What is Free-Space PADLES?
The Free-Space PADLES equipment consists of 8 sealed and hemisphere shielding cases of varying aluminum thickness (6.4cm diameter) with two PADLES dosimeters and temperature sensors inside each case.. The domed aluminum case was developed to maintain long-term pressure of 1 atm in order to measure the accurate radiation dose in the exposed environment.
The PADLES dosimeter consist of two types of radiation detectors: plastic nuclear track detectors (CR-39) and Thermoluminescent Dosimeters (TLDs) that are sealed in aluminum heat-sealed bags. The condition of each case was kept at 1 atm with dry air due to the O-ring seal.
In this technological verification mission, shielding effects of the KIBO's hull wall is to be verified for a benchmark study to develop existing simulation codes and space radiation models, EVA risk assessment, and the shielding design of future space vehicles toward future interplanetary missions.
The Free-Space PADLES equipment was launched aboard the SpaceX CRS-6 on April 15, 2015 from the Cape Canaveral Air Force Station, and then delivered to the KIBO. On May 14, 2015, on the KIBO, it was attached to the Multi-Purpose Experiment Platform (MPEP) on the slide table of the KIBO's airlock by Astronaut Scott Kelly Afterwards, the slide table was retracted into the airlock, which was then internally depressurized.
The Free-Space PADLES equipment at a tip of the JEM Remote Manipulator System (JEMRMS) in measurement position for the Free-Space PADLES outside the ISS
On June 1, 2015, t the Free-Space PADLES equipment was installed on the Multi-Purpose Experiment Platform (MPEP) facing the AFT, at a tip of the JEM Remote Manipulator System (JEMRMS) in measurement position for the Free-Space PADLES outside the ISS.
On June 15, 2015, the Free-Space PADLES equipment were removed from the Multi-Purpose Experiment Platform (MPEP) using the robotic arm under remote control operation from the Tsukuba Space Center. Then it was retrieved into the airlock by the operation of Astronaut Scott Kelly from the inside of the ISS KIBO.
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In November 2015, image are shown from the internal camera aboard the KIBO: Astronaut Yui detaching the Free-Space PADLES dosimeter.
In March 2016, the Free-Space PADLES equipment was returned and analyzed at the Tsukuba Space Center.
The Free-Space PADLES equipment after recovery from the ISS |
The Free-Space PADLES equipment being unpacking on the ground laboratory |
Links:
Free-Space PADLES experiment conducted
https://iss.jaxa.jp/en/kiboexp/news/150714_freespace_padles_conducted.html