Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) - 04.10.14

Overview | Description | Applications | Operations | Results | Publications | Imagery
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Science Objectives for Everyone

The Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) investigation aims to globally map stratospheric trace gases by means of the most sensitive submillimeter receiver. Although SMILES stopped atmospheric observation due to instrumental failures since April 2010, highly sensitive data obtained for a half year provides accurate global datasets of atmospheric minor constituents related to ozone chemistry. SMILES continues operations for instrumental calibration and cooling of a mechanical cooler, as well as a brush-up of retrieval algorithms for atmospheric constituents.
 

Science Results for Everyone

Earth has gas problems. This investigation mapped stratospheric trace gases around the globe with an instrument on the space station that detects weak, sub-millimeter electromagnetic waves emitted from atmospheric molecules. Researchers used the data to reveal global distributions of ozone and related atmospheric constituents during the 24-hour day/night cycle on Earth. These highly sensitive observations provide a better understanding of processes controlling the stratospheric ozone chemistry and those related to climate change. Data revealed anomalous distribution of stratospheric ozone in tropic regions from autumn of 2009 to spring of 2010 and ozone depletion in the Arctic in January of 2010.



This content was provided by Masato Shiotani, 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

Principal Investigator(s)

  • Masato Shiotani, Kyoto University, Uji, Japan

  • Co-Investigator(s)/Collaborator(s)
  • Masahiro Takayanagi, Japan Aerospace and Exploration Agency, Sagamihara, Japan

  • Developer(s)
    Japan Aerospace Exploration Agency (JAXA), Tsukuba, , Japan

    Sponsoring Space Agency
    Japan Aerospace Exploration Agency (JAXA)

    Sponsoring Organization
    Information Pending

    Research Benefits
    Information Pending

    ISS Expedition Duration
    March 2009 - September 2014

    Expeditions Assigned
    19/20,21/22,23/24,25/26,27/28,29/30,31/32,33/34,35/36,37/38,39/40

    Previous ISS Missions
    None

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    Experiment Description

    Research Overview

    • The main scientific target of the SMILES mission is to evaluate quantitatively the recovery and stability of the stratospheric ozone layer. There are still considerable uncertainties in factors affecting ozone levels. There is a need for a detailed understanding of ozone chemistry based on a high sensitive observation.


    • SMILES will demonstrate its high potential to observe atmospheric minor constituents which contribute the ozone destraction in the middle atmosphere.


    • The unprecedented high sensitive observation by SMILES will provide accurate global datasets of ozone-depletion gas concentrations. It will provide important insights into the ozone trend. Especially, chroline and bromine compounds related to ozone chemistry will be determined quantitatively.

    Description

    SMILES (Superconducting Submillimeter-Wave Limb-Emission Sounder) is a sensitive submillimeter-wave sounder. The objective of SMILES is to monitor global distributions of the stratshperic trace gases which contribute ozone depletion. SMILES is the first to use a superconductive low-noise receiver with a mechanical 4-K refrigerator in space to realize a high sensitive observation.

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    Applications

    Space Applications

    SNFM watches the space station’s payload local area network (LAN) to analyze and troubleshoot data traffic. By understanding how traffic flows through the local area network, engineers could devise new faster and more efficient computer networks for future space missions.
     

    Earth Applications

    By monitoring how the station’s computers transfer data, SNFM could improve computer access for a variety of experiments, allowing faster and better transmission from the station to the ground. Scientists can be better served with this more efficient method of data downlink.
     

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    Operations

    Operational Requirements

    SMILES will perform cooling operation and instrumental calibration operaion. For the cooling operation, low-rate downlink will be used, and will be performed four times in 2011, each of the operations will take a few weeks. For the instrumental calibration operation, both low- and medium-rate downlink will be used.

    Operational Protocols

    For the cooling operation, two mechanical cryocoolers are operated. The operation procedures will be adjusted aiming to achieve a cryogenic temperature of about 4 Kelvin. For the instrumental calibration operation, subsystems related to a signal chain are powered on. The internal calibration signals are generated to investigate the response of the subsystems.

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    Results/More Information

    SMILES has performed atmospheric observation for a half year, from October 2009 to April 2010. After the cryocooler failure occurred at June 2010, 14-times cooling operations have been performed. Although the analysis of the atmospheric data is still continuing, we have derived some preliminary results to date. The profiles and horizontal distributions of ozone and HCl are reasonable. Even for those species with weak signals, such as BrO and HO2, we can get promising results, even for a single scan. Averaging, such as daily zonal means, will produce scientifically useful signal-to-noise ratios for these species. We have shown the capability of obtaining high-quality scientific data that will be important to addressing scientific issues such as the ozone trend problem, middle atmosphere chemistry with a special focus on the diurnal cycle, and the transport process of minor species. These outcomes from SMILES will demonstrate the high potential to observe atmospheric minor constituents in the middle atmosphere. And the knowledges obtained through the cooling operations will provide useful informations for future cryogenic missions

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    Results Publications

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    Ground Based Results Publications

      Baron P, Urban J, Sagawa H, Moller J, Murtagh DP, Mendrok J, Dupuy E, Sato TO, Ochiai S, Suzuki K, Manabe T, Nishibori T, Kikuchi K, Kikuchi K, Sato R, Takayanagi M, Murayama Y, Shiotani M, Kasai Y.  The Level 2 research product algorithms for the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES). Atmospheric Measurement Techniques Discussions. 2011 June 9; 4(3): 3593-3645. DOI: 10.5194/amtd-4-3593-2011.

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    ISS Patents

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    Related Publications

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    Related Websites
    JEM SMILES

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    Imagery

    image SMILES. Image courtesy of JAXA.
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    image On January 23, 2010, SMILES observed destruction of the ozone layer at an altitude of 22 kilometers. Utilizing its high sensitivity, SMILES not only observes ozone depletion (shown in fi gure 1) but also captures changes in chlorine compound levels over a single day (the increase shown in fi gure 2 and the decrease shown in figure 3).
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