## 4 Challenges in the Creation of Predictive Models  
Obtaining accurate predictive models of radiation in space is a significant challenge due to the complexity of the space environment, lack of precise and complete data, modeling difficulties, and uncertainty in predictions. The simulation of solar energetic particle fluxes is a multi-level process. The maximum possible fluxes and energy spectra of solar energetic protons are defined, but these values are not enough to determine radiation exposure for long-term space missions with repeated occurrences of large solar events. Hence, knowledge of the solar event distribution function \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Experiment**} & \multirow{2}{*}{**Period**} & \multirow{2}{*}{**Days**} & \multicolumn{2}{c}{**Measured**} & \multicolumn{2}{c}{**SPENVIS**} & \multicolumn{1}{c}{**SPENVIS**} \\  & & & **(km)** & **Dose Rate** & **STK** & **AE8-AP8** & **CRRES** \\  & & & **(km)** & **(uGy/Day)** & **(uGy/Day)** & **(uGy/Day)** & **(uGy/Day)** \\ \hline Mir-10 & Feb 91 & 175 & 402.2 & 289 & 749 & 865 & 7745.21 \\ Mir-11 & March 92 & 146 & 405.8 & 272 & 987 & 917.26 & 7887.67 \\ Mir-12 & July 92 & 190 & 414.5 & 360 & 1237 & 1000.27 & 8339.73 \\ Mir-13 & Jan 93 & 180 & 405 & 474 & 1033 & 886.58 & 7495.89 \\ Mir-14 & July 93 & 197 & 403.7 & 452 & 1103 & 910.96 & 7791.78 \\ Mir-15 & Jan 94 & 183 & 405.6 & 508 & 1170 & 910.68 & 7172.60 \\ Mir-18 & March 95 & 115 & 293.7 & 295 & 1099 & 401.64 & 3802.74 \\ Mir-21 & Feb 96 & 195 & 389.8 & 339 & 1169 & 1444.66 & 7139.73 \\ Mir-22 & Aug 96 & 198 & 382.3 & 379 & 1151 & 1292.60 & 6553.42 \\ Mir-23 & Oct 97 & 187 & 386.8 & 329 & 1146 & 1351.23 & 6736.99 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Comparison of absorbed dose rate measurements aboard the MIR, and predictions from SPENVIS (AE8-AP8 and CRRES) and STK models with 12 mm of aluminum shielding thickness. As in the ISS case, substantial differences between the modeling and the dosimetry are observed. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Experiment**} & \multirow{2}{*}{**Period**} & \multirow{2}{*}{**Days**} & \multicolumn{2}{c}{**Measured**} & \multicolumn{1}{c}{**SPENVIS**} & \multicolumn{1}{c}{**SPENVIS**} \\  & & & **(km)** & **Dose Rate** & **STK** & **AE8-AP8** & **CRRES** \\  & & & **(km)** & **(uGy/Day)** & **(uGy/Day)** & **(uGy/Day)** \\ \hline SATRAM- & & & & & & & \\ Timepix & August 2015 & 30 & 820 & 80.64 & 530 & 1260 & 1180 \\ \hline FOTON-M4 & 2014 & 44 & \(250\times 571\) & 0.048 & 4.55 & 26.6 & 51.20 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Comparison of absorbed dose rate measurements for SATRAM-Timepix and FOTON-M4 experiments, and predictions from SPENVIS (AE8-AP8 and CRRES) and STK models with 0.5 mm of aluminum shielding thickness for SPENVIS and 2 mm for CRRES. Based on the results, we can observe a significant difference between the data from the models and those obtained through actual dosimetry. is also necessary. A model of particle fluxes should be probabilistic in nature and take into account all relevant factors, such as mission duration, solar activity, and particle composition. [PERSON] [40] developed the SINP MSU model of SEP fluxes and pointed out that other known models are not sufficiently complete due to issues in SEP event selection, assigning solar activity, and constructing a particle flux model for the selected energy value. [PERSON] et al. [41] discuss the importance of space radiation in the design of spacecraft and missions, with a focus on the solar energetic particle (SEP) population as the dominant source of particle radiation over short timescales. The authors highlight the difficulty in determining a worst-case SEP spectrum for all spacecraft components, as different components have different characteristics and shielding geometry. The study defines a worst-case event based on the mission duration and a user-defined confidence level, which provides a more coherent statistical approach to determine the worst-case event fluence.