Thermal Vacuum Test of the Inter-orbit Communication System - Exposed Facility Subsystem

Measurement and Control Room	ISC-EF in the 8m diameter Space Chamber

A thermal vacuum test of the Inter-orbit Communication System - Exposed Facility Subsystem (ICS-EF) is being conducted in the 8m diameter Space Chamber at Tsukuba Space Center (TKSC).

The Inter-orbit Communication System (ICS) is a communication system of the Japanese Experiment Module "Kibo" that allows two-way communication of data, images, and voice between Kibo and TKSC, via JAXA’s Data Relay Test Satellite (DRTS). The ICS-EF is composed of equipment such as a DRTS-oriented antenna, various types of sensors, and a transmitter-receiver.

Temperatures in space range from 120°C in the sunlight to -150°C in the shade. Without air convection to transfer heat, surface areas exposed to the sunlight quickly heat and shaded surfaces get cold.
The ISS circles the Earth in 90 minutes, during which time it is cold for 30 minutes, and hot for 60 minutes.
A thermal blanket insulates the ICS-EF allowing proper equipment performance under severe temperature changes. A heater also helps control the temperature of the equipment.

Thermal Vacuum Test

ISC-EF being carried into the 8m diameter Space Chamber

ICS-EF located in the 8m diameter Space Chamber Closing the 8m diameter Space Chamber with ICS-EF inside

In this test, with the ICS-EF on/off, we verify that various parts maintain their temperature within specified ranges in orbit, tested under simulated thermal conditions of space, using a liquid nitrogen panel for refrigeration, and a sunlight simulator for heating. Simultaneously, we ensure that the onboard equipment performs as expected under the thermal vacuum conditions.

This data will be evaluated and compared with the simulation results of the thermal mathematical model generated in the design phase. After the evaluation, the thermal mathematical model will be corrected, if necessary, to make it more realistic. The test will continue until the end of March.