Materials International Space Station Experiment - 7 (MISSE-7) - 11.19.14

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

Science Objectives for Everyone
The Materials International Space Station Experiment-7 (MISSE-7) is a test bed for materials and coatings attached to the outside of the International Space Station being evaluated for the effects of atomic oxygen, ultraviolet, direct sunlight, radiation and extremes of heat and cold. This experiment allows the development and testing of new materials to better withstand the rigors of space environment. Results will provide a better understanding of the durability of various materials when they are exposed to the space environment with applications in the design of future spacecraft.

Science Results for Everyone

Leave spacesuits outside for 18 months and you expect a little wear and tear. That is what happened when researchers exposed fabrics to the rigors of space in a sample box outside the station. Results showed that fibers lost strength and stretched out, and space radiation darkened the fabrics, causing them to absorb more radiation over time. Researchers need to reduce this radiation damage to adequately protect astronauts. The investigation also found that solar cell coatings changed little during space exposure. This suggests we can develop coatings more resistant to radiation and improve solar technology for weather, communication, and Earth observation satellites.



The following content was provided by Robert J. Walters, Ph.D., and is maintained in a database by the ISS Program Science Office.

Experiment Details

OpNom

Principal Investigator(s)

  • Robert J. Walters, Ph.D., Naval Research Laboratory, Washington, DC, United States

  • Co-Investigator(s)/Collaborator(s)
    Information Pending
    Developer(s)
    United States Department of Defense Space Test Program, Johnson Space Center, Houston, TX, United States

    Langley Research Center, Hampton, VA, United States

    Sponsoring Space Agency
    National Aeronautics and Space Administration (NASA)

    Sponsoring Organization
    National Laboratory - Department of Defense (NL-DoD)

    Research Benefits
    Information Pending

    ISS Expedition Duration
    October 2009 - September 2011

    Expeditions Assigned
    21/22,23/24,25/26,27/28

    Previous ISS Missions
    NASA has conducted a series of space experiments to determine the best materials to survive in the space environment on Shuttle and Mir. MISSE-1 and 2 were delivered to ISS on STS-105 in August 2001 and returned on STS-114 in August 2005. MISSE-5 was deployed during STS-114 and returned on STS-115. MISSE-3 and 4 were delivered to ISS on STS-121 in July 2006 and returned on STS-118 in August 2007. MISSE-6A and 6B were delivered to the ISS on STS-123 in March 2008 and will return in 2009.

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    Experiment Description

    Research Overview

    • Materials International Space Station Experiment-7 (MISSE-7) will assess impacts of the space environment (vacuum, solar radiation, atomic oxygen, micrometeorites and thermal cycling, etc.) on materials.


    • Specimens include solar cells and candidate spacecraft materials for long-term exposure to the space environment.


    • Following return to Earth these materials will be analyzed to determine which materials could withstand the harsh environment of space and can be used in the design of future spacecraft.

    Description
    Materials International Space Station Experiment-7 (MISSE-7) is a suite of experiments that include over 700 new and affordable materials. The samples tested have potential use in advanced reusable launch systems and advanced spacecraft systems including solar cells, optics, sensors, electronics, power, coatings, structural materials and protection for the next generation of spacecraft. The development of the next generation of materials and material technologies is essential to the mission of traveling beyond Earth’s orbit.

    The samples are installed in holders and placed in experiment trays, called Passive Experiment Containers (PECs). For MISSE-7 there are two PECs, 7A and 7B, which will be mounted on the outside of the ISS and hold samples on both sides of the PECs. PEC 7A’s orientation will be zenith/nadir (space facing/Earth facing) while PEC 7B will face ram/wake (forward/backward) relative to the ISS orbit. This installment of experiments for the MISSE program will be the first to receive power directly from the ISS and use the ISS communication system uplink/downlink capabilities to receive commands downlink data.

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    Applications

    Space Applications
    Results will provide a better understanding of the durability of various materials when they are exposed to the space environment. Many of the materials may have applications in the design of future spacecraft.

    Earth Applications
    The new advanced materials and components that will be demonstrated in MISSE-7 will improve the performance, increase the useful life, and reduce the costs of future space operations of commercial weather, communication and Earth observation satellites that we all now depend on, as well as enhance solar cell technology.

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    Operations

    Operational Requirements
    MISSE-7 is mounted to the Station's exterior on an EXPRESS Logistics Carrier (ELC). It requires power and data provided by the Station, but does not require crew interaction. The critical interaction is between the samples and the space environment.

