Quest for the Compositional identification and Chemical evolutional understanding of the Interstellar Dust (ExHAM-Interstellar Carbonaceous Solids) - 07.05.17

Overview | Description | Applications | Operations | Results | Publications | Imagery

ISS Science for Everyone

Science Objectives for Everyone
Grains of dust formed in the stellar ejecta of dying stars fills the interstellar space, or the space between stars, in a galaxy by being affected by various astrophysical events. Scientists have been unable to identify the precise nature of the carbon-containing compounds included in interstellar dust, which makes for an incomplete picture of the cycling of matters in galaxies. The Quest for the Compositional identification and Chemical evolutional understanding of the Interstellar Dust (Ex-Ham Interstellar Carbonaceous Solids) investigation takes dust-like particles that have been created in the laboratory and exposes them to space, providing new information about the chemical and physical processes that bridge over the laboratory dust and the cosmic dust grains.
Science Results for Everyone
Information Pending

The following content was provided by Itsuki Sakon, Ph.D., and is maintained in a database by the ISS Program Science Office.
Information provided courtesy of the Japan Aerospace and Exploration Agency (JAXA).
Experiment Details

OpNom: Interstellar Carbonaceous Solids

Principal Investigator(s)
Itsuki Sakon, Ph.D., University of Tokyo, Bunkyo-ku, Tokyo, Japan

Takashi Onaka, Ph.D, University of Tokyo, Bunkyo-ku, Tokyo , Japan
Yuki Kimura, Ph.D., Hokkaido University, Sapporo, Japan
Seiji Kimura, Ph.D., The University of Electro-Communication, Chofu, Tokyo , Japan
Masato Nakamura, Ph.D., Hokkaido University, Funabashi, Chiba , Japan
Atsushi Ichimura, Ph.D., Hokkaido University, Sagamihara, Kanagawa , Japan

University of Tokyo, Tokyo, Japan

Sponsoring Space Agency
Japan Aerospace Exploration Agency (JAXA)

Sponsoring Organization
Japan Aerospace Exploration Agency

Research Benefits
Scientific Discovery

ISS Expedition Duration
March 2016 - September 2016; April 2017 - September 2017

Expeditions Assigned

Previous Missions

^ back to top

Experiment Description

Research Overview

  • The basic form of cosmic solids are produced as a result of the dust/molecular nucleation in the stellar gas wind ejected from evolved stars, and these solids are broken down in the interstellar environment to become interstellar dust. However, the true compositional identification of cosmic carbonaceous dust grains is unknown. As a result, the evolutionary processes of interstellar dust in galaxies are not fully understood from an observational point of view. Laboratory approaches have played an important role in providing astronomers with accurate information to derive the compositional, chemical, and physical properties of interstellar dust from the observed infrared spectrum of various astrophysical sources. In many cases, however, the dust particles that are treated in the laboratory are not always identical to the actual interstellar dust. Therefore, the attempts to identify the physical and chemical processes that associate the laboratory-synthesized dust with the actual interstellar dust are in great demand.
  • The goal of the Quest for the Compositional identification and Chemical evolutional understanding of the Interstellar Dust (Ex-Ham Interstellar Carbonaceous Solids) investigation is to collect more data to enable researchers to demonstrate the linkage between the laboratory-synthesized carbonaceous compounds, and the interstellar carbonaceous dust based on this exposure experiment on the ExHAM exposed facility on the International Space Station (ISS).
  • The fundamental knowledge needed to derive the compositional, chemical, and physical properties of interstellar dust from the observed infrared/ultraviolet spectra is obtained from this experiment.

Information Pending

^ back to top


Space Applications
It is difficult to recover pieces of interstellar dust, although spacecraft have retrieved a few small samples in recent years. To study interstellar dust and its lifecycle in various astrophysical environments, scientists replicate carbon-containing compounds in the laboratory, using observations from telescopes to compare with the infrared/ultraviolet properties of cosmic dust grains. But this is an imprecise method for studying dust grains, which are weathered and changed while being bombarded by gas, radiation and other particles in the interstellar medium. This investigation exposes some laboratory-created carbon compounds to space, using the JAXA Exposed Experiment Handrail Attachment (ExHAM) on the International Space Station. Results provide new information about the changes that take place in carbonaceous compounds while exposed to the harsh environment of space.

Earth Applications
Scientists study interstellar dust grains to better understand how material ejected from dying stars condense in solid phase, how they travel through the galaxy, how they are taken in dense molecular clouds where new stars and planets, like the Sun and solar system, in the next generation are born. But interstellar dust grains are almost impossible to obtain, so scientists try to replicate them in the lab. This investigation would not be possible on Earth, where scientists cannot simultaneously replicate the microgravity, radiation, and bombardment by high energy photons and cosmic rays.

^ back to top


Operational Requirements and Protocols

  • Ground experiments- in which samples are exposed to space environment factors such as high energy radiation, ultraviolet rays, and atomic oxygen- are conducted separately as a reference experiment.
  • The samples are attached on ExHAM in the ISS-JEM airlock by an ISS crew, prior to the exposure of ExHAM on the Exposed Facility (EF) of ISS.
  • After the designated duration of time, ExHAM is detached from the Handhold and taken into the JEM Pressurized Module, via the airlock, with the Robotic Arms.
  • The samples are detached and are stowed until the return trip to Earth.
  • The samples are returned to the Earth.
  • Investigators analyze the degradation condition of the specimens which have been exposed to long-term space environment.

^ back to top

Decadal Survey Recommendations

Information Pending

^ back to top

Results/More Information

Information Pending

^ back to top

Related Websites

^ back to top