Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SHUTTLE/ORBITER.TXT

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SPACE SHUTTLE STATISTICS


N A S A
EDUCATIONAL BRIEFS For The Classroom


The Space Shuttle is NASA's first true aerospace vehicle. It takes off
like a rocket, operate in orbit as a spacecraft, and land on the Earth
as an airplane. The Shuttle is a four part vehicle consisting of the
Orbiter, an expendable External Tank (ET), and two Solid Rocket
Boosters (SRB's).

Launched in a conventional manner, the Space Shuttle's Main Engines
(SSME's) and the SRB's produce approximately 30,800,000 newtons of
thrust. At 45 kilometers above the Earth the boosters separate and
return to the Earth by parachute for sea recovery. Eight minutes into
the flight, at an approximate altitude of 110 kilometers, the ET
propellants are exhausted. The tank will separate from the Orbiter and
disintegrate upon reentry into the Earth's atmosphere. Any surviving
pieces fall into remote ocean areas. To complete orbital insertion to
altitudes between 160 and 1110 kilometers, and later to make orbital
adjustments, two Orbiter Manuvering System (OMS) engines fire.

Once in space, the Space Shuttle Orbiter serves as a base to deploy
payloads such as satellites or space probes. Satellites needing repair
or servicing can be brought on board and later released or returned to
Earth. The Orbiter can also be used as a platform for scientific
research.

At the completion of the orbital phase of the mission, the Orbiter is
rotated in space by firing combinations of small rockets called the
Reaction Control System (RCS). When the OMS engines are aimed in the
direction of motion, they fire and the resulting thrust slows the
Orbiter, initiating reentry. Before making atmospheric contact, the
Orbiter is again rotated so that the underside will experience the
major share of atmospheric friction. To protect the Orbiter, three
types of reusable surface insulation are used. In areas of greatest
heating, the nose area, and leading edges of the wings, reinforced
carbon is used (carbon cloth impregnated with additional carbon, heat
treated, and then coated with silicon carbide). Other areas are
covered with thermal tiles made of silica fibers or a Nomex felt
blanket material (nylon felt coated with silicon). To aid in heat
rejection, the tiles are given a glassy ceramic coating.

As the altitude and speed of the orbiter decreases, the Orbiter begins
to function as a glider. The glide angle to the runway is about six
times steeper than a commercial jet liner on landing approach. Landing
speeds are approximately 340 kilometers per hour.

Following landing, the Orbiter undergoes refurbishment, new payloads
are inserted, a new External Tank installed, the booster refueled and
the entire vehicle assembly is made ready for a new launch a few
months later. To reduce costs, the Orbiter is designed to be used
again for up to 80 missions and the SRB's are designed for about 6
flights each.


          S O L I D     R O C K E T     B O O S T E R S

The SRB's provide the major portion of the thrust at the time of
liftoff. They are the largest solid rocket boosters ever built, the
first to be used to launch humans into space, and the first designed
for reuse. The SRB's are assembled out of four tubular segments of
1.25 centimeter steel. The fore end is capped with a nose cone
containing a parachute assembly. The aft end has a steerable nozzle.
Eight small rocket motors, four in the nose and four in the aft, are
used, at burn out, to separate the SRB's from the external tank.

Each booster contains a solid propellant that looks and feels like the
hard rubber of a typewriter eraser. A hollow core runs the entire
length of the propellant load. To ignite the propellants, a small
rocket motor, fixed at the fore end of the core, is fired first.
Flames from the small rocket spread across the entire face of the core
and the SRB's come to full thrust in less than one-half second.


                        S T A T I S T I C S


Length  ....................................          45.46 meters
Diameter ...................................           3.70 meters
Mass empty .................................   82,879  kilograms each
Propellant Mass ............................  503,627  kilograms each
Thrust.................................... 12,899,200  newtons each at
                                                       sea level
Nozzles...................................Covergent-divergent. All-
                                          axis gimbaling of 8 degrees.

