Validation of PREDICCS using LRO/CRaTER observations during three major solar events in 2012

Joyce, Colin J.; Schwadron, N. A.; Wilson, J. K.; Kasper, J. C.; Golightly, M. J.; Blake, J. B.; Mazur, J. E.; Townsend, L. W.; Case, A. W.; Semones, E.; Smith, S. S.; Zeitlin, C.

doi:10.1002/swe.20059

Cited by 21 publications

(29 citation statements)

References 11 publications

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“…We study the probability of SEP events using a near‐real‐time tool called PREDICCS (Predictions of Radiation from REleASE, EMMREM, and Data Incorporating the CRaTER, COSTEP, and other SEP measurements, http://prediccs.sr.unh.edu [ Schwadron , ]), an online system for nowcasting the radiation environment in near‐Earth, lunar, and Martian space environments. The PREDICCS tool has been shown to be very accurate for dose rate calculations [ Joyce et al , ] in comparison to CRaTER observations. We use the tool here to determine the probability distribution of integrated doses of SEP events from mid‐2011 through April 2014, which covers the progression in the rise of solar activity in cycle 24.…”

Section: Worsening Hazard From Galactic Radiationmentioning

confidence: 99%

Does the worsening galactic cosmic radiation environment observed by CRaTER preclude future manned deep space exploration?

et al. 2014

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The Sun and its solar wind are currently exhibiting extremely low densities and magnetic field strengths, representing states that have never been observed during the space age. The highly abnormal solar activity between cycles 23 and 24 has caused the longest solar minimum in over 80 years and continues into the unusually small solar maximum of cycle 24. As a result of the remarkably weak solar activity, we have also observed the highest fluxes of galactic cosmic rays in the space age and relatively small solar energetic particle events. We use observations from the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) on the Lunar Reconnaissance Orbiter to examine the implications of these highly unusual solar conditions for human space exploration. We show that while these conditions are not a show stopper for long‐duration missions (e.g., to the Moon, an asteroid, or Mars), galactic cosmic ray radiation remains a significant and worsening factor that limits mission durations. While solar energetic particle events in cycle 24 present some hazard, the accumulated doses for astronauts behind 10 g/cm2 shielding are well below current dose limits. Galactic cosmic radiation presents a more significant challenge: the time to 3% risk of exposure‐induced death (REID) in interplanetary space was less than 400 days for a 30 year old male and less than 300 days for a 30 year old female in the last cycle 23–24 minimum. The time to 3% REID is estimated to be ∼20% lower in the coming cycle 24–25 minimum. If the heliospheric magnetic field continues to weaken over time, as is likely, then allowable mission durations will decrease correspondingly. Thus, we estimate exposures in extreme solar minimum conditions and the corresponding effects on allowable durations.

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Section: Worsening Hazard From Galactic Radiationmentioning

confidence: 99%

Does the worsening galactic cosmic radiation environment observed by CRaTER preclude future manned deep space exploration?

et al. 2014

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“…This is also evident in Figure 5 where PREDICCS dose rates fall off quicker than CRaTER and RAD. The discrepancy between the 0.3 g cm À2 shielded dose rate of PREDICCS and dose rates from CRaTER (~0.22 g cm À2 aluminum-equivalent shielding) was concluded to be due to EMMREM not handling low-energy protons well (Joyce et al 2013). Heavy ions, not included in PREDICCS, may still account for increased dose from fragmentation within the heavier shielding.…”

Section: à2mentioning

confidence: 96%

“…PREDICCS has been verified to provide a credible characterization of the lunar radiation environment (Schwadron et al 2012;Joyce et al 2013).…”

Section: Introductionmentioning

confidence: 99%

“…Zeitlin et al (2013) determined the GCR background dose rate measured by RAD's B detector (after converting to dose rate in water) to be 0.0481 cGy/day ± 0.0080 cGy/day. For CRaTER, Joyce et al (2013) used the Badhwar-O'Neill model (O'Neill 2006) to approximate the GCR background dose rate as seen by CRaTER at the Moon for the January, March, and May 2012 solar events. The respective GCR background dose rates were 0.0213 cGy/day, 0.0203 cGy/day, and 0.0199 cGy/day.…”

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confidence: 99%

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Modeling the effectiveness of shielding in the earth-moon-mars radiation environment using PREDICCS: five solar events in 2012

