Developing electronic devices for space exploration requires understanding the response of the individual components to harsh environments including extreme temperatures and ionizing radiation. In this work, InAs-based devices were studied using multiscale computations. It was found that arsenide vacancies and arsenide anti-sites were the most energetically favorable point defects to form under indium-rich and indium-poor conditions, respectively, with the arsenide anti-site reducing the electron mobility by a factor of 10 at 300 K. Both defect types were found to introduce relatively deep charge transition levels in the band gap and mediate n-type conduction with ionization energies of 0.26 eV and 0.31 eV, respectively. Under indium-rich conditions, indium substitutional defects had comparable stability to the arsenide vacancies and introduced a shallow donor level with ionization energy of 0.03 eV and may play a role in n-type behavior in response to radiation damage. Indium vacancies were significantly less stable than other defects under all conditions and were the only defects to mediate p-type conduction by introducing shallow levels in the band gap. The Seebeck coefficient was found to increase monotonically from -5 × 10–4 V/K toward zero as the concentration of n-type dopants increased from 1015 to 1021 cm−3. The electrical conductivity was shown to increase dramatically by several orders of magnitude around doping concentration of 1020 cm−3 for both donors and acceptors. Finally, I–V characteristic curves showed dramatic increase of current in response to increase in temperature and radiation dose consistent with the available literature. [ABSTRACT FROM AUTHOR]