Science in a Box
To many people, gloveboxes are what medical researchers use to separate themselves from deadly viruses. The former Lunar Receiving Laboratory at Johnson Space Center had several gloveboxes to isolate Earth from possible germs in moon rocks - and to protect the rocks from earthly contamination. But gloveboxes come in many sizes and shapes, and levels of containment.
The Middeck Glovebox, or MGBX, on board MSL-1 is not as tightly sealed as a virus research glovebox. The MGBX is designed to keep particles from floating out of experiments and into the module where the astronauts might breath them since, in weightlessness, dust and aerosols don't fall to the floor. The first level of protection is sealable doors and gloves which seal the work area off from the crew cabin. Another level is provided by a fan which draws air from the work area through two banks of filters that trap particles, droplets, and gases, preventing them from entering the crew cabin. Other levels include sleeves that close around the operator's wrists, or true gloves that completely isolate skin on the outside from test samples on the inside.
|Using the MGBX means getting up close and personal with the experiments. At left, Cady Coleman (mission specialist on USML-2) trains with an early model on board the DC-9 low-g aircraft. At right, top, Don Thomas conducts an experiment on MSL-1, Flight Day 1.||
One reason for building the MGBX, Reiss said, is to provide a way for scientists to design and build low-cost experiments and get them flown quickly. The Spacelab glovebox design was developed by the European Space Agency and suggested to NASA in 1989. Reiss, Roger Kroes, and Barbara Facemire of SSL developed an initial list of experiments to illustrate how the glovebox might be used.
As a result, NASA and the investigators for the first U.S. Microgravity Laboratory (USML-1) added the glovebox to the USML-1 mission. From the time the investigations were selected until flight took about 18 months and often cost less than $50,000.
Reiss said that he and Kroes developed a crystal nucleation experiment for about $46,000. Since then, this MGBX has flown on the Shuttle several times, and a second unit has been installed aboard Russia's Mir space station.
|Fiber-supported droplet combustion (FSDC) is carried out inside a small box mounted inside the Middeck Glovebox.||
On MSL-1, the glovebox is supporting experiments in capillary heat transfer, fiber-supported droplet combustion, bubble and drop nonlinear dynamics, and internal flows in a free drop, and coarsening in solid-liquid mixtures.
In exchange for the low cost of developing experiments, scientists face other challenges.
"You're working in pretty cramped quarters," Reiss said of the space inside the glovebox, "so it requires some manual dexterity."
As he spoke, an interviewer carefully maneuvered a mockup of the CHT experiment (pictured below) into a training model (complete with English and Russian labels) of the glovebox. The experiment itself was the size of a school kid's lunchbox, and had thick plastic panels on each side so video cameras can watch the flow of alcohol in glass tubes.
The experiment is meant to help scientists understand why this promising method of cooling spacecraft equipment will often lock up and stop moving heat. A box with banks of light emitting diodes (LEDs) displays temperatures and other conditions in the experiment.
This also displays the low-cost philosophy of the MGBX. While the data could be downlinked through the Spacelab data system, it is less expensive to put one of the HiPac cameras on the display.
|Looks can be deceiving. The closeup image (left) of the capillary heat transfer experiment is taken by a TV camera mounted on the window atop the MGBX which makes it appear larger than life. The experiment hardware (right) is a little larger than a school kid's lunchbox.|
"It requires a lot of ingenuity and design work by the principal investigators," Reiss said. It also allows the use of the most valuable of orbital research tools: the astronauts' hands and eyes. "This is what it was designed for," Reiss said. "It takes full advantage of the capabilities of the crew."
As the astronauts run the experiments, investigators can watch on the ground and redirect their activities. "These experiments are so crew intensive that it's like normal ground-based lab activities where the scientist goes in and works the hardware himself," Reiss said.
Two separate sets of MSL-1 experiments on flows inside droplets (to understand why air bubbles sometimes stick inside, and how sound might be used to clean up samples before growing crystals) "have required a lot of skill by the astronauts to get these droplets deployed properly," Reiss said. "Sometimes they fly off. Getting them captured and stabilized is not a trivial thing."
At least one more flight is scheduled for the glovebox, on the U.S. Microgravity Platform (USMP-4) on STS-87 in November; other flights are being considered. Eventually, most of the glovebox activity will be in the large Microgravity Science Glovebox facility being developed for International Space Station.
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Author: Dave Dooling
Curator: Bryan Walls
NASA Official: John M. Horack