Minus Eighty-Degree Laboratory Freezer for ISS (MELFI) - 10.08.14

Summary | Overview | Operations | Results | Publications | Imagery
ISS Science for Everyone

Science Objectives for Everyone
The Minus Eighty-degree Laboratory Freezer for ISS (MELFI) is a cold storage unit that maintains experiment samples at ultra-cold temperatures throughout a mission.

Science Results for Everyone
Information Pending



The following content was provided by Kimberley Hostetler, and is maintained in a database by the ISS Program Science Office.

Facility Details

OpNom:

Facility Manager(s)

  • Kimberley Hostetler, Johnson Space Center, Houston, TX, United States

  • Facility Representative(s)
    Information Pending
    Developer(s)

    Air Liquide, Paris, , France
    Computadoras Redes e Ingenieria S.A (CRISA), Madrid, , Spain
    Danish Aerospace Medical Centre (DAMEC), Odense, , Denmark
    EADS Astrium, Velizy Villacoublay, , France
    ETEL, Motiers, , Switzerland
    European Space Agency (ESA), Noordwijk, , Netherlands
    Kayser Threde, Munich, , Germany
    Linde, Munich, , Germany

    Sponsoring Space Agency
    National Aeronautics and Space Administration (NASA)

    Sponsoring Organization
    Human Exploration and Operations Mission Directorate (HEOMD)

    ISS Expedition Duration
    April 2006 - September 2015

    Expeditions Assigned
    13,14,15,16,17,18,19/20,21/22,23/24,25/26,27/28,29/30,35/36,37/38,39/40,41/42,43/44

    Previous ISS Missions
    Information Pending

    Availability
    Information Pending

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    Facility Description

    Facility Overview

    • This multi-purpose freezer significantly enhances the research capabilities of the U.S. Laboratory on ISS.


    • MELFI will support a wide range of life science experiments by preserving biological samples (such as blood, saliva, urine, microbial or plant samples) collected aboard ISS for later return and analysis back on Earth.


    • Samples from the ISS Medical Project will be stored in MELFI and contribute to multiple studies of the effort of space flight on human health.

    The cooling system of the Minus Eighty-Degree Laboratory Freezer for ISS (MELFI) is based on the Reverse Brayton Thermodynamic Cycle which uses nitrogen gas as a working fluid. This system was chosen for its power efficiency at the desired operating temperatures and for its low perturbation of the microgravity environment aboard the ISS. The cooling engine is Brayton Machine (BM) which utilizes a compression wheel and expansion wheel on the same shaft supported by a gas bearings system. The BM can rotate at speeds up to 96,000 rpm depending on the cooling requirements.. After the nitrogen is cooled in the BM, it is distributed to each of four independently-controlled, thermally-insulated volumes (dewars). At each dewar, the nitrogen tubing is ended by a cold finger, which provides refrigeration to that dewar. Distribution of cold gas in each dewar is controlled by a valve in the cold finger depending upon the set point of that dewar. The nitrogen loop is a closed loop system; the nitrogen never comes in contact with the samples in the dewars.

    Four cross members on each cold finger provide a conduction path from the cold finger to the tray, which is the basic utilization hardware provided by MELFI. Each dewar includes four trays that can be extracted without disturbing the samples in the other locations. Furthermore, each tray contains a combination of one-quarter size box modules and one one-half size box modules to hold science samples. Standard accommodation hardware is provided for the insertion of samples of different sizes and shapes.

    Although MELFI is techinically capable of operation at any setpoint between 10 degrees C and -99 degrees C, there are three standard operating modes; -95 degrees C, -35 degrees C and 2 degrees C. The dewar temperature is continuously monitored and recorded realtime. During power-off phases, a battery-powered temperature data recorder operates to continue recording dewar temperatures. To ensure efficient thermal insulation, the space between the double walled dewars is pumped to a very high, molecular vacuum. The on-orbit commissioning of the first MELFI flight unit included verification of the actual cooling performance provided to the samples. For this, the European Space Agency developed the MELFI On Orbit Commissioning Experiment (MOOCE) which provided additional instrumentation in the dewar tray that holds the scientific samples. MOOCE's 24 thermocouples provided comprehensive temperature mapping of the tray, the box modules and the samples. During the test, the MOOCE's external data acquisition unit provided continuous recording of the test sample temperature data which was retrieved via the ISS Laptop. The test results were sent to the ground using the ISS downlink communication services.

