Sunday Science: Rockets

Rockets are used to transport objects and people into space. That's a really dull sentence to describe potentially the most EXCITING engineering achievement of the human race.

But how do they work? Well, there are four basic forces of flight: lift, gravity, thrust and drag. Thrust and lift are positive forces that propel a rocket into space. Gravity and drag are negative forces that slow a rocket down.

It's a bit like letting air out of a balloon. The weight of the balloon tries to pull it down to Earth (gravity) and when it's flying around the room, air resistance (drag) pulls the balloon in the opposite direction of its movement.

The air whooshing out of the balloon provides the thrust it needs to oppose its weight. The lift is a force at right angles to the thrust, which stabilises and controls the direction of flight. 

Rockets don't have air. They carry a lot of fuel to get them into space. When this liquid fuel burns, it produces gas. The build-up of this exhaust gas escapes the rocket with a lot of force and provides enough thrust for the rocket to blast off.

Rockets need a huge amount of energy to overcome gravity and stop them falling back to Earth. In his famous 1962 speech championing travel to the Moon, US President John F. Kennedy compared the power of a rocket to "10,000 automobiles with their accelerators on the floor." 

To give you a more exact figure, a rocket needs to achieve speeds of 25,000 mph to escape the Earth's gravity. 

Ironman uses "repulsors" to make him fly. Similar to a rocket, he has to overcome the forces of gravity and drag to fly. The only difference is that Ironman also flies horizontally, like an aeroplane.

ALSO ON THE BLOG: DID TIM PEAKE BEAT ELON MUSK WITH HIS MARS PREDICTION?

Inside a rocket

Modern rockets are made up of several parts. The main parts are the propulsion system (to get the rocket into space), payload system (where the astronauts sit) and guidance system (to manoeuvre the rocket), but they can contain around three million different parts.  They all look different too, but here's a basic picture of a rocket, courtesy of NASA:

Extra reading

This is a more thorough (but not overly complicated) explanation on how rockets work and here's some more information on their structure. If you want to know a little bit more about how Ironman flies, check out this awesome explanation.

I've distilled a really interesting topic into a short post. For example, there's been a lot written about the space race between the Russians and Americans, but I'd hardheartedly recommend you read Hidden Figures: The Story of the African-American Women Who Helped Win The Space Race. Also, did you know that the first true rocket was used in 1232? The history of the rocket is a fascinating tale that goes beyond the space race - you can read more here and here. Check out this in-depth explanation of the final stages before blast off - and hear what Apollo astronaut Charlie Duke said on the future of space exploration at a recent talk.

A rocket launch is a pretty spectacular sight. Speaking last week, Tim Peake said: “I was mesmerised by the noise and the power of the rocket launch when I first saw one.” So, here's a launch in action - make sure you turn up the volume to get an idea of how LOUD one can be!

What is Sunday Science?

Hello. I’m the freelance writer who gets tech. I have two degrees in Physics and, during my studies, I became increasingly frustrated with the complicated language used to describe some outstanding scientific principles. Language should aid our understanding — in science, it often feels like a barrier.

So, I want to simplify these science sayings and this blog series “Sunday Science” gives a quick, no-nonsense definition of the complex-sounding scientific terms you often hear, but may not completely understand. 

If there’s a scientific term or topic you’d like me to tackle in my next post, fire an email to [email protected] or leave a comment below. If you want to sign up to our weekly newsletter, click here.