GRAVITY - Worst Enemy of a Rocket

Why do rockets pump out so much fuel? Ever wondered...? Just to get over those thick layers of gravity. Ain't cool right! The harsh truth of life. Let's say you want to put 1000 kilos in space. For that, you roughly need 2.4 million kilos of fuel. Now to convert that to litres, by assuming RP-1 fuel. Density = mass/volume and but putting in the density of RP-1 as 0.81kg/m^3, mass to be 2.4 million kilos, we get 2.9 million litres of fuel. That's insane! Just to put a few thousand kilos, you need an insane amount of fuel. Now the question is, why do we need so much fuel. Well, it's a term introduced by Newton. "GRAVITY" Therefore, the title ENEMY. 

To understand gravity, we will need to dive deep into its definition. It's a force of attraction expressed by everybody in this universe. (Except the anti-matter- that's sci-fi stuff) Bigger the object, the greater the mass, and therefore greater the gravitational force. Smaller the planet body, the less fuel you must carry to launch an object. Let's take the example of the moon. Moon's diameter is just 3.6 times less than that of Earth as well as moon's mass is 0.012 times the mass of Earth, which makes it an ideal place to launch a rocket. The gravitational pull of the moon is 1/6th of that of Earth. This means you can jump quite high with the least amount of force on the moon's surface. 

Gravity is responsible for the heavyweights of rockets. You wish you had a lesser gravity. You would have no need to go to the gym worrying how much you weighed. 

To lift a rocket up, you need to produce a lot more thrust. The Force of  Thrust pushing it upward shall be greater than the weight force acting downwards. This unbalance causes the rocket to lift off the ground. At any point in time, if the engine shut down, the delta-V (net velocity) of the rocket reduces and after a point rocket will be redirected towards the surface of the Earth and BOOM! We are done there. This thrust and weight have to be monitored every millisecond as the rocket loses a lot of fuel every second. Concepts like hovering and going up, returning down, I have made them pretty clear a few weeks ago here. (Click here)

That's all for today, now you know how gravity threatens rocket launches.