"6_2_15_4.TXT" (3096 bytes) was created on 11-02-87

         SOLID ROCKET BOOSTERS
              Prior to launch, the entire weight of the Space  Shuttle is
         supported on the launch pad by two solid rocket boosters.  Each
         booster is attached to the pad by four large bolts.
              The heart of each booster is the motor, the largest solid
         rocket ever to be flown and the first designed for reuse.  It is
         made of four factory prepared segments filled with propellant at
         the manufacturer's facility and assembled at the launch site.
         The segmented design permits ease of fabrication, transportation
         and handling.
              The motor segments are loaded in pairs from one batch of
         propellant ingredients to minimize any thrust imbalances between
         boosters used for a single Shuttle flight.  Propellant loading is
         also done in such a manner as to cause a reduction in thrust 55
         seconds into the Shuttle flight to prevent overstressing the
         Shuttle vehicle during its critical phase of flight, the period
         of maximum dynamic pressure.  Each booster develops approximately
         11.8 million Newtons (2.65 million pounds) of thrust.
              The exhaust nozzle in the aft segment of each motor, in
         conjunction with the orbiter main engines, steers the Shuttle
         during flight.  It can be moved up to eight degrees by the booster
         thrust vector control system which is controlled by the orbiter
         guidance and control computer.
              At burnout the two solid rocket boosters are separated from
         the external tank by pyrotechnic (explosive) devices and moved
         away from the Shuttle vehicle by eight separation motors -- four
         housed in the forward compartment and four mounted on the aft
         skirt.  The separation motors are fired by a command from the
         orbiter.  
              The recovery system, in the forward section of the booster,
         consists of parachutes and a homing  device.  Following separation
         -- at about 5.8 kilometers (19,000 feet) -- the booster is slowed
         by a drogue parachute and finally by three main parachutes to
         impact water at a speed of about 25 meters/second (85 feet/sec),
         aft end first.  By entering the water this way, the air in the
         empty booster is trapped and compressed, causing the booster to
         float with the forward end out of the water.  After divers insert
         a nozzle closure and force the  water from the booster using air
         pumps, the booster is towed to shore.
              After recovery, the booster is disassembled and refurbished.
         The motor segments are shipped to the manufacturer for reloading
         for another Shuttle flight.  The other systems are refurbished
         either at the launch site or at the respective manufacturers'
         locations.
         
         Solid Rocket Booster
              Length      45.5 meters (149.1 feet)
              Diameter     3.7 meters (12.2 feet)
         

"6_2_15_9.TXT" (7048 bytes) was created on 11-28-88

  SPACE SHUTTLE SOLID ROCKET BOOSTER RETRIEVAL SHIPS

   When the Space Shuttle's two solid rocket boosters (SRBs)
burn out just over two minutes after shuttle liftoff, the
rockets separate from the external tank and fall toward the
Atlantic Ocean.  Unlike SRBs previously used in the space
program, the rocket casings and associated flight elements
are recovered so that they can be reloaded with propellant
and reused. The boosters are retrieved about 258 kilometers
(160 miles) downrange by two identical retrieval ships
leased by NASA.

   The ships, Liberty Star and Freedom Star, were built at
the Atlantic Marine Shipyard at Fort George Island near
Jacksonville, Fla., and leased by NASA.

   SRB separation is at  49.7 kilometers (30.8  miles),  but
the  spent boosters' momentum continues to carry them upward
for 70 more seconds to an altitude of  67  kilometers  (41.6
miles) before they begin to freefall into the Atlantic.

   During the fall,  at 4.7 kilometers (2.9 miles) altitude,
the nose cap is jettisoned,  and a drogue parachute  deploys
from  the frustum,  the truncated cone-shaped structure near
the forward end of the  boosters.  At  an  altitude  of  two
kilometers  (1.24  miles),  the  frustums  separate from the
boosters'  forward  skirts,   releasing   the   three   main
parachutes  on  each booster that carry the main sections of
the casings down to the sea.

   The SRBs splashdown in an area about 11 by 17  kilometers
(7  by  10  miles).  Impact  velocity is about 97 km/h (60.7
miles per hour).  Impact time is  just  over  seven  minutes
after liftoff.

   The  waiting  ships are each 53.6 meters (176 feet) long.
Beam is 11.3 meters (37 feet),  and they are 4.6 meters  (15
feet) deep from main deck to keel.  They draw 3.7 meters (12
feet) of water and displace 955.9 metric tons  (1,052  tons)
each.

   Of  molded  steel  construction,  each  is powered by two
diesel engines that produce a total of 2,900 horsepower.  At
sea they can cruise at 27 km/h (17 miles per hour),  and can
carry fuel for a range of 11,104 km (6,900 miles).  Each can
carry  food  and  water  for  30  days.  Ten  of each ship's
complement  are  operating  crew  and  nine  are   retrieval
specialists.  Also  part of each crew is a representative of
KSC's STS Processing Directorate.  Technical  observers  can
also be carried.

