PEAR corner: The Space Shuttle

In the seventies, NASA began the design and construction of a new manned vehicle that would let astronauts travel to the space and go back to earth. Unlike previous spacecrafts the new vehicle would be reusable. On April 12, 1981 the first space shuttle was launched beginning a new era on space exploration history. The space shuttle has three components the external tank, the solid rocket busters and the orbiter, and it was designed to be launched like a rocket, orbit like a spacecraft and re-entry like a space plane.

Atlantis Space Shuttle

External Tank

The external tank (ET) supplies fuel to orbiter’s main engines and it is also used as a backbone during the launch providing attachment points to the solid rocket buster and the orbiter. The external tank weights 78,100 pounds empty and 1,585,379 pounds with propellant (liquid oxygen and hydrogen). It’s made of aluminum and lithium alloy and It’s covered with an external protection of 2.5cm (1 inch) thick coating of sprayed polysocyanurate foam to manage temperatures, prevent ice formation, and protect from aerodynamic heat.

The external tank entering into vehicle assembly building (VAB) in Kenedy Space Center Florida

The components of the external tank are the oxygen tank, hydrogen tank, and intertank. The intertank connects both tanks and has instrumentation and processing equipment.

The external tank also has a propellant feed system to duct propellant to the orbiter’s main engines, pressurization and vent system to regulate tank pressure, environmental conditioning system to regulate temperature, and electrical system to control power, instrumentation signals and lightening protection.

The external tank is the only part of the space shuttle expendable. It’s jettisoned 8.5 minutes after shuttle’s lift off and burned in the atmosphere.

Parts of external tank

Solid Rocket Busters

Solid rocket boosters. Vehicle assembly building (VAB), Kenedy Space Center Florida

During the lift off the Solid Rocket Busters help the orbiter’s main engines providing the additional thrust needed to escape of the Earth’s gravity. Both rockets provide a thrust equal to 5,300,000lbs (around 83% of total lift off thrust) . Two minutes after the lift off, the solid rocket busters separate from the shuttle and fall into the Atlantic Ocean, where they are recovered.

Parts of Solid Rocket Busters

The boosters are the largest rockets developed for space flight. The motor is composed of a segmented motor case loaded with solid propellants, an ignition system, a movable nozzle, and the instrumentation and integration hardware.

In addition to the motor, it also contains a structural, thrust vector control, separation, recovery, and electrical and instrumentation subsistem

Each booster weights 87,543 kg (193,000 pounds) empty and 589,670kgr (1,300,000 pounds) filled with propellant.

The propellant consist of ammonium perchlorate, aluminum, iron oxide , polymer and epoxy.

The Orbiter

Atlantis Orbiter

The orbiter is the vehicle that carries the crew and payload. It is 37.23m (122.7ft) long and 17.2m (56.58feet) high (on runaway). The wing span is 23.79m (78.06ft) long. The orbiter’s weight is 78,000 kg (172,000 lb) empty, but this may vary because of payload, and its structure is made of aluminum alloy.

The orbiter is divided in three sections forward fuselage, mid fuselage and aft fuselage.

Forward Fuselage: The forward fuselage houses the crew module. The cockpit, living quarters and experiment station are located in this area, and it also offers support for the nose section, nose gear, nose gear wheel well, and doors.

The crew module is 65.8 m3 (2,325 ft3) (5.48 m x 6.7 m x 6.09 m or 18ft x 22ft x 20 ft). It is pressurized. Outside the aft of the crew module in the payload bay , a docking module and a transfer tunnel can be fitted to allow transfer crew and equipment.

The crew module is divided in three areas the flight deck, the middeck/equipment bay and the airlock.

Sections of the crew module

Flight deck houses the orbiter’s cockpit. The pilot and copilot seats are located in the front section. Both pilot and copilot seats include manual flight control, rudder pedals and speed-bracke controllers. Inside the flight deck are more than 2020 displays and controls. Also, there are six pressure windshield, two overhead windows, two rear-viewing payload bay windows and the crew entrance/exit hatch.

Glass cockpit

Orbiters windows

Inside the middeck, there are four crew sleeping stations, a personal hygiene station, a work dinning table, and stowage facilities. Also, there is a waste management system.

The airlock provides access for spacewalks (Also called extravehicular activity or EVA). There are two space suits inside the airlock, and it has space for only two crew members.

Mid Fuselage: It is 18.28m by 4.6m by 3.96 m (60ft by 15.4ft by 13ft), and It is not pressurized. Inside the midfuselage is the payload bay, the forward wing globe, and the remote manipulator System (RMS).

The payload bay doors are also in the middeck. Both support radiation panels.

Orbiter's payload section

The RMS is a 15.2 (50ft) long arm, which is controlled from the flight deck. There are cameras and lights near the outer end of the arm providing a better vision to the controller. Also, along each side of the payload are three flood lights.

Orbiter's Robotic Arm

Aft Fuselag: The space shuttle main engines (SSME), orbital maneuvering system, body flap, and the vertical tail are located in the aft fuselage. The aft fuselage is 18.28m by 4.57m by 6.9m (60ft x 15ft x 22.67ft).

The main engines are the orbiters main engines. Both main engines and solid rocket busters are responsible for providing the thrust needed to escape earth’s gravity during lift off. On the first six minutes of lift off the main engines accelerates from 4,828 KM/h (3,000mi/h) to 27,358Km/h(17,000 mi/h) providing a 1.2 million pounds of thrust. During the ascent, it burns 0.5 million gallons of propellant. The main engines are designed to have a life span of 7.5 hours and 55 stars.

Space Shuttle Main Engines

The orbital maneuvering system (OMS) is located at the external pads on each side of the aft fuselage. The OMS provides thrust for orbit insertion and orbit change. It’s designed for a service life of 10 years, and 1000 starts.