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Facility/Payload OverviewBrief Facility Summary
ADdvanced Space Experiment Processor (ADSEP) is a thermally controlled single middeck locker equivalent that accommodates up to three cassette-based experiments that can be independently operated. Its companion hardware consists of a collection of several experiment cassettes, each doubly or triply contained, that accommodate experiments in cell technology, model organisms, multiphase fluids, solution chemistry, separation science, microencapsulation and crystal growth.
Facility Manager(s)Information Pending
Facility DeveloperTechshot, Incorporated, Greenville, IN
Sponsoring AgencyNational Aeronautics and Space Administration (NASA)
Expeditions Assigned|18|
Previous ISS MissionsADSEP has flown on two Space Shuttle missions, STS-77 and STS-95.
Facility/Payload Description
Facility Summary
- ADdvanced Space Experiment Processor (ADSEP) can be used as a thermal carrier for a wide variety of experiments.
- ADSEP is applicable to any experiment that must be doubly or triply contained, requires thermal control and programmed operation. ADSEP has been proven during space flight in applications to cell cultures, microbial experiments, biphasic extraction, protein and oligonucleotide crystal growth, microencapsulation and is applicable to any experiment involving fluid transfers and/or fluid contacting.
The ADdvanced Space Experiment Processor (ADSEP) biotechnology facility contains three independent thermal zones, each accommodating one cassette, and an internal computer that controls the internal functions of all three cassettes. The number of completely interchangeable cassettes that can be processed on a single mission is limited only by spacecraft storage space. Cassettes can house three bioseparation methods, diffusion-cell and mixing-cell capabilities, and at least two versions of cell-culturing equipment. ADSEP is a fully automated, multi-use single locker processing facility for interface with middeck, SPACEHAB, or International Space Station (ISS) EXpedite the PRocessing of Experiments to Space Station (EXPRESS) Racks. Modular, on-board microprocessors, video cards, and motor driver cards allow ADSEP to be configured for a variety of biotechnology and life science experiments. There currently are several applications using individual cassettes within the unique Techshot ADSEP system:
- Cell Culturing (CellCult) - Each cassette contains a single 50-ml rotating filtered bioreactor, a reservoir for fresh medium, two programmable peristaltic pumps, a waste reservoir and up to six sample-collection or reagent containers connected by manifold to the reactor. Cultures can be operated in continuous perfusion, batch fed, static, or sampling mode. In addition to the removal of samples the addition of additives to the reactor volume can be programmed or teleoperated. Aeration and humidity control are available. At least two of these can currently be made available.
- Microorgamisms and C. elegans (Fluid Processing Cassette) - Each cassette contains a triple-containment system within which a combination of four pumps, eight valves and twelve 30-ml bags can be combined in any way to transfer fluids among containers according to experiment requirements. This versatility affords, for example, up to nine serial transfers, four parallel three-container experiments, or six single-fluid-change experiments. Feeding and fixing of microbial or model-organism (insects, worms) cultures is a typical application. Internal events (starting and stopping flows) are controlled by the ADSEP computer. These cassettes are also designed to operate autonomously (without the ADSEP facility) by battery and manual programming using external toggle switches for which nearly 100 operations can be programmed. Four Fluid Processing Cassettes are currently available.
- Microencapsulation - A process in which tiny particles or droplets are surrounded by a coating to give small capsules with many useful properties. In its simplest form, a microcapsule is a small sphere with a uniform wall around it. The material inside is referred to as the core, internal phase, or fill, whereas the wall is sometimes called a shell, coating, or membrane. The reasons for microencapsulation are many. In some cases, the objective is not to isolate the core completely but to control the rate at which it leaves the microcapsule, as in the controlled release of drugs. The microgravity environment is optimal for the production of microcapsules and an ADSEP cassette is available for this purpose.
- Biphasic Separation (BISEP) - Each cassette contains two pairs of rotating plates. Each pair of plates has 22 pairs of sample cavities. Normally the sample cavities are separate from one another until activation. Upon activation a half-step rotation of the plates brings opposing cavities and their fluid contents into contact with one another. This arrangement provides up to 44 shear cells or diffusion chambers or mixing cups or fluid contactors per cassette. Inserts provide up to four membrane-based diffusion experiments per pair of cavities suitable for crystal growth experiments. Without dynamic control up to 176 such experiments could be accommodated per BISEP cassette. Some plates provide magnetic stir bars for mixing experiments, including mixing-demixing studies. The mixing speed and duration for each pair of plates is controlled by the ADSEP computer. Experiments may be left in contacting position or half stepped to the uncontacted position for sample return and recovery. At least three BISEP cassettes are available currently.
Using its half-stepped mode, ADSEP is capable of conducting up to 44 separate experiments in each cassette assembly. Biological samples are loaded (preflight) into cassettes that provide appropriate levels of containment. Processing module doors are opened with two thumb screws, allowing cassettes to be installed in, and removed from, each processing module on orbit. Cassette interfaces with the processing module through blind-mating power/data connector on back side of cassette. Maximum mass is 34 kg with a peak power requirement of 130 W.
Operations
Facility Operations
ADSEP is launched with power. Upon launch it will contain up to three cassettes that would need temperature control during ascent. Additional cassettes are launched in a stowage locker or another environmentally controlled facility (possibly frozen). The facility with its cassettes is transferred to ISS and installed in an EXPRESS rack and checked out by a crewmember. With a small amount of crew assistance the investigation is initiated from the ground.
The programmed timelines are followed and executed automatically or from the ground (normally), and crewmembers are notified when the cassette in a given compartment is to be replaced by a stowed cassette. All timelines include dynamic control of temperature.
In addition to data recorded during experiments, most investigators require return of their processed samples. ADSEP cassettes return to Earth with or without the ADSEP facility, depending on user requirements and other requirements for sharing the ADSEP facility on subsequent increments.
Results/More Information
Information Pending
Availability
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Publications
Results Publications
Related Publications
Images
ADSEP Cassette. Image courtesy of Techshot, Incorporated.+ View Larger Image
Payload Specialist John Glenn worked with Techshot's ADSEP hardware on orbit aboard space shuttle Discovery on STS-95. Image courtesy of Techshot, Incorporated.+ View Larger Image
Information Provided and Updated by the ISS Program Scientist's Office