eq 80 60 Head & Neck Chest Abdomen Pelvis Thighs Lower Legs Arms 40 20 0 DLOC1 DLOC2 DLOC3 DLOC4 DLOC5 DLOC6

Was Carrington Event (1859) Lethal? 1859 event has largest F>30 Flux known 100 Blood Forming Organ Dose, cgy-eq 1 10 100 % Probability in 2-Week Missions 10 1 0.1 0.01 0.001 3 missions/year for 5-yr Program Single Mission Arctic ice-core data Modern data (1956-2005) Mission disruption-days lost? Increased fatal cancer risk and other late effects 30-day Dose Limit Violation 5% Prodromal Sickness 10 8 10 9 10 10 Proton Fluence >30 MeV per cm 2 5% Acute Lethality Uniform Dose Conditions under Apollo Spacecraft -type shielding Ice-Core data -F >30MeV flux from 1450-1990

Large SPE s

Long-Term Forecasting Climax Neutron Monitor and Deceleration Potential (Φ) 4400 2900 Climax Cosmic Ray Monthly Means 3900 3400 2900 Measured ClimaxNM Estimated Cli(DR75%) PHI(T) 3-month Ave PHI(T) 2400 1900 1400, MV 2400 900 1900 1953 1963 1973 1983 1993 2003 2013 400 Time

SPE Probability in 1-Week Mission and BFO Exposure Level inside a Typical Equipment Room in Free Space 1.E+00 1000 1.E-01 100 SPE/Mission 1.E-02 1.E-03 NCRP 30-day limit at BFO for LEO mission 10 BFO Dose, cgy-eq Average Probability of Space Era Extended Average Probability Impulsive Nitrate Events BFO Dose of Worst Case SPE Model BFO Dose of SPE during Space Era 1 1.E-04 1.E-05 0.1 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08 1.E+09 1.E+10 1.E+11 Size of Event (>Φ 30 )

Frequency of SPE Occurrence in 3-Month Periods Φ 30 > 10 8 protons/cm 2 for Solar Cycle 21. 8 Dec 1982 200 7 Apr 1981 Apr 1984 Frequency 6 5 4 3 2 Apr 1978 Feb 1978 Jan 1982 Sept 1978 Sept 1979 Oct 1981 150 100 50 Smoothed Monthly Sunspot Number Frequency Monthly sunspot number 1 3 12 21 30 39 48 57 66 75 84 93 0 Time from Solar Minimum, month 102 111 120 0

Frequency of SPE Occurrence in 3-Month Periods Φ 30 > 10 9 protons/cm 2 for Solar Cycle 22. 8 Aug 1989 Sept 1989 Oct 1989 200 7 Mar 1991 Frequency 6 5 4 3 2 150 100 50 Smoothed Monthly Sunspot Number Frequency Monthly sunspot number 1 3 12 21 30 39 48 57 66 75 84 93 0 Time from Solar Minimum, month 102 111 120 0

Frequency of SPE Occurrence in 3-Month Periods Φ 30 > 10 9 protons/cm 2 for Solar Cycle 23. 8 7 Jul 2000 Nov 2001 Nov 2000 200 Frequency 6 5 4 3 2 Oct 2003 Jan 2005 150 100 50 Smoothed Monthly Sunspot Number Frequency Monthly sunspot number 3 12 21 30 39 48 57 66 75 84 93 1 0 Time from Solar Minimum, month 102 111 120 0

GCR and SPE Dose: Materials & Tissue GCR higher energy >> secondary radiation No Tissue Shielding With Tissue Shielding Dose Equivalent, csv/yr 10000 1000 100 10 GCR Hydrogen GCR Polyethylene GCR Graphite GCR Aluminum GCR Regolith SPE Graphite SPE Regolith Dose Equivalent, csv/yr 1000 100 10 GCR Hydrogen GCR Polyethylene GCR Graphite GCR Aluminum GCR Regolith SPE Graphite SPE Regolith SPE Hydrogen 1 0 5 10 15 20 25 30 35 Shielding Depth, g/cm 2 1 0 5 10 15 20 25 30 35 Shielding Depth, g/cm 2

Risk and Uncertainties increase with Linear Energy Transfer (LET) TEPC Data on NASA-MIR 7 (1/21/1998 to 5/28/1998) 95% CL of Risk Model 10000 8 7 Dose = 0.01 Gy F(>y), (day cm 2 ) -1 1000 100 10 1 GCR Trapped Total REID(%) 6 5 4 3 2 Fold uncertainty 0.1 1 0.01 0.1 1 10 100 1000 y (~LET), kev/µm 0 1 10 100 1000 LET, kev/µm Dose = Flux x LET Biological Dose H = Dose X Q(L) REID = Risk of exposure induced death = H x R 0 (sex,age)

Accuracy of Space Radiation Transport Models

Model vs. Phantom Expt. (STS and ISS) ISS Increment-2 results

Phantom Torso TEPC Trapped + GCR Differential Flux June 25 - July 3, 2001 10 5 Differential Flux, Number/cm 2 sr day kev/µm 10 4 10 3 10 2 10 1 10 0 10-1 10-2 10-3 10-4 10-5 10-1 10 0 10 1 10 2 10 3 10 4 Lineal Energy (Tissue, kev/µm)

NASA-MIR 7 (1/21/1998 to 5/28/1998) 10000 F(>y), (day cm 2 ) -1 1000 100 10 1 GCR Trapped Total 0.1 0.01 0.1 1 10 100 1000 y, kev/µm

1.E+07 1.E+05 1.E+03 1.E+01 1.E-01 1.E-03 0" (x100) 5" (x10) 7" (x1) 9" (x0.1) LET vs TEPC 1.E-05 0.01 0.1 1 10 100 1000 1.E+07 1.E+05 1.E+03 1.E+01 1.E-01 0" (x100) 5" (x10) 7" (x1) 9" (x0.1) TEPC model Vs TEPC (no TF) 1.E-03 1.E-05 0.01 0.1 1 10 100 1000