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    Operations

    Facility Operations

    • The freezer is based on the Reverse Brayton Thermodynamic Cycle which uses nitrogen gas as a working fluid. It includes four individually-controlled dewars which can be configured to support samples at temperatures between 10 degrees C and -99 degrees C.


    • The three common modes of operation being -95 degrees C, -35 degrees C and 2 degrees C.

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    Results/More Information
    Information Pending

    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

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    Imagery

    image NASA Image: ISS013E51695 - MELFI after installation on the International Space Station during Expedition 13.
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    image A one-fourth size standard box module for MELFI, full of standard vial cards with frozen samples.
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    image NASA Image: ISS033E016184 - ISS Commander Sunita Williams and Aki Hoshide transferring MELFI samples during Expedition 33.
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    image NASA Image: ISS013E64641- Astronaut Jeff Williams, Expedition 13 ISS Science Officer, places a POEMS sample into the MELFI freezer (Minus Eighty Laboratory Freezer for ISS).
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    image NASA Images: ISS014E13005 - Expedition 14 Commander, Astronaut Michael E. Lopez-Alegria, inserts ISS Cold Enclosure PCM Augmenting Capsules (ICEPACs) into the MELFI in the Destiny laboratory module.
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    image NASA Image ISS015E10573 View of Expedition 15 astronaut and Flight Engineer (FE-2), Sunita Williams, inserting blood samples into the MELFI for the Nutritional Status Assessment (Nutrition) experiment to help understand human physiologic changes during long-duration space flight. Photo was taken in the U.S. Laboratory/Destiny.
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    image NASA Image: S126E008593 - Mission Specialist Greg Chamitoff and Expedition 18 Flight Engineer Sandra Magnus conduct a sample transfer from the General Laboratory Active Cryogenic ISS Experiment Refrigerator (GLACIER) to Minus Eighty Degree Laboratory Freezer For ISS (MELFI). Image was taken in the Japanese Experiment Module (JEM), Kibo during joint operations between Expedition 18 and STS-126/ULF2.
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    image NASA Image: ISS017E017539 - NASA astronaut Greg Chamitoff, Expedition 17 flight engineer, works with the Minus Eighty Degree Laboratory Freezer for ISS (MELFI) as part of the Nutritional Status Assessment (Nutrition) experiment in the Destiny laboratory of the International Space Station.
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    image NASA Image: ISS024E006978 - NASA astronaut Doug Wheelock, Expedition 24 flight engineer, services the Minus Eighty Laboratory Freezer for ISS (MELFI-1) in the Kibo laboratory of the International Space Station.
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    image NASA Image: JSC2008e157029 - Minus Eighty Degree Laboratory Freezer for ISS (MELFI) before launch to ISS.
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    image NASA Image: ISS019E005715 (11 April 2009) Astronaut Michael Barratt, Expedition 19/20 flight engineer, performs an insertion of urine samples into the Minus Eighty Degree Laboratory Freezer for ISS (MELFI) as part of the Nutritional Status Assessment (NUTRITION) study in the Japanese Kibo laboratory of the International Space Station.
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    image NASA Image: S116E07446: European Space Agency (ESA) astronaut Thomas Reiter, STS-116 mission specialist, works with the Passive Observatories for Experimental Microbial Systems in Micro-G (POEMS) payload in the Minus Eighty Degree Laboratory Freezer for ISS (MELFI) in the Destiny laboratory of the International Space Station while Space Shuttle Discovery was docked with the station. MELFI is a low temperature freezer facility with nominal operating temperatures of -80, -26 and +4 degrees Celsius that will preserve experiment materials over long periods.
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