Hans.Moravec%CMU-RI-ROVER@sri-unix.UUCP (01/07/84)
n507 2246 06 Jan 84
BC-SHUTTLE-2takes-01-07
ADVANCE FOR SUNDAY
By Albert Sehlstedt Jr.
(c) 1984 The Baltimore Sun (Independent Press Service)
WASHINGTON - Capitalizing on a maturing shuttle program, the United
States will fly a record number of manned missions in space this year
and experiment with a new method of maneuvering astronauts between
orbiting vehicles.
Ten shuttle flights, beginning with a Feb. 3 mission that will test
a ''Buck Rogers'' backpack, will double the number of astronaut
voyages attempted in any year of the National Aeronautics and Space
Administration's 25-year history.
A previous maximum of five manned missions were flown in 1965 and
1966 when NASA was preparing for the moon landings that began in the
summer of 1969.
The maximum number of cosmonaut flights conducted by the Soviet
Union in any year was six in 1980. However, the USSR, unlike the
United States, has been constantly active in manned flight
operations, accumulating extensive medical data and experimenting
with long-duration missions lasting months at a time.
The Russians appear also to be developing their own version of a
space shuttle, and last month a congressional report said they were
embarked on long-range programs to colonize the moon and Mars.
NASA's plans this year call also for the deployment of 10 unmanned
satellites from the 60-foot-long cargo bays of the shuttles as well
as conducting 12 other space missions with so-called expendable
launching vehicles; rockets that are used once and not recovered
after a launching.
Two of the highlights of the American program in 1984 will be the
first test of the rocket backpack early next month, followed by a
similar operation in April when other astronaut crewmen will leave
the shuttle, fly to an inoperative scientific satellite and haul it
back into the cargo bay for repairs.
Next month's flyers will be Bruce McCandless 2d and Robert L.
Stewart, the first Army astronaut assigned to the space program. All
others have come from the Air Force, Navy, Marine Corps and civilian
pursuits.
McCandless and Stewart will venture from the shuttle on the fifth
and seventh days of the eight-day mission, which is scheduled to end
with the first landing of a shuttle on the 15,000-foot runway of
NASA's Kennedy Space Center in Florida.
The two crewmen will fly several hundred feet away from the shuttle,
simulating the exercises future astronauts will employ when repairing
or recovering inoperative satellites or, perhaps, rescuing comrades
from a disabled space vehicle.
Neither astronaut on this mission (or future missions) will be
attached to the shuttle by any sort of tether, though the February
test is a first.
NASA abandoned the tether idea when, on reflection, the astronauts
and other experts concluded that a dangling rope or other kind of
line could become twisted in a man's legs or, worse yet, flap him
whip-like against the side of the shuttle or a satellite he was
attempting to reach.
Indeed, one of the principal objectives of the McCandless-Stewart
venture is a better understanding of how this sort of Buck Rogers
maneuvering actually works in weightless flight as shuttle and
astronauts orbit the earth at 17,000 miles an hour 150 miles above
the atmosphere.
The backpack, which would weigh more than 300 pounds on earth, was
designed and built by the Denver division of Martin Marietta
Aerospace under research and development contracts totaling
approximately $40 million and extending over a period of years.
NASA refers to the pack (two have been built for use in space) as a
manned maneuvering unit, or MMU.
Each MMU is equipped with 24 small jets positioned in such a way
that the astronaut can move in any direction or roll, pitch and yaw
like an airplane in flight.
The astronaut's arms rest on two rigid supports, resembling splints,
that extend forward from the backpacks. At the end of each splint are
hand controllers that he manipulates to propel himself in any desired
direction.
There is enough propellant (nitrogen) in the MMU to allow a flyer up
to six hours of flight outside the shuttle.
The maneuvering system is divided into two parts so that if one part
fails the other can be used to propel the astronaut back to the
shuttle.
Should both systems fail, the shuttle pilots could maneuver close
enough to the stranded astronaut that he could be retrieved with the
craft's mechanical arm. The 50-foot-long arm would be operated by
another crewman through electronic controls on the shuttle's flight
deck.
The second mission using the MMUs is scheduled April 4 when another
shuttle crew will fly up to a satellite called the Solar Maximum
Mission (SMM) that was launched on Valentine's Day in 1980 for
scientific studies of solar flares.
The following winter, the 17,000-pound SMM became partly disabled
when one of its control systems failed and one of its seven
scientific instruments became inoperative.
A shuttle crewman will stabilize the tumbling satellite so that it
can be grasped by the mechanical arm and brought into the cargo bay
for repairs.
Retrieval and repair of satellites is one of the principal functions
of the shuttle program.
In June, NASA plans to launch the shuttle Discovery on its maiden
voyage, bringing to three the number of craft in regular service. (A
fourth shuttle, now being built, will complete the fleet, which is
being developed and built at a cost of about $10 billion.)
Additional shuttle flights are scheduled through the summer and
fall. Barring unforeseen difficulties, NASA intends to complete the
10-mission shuttle year with another flight of the Discovery on Dec.
17.
END
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