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