The Space Shuttle: the rocket that kept coming back!

The development of NASA’s reusable space-plane, the Space Shuttle, launched a whole new age of space exploration. Previous spacecraft had lasted only for one mission, but the Shuttle, which took off like a rocket and flew back like a plane, could be reused up to 100 times. Between its maiden flight in 1981, and its final voyage in 2011, the Shuttle made 135 missions, successfully launching and repairing numerous satellites and the Hubble Space Telescope, and playing a major role in assembling the International Space Station. Now it’s retired, we bid it a very fond farewell. So long Space Shuttle!

How did the Shuttle work?

The main component of the Shuttle was a spacecraft about two thirds the size of a 747 airplane (“Jumbo Jet”) called the orbiter. This was launched by two solid rocket boosters (SRBs) fixed to its underside, which burned solid fuel inside them. In between the SRBs, a giant external tank (ET) fed around 528,000 gallons (2 million liters) of liquid fuel to the orbiter’s three engines. This vast amount of fuel was needed to accelerate the Shuttle to a speed of roughly 17,500 mph (28,000 km/h) to reach an orbit of 190–330 miles (304–528 km) above Earth. During liftoff, the Shuttle’s main engines burned fuel so quickly that they could drain a family-sized swimming pool in just 25 seconds! Each orbiter cost roughly $2 billion to build and each Shuttle mission cost roughly $450 million.

Life in the Shuttle

Each Space Shuttle mission lasted up to two weeks, so the orbiter needed a comfortable-but-compact, two-story living area. On the top level were the pilot’s seats and cockpit controls. A ladder led down to a large sleeping area, galley kitchen, storage lockers, gym—and a vacuum toilet that worked even in space. The astronauts ate their food with metal knives and forks held to metal trays with magnets; this stopped them floating away in the Shuttle’s near-zero gravity.

Shuttle missions

Space Shuttle missions often made headline news around the world. The maiden voyage on April 12, 1981, confirmed the Shuttle could successfully return from space. Another notable flight in April 1984 involved astronauts repairing a crippled satellite in the Shuttle’s cargo bay before returning it successfully to space. Two years later, the orbiter Challenger exploded shortly after takeoff killing all seven crew members. Flights resumed in late 1988 and the Hubble Space Telescope was launched in 1990. Disaster struck again in February 2003, when the Space Shuttle Columbia was destroyed as it returned to Earth. The final Shuttle voyage launched on July 8, 2011, after which the four remaining orbiters were retired to science and aviation museums spread across the United States.

From takeoff to landing

During a typical one-week voyage, the Shuttle launched from its base at Kennedy Space Center (KSC), Florida, and carried out its mission several hundred miles above Earth’s surface. When the mission was complete, it returned to Earth’s atmosphere and made an unpowered landing, like a glider, either at KSC or at Edwards Air Force Base in California. At 15,000 ft (4572 m) long, the Edwards landing strip is roughly twice the length of a typical airport runway.

Reentry

The Shuttle’s unique feature was its ability to venture into space and return to Earth intact. The main problem with this, however, was that friction would heat up the orbiter to nearly 1927°C (3500°F) as it passed into Earth’s atmosphere, so it was coated with about 20,000 heat-resistant ceramic “tiles” (refractory bricks) to stop it burning up on reentry. A tough material called reinforced carbon-carbon was used in the tiles on the wing edges, the nose, and other areas where temperatures could exceed 1260°C (2300°F). Black high-purity silica tiles 1–5 inches (2.5–12.7 cm) thick were individually cemented to the underside of the orbiter to protect it from temperatures of 649–1260°C (1200–2300°F). Less heat reached the upper surface of the craft, so it was protected either by white tiles or by a blanket made from a silica composite.

There and back—in seven easy steps!

1. At liftoff, three engines on the orbiter burned liquid fuel from the large brown tank underneath. Two SRBs either side burned solid fuel and made over 70 per cent of the liftoff thrust. Together, these five engines produced some 7.3 million pounds of thrust—150 times as much as a single Jumbo Jet engine! During this part of the flight, the temperature inside the Shuttle’s engine was two thirds as hot as the surface of the Sun.
   
2. Two minutes later and 32 miles (48 km) into the sky, the empty SRBs were detached.
   
3. When the Shuttle reached its orbit, the ET was detached and burned up on its way back to Earth.
   
4. A typical mission lasted 4–7 days.
   
5. Once the mission was over, the orbiter flew backward for the first part of its descent.
   
6. As the orbiter turned, its nose was raised so its heat-resistant undercarriage met Earth’s atmosphere first.
   
7. During descent, the orbiter slowed from 28,000 km/h (17,500 mph) to 350 km/h (220 mph) and a parachute brought it completely to rest as it touched down to land.
   

Inside the Shuttle cargo bay

At 60 ft (18.3 m) long and 15 ft (4.6 m) wide, the orbiter’s cargo bay was big enough to hold a a satellite or a couple of trucks parked side by side. It contained a variety of sensors and scientific instruments and a 50 ft (15 m) grabber arm, used for launching and retrieving satellites. The reflective inside doors of the cargo bay doubled up as heat shields to protect the cargo from solar radiation.

The Shuttle could not launch a satellite directly into geostationary orbit (a fixed orbit over a certain place on Earth). Instead, it spun the satellite slowly out of the cargo bay. When the satellite was clear, its own rocket motors would fire and power it into position.