Space Exploration

Space Exploration

Kepler Telescope

How do astronauts travel to space?

The journey into space is not as easy as simply boarding an aeroplane and heading for the stars. The vehicle required to carry astronauts beyond the Earth must be extremely fast, powerful and able to survive extreme conditions.

The spacecraft used to carry astronauts into space is called a space shuttle. Space shuttles are made up of three parts: an orbiter, a fuel tank and booster rockets. The orbiter is similar to a space plane. It holds the astronauts and any cargo. It is the section of the shuttle that travels into space.

The fuel tank carries the liquid fuel required for the orbiter's engines. The booster rockets are extremely powerful rockets that are used during the launch to blast the shuttle into space.

The space shuttle resembles a huge, fat crayon (which represents the massive fuel tank), with two thinner crayons attached to the sides (these are the powerful rockets). The orbiter looks similar to a fighter jet plane that sits on top of the fuel tank.

Who travels in the space shuttle?

The crew of a space shuttle is made up of astronauts with various roles. Some of the different roles include a commander, a pilot, a mission specialist and a payload specialist.

The commander is the person responsible for the safety of the crew, the success of the mission and the shuttle's safe return to Earth. The pilot is responsible for assisting the commander in the operation of the shuttle. The pilot also helps to deploy (set up) and retrieve satellites.

The mission specialist conducts experiments and is in charge of systems. Mission specialists also carry out space walks when necessary.

Finally, the payload specialist (who is usually a professional scientist) works with scientific equipment on board and conducts experiments.

What is involved in the journey to space?

In preparing for the mission, the three sections of the space shuttle are attached in the weeks prior to the launch date. The external fuel tanks are connected to the main orbiter and the two powerful rocket boosters are also positioned onto the shuttle. Thorough checks are completed before the shuttle is very slowly and carefully transported to the launching area.

More checks are carried out on the vehicle once it has reached the launching pad and is placed in position for take-off. Several practice countdowns are also carried out.

Hours before take-off, the fuel tank is filled with liquid hydrogen and oxygen fuel. The fuel tanks sit on the outside of the shuttle so that they can be easily detached once fuel supplies run out.

The crew are strapped into their seats for a couple of hours prior to take off. This allows them time to do final checks and assure that they are well prepared.

When it is time for take-off, everyone involved in the mission on the ground, including the builders of the shuttle and medical staff, are on hand just in case an emergency occurs.

What happens after take off?

During take-off, the powerful rockets attached to the shuttle build up enough force to lift the extremely heavy shuttle off the ground. The speed at which the shuttle leaves the Earth must be great enough to resist the pull of the Earth's gravity as it leaves our atmosphere. Not long after take-off, the rocket boosters are detached from the shuttle as they are no longer required. They fall back down to Earth.

Approximately eight minutes after take-off, the orbiter shuts down its main engines that are powered by the massive external fuel tank. The orbiter separates itself from the fuel tank as it can now survive in orbit on two small engines called the orbital manoeuvring system.

After shutting down the main engines, the shuttle becomes much quieter. Once the orbiter is in orbit, the crew open the payload doors on the top of the shuttle. These doors remain open for the remainder of the mission. This prevents internal heat build- up caused by the orbiter's electronic systems.

Once in orbit, the crew begin carrying out their mission tasks. An average mission takes approximately a week to complete. During this time the crew continue to orbit the Earth, carrying out the specified tasks of the mission.

How does a space shuttle return to Earth?

When all the mission tasks have been completed, the crew close the payload bay doors and prepare to re-enter the Earth's atmosphere. This preparation involves slowing the orbiter down considerably. The crew slow the shuttle down by turning it around into a tail-first position and releasing the small orbital engines.

When the craft has slowed down, it is turned around front-on once again and begins to re-enter the Earth's atmosphere. As the orbiter enters the atmosphere, it is protected from quickly rising temperatures. Specially designed heat-absorbent tiles that cover the outside of the shuttle stop these extreme temperatures from affecting the crew.

An amazing feature of the space shuttle is that it is able to take-off in a vertical position, powered by rockets, yet its landing resembles that of an ordinary plane. The crew line the orbiter up on a landing strip and the shuttle glides down to Earth. Just as an aeroplane releases flaps before landing, the wings on the orbiter carry out similar movements to reduce speed.