   Electrical   power   is   supplied  by  two  165-kilowatt
generators,   backed  up  by   a   four-kilowatt   emergency
generator.

   Steerage  is  by  rudder  and  the maneuvering capability
inherent in twin,  variable-pitch screws.  This is augmented
by  a  425-horsepower  bow thruster providing port/starboard
thrust and a stern water-jet thruster which can be  directed
through a full 360-degree circle.

   Each  ship  can  apply  a towing pull of 27,216 kilograms
(60,000 pounds or 30 tons).

   An SRB casing, after the fuel is exhausted, weighs 74,840
kilograms (165,000 pounds).  Its three parachutes each weigh
680  kilograms  (1,500 pounds) dry and about twice that when
wet.  The frustum weighs 2,270 kilograms (5,000 pounds)  and
its drogue weighs 499 kilograms (1,100 pounds) dry.

   The  spent SRB casings carry radio signaling devices that
allow the ships to home in  on  their  locations.  The  main
parachutes   and  frustum  drogue  combination  are  located
visually.

   The main parachutes are the first items to be  retrieved.
Their  winch lines are wound onto three of the four reels on
deck. Each reel is 1.7 meters (5.5 feet) in diameter.

   The drogue parachute attached to the frustum is reeled in
the same way until the frustum is  approximately  30  meters
(100 feet) from the ship.  Then the chute's shroud lines are
wound in until the frustum can be hoisted from the water  by
the nine metric ton (10-ton) capability deck crane.

   Recovery  of  the  SRB  casings  is  the  final retrieval
operation.  As the water is displaced,  the casings rise  so
that they can be towed horizontally.

   After  recovery  at  sea,  the  SRBs  are  towed  to Port
Canaveral  for  complete  dewatering   and   then   to   the
disassembly  location  at  Hangar AF on the eastern shore of
the Banana  River  on  Cape  Canaveral  Air  Force  Station.
Depending  upon  weather  conditions  and  sea  states,  the
recovery and towing operations normally take two days.

   The Banana River is a shallow arm of  the  sea  which  is
populated by manatees,  or sea cows - an endangered species.
To avoid injuring the manatees,  the retrieval ships use the
diesel-driven  waterjet  stern  thrusters  for  traveling on
inland waterways. The bow thrusters can also be used.

   While waterjets are not new, the Liberty Star and Freedom
Star are believed to be the first and only vessels in  which
this propulsion system has been used to protect the ungainly
sea cows from injury by conventional propellers.

   The  ships  are  also  suited  for other uses,  including
mapping  the  ocean   floor   for   seismographic   studies,
underwater  search and research.  They may be used for those
purposes when not required for NASA missions.






SRB Retrieval Ships

Liberty Star and Freedom Star



Length     53.6 meters (176 feet)


Beam       11.3 meters (37 feet)


Depth      4.6 meters (15 feet)
              (main deck to keel bottom)


Draft     2.7 meters (9 feet)  to  3.9  meters  (12  feet  8
inches depending on load conditions



Construction                       Molded steel hull



Propulsion at sea                  Two  General Motors (EMD)
12-645E6A diesel engines,  combined 2,900 hp.,  with  Lufkin
gears and Lips control lable pitch propellers



Propulsion and maneuvering in inland waterways    One    425
hp.   White  Gill  waterjet  stern   thruster,   driven   by
8V71turbo-intercooled (TI) Detroit diesel engine



Maneuvering                        One 425 hp.  Schottel bow
thruster,  driven by  8V71  turbo-intercooled  (TI)  Detroit
diesel engine


Auxiliary power                    Two     165    kw    Kato
generators and one 4 kw Kohler emergency generator



Towing pull                        27,216 kg. (60,000 pounds
or 30 tons)



Displacement                       955.9 metric tons  (1,052
tons) 660 to 1140 long tons depending on load condition








Normal cruising speed    24 km/hr (17 mph or 15 knots)



Range                    11,104 km (6,900 miles)



Endurance                Food and water for 30 days



Complement           10 crewmen and 9 retrieval specialists,
plus technical observers. Total berthing: 24 persons



Retrieval support equipment
   Diver operated plug, barb, pump and associated dewatering
gear.
One Quincy QR100 air-cooled, two-stage air
compressor (for nozzle plug operation)


UHF, VHF, HF and SATCOM communications
equipment



One  Model  410  Hallmark-Prentice  deck  crane,   9  metric
ton (10 ton) capacity (for frustum retrieval)


Four parachute reels


One  towing  winch  and  one  H-bit  (for securing tow line)
for towing one solid rocket booster casing with nozzle


One air hose reel

