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Submitted by Arthur - N1ORC

Kyle Herring
Headquarters, Washington              March 19, 2002
(Phone: 202/358-4504)

James Hartsfield
Johnson Space Center, Houston
(Phone: 281/483-5111)

RELEASE: 02-58


     Expanding the new frontier just as they did the old, 
railroads will take flight next month as the first space 
railroad is launched aboard Space Shuttle Atlantis.

Circling Earth aboard the International Space Station, the 
car on this railway will have a top speed of only 300 feet 
per hour, but the entire line -- tracks and all -- will 
travel almost nine times faster than a speeding bullet, over 
17,000 miles per hour, in orbit. The rail line eventually 
will stretch almost 100 yards along the structural backbone 
of the station, serving as a mobile base from which the 
station's Canadian-built robotic arm can assemble and 
maintain the complex.

"To build the rails that linked the east and west coasts of 
the United States, thousands of workers endured desert heat, 
frigid mountains and countless obstacles. These rails in 
space will run in temperatures far hotter than any desert and 
far colder than any mountain," said NASA Mobile Transporter 
Subsystem Manager Tom Farrell at the Johnson Space Center in 
Houston. "And just like the transcontinental rails pulled 
together our country, these rails pull together 16 nations 
around the world, cooperating in orbit."

Atlantis will launch the railcar, called the Mobile 
Transporter, and an initial 43-foot section of track as it 
delivers the first segment of the International Space 
Station's exterior truss. Designated "S0 (S-zero)," the first 
section of truss will be carried aloft by Atlantis on shuttle 
mission STS-110 in April. More sections of track will be 
added during the next two years as eight segments of the 
girder-like truss are launched aboard the shuttle. By the end 
of this year, the tracks already will stretch more than 130 
feet. When completed, the truss will stretch over 360 feet, 
the longest structure ever built in space.

An additional base system will be attached atop the flatcar-
like Mobile Transporter during a shuttle flight in May, but 
the space train will leave the depot for its inaugural run 
during Atlantis' April mission. After spacewalkers loosen 
launch restraints and attach electrical and computer cable 
reels, Mission Control will command the Mobile Transporter 
railcar to inch its way up and down the 43-foot section of 

"It's built for precise positioning and smooth velocity 
control; it's not built for speed," said Randy Straub, 
subcontract technical manager for the system with The Boeing 
Company in Huntington Beach, Calif.

The operation of the railway is critical for continued 
assembly of the station. It will allow the station's 
Canadarm2 robotic arm to carry future truss segments and 
solar arrays down the tracks to install them. Part flatcar 
and part locomotive, the Mobile Transporter weighs 1,950 
pounds and is a horse made of aluminum, not iron. The Mobile 
Transporter was built by TRW Astro in Carpinteria, Calif., 
for Boeing, the prime contractor for station construction. It 
measures three feet high, nine feet long and eight feet wide 
and moves along two parallel rails attached to the station 
truss at speeds varying from one-tenth of an inch to one inch 
per second. Although driven by dual electric motors that 
generate only about a hundredth of one horsepower, the 
transporter can move 23 tons of cargo down the rails.

What is the hardest part about building a zero-gravity 

"We've done a lot of work to make certain it can't jump the 
tracks," said Farrell. "We have to be sure it will be safe 
during all the station's activities, like reboosting its 
orbit or having visiting vehicles dock."

The transporter stays on track with three sets of wheels, one 
set that propels it and two sets in roller suspension units, 
spring-loaded units that have rollers on both sides of the 
track to ensure the transporter can't float loose. The 
railcar will have 10 stops, specific locations called 
worksites where it can be locked down with a 7,000-pound 
grip, allowing the robotic arm to safely maneuver cargo. 
Although it can be driven from the station or from the 
ground, the engineers for NASA's space railroad will normally 
reside in Mission Control, Houston, driving the train from 
thousands of miles away and hundreds of miles below.

Although the Mobile Transporter will be a freight train and 
not a passenger train, space- walking astronauts will have 
their own form of personal rail transportation aboard the 
station. Astronauts will operate a small handcar to maneuver 
up and down the rail line, a car that they will pull along 
the zero-gravity railway by hand to move themselves and their 
gear from place to place. Called the Crew and Equipment 
Translation Aid, two such carts will be delivered to the 
station before the end of the year.



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