Space Radiation API: on demand access to Van Allen Belt models
A hostile radiation environment awaits any space mission. Space radiation increases the risk of cancers in humans and malfunctions in spacecraft electronics. Space radiation effects are increasingly significant, with longer duration missions to cislunar space and beyond. Moreover, the use of commercial off-the-shelf electronics that may not be resilient to radiation damage is prevalent in low cost satellites.
The environment is dominated by three sources of radiation: galactic cosmic rays (GCR), solar energetic particles (SEP), and trapped radiation. GCRs are high energy atomic nuclei that originate from outside our solar system, generated by supernovae and other phenomena. SEPs, on the other hand, are generated by our Sun during sporadic and intense solar flares. Trapped radiation comprises charged particles that are confined by the magnetic field of the Earth. Also known as Van Allen Belts (named after James Van Allen who was instrumental to their discovery) they usually consist of an inner belt of high energy protons (products of GCR interaction with the atmosphere) and an outer belt of lower energy particles (mostly electrons captured from the solar wind). A third ring between the two has also been observed [1]. Satellites in low earth orbit will traverse the inner belt when they fly over the South Atlantic ocean; craft in higher orbits or transiting to the moon or mars must endure the outer belt as well.
Mitigating the risk of space radiation effects requires both theoretical and experimental approaches. Terrestrial-based particle accelerator facilities can bombard components and subsystems with a similar mix of radiation types and energies to ensure they are fit for purpose. However, such facilities are often prohibitively expensive or unavailable to many organizations. Theoretical studies have an important role to play. Researchers are working hard to develop and validate scientific models that can predict the space radiation environment [2]. The models are used to design radiation shielding, select components, and implement mitigation strategies such as having redundant systems or changing the state of vulnerable components in high radiation regions.
The United States Air Force Research Laboratory, in collaboration with industry partners, has developed models of Earth’s trapped radiation field. The AE9/AP9/SPM models predict the particle flux on a particular date at a particular position, or indeed for an entire mission profile.
Integrating scientific models into software systems can be challenging. Amentum Scientific develops web Application Programming Interfaces to Earth science models.
We have developed the Space Radiation API — a web API that provides on demand access to the AE9/AP9/SPM models for mission planners and engineers seeking to understand the space radiation environment. Visit our website to try the API, and please contact us if you have any questions.
Good luck and godspeed!
The A-Team
References
[1] https://www.nature.com/news/ephemeral-third-ring-of-radiation-makes-appearance-around-earth-1.12529
[2] Xapsos, Michael A., Patrick M. O’Neill, and T. Paul O’Brien. “Near-Earth space radiation models.” IEEE Transactions on Nuclear Science 60.3 (2012): 1691–1705.