Propellant Composition....................Aluminum perchlorate powder
                                          (oxidizer)
                      ....................Aluminum powder (fuel)
                      ....................Iron oxide  (catalyst)
                      ....................Polymer (binder and fuel)
                      ....................Epoxy curing agent

SRB Surface Insulation....................Ablative


                   E X T E R N A L     T A N K

The external tank contains the propellants used for liftoff and ascent
by the Shuttle Orbiter's three main engines. The ET has an external
shell which encloses three inner tanks. The forward inner tank
contains liquid oxygen under pressure. An unpressurized intertank
holds most of the electrical components. The aft inner tank contains
liquid hydrogen under pressure. Tank walls are manufactured of
aluminum alloys and are up to 5.23 centimeters thick. Antivortex and
antislosh baffles are built inside the fore and aft tank walls to
dampen any motions of the liquid propellants that might throw the
Shuttle off course.

Propellants are fed to the Orbiters SSME's by gas pressure derived
from the controlled boiling of the propellants. Following the
depletion of the liquid propellants. Following the depletion of liquid
propellants, the ET is destroyed on atmospheric reentry.


                        S T A T I S T I C S


Length .....................................         47 meters
Diameter....................................       8.38 meters
Mass empty..................................  37,452 kilograms

Propellants................................. Liquid oxygen (LO2)
           ................................. Liquid hydrogen (LH2)

Propellant mass ............................. LO2--609,195 kilograms
               ............................. LH2--101,606 kilograms
Propellant feed lines ...................... (2) 43 centimeters in
                                             diameter
Propellant feed rate.................LO2--242,000 liters per minute
                    .................LH2--184,420 liters per minute

Surface insulation  ................ 1.27 centimeters thick core/epoxy
                                     layer covered with a 2.54 centi-
                                     meter thick Spray-on foam.



                            O R B I T E R


The Space Shuttle Orbiter is a wide-body, delta-winged airplane and
space vehicle. It is constructed primarily out of aluminum and covered
with reusable surface insulation. The Orbiter is propelled by 49
rocket engines employed in various combinations for liftoff, attitude
control in space, and in initiating reentry. Electrical power for
Orbiter systems is provided by fuel cells which produce, as a
byproduct, water for drinking.

The heart of the Orbiter is the cargo bay which can carry up to four
satellites for launching at one time. The cargo bay permits the
science laboratory Spacelab, to be carried into space and returned to
the Earth at the completion of a mission. A highly articulated
mechanical arm called the Remote Manipulator System (RMS), can be
operated by Shuttle astronauts while inside the Orbiter cabin. The arm
will be used to extract payloads from the cargo bay and deploy them
outside of the Orbiter.

The forward section of the Orbiter contains the flight deck and crew
quarters for the astronauts. During launch up to four astronauts may
sit on the flight deck and up to three more may sit on the crew
quarters deck. The forward portion of the flight deck resembles the
cockpit of a jet liner but features separate controls for flying in
space and flying in the atmosphere. The aft portion of the flight deck
contains four stand-up duty stations including the controls for the
RMS. The crew quarters deck is entered through an open hatch through
the flight deck floor. The crew quarters contain eating, sleeping, and
sanitary facilities. When extravehicular activities are necessary, an
airlock is installed in the orbiter cargo bay and entry is gained
through a hatch in the crew quarters.


                       S T A T I S T I C S

EXTERIOR DIMENSIONS

Length....................................        37.24 meters
Body width................................         6.9  meters
Wingspan..................................        23.79 meters
Height with gear extended.................        17.27 meters
Mass empty................................    68,040 (Orbiter 102.
                                         Other orbiters have lower
                                         masses.)
Cargo Bay length..........................        18.28 meters
Cargo Bay diameter........................         4.57 meters
Payload mass for launch...................    29,484 kilograms
                                         to low Earth orbit.
Payload mass on return....................    14,515 kilograms

ENGINES

SSME: 3 (Total)
Liquid hydrogen and liquid oxygen propellants. Gambaling +/- 10.5
degrees on pitch axis and +/- 8.5 degrees on yaw axis.

