NASAexplores 9-12 Article: Two-Ton Hockey Pucks (PDF)

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NASAexplores 9-12 Article: Two-Ton Hockey Pucks (PDF)

Two-Ton Hockey Pucks

Superman isn’t the only one who can move a

2-ton automobile with his pinkie finger.

Astronauts can do it, too. There aren’t any

cars in space, but the crew can move objects

of similar weight with just as much ease. In

microgravity, there isn’t any friction to

provide resistance; therefore, massive objects

can become air-borne with a simple nudge.

While it’s easy to move large pieces of

equipment, they may be difficult to maneuver

or stop. Nobody wants a 2-ton object drifting

out of control! To help astronauts maintain

control in space, astronauts practice what it’s

like to work in microgravity while still on

Earth.

That’s where it gets complicated. There isn’t a microgravity simulator that perfectly

replicates the environment of space. That’s why NASA has developed many different

simulators. Each one of these simulators re-creates a specific part of microgravity. The

KC-135 airplane allows astronauts to tumble through the air in a free fall. The Neutral

Buoyancy Laboratory permits astronauts to work in an underwater lab with similar

conditions to floating in space. Virtual reality simulators show astronauts the visual

aspects of space. Drop towers put objects and experiments in a near-microgravity setting

for short periods of time. But, where do astronauts practice moving those large,

cumbersome objects? They proceed to the Precision Air Bearing Facility (PABF) at

Johnson Space Center in Houston.

At this facility, astronauts use the airbearing

floor. Imagine a giant air

hockey table about 6 meters [m] (20

feet [ft]) wide and 9.1 m (30 ft) long,

says Tom Smith. He is the mock-up

manager for the PABF. Once on the

special floor, astronauts can manipulate

massive objects as easily as an air

hockey puck floats across a game table.

If you have ever played air hockey,

you’ve seen the hockey puck float on a

thin cushion of air blown from the

surface of the table. On the air-bearing

floor, it works conversely. The air is blown down through the hockey puck. This causes

the puck to hover just millimeters off the floor. For 2-ton hockey pucks to stay in a

position so close to the surface, that surface must be very smooth and level.

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The floor is constructed of steel plates lined up alongside one another. More steel plates

are combined to form pads. These pads are attached to the bottom of the objects that

astronauts practice moving. Compressed air is then released into a tube that runs along

the side and bottom of the plate. When running, the air-fed plates hover just above the

floor’s surface so that it only requires a nudge for large objects to effortlessly glide across

the surface.

What kind of maneuvers do astronauts practice on the

air-bearing floor? They mainly handle large orbital

replacement units—some as large as a car—and

learn how to carefully guide them in the right

direction. They also practice using tools the way

they’d be used in space. Without gravity to keep the

astronaut in place, a simple twist of a screwdriver can

send him or her spinning. Astronauts can compensate

for the torque created by drills, wrenches, and pliers

by anchoring themselves or bracing their bodies.

Engineers also use the air-bearing floor as they’re

developing products and parts that will travel into

space, Smith says. Something as simple as a door hinge can be tested to see how it will

work without the friction found on Earth. By moving the hinge on the giant precision airbearing

floor, it’s easy to see if modifications need to be made because of microgravity.

“Some people call this a zero-gravity room, but that’s not accurate,” says Smith.

“There’s plenty of gravity in here. This floor simulates the effects of reduced gravity on

one plane only, not throughout the entire room. It’s pretty amazing, though, to see how

easy it is to move something weighing 2 tons with just your pinkie.”

Related NASAexplores articles:

“Just In Case”—Emergency landing sites for Space Shuttle launches

http://www.nasaexplores.com/show2-articlea.php?id-02-010

“Drop Everything!”—Drop towers

http://www.nasaexplores.com/show2_articlea.php?id=02-006

“Microgravity: Always a Bad Hair Day”—Effects of microgravity

http://www.nasaexplores.com/show2_articlea.php?id=01-044

“The Weightless Wonder”—The KC-135 airplane

http://www.nasaexplores.com/show2_articlea.php?id=03-008

“Astronauts Take a Dive”—The neutral buoyancy laboratory

http://www.nasaexplores.com/show2_articlea.php?id=02-066

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