ISO 17761:2015

Overview

ISO 17761:2015 is an international standard published by the International Organization for Standardization (ISO) focused on the characterization of high energy radiation in near-Earth space. Specifically, it provides a comprehensive model of charged particle fluxes-primarily protons with energies exceeding 100 MeV-at low altitudes ranging from 300 km to 600 km above Earth’s surface. The standard utilizes data primarily from the PAMELA experiment, a satellite mission that provided precise measurements of cosmic rays and trapped radiation.

The core purpose of ISO 17761:2015 is to accurately estimate the fluxes of high-energy charged particles in Earth's magnetosphere to assess their impact on spacecraft instrumentation and astronaut safety. This is crucial for designing resilient spacecraft systems and planning manned space missions.

Key Topics

• Charged Particle Fluxes: Describes proton flux with energies above 100 MeV, extending to the geomagnetic cut-off rigidity at low Earth orbit altitudes, integrating both natural and artificial space radiation sources.
• PAMELA Data Integration: Uses innovative particle detection data from the PAMELA space mission, enhancing previous radiation models with high-precision measurements.
• Geomagnetic Cut-Off Rigidity: Accounts for the magnetic rigidity threshold below which charged cosmic rays are deflected by Earth's magnetic field, defining regions where primary cosmic rays are either allowed or blocked.
• Geomagnetic Coordinates (L-shell and B): Utilizes geomagnetic reference frames to map radiation flux distributions in the magnetosphere.
• Albedo Trapped Particles: Includes secondary charged particles (such as protons and electrons) generated by cosmic ray interaction with Earth's atmosphere and trapped by the geomagnetic field, including detailed consideration of phenomena like the South Atlantic Anomaly (SAA).
• Radiation Environment Modeling: Provides data tables and smoothed flux profiles for protons, electrons, and positrons as functions of energy and geomagnetic location for the 2006–2009 epoch.

Applications

• Spacecraft Design: Engineers can use ISO 17761:2015 to predict the radiation environment that spacecraft electronics and materials will encounter in low Earth orbit (LEO), helping mitigate risks of radiation damage.
• Astronaut Safety: Critical for mission planners to estimate astronaut exposure to high-energy radiation during missions at altitudes between 300 km and 600 km, facilitating protective measures and safety protocols.
• Radiation Shielding Analysis: Supports the development of better radiation shielding solutions by providing detailed flux data for high-energy protons and electrons encountered on LEO spacecraft.
• Space Mission Planning: Enables accurate assessments to ensure reliability of satellite instruments and communication systems in varying geomagnetic environments, particularly near sensitive regions such as the SAA.
• Scientific Research: Serves as a reference for astrophysicists and space scientists studying cosmic ray interactions and trapped radiation dynamics in Earth’s magnetosphere.

Related Standards

• ISO 15390 – Galactic Cosmic Ray Model: Complements ISO 17761 by modeling cosmic ray flux outside Earth's magnetosphere, essential for understanding primary cosmic radiation impacting satellites.
• ISO 16695 – Geomagnetic Reference Models: Provides geomagnetic field models vital for calculating particle trajectories and cut-off rigidities that are integral to ISO 17761's flux estimations.
• ISO 22009 – Earth's Magnetospheric Magnetic Field Model: Offers foundational geomagnetic field data used in conjunction with charged particle flux modeling.
• NASA AP-8 and AE-8 Models: Though based on legacy data, these models have historically been used for trapped proton and electron radiation estimates; ISO 17761 improves upon them with modern PAMELA data.
• PAMELA Mission Publications: The experimental results and data interpretations from the PAMELA collaboration form the empirical basis for ISO 17761.

Using ISO 17761:2015 supports accurate, data-driven analysis of the natural and artificial space radiation environment at low Earth orbit altitudes. By incorporating cutting-edge measurements of high-energy charged particles, this standard ensures that space systems and astronaut health considerations are informed by the latest scientific knowledge, enhancing mission success and safety in the challenging near-Earth space environment.