Thrust...................................  1,668,000 newtons each at
                                           sea level

OMS 2 (Total)
Nitrogen tetroxide (N2 O4) and monomethyl hydrazine (MMH) propellants

Thrust.................................... 26,688 newtons in a
                                           vacuum


RCS
Primary Thrusters..........................38 (14 fore and 24 aft)
                                           N2 04 and MMH propellants
Thrust.................................... 3,870 newtons each in a
                                           vacuum
Vernier Thrusters..........................6 (2 fore and 4 aft)
                                           N2 04 and MMH propellants
Thrust.....................................106 newtons each in a
                                           vacuum


CREW QUARTERS..............................2 decks
Cabin volume...............................71.5 meters (cubed)
Atmosphere.................................normal
Pressure...................................normal


THERMAL PROTECTION SYSTEM..................Reusable
                                           RCC, coated silica tiles,
                                           and coated Nomex felt



----------------------------------------------------------------------

ACTIVITIES AND QUESTIONS FOR THE CLASSROOM

1.  What are the four main parts of the Space Shuttle?

2.  What is the major cost saving feature of the Space Shuttle over
    previous launch vehicles?

3.  Describe the sequence of events for the Space Shuttle from launch
    to landing.

4.  Compare the mass of the Space Shuttle empty to the mass of all
    propellants used to thrust it into space. Why is there such a
    difference between the two masses?

5.  What is a newton of thrust in English system measurement?

6   Illustrate the size of the Orbiter by measuring and marking its
    outline on a large open area such as an athletic field or play-
    ground.

7.  Why is the thrust for some rocket engines listed as "sea level"
    and for others as "vacuum"?

8.  What is the volume of the cargo bay of the Orbiter?

9.  Research previous launch vehicles and compare their sizes and
    payload capacities to the Space Shuttle.

10. What is the orbiter altitude range of the Space Shuttle?

----------------------------------------------------------------------
NASA EDUCATIONAL BRIEFS For The Classroom, EB-81-1

"6_2_9_3.TXT" (9813 bytes) was created on 10-29-92

                   NASA'S ORBITER FLEET
COLUMBIA
   Columbia (OV 102), the first of NASA's orbiter fleet, was
elivered to Kennedy Space Center in March l979.

   Columbia initiated the Space Shuttle flight program when
t lifted off from Launch Complex 39's Pad A on April 12,
981. It proved the operational concept of a winged,
eusable spaceship by successfully completing the Orbital
light Test Program -- missions STS-1 through 4.

   Other achievements for Columbia include the first launch
of satellites from a Space Shuttle (STS-5) and the first
flight of the European-built scientific workshop -- Spacelab
-- on mission STS-9.

   Columbia is named after a small sailing vessel that
operated out of Boston in l792 and explored the mouth of the
Columbia River. One of the first U.S. Navy ships to circum-
navigate the globe was named Columbia. The command module
for the Apollo 11 lunar mission was also named Columbia.

DISCOVERY

   Discovery (OV 103), the third of NASA's fleet of
reusable, winged spaceships, arrived at Kennedy Space Center
in November 1983. (Challenger was the second orbiter to ar-
rive at KSC.  See "Challenger" for its history.)  It was
launched on its first mission, flight 41-D, on August 30,
1984, from Pad A. It carried aloft three communications
satellites for deployment by its astronaut crew. Other Dis-
covery milestones include the first dedicated Department of
Defense mission, the first flight to retrieve and return
disabled satellites to Earth for repair and the first Space
Shuttle mission of the post-Challenger era.