Quinn¹,

Schwadron²,

Townsend³

et al. 2017

J. Space Weather Space Clim.

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Radiation in the form of solar energetic particles (SEPs) presents a severe risk to the short-term health of astronauts and the success of human exploration missions beyond Earth's protective shielding. Modeling how shielding mitigates the dose accumulated by astronauts is an essential step toward reducing these risks. PREDICCS (Predictions of radiation from REleASE, EMMREM, and Data Incorporating the CRaTER, COSTEP, and other SEP measurements) is an online tool for the near real-time prediction of radiation exposure at Earth, the Moon, and Mars behind various levels of shielding. We compare shielded dose rates from PREDICCS with dose rates from the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) onboard the Lunar Reconnaissance Orbiter (LRO) at the Moon and from the Radiation Assessment Detector (RAD) on the Mars Science Laboratory (MSL) during its cruise phase to Mars for five solar events in 2012 when Earth, MSL, and Mars were magnetically well connected. Calculations of the accumulated dose demonstrate a reasonable agreement between PREDICCS and RAD ranging from as little as 2% difference to 54%. We determine mathematical relationships between shielding levels and accumulated dose. Lastly, the gradient of accumulated dose between Earth and Mars shows that for the largest of the five solar events, lunar missions require aluminum shielding between 1.0 g cm À2 and 5.0 g cm À2 to prevent radiation exposure from exceeding the 30-day limits for lens and skin. The limits were not exceeded near Mars.

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“…Table shows the peak dose rates and accumulated doses for skin/eye and BFO with the four different levels of shielding. The hourly dose rate for spacesuit shielding peaks at approximately 1970 cGy‐Eq/d, almost four times as large as the peak rate computed by EMMREM for the 2003 Halloween Storms (∼500 cGy‐Eq/d) [ Schwadron et al , ] and more than an order of magnitude greater than the peak dose rates computed by EMMREM for the January (140 cGy‐Eq/d) and March (167 cGy‐Eq/d) events of 2012 [ Joyce et al , ]. While the peak dose rate for this event is much higher than the previous events, it lasted for only an hour, whereas the previous events maintained dose rates at or near the peak levels for a day or more and also contained multiple peaks.…”

Section: Computed Dose Rates At Stereo a During The 23 July 2012 Evenmentioning

confidence: 99%

Analysis of the potential radiation hazard of the 23 July 2012 SEP event observed by STEREO A using the EMMREM model and LRO/CRaTER

et al. 2015

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We present a study of the potential radiation hazard of the powerful, superfast interplanetary coronal mass ejection (ICME) observed by STEREO A on 23 July 2012. Using energetic proton flux data from the High Energy Telescope and Low Energy Telescope instruments aboard STEREO A together with the Earth-Moon-Mars Radiation Environment Module, we compute dose rates and accumulated doses during the event for both skin/eye and blood forming organs using four physically relevant levels of shielding. For spacesuit equivalent shielding, we compute a peak skin/eye dose rate of 1970 cGy-Eq/d, a value far greater than those of the 2003 Halloween storms or the January and March solar energetic particle events of 2012. However, due to the relative brevity of the event, the resulting accumulated dose was just 383 cGy-Eq, which is more aligned with the total doses of the 2003 Halloween and 2012 January/March events. Additionally, we use dose rates at STEREO B and Lunar Reconnaissance Orbiter/Cosmic Ray Telescope for the Effects of Radiation (LRO/CRaTER) during the event to show how the radiation impact is affected by the position of the ICME relative to the observer. Specifically, we find that the energetic particle event associated with the local shock and ICME passage at STEREO A caused greatly enhanced dose rates when compared to STEREO B and LRO/CRaTER, which were longitudinally distant from the ICME. The STEREO A/B dose rates used here will soon be made available to the community as a tool for studying the energetic particle radiation of solar events from different longitudes as a part of NASA's Heliophysics Virtual Observatories and on the Predictions of radiation from REleASE, EMMREM, and Data Incorporating CRaTER, COSTEP, and other SEP measurements (PREDICCS) and CRaTER websites.

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Validation of PREDICCS using LRO/CRaTER observations during three major solar events in 2012

Cited by 21 publications

References 11 publications

Does the worsening galactic cosmic radiation environment observed by CRaTER preclude future manned deep space exploration?

Does the worsening galactic cosmic radiation environment observed by CRaTER preclude future manned deep space exploration?

Modeling the effectiveness of shielding in the earth-moon-mars radiation environment using PREDICCS: five solar events in 2012

Analysis of the potential radiation hazard of the 23 July 2012 SEP event observed by STEREO A using the EMMREM model and LRO/CRaTER

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