Coming Home: How Does Spaceship Return To Earth

A spaceship’s return to Earth is even more dangerous than its journey to space.

Its successful return to its home, requires many precise plans, intricate maneuvers, and detailed planning.

If the space shuttle is not controlled properly and if anyone steps out of the plan, then the spaceship can burst into flames.

Everything needs to go just right to make sure that the spaceship returns to the Earth successfully. 

The spaceship’s journey back to Earth is also called space shuttle reentry.

But, while we know that dozens of things need to go right for the space shuttle to land on Earth, how does it exactly fulfill these things? How does a spacecraft return to earth?

The Command

The journey back to Earth on a shuttle starts when it is halfway around the world from the landing site.

The space shuttle landing site can be Kennedy Space Center or Edwards Air Force Base.

The mission control has to give a command to the spacecraft to come back home :

a. As soon as the crew receives the command of coming back home from the mission control, they need to start prepping for space shuttle reentry. 

b. The crew starts by closing the cargo bay doors. In some cases, the shuttle might be flying nose first or upside down. In this case, the crew needs to fire the RCS thrusters to make sure it turns the orbiter tail first.

c. As soon as the orbiter is tail first, the crew then starts to OMS engines, to slow the orbiter down and let it fall back to Earth. It usually takes 25 minutes for the space shuttle to reach the upper atmosphere of the Earth. 

d. While the spaceship is slowly falling towards Earth, the crew fires the RCS thrusters. This allows to pitch the orbiter over, to ensure that the bottom of the orbiter is facing towards the atmosphere. Once again the spacecraft is nose-first. 

e. As the spacecraft is moving towards Earth, it has to go through Earth’s atmosphere. This is the most dangerous area due to the high heat. The leftover fuel from the RCS burns in these areas as a safety precaution to counter the high level of heat.

The SpaceShip Columbia Disaster 

To reinforce how difficult it is to sustain the heat of Earth’s atmosphere, we can look back at the tragic Columbia Disaster.

Columbia was a space shuttle of NASA. One of its insulating materials had come off. 

As the spaceship was re-entering the Earth, the damage to the insulating materials allowed hot gases to come in and destroy the wing structure.

This led the spaceship to become unstable and finally, it exploded.

The crew could not have repaired it even if they had known of the damage. All of the crew members died. 

Heat Protection 

The Columbia spaceship disaster is one such example of how difficult and dangerous space shuttle reentry is.

So, how do the space shuttles manage these extreme conditions?

The spaceships travel at a speed of 28,000 km/h.

Due to this, the orbiter hits air molecules, leading to a heat build-up due to friction (1650 degrees celsius).

Thus, the orbiter needs to be covered with ceramic materials that protect it from heat. The materials used are: 

a. RCC or reinforced carbon-carbon. This is used on the wing surfaces and underside. 

b. Insulation tiles are used on the upper forward fuselage and around the window. 

c. Nomex blanks white in colors. There are upper payload bay doors and the upper wing. 

d.And lastly, low-temperature white tiles. They are put on the remaining areas. 

Manoeuvring The Shuttle 

All of these materials used on the spaceship are essential for its reentry.

The materials absorb heat, they have a high heat capacity.

The next step requires maneuvering of the orbiter to make sure it is in position for successful reentry. 

a. The crew needs to keep the orbiter at about 40 degrees. During this time, there is a lot of ionized gas around the orbiter due to the atmosphere. Thus, radio communication is completely cut off during this period.

This is called ionization blackout and it lasts about 12 minutes. 

b. As the orbiter successfully crosses this phase, it is said that the space shuttle reentry is successful. Now, the spacecraft can fly like an airplane.

c. Spaceships have a lifting body design which has delta wings. During this time, the computers take over the controls and fly the space shuttle. 

d. The shuttles make several S-shaped turns to slow the descent speed, as the runaway approaches for the final touchdown. 

e. When the shuttle is 224 km from the landing site and about 45,700 m high, the commander uses a radio beacon.

f. As the spaceship is 40 km away, the commander takes control of the computers. The commanders are now in charge of flying the shuttle around. Its commander needs to line the spacecraft with the runaway and start to drop the altitude. 

g. As the final touchdown approached, the commander steeped the angle to -20 degrees. 

The Final Touchdown 

As the space shuttle is now 610 m above the ground, the commander finally pulls the nose to reduce the rate of descent.

The pilot then employs the landing gear to get ready for the final touchdown. 

a. The commander then starts to break the spacecraft. A parachute comes out from the tail of the spaceship. This helps to stop the space shuttle. Both the parachute and the speed brake located on the tail help to stop the space shuttle as it touches the runway. 

b. Once landing is over, the crew needs to go through a shutdown procedure. The spacecraft has to power down. The entire process is elaborate and done intricately. It takes about 20 minutes for the process to complete. The process includes- clearing the spaceship, cooling it down, and getting rid of the noxious gases. 

Finally, the crew starts to service the spaceship and repair any damage that the spaceship has encountered. And just like that spaceship is back home.