Earth and space sciences

Experiment BTN-Neutron


  • Building a physical model for generation of charged and neutral particles during solar flares.
  • Developing a physical model of neutron albedo of the earth atmosphere with regard to helio- and geophysical environment, measurement point longitude and altitude effects, time of the day and lighting conditions, atmosphere conditions.
  • Developing a physical model of neutron background in the vicinity of the ISS in different flight conditions, as well as recording space gamma bursts.


  • Mounting the onboard neutron telescope, cable routing inside and outside the pressurized compartment and conducting photo (video) imagery of their location during EVA
  • Measuring direct and scattered fluxes of high-energy neutrons of solar flares with energies from 10 to 15 MeV.
  • Measuring neutrons resulted from nuclear reactions induced by space rays in the earths upper atmosphere in the range of thermal (0.001 0.1 eV), epithermal (0.1 1.0 eV), resonance (1 0.3 eV) and fast (0.3 15 MeV) energies.
  • Measuring gamma radiation in energy ranges between 30 keV to 100 MeV.

Science Hardware Used:

  • Electronics unit BTN-ME;
  • Spare BTN;
  • BTN unit.

Support Items:

  • Platform with locks;
  • Cable set;
  • Cable holder;
  • Cable reel with cable.

Expected Results:

Experimental spectrometric investigations of neutron fields on the ISS will allow to

  • Clarify the on-orbit radiation environment models;
  • Clarify neutron source models in near-earth space environment and evaluate their contribution in a complete radiation dose received by cosmonauts during EVA;
  • Obtain data on high-energy neutron fluxes with energies up to 16 MeV coming from powerful solar flares with regard to albedo radiation of the earth;
  • Build an operational model of neutron background environment on the station;
  • Clarify existing solar activity models;
  • Obtain data on fluxes of rigid electromagnetic space rays component.

Experiment Results:

  • Measurement data on spatial and time distributions of radiation characteristics of space ionizing radiation (neutron and gamma components) outside the Service Module of the ISS RS;
  • Correlation data on radiation environment parameters outside the Service Module of the ISS RS obtained through calculation with the results of measurements made by science hardware BTN-M1 and results of other Russian and international experiments;
  • Measurement data on solar flare parameters in neutron and gamma range.

ISS Crew

Hoshide  AkihikoHoshide

leg Novitskiy Novitskiy

Petr Dubrov Dubrov

Mark Vande Hei Vande Hei

Robert Shane

Megan McArthur McArthur