   Discovery is named for two famous sailing ships; one
sailed by Henry Hudson in 1610-11 to search for a northwest
passage between the Atlantic and Pacific Oceans, and the
other by James Cook on a voyage during which he discovered
the Hawaiian Islands.

ATLANTIS

   Atlantis (OV 104) was delivered to Kennedy Space Center
in April 1985, as the fourth spaceship of NASA's orbiter
fleet.

   Atlantis lifted off from Pad A on its maiden voyage on
Oct. 3, 1985, on mission 51-J, the second dedicated Depart-
ment of Defense flight. On its second mission, 61-B, Nov.
26, 1985, its astronaut crew conducted the first experiments
for assembling erectable structures in space.

   Atlantis is named after a two-masted sailing ship that
was operated for the Woods Hole Oceanographic Institute from
1930 to 1966.


ENDEAVOUR


     Endeavour was the first ship commanded by James Cook, the 18th century
British explorer, navigator and astronomer.  In August 1768, on Endeavour's
maiden voyage, Cook sailed to the South Pacific, around Tahiti, on a mission to
observe and record the important and seldom occurring event when the planet
Venus passes between Earth and the sun.  Determining the transit of Venus
allowed early astronomers to determine the distance of the sun from Earth. This
distance then could be used as a unit of measurement essential in calculating
the parameters of the universe.  On June 3, 1769, Cook completed this mission
and continued his voyage to explore the southern hemisphere.  He discovered and
charted New Zealand and surveyed the eastern coast of Australia and navigated
the Great Barrier Reef.

     In addition, Cook's voyage on the Endeavour set a precedent of
establishing the usefulness of sending scientists on voyages of exploration.
Joseph Banks and Carl Solander, who sailed with Cook, became the first
naturalists to examine plants and animals in an organized manner.  The wealth
of scientifically collected material was unique.  They collected specimens from
more than 100 new plant families with 800 to 1,000 new species.  They also
encountered hundreds of new species of animals.  Cook also had astronomers and
artists onboard.

     Endeavour and her crew made the first long-distance voyage on which no
crewmen died from scurvy, the dietary disease caused by the lack of ascorbic
acids.  Cook is credited with being the first to use diet as a cure for scurvy,
making his crew follow a strict diet that included cress, sauerkraut and an
orange extract.  He also ensured cleanliness and ventilation in the crew's
quarters.

     The Endeavour was small, 368 tons, about 100-feet long and 20-feet wide.
She had a round bluff bow and a flat bottom that provided uncommon spaciousness
and helped prevent her from being torn apart by coral.  However, in 1795,
Endeavour ended her career on a reef along Rhode Island.


   Atlantis (OV 105) was delivered to Kennedy Space Center
in May, 1991, as the fifth spaceship of NASA's orbiter
fleet.

   Endeavour lifted off from Kennedy Space Center for the first time on
May 7, 1992, on mission STS-49.



MISSION

   The delta-winged orbiter  resembles an airplane and is
about the size of a DC-9 jetliner. It is  launched  into
space like a conventional rocket while bolted to an external
propellant tank  and two solid rocket boosters.

   After liftoff, the boosters burn for a little over two
minutes before being jettisoned and  carried by parachutes
to  a watery landing. After splashdown, they are  retrieved
and returned to  Kennedy Space Center  for refurbishment.

   The orbiter's main engines continue to burn  until about
8 1/2 minutes  into the flight.  After shutdown, the exter-
nal tank is jettisoned, breaks up in the atmosphere, and
falls into the Indian Ocean.  It is the only piece of
Shuttle flight hardware that is not reused.  The orbiter
then carries out its mission in space and returns to Earth
like a glider.

LAUNCH PROCESSING

   After completing a space mission, the orbiter is returned
to Kennedy Space Center to undergo preparations  for its
next flight in a sophisticated  aircraft-like hanger  called
the Orbiter Processing Facility (OPF).  Here, the vehicle is
safed, residual propellants are drained and any returning
payloads are removed.

