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Neutron measurement experiment to be conducted in the International Space Station

US Laboratory of the ISS
The US Laboratory, nicknamed DESTINEY, is scheduled to be launched in January 2001 on mission STS-98 by Space Shuttle Atlantis.
NASDA(JAXA) will conduct a neutron measurement inside the International Space Station (ISS) for about eight months using the NASDA(JAXA)-developed BBND located in the US experiment module of the ISS from February 15, 2001.

Purpose of the Neutron Measurement Experiment
The Neutron Measurement Experiment will be conducted as a part of the Human Research Facility (HRF) project of NASA. NASDA(JAXA) will take part in this HRF project with the BBND. NASDA(JAXA) will offer the obtained data to the international partners and will utilize the data for enhancing the space radiation exposure management technology needed for human activity in the ISS.

Human Research Facility project
The HRF project is a widely ranging international cooperative project conducted on the ISS to study the effects of the space environment on the ISS. Experiments on space radiation measurement, nerve medicine, and space psychology are planned for the HRF project. The HRF project will be conducted by the US with participation of universities and national research organizations from Japan and Germany and other countries.
In the space radiation measurement field, neutrons will be measured inside the ISS using NASDA's(JAXA's) BBND, charged particles will be measured (DOSMSP) by the aerospace laboratory of Germany (DLR), and human internal organs radiation will be measured (TORSO) using NASA's human body model from February 2001 in the US laboratory of the ISS.

Outline of the Bonner Ball Neutron Detector
NASDA's(JAXA's) BBND was developed by attaching a control unit that processes, controls and records the data to the neutron detector that was on board the STS-89. The data will be transmitted to the ground once a week. This experiment will be continued for as long as eight months to acquire the neutron energy spectrum inside US module.

What is Neutron?
A neutron is an elementary particle. Since a newtron has no electric charge, it can penetrate most substances. Even low-energy neutrons can reach the internal human organs including marrow. It is said that 5% to 30% of the whole radiation astronauts receive is neutron energy.

Internal view of the BBND detector unit

BBND specification
  • Weight: 127 lb
  • Size: 483mm X 493 mm X 715 mm
  • Power requirement: Max 60 w
  • Data storage capacity : 4 GB (for 50 days) X 5
  • Neutron measurement range: 0.025 eV thru 10 MeV
  • Number of maximum events processed: 10,000/sec

Time schedule
  • Ship to NASA: June 12, 2000
  • BBND launch: February 2001, STS-102 (5A.1)
  • BBND recovery: August 2001, STS-109 (UF-1)

Future plan of Space Environment Measurement Experiment

Space Environment Data Acquisition
equipment-Attached Payload (SEDA-AP)
NASDA(JAXA) is developing the Space Environment measurement device (SEDA-AP) that will be used for one of the experiments conducted on the Exposed Facility of Kibo, which has a launch target of 2006. SEDA-AP carries a neutron detector and other space environment sensors. It measures the external space environment including neutrons, light particles with high energy, heavy ions, small particles, and atomic oxygen. The data collected by SEDA-AP is expected to be utilized for resolving questions including solar flare acceleration mechanisms by directly measuring the solar neutrons.

Last Updated : October 1, 2003

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