    Operational Protocols
    During extravehicular activity astronauts will install the MISSE-7 on the ISS. During EVAs throughout the deployment of MISSE-7 crewmembers will capture snapshots of the PECs, if time permits. Another set of crewmembers in a later increment will retrieve MISSE-7 when the experiment is completed. The samples will be returned to the investigators, who will carefully examine each to determine how the materials fared.

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    Results/More Information

    The following information is a sampling of the results obtained from MISSE-7 thus far.

     

    Six samples of pristine and dust abraded outer layer spacesuit fabrics were exposed to the wake low-Earth orbit (LEO) environment on the International Space Station (ISS) for 18 months in order to determine whether abrasion by lunar dust increases fabric deterioration from radiation. Comparison of pre- and post-flight showed that space radiation darkened and reddened all 6 fabrics increasing their integrated solar absorptance by 7 to 38%. There was a decrease in the ultimate tensile strength and elongation to failure of lunar dust abraded Apollo spacesuit fibers by a factor of 4 and an increase in the elastic modulus (tendency to be deformed) by a factor of 2. The lunar dust laden Apollo 12 sample darkened, but did not appreciably redden, though it appears redder to the eye. No evidence of contamination was found suggesting that the discoloration was due to radiation damage. Even though the samples were positioned on the wake (backward) side, because the ISS periodically reorients the samples were exposed to the equivalent of about 38 days of ram (forward)  atomic oxygen (AO) bombardment. Evidence for this was seen in the oxidation of silver-coated fasteners and the etching of fabric fibers. The erosion seen in the fibers was consistent with previously reported values for the erosion yields of the materials. The severity of the degradation of the fabric samples over the 18-month exposure period show that as materials wear out over time they absorb more energy and get hotter demonstrating the necessity to find ways to reduce radiation damage to spacesuits when planning extended exploration-class space missions.

     

    Modern multijunction (MJ) solar cells require stable optical coatings that provide wider spectral protection. The requirement to transmit shorter wavelengths to the top cell of the MJ device imposes new challenges for coatings. Ultraviolet reflection (UVR) and wide-band antireflection (AR) multilayer coatings were applied on working solar cell covers and test  substrates and subsequently exposed in space on MISSE-7 along with space-simulated ground tests to determine their performance and stability. Observed effects of long space exposure on the coatings and assembled solar cells were small.  UVR/AR coatings showed stable optical properties after exposure to proton, UV,  atomic oxygen, and  protected flexible polymer substrate materials. The technology for producing effective space-mission coatings that operate   to UV wavelengths near 200 nm was successfully demonstrated. Further development is pending, including more exposure tests of  UVR, AR, and transparent conductive oxide (TCO) coatings on flexible substrate alternatives and coatings integrated with MJ cells.  Progress is made toward developing stable and protective coatings with improved resistance to radiation-induced darkening for extended space-mission applications. The additional requirements that the coatings on MJ flexible solar arrays tolerate deployment from being rolled up, and prevent static accumulation and discharge, are also  satisfied. 

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    Results Publications

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    Ground Based Results Publications

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    ISS Patents

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    Related Publications

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    Related Websites
    ISS Research Project- MISSE-7
    MISSE Experiment
    Langley News

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    Imagery

    image NASA Image: STS105-346-007 - Astronaut Patrick G. Forrester, during the second STS-105 extravehicular activity, prepares to work with the Materials International Space Station Experiment 1 and 2(MISSE-1 and 2). The experiment was installed on the outside of the Quest Airlock during the first extravehicular activity (EVA) of the STS-105 mission. MISSE will collect information on how different materials weather in the environment of space.
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    image NASA Image ISS013E63407: Image of MISSE 3 following deployment on the outside of ISS on August 3, 2006.
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    image This image shows MISSE-7 prior to launch. In the foreground is the ExPA platform on which the PECs are to be mounted. In the background are the two PECs that will be opened on orbit. Courtesy of KSA.
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    image This image shows the PECs mounted on the ExPA prior to launch. Image courtesy of KSA.
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    image NASA Image: S133E010858 - MISSE image taken from the STS-133 mission mounted outside the shuttle.
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    image NASA Image: S133E010727 - MISSE image taken from the STS-133 mission mounted outside the shuttle.
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    image NASA Image: S133E010929 - MISSE image taken from the STS-133 mission mounted outside the shuttle.
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    image NASA Image: S133E010099 - MISSE image taken from the STS-133 mission mounted outside the shuttle.
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    image NASA Image: S134E007533
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