NASDA is developing the Japanese Experiment Module (JEM) named “Kibo” as one of Japanese participation in the program of the International Space Station (ISS) for launch in the breaking of next century. The Exposed Facility of JEM (JEM-EF) is one of most characteristic accommodations in ISS to provide an environment directly exposed to the outer space. JEM-EF is expected to be suitable for experimental missions of a wide variety of field such as earth and space sciences and technological development. In this paper, JEM-EF and its standard payload will be outlined. The interface between JEM-EF and payloads and some significant constraints which must be taken into consideration are also discussed. Four candidate Japanese experiments for the early stage utilization of JEM-EF as well as their selection procedure are introduced.

The long-term variability as well as transient outbursts of high-energy astronomical objects from all over the sky will be monitored by this instrument (MAXI, Monitor of All-sky X-ray Image). The high-energy objects, which extend deep into the universe, emit X-rays accompanying bursts, jets and gas accreting on to neutron stars or black holes. The MAXI which is a slit X-ray camera with a wide field of view consists of gas proportional counters with total area of 5000cm² and X-ray CCD's with total area of 200cm².

A laser communication demonstration experiment (LCDE) to be performed around the year 2005 between the exposed facility at the Japanese experiment module attached to the International Space Station and a ground station is described. The bit-rate of the downlink from the Space Station to the ground station is 2.5 Gbps while the uplink bit-rate is 1. 2 Gbps. LCDE will demonstrate the capability of high-speed optical downlink even from a manned spacecraft where vibrational environment is not suitable for very accurate tracking/pointing system required for laser communications. A preliminary observation of space debris will also be performed utilizing the tracking/pointing system for the laser communication.

The sub-millimeter wavelength region is advantageous for high-precision observations of trace species in the stratosphere. A Superconducting Sub-Millimeter-Wave Limb Emission Sounder (SMILES) is scheduled to demonstrate the measurements of extremely faint sub-millimeter-wave emissions of the atmospheric trace gases on the Exposed Facility (EF) of the Japanese Experimental Module (JEM) of the International Space Station in 2005. ]EM/SMILES utilizes the 640 GHz-band to measure the vertical profiles of trace gases involved in the stratospheric ozone depletion, such as chlorine monoxide (ClO), bromine monoxide (BrO), etc. The applications of superconductivity and mechanical 4 K-refrigerator in space will be demonstrated in the experiment. ]EM/SMILES employs a Superconductor-Insulator-Superconductor (SIS) receiver to improve measurement precision and spatial resolution with its very high sensitivity, thereby enabling us to quantitatively understand the interactive processes between chemistry and dynamics. ]EM/SMILES is a pre-phase of SMILES to be equipped on an Atmospheric Chemistry and Dynamics Mission, A TMOS-C, proposed to an Earth observation scenario estimated in the National Space Development Agency of Japan (NASDA).

Space Environment Data Acquisition Equipment (SEDA) was selected as one of the theme which takes on “being dealing with the needs of a lot of use as the cooperation use platform”out of the JEM exposed facility use. It begins a detailed design from 1998 and it aims to launch in 2004. It is possible to use as the open data and the data which was gotten by these equipment becomes useful data to the related science study and the operation of the space station and the space weather forecast, too.