Summary of Operational Capabilities

BIOTUBE is the first in a series of generic payloads that can accommodate a wide variety of space flight research. The BIOTUBE is a fully automatic apparatus not requiring continuous supervision. It allows crew interaction on-orbit through the front panel user interface and provides for environment (temperature, humidity, pressure) monitoring. It also provides fixative delivery to the specimen. A digital imaging system allows video images to be viewed on the front panel user interface and to be downlinked in realtime during the mission.

The Magnetic Field Apparatus (MFA) hardware is designed to conduct experiments exposing plant tissue to high gradient magnetic fields in a microgravity environment. The MFA hardware consists of three Magnetic Field Chambers, three HOBO temperature data loggers, a water delivery system, a fixative delivery system and a Digital Imaging System.

All hardware components are contained within the Generic External Shell (GES), which is geometrically equivalent to and replaces a single standard Orbiter middeck locker. The Generic Containment Unit (GCU) provides three levels of redundant containment for the MFA hardware and is located inside the envelope of the GES. The Command and Data Management System (CDMS) is located outside the GCU but is contained within the GES.

The BIOTUBE/MFA utilizes Orbiter provided 28 VDC power and an onboard fan to cool the CDMS electronics.

Usage

The BIOTUBE has flown on the following payloads:

Mission	Payload (Experiment)
STS-107	BIOTUBE/MFA (Biotube-01)

BIOTUBE succesfully flew in STS-107.

Technical Details

The BIOTUBE/MFA apparatus consists of several hardware components designed to provide a device targeted at growing seeds in space flights. The main hardware components and their function are summarized here:

1. generic shell - A generic housing system for SSP middeck experiments. It houses all the sub-elements of the BIOTUBE/MFA experiment, providing structural support to the sub-elements via a pair of attached rails.
2. generic containment unit - Provides three levels of containment to all sub-elements of BIOTUBE/MFA except for the command and data management system. This is necessary since the hardware contains and delivers both water and a fixative liquid that need to be contained in the event of a malfunction.
3. magnetic field chamber - A container holding the eight separate seed cassettes (arranged in two rows). Each of the seed cassette holds eight seeds attached to germination paper and provides a conduit for water to imbibe the seeds in orbit (they are dry at launch). The germination paper acts as a liquid distributor (putting wicked water in contact with the seeds) and temporary water reservoir for germinating seeds. Each chamber has a clear polycarbonate cover that enables imaging of the gowing seeds. Ten magnets are placed around the seed cassettes to provide the experiment's magnetic fields. Since these magnets are exposed to both water and fixative, they are teflon coated in order to provide a hydrophobic surface.
4. water delivery system - Consists of the "micro-effusion delivery unit for space applications", a stepper motor and tubing. It is controlled by the Biotube/MFA command system and requires no crew intervention for activation and liquid delivery. The system can deliver up to 0.6 ml of water to each seed cassette. No fixative is present in the water delivery system. A piston driven system ensures that the water is delivered simultaneously to all seed cassettes.
5. fixative storage and delivery system - Stores and delivers the fixative to the magnetic field chambers. This is a self-contained and sealed system. An air pump pressurizes the fixative storage container triggering the opening of a valve to allow the fixative to flow serially through all seed cassettes in the magnetic field chambers. A waste bag at the end of the circuit takes in the fixative as it is expelled from the magnetic field chambers. Each magnetic field chamber has its own fixative reservoir bag (maximum fixative capacity 165 ml), valve and waste bag.
6. digital imaging system - To support the experiment requirement of observing the effect of a high gradient magnetic field on root curvature, images of the growing roots are obtained using the digital imaging system. The system consists of 4 CCD cameras, a video multiplexer, lighting multiplexer and sixteen infrared LEDs. The LEDs provide illumination while the photos are being taken. A total of two magnetic field chambers are imaged, the third one is not.
7. command and data management system - This system houses the bulk of the electronics used to provide overall control of the magnetic field chamber’s integrated subsystems. It also houses the man-machine interface (the latter consists of a graphical user interface with a mouse pointer, system status and error message display, image display and other functions as well).