Kennedy Space Center Fixation Tube (KFT) - 10.31.18

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ISS Science for Everyone

Science Objectives for Everyone
The Kennedy Space Center Fixation Tube (KFT) is an apparatus designed to contain plant or other small biological samples during flight and chemically fix and stain the tissue samples while providing three safety-levels of containment.
Science Results for Everyone The Kennedy Space Center Fixation Tube (KFT), which carries and chemically fixes biological samples in space, holds promise for future molecular biological experiments. It uses a triple-redundant sealed environment for chemical fixatives extremely hazardous to humans. In a plant investigation using RNALaterTM sample preservative, the KFT resulted in better preservation. Onboard modifications also enhanced KFT’s functionality and storage potential in support of a plant gene-expression investigation. The KFT quickly preserves samples, holds potential for long-term storage without compromising RNA integrity, and offers simplified stow and descent procedures. KFTs filled with RNALaterTM can be deployed months or possibly years prior to use.

The following content was provided by Orlando Melendez, and is maintained in a database by the ISS Program Science Office.
Facility Details


Facility Manager(s)
Orlando Melendez, NASA Kennedy Space Center, Kennedy Space Center, FL, United States

Facility Representative(s)
Charles D. Quincy, NASA Kennedy Space Center, Kennedy Space Center, FL, United States

NASA Kennedy Space Center, Space Life Sciences Laboratory, FL, United States

Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)

Sponsoring Organization
Human Exploration and Operations Mission Directorate (HEOMD)

ISS Expedition Duration
December 2001 - June 2002; October 2007 - October 2008; April 2009 - March 2010

Expeditions Assigned

Previous Missions
The KFT was utilized by investigations on ISS Increment 4 (PESTO), 16 and 17 (CWRW).


  • Available for Launch
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    Facility Description

    Facility Overview

    The Kennedy Space Center Fixation Tube (KFT) is a device designed to contain small biological samples during flight and chemically fix and stain the tissue samples. KFT is small and easy to use, and is well suited to use in the field as well as in the laboratory. Because typical chemical fixatives are extremely hazardous to humans, the device is also designed to contain its fixative solution within a triply-redundantly sealed environment.
    The KFT provides three levels of containment for the chemical fixative during stowage and operations. The KFT is comprised of the following elements: a polycarbonate main tube where fixative is loaded preflight, the sample tube which is used to keep the plant or other specimen in place during operations, the expansion plug, top plug, base plug, and the plunger. The KFT contains approximately 25 ml of fixative solution and provides a usable sample volume of 25 ml.  KFTs are proven to provide very robust containment.
    The KFT has demonstrated to maintain its containment at ambient temperatures, +4ºC refrigeration, and -99ºC freezing. The KFT has been shown to be compatible with many fixative reagents. Some of the tested reagents are: 
    • KFT, Glutaraldehyde (2%),(3%),(5%)
    • KFT, Formaldehyde (0.4%),(2.5%),(5%)
    • KFT, RNALater
    • KFT, Glutaraldehyde (2%) + KFT, Formaldehyde (2.5%)
    • KFT, Formaldehyde (5%) + DMSO (5%)
    • KFT, X-GLUC • KFT, Glutaraldehyde/Paraformaldehyde
    • KFT, Paraformaldehyde (4%) + Gluataraldehyde (3%).
    In flight, in order to perform fixation of the samples, the KFT system is removed from the zip lock storage bag in which the hardware is stowed. The crew inspects the bag prior to opening to ensure there are no leaks. After a specimen is placed into the sample tube, a plunger is removed from the locker and inserted into the main tube to provide three levels of containment between the sample tube and the outside environment. The plunger is locked into place at the top of the tube and cannot be removed from the main tube once engaged. The fully assembled KFT is actuated by turning the plunger handle several turns to release the internal expansion plug. Fixative is forced through openings located in the bottom of the sample tube. The expansion plug continues to be forced down until it reaches the base plug of the main tube. The specimen is now partially to fully submerged in the fixative solution, thus completing the operation. The fired KFT is then replaced in the plastic bag and restowed in a locker or transferred to Minus Eighty-Degree Laboratory Freezer for ISS (MELFI) or other conditioned stowage as required.

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    Facility Operations

    • The KFT includes a main tube, sample tube, expansion plug, base plug, and top-plug/plunger assembly.
    • Prior to use, the fixative solution is contained at the bottom of the main tube, below the expansion plug. The sample is placed in the sample tube, which is then inserted in the main tube and sealed in the main tube by inserting the top plug.
    • Next, the plunger is used to actuate a mechanism that loosens the seals on the expansion plug, then pushes the sample tube down against the sample plug, thereby pushing the sample into the fixative solution.

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    Decadal Survey Recommendations

    Information Pending

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    Results/More Information

    When conducting biological studies, it is important to maintain the integrity of the samples. The standard method to preserve samples is quick freezing at low temperatures, -80º C (-112º F) and below, but strict temperature control of samples on station is not always uniform or possible. Therefore, a preservation method is needed that will maintain the integrity of biological samples. In conjunction with the KFT, RNALaterTM was used to preserve some of the PESTO samples on station during increment 4. Results indicated that the method utilized resulted in a sample which was better preserved for future analysis (Paul 2005).

    Certain modifications of the KFTs were designed to enhance on orbit functionality and storage potential in support of the TAGES (Transgenic Arabidopsis Gene Expression System) investigation. The KFT main tube was shortened allowing it to fit into certain areas and changes to the actuator mechanism and the expansion plug mechanism were made to create a more reliable system. Analysis of the returned TAGES samples was performed and determined that the RNA integrity was very good. The KFT device is extremely valuable because it quickly preserves harvested samples, it holds potential for long term storage without compromising the RNA integrity and because it does not require specific temperature regulations, destow and descent procedures have been simplified. We also established that KFTs filled with RNALaterTM can be effectively deployed to orbit months or possibly years prior to use. Utilizing KFT devices creates a large window of opportunities for future molecular biological experiments (Ferl 2011).

    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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    Kennedy Space Center Fixation Tube (KFT).

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