   Any  problems that may have  occurred with orbiter sys-
tems and equipment  on the previous mission  are  checked
out and  corrected.  Equipment is repaired or replaced and
extensively tested. Any  modifications  to the orbiter that
are required  for the next mission are also made in the OPF.

   Orbiter refurbishment operations  and processing for the
next mission also begin in the OPF. Large horizontal
payloads, such as Spacelab, are installed in the orbiter
cargo bay.  Vertical payloads  are installed at the launch
pad.

   Following  extensive testing and verification of all
electrical and mechanical interfaces, the orbiter is trans-
ferred to the nearby Vehicle Assembly Building where it is
mated to the external tank  and solid rocket boosters. Then,
the assembled Space Shuttle vehicle is carried to the launch
pad  by a large tracked vehicle called the crawler-
transporter.

   At the launch pad, final preflight and interface checks
of the orbiter, its cargo and associated ground support
equipment are conducted. After a positive Flight Readiness
Review, the decision  to launch is given and the final
countdown begins.

ORBITER MODIFICATIONS

   More than  200 significant modifications are being made
to  the orbiter fleet. These modifications involve  orbiter
main engines, brakes and landing gear, thermal protection
system and propellant supply systems, as well as a new crew
escape system.

   Main engine  modifications include  changes to the high-
pressure  turbomachinery, hydraulic actuators, and main
combustion chamber.

   The orbiter braking system will be upgraded to increase
braking  capacity, improve steering, and reduce the effects
of tire damage and failure. Additions to the system also in-
clude  tire pressure monitoring.

   Some of the tiles that make up the orbiter thermal
protection system have been replaced with thermal blankets
to make the system lighter, stronger and more durable. Also,
a reinforced carbon-carbon panel  will be added  to  the or-
biter chin  between the nose cap and the nose wheel door  to
provide improved insulation against the searing heat of
reentry.

   Improvements to the orbiter propellant supply system in-
clude a redesigned 17-inch  quick disconnect  valve between
the  orbiter and the external tank. Additional modifications
will be made to the propellant systems of the orbiter reac-
tion control system, orbital maneuvering system, and the
auxiliary power units.

   A new crew  escape  system has been added  that allows
the Space Shuttle  crew to bail out  if the orbiter has to
make  an emergency  return descent and a safe runway cannot
be reached. This system consists of an escape pole that
would be extended from the opened crew hatch. The crew would
then fasten a lanyard hook assembly that is a part of the
pole  to their parachute harnesses. Once attached to this
hook, the crew would slide down the deployed pole, away from
the orbiter. Once free of the pole, they would parachute to
safety.



SPACE SHUTTLE

Height: 184.2 feet

Gross liftoff weight: 4,500,000 pounds

Total liftoff thrust: 7,700,000 pounds

ORBITER

   Length: 122.17 feet

   Wingspan: 78.06 feet

Dry Weight:

   Columbia  (OV 102) 178,000 pounds

   Discovery (OV-103) 171,000 pounds

   Atlantis  (OV-104) 171,000 pounds

Main Engines: (3) 375,000  pounds of
               thrust each (sea level)

Cargo Bay:  length - 60 feet

            diameter - 15 feet

SOLID ROCKET BOOSTERS (2)

   Length: 149.16 feet
   Diameter: 12.17 feet
   Liftoff Weight: (each) 1,300,000 pounds
   Recovery weight: (each) 192,000 pounds
   Thrust: (each) 3,300,000 pounds (sea level)

EXTERNAL TANK

   Length: 153.8 feet
   Diameter: 27.6 feet
   Weight:
     Liftoff: 1,655,600 pounds (535,000 gallons)
     Empty : 66,000 pounds
   Propellants
     Liquid Oxygen:
          Capacity: 143,351 gallons
          Volume: 19,600 cubic feet
    Liquid Hydrogen:
          Capacity: 385,265 gallons
          Volume: 53,500 cubic feet