Solar Storm Radiation Model (SStoRM) Prepared by: Joshua Lande–Marlboro College, VT and Ron Turner–ANSER, 2900 South Quincy Street, Suite 800, Arlington, VA Overview The Solar Storm Radiation Model (SStoRM) is a JAVA applet that estimates the radiation exposure of an astronaut from a Solar Particle Event. SStoRM is useful as a teaching and illustration aid in understanding the severity of SPEs as our nation embarks on future missions to the Moon, Mars and beyond. SStoRM can be used to help establish how the time evolution and spectral character of an SPE, not just the total fluence, impacts the astronaut, enabling investigators to expand beyond case studies of a limited number of historical events. It provides an accessible Graphical User Interface, allowing the user to specify –The character of the SPE (fluence and energy spectrum) –The time evolution of the SPE It produces radiation exposure estimates: –Absorbed Dose and Dose Equivalent –Skin, Eye, BFO –In free space and on a simplified lunar surface There is an “Exercise Mode” of a simulation of an astronaut on EVA on the lunar surface Details Input to SStoRM: 8,500 BRYNTRN-3 runs, each with six products: –Dose Equivalent (Skin, Eye, BFO) –Absorbed Dose (Skin, Eye, BFO) Human represented by CAM to account for body self-shielding Five Aluminum shielding configurations –0.3 g/cm 2 (spacesuit) –1.0 g/cm 2 (nominal rover) –5.0 g/cm 2 (heavy rover/light spacecraft) –10.0 g/cm 2 (nominal spacecraft) –30.0 g/cm 2 (nominal shelter) Solar Energetic Particle spectra represented by: Input to SStoRM: 8,500 BRYNTRN-3 runs, each with six products: –Dose Equivalent (Skin, Eye, BFO) –Absorbed Dose (Skin, Eye, BFO) Human represented by CAM to account for body self-shielding Five Aluminum shielding configurations –0.3 g/cm 2 (spacesuit) –1.0 g/cm 2 (nominal rover) –5.0 g/cm 2 (heavy rover/light spacecraft) –10.0 g/cm 2 (nominal spacecraft) –30.0 g/cm 2 (nominal shelter) Solar Energetic Particle spectra represented by: Choose the Energy Spectrum SStoRM allows the user to specify the K, , and E 0 parameters of the event They also get to specify E min, or the minimum energy value to integrate from when finding the integral flux When the calculate button is pressed, the flux is graphed along with the spectral curve of several historical SPEs The integral flux for all the graphed curves is compared in the chart to the right Choose the Time Evolution Here, the user can select A, B1, and B2, the parameters of the time evolution curve C is calculated automatically to ensure that the integral flux of the time evolution of the event is the same as the integral flux of the energy spectrum of the event Once the calculate button is pressed, the C factor and the graph of the time evolution of the event are displayed The Estimated Dose (or “How Bad is Your SPE”) SStoRM gives total event dose to the Skin, Eye, and BFO It does so for thicknesses 0.3, 1, 5, 10, and 30 g/cm 2 The radio buttons let the user select absorbed dose or dose equivalent Also, exposure is either for free space or on the lunar surface The difference is that the dose on the lunar surface is half of the dose in free space (no explicit allowance for backscattered particles) Lunar EVA Exercise This exercise allows the user to simulate an astronaut working on the moon during an SPE The user can select a warning time that an astronaut would receive prior to the onset of the event –A negative value means that they are warned about the SPE that many hours after the event has started They then take a given time to pack up and enter the rover They then drive back to the base Once at base, they stay under a heavy shielding for the remainder of the event Shielding for spacesuit, rover, and base can be varied