What makes rockets go

Trenches beneath the launch pad also direct the rocket's exhaust out and away from the craft, so the flames can't rise back up and engulf the rocket itself. There are many launch sites around the world, each with different pros and cons. In general, the closer a launch site is to the Equator, the more efficient it is. That's because the Equator moves faster than Earth's poles as the planet rotates, like the outer edge of a spinning record.

Launch sites at higher latitudes more easily place satellites into orbits that pass over the poles. Between and , 29 spaceports sent satellites or humans into orbit. Many of the sites are still active, including the only three facilities ever to launch humans into orbit. More spaceports are on the way, both public and private. In , the U. The European Space Agency's spaceport in French Guiana is open to visitors , but the agency encourages travelers to plan ahead. Tourists can visit Kazakhstan's Baikonur Cosmodrome, the storied home of the Soviet and Russian space programs, but only by booking a tour.

The facility remains closely guarded. See pictures of the villages near Russia's Plesetsk Cosmodrome, where salvaging discarded rockets is a way of life. If you can't visit a spaceport in person, never fear: Many public space agencies and private companies offer online livestreams of their launches.

All rights reserved. How do rockets work? What are the stages of a rocket launch? Share Tweet Email. Read This Next Wild parakeets have taken a liking to London. Animals Wild Cities Wild parakeets have taken a liking to London Love them or hate them, there's no denying their growing numbers have added an explosion of color to the city's streets.

India bets its energy future on solar—in ways both small and big. Environment Planet Possible India bets its energy future on solar—in ways both small and big Grassroots efforts are bringing solar panels to rural villages without electricity, while massive solar arrays are being built across the country.

Epic floods leave South Sudanese to face disease and starvation. Travel 5 pandemic tech innovations that will change travel forever These digital innovations will make your next trip safer and more efficient. But will they invade your privacy? Go Further.

Animals Wild Cities This wild African cat has adapted to life in a big city. Animals This frog mysteriously re-evolved a full set of teeth. Animals Wild Cities Wild parakeets have taken a liking to London. Animals Wild Cities Morocco has 3 million stray dogs. Meet the people trying to help. Animals Whales eat three times more than previously thought. Environment Planet Possible India bets its energy future on solar—in ways both small and big. Environment As the EU targets emissions cuts, this country has a coal problem.

The first person to seriously study the rocket's potential for space travel, Russian schoolteacher and amateur scientist Konstantin Tsiolkovsky , first published his conclusions in He correctly identified the launch as one of the biggest challenges — the moment where the rocket has to carry all the fuel and oxidant it needs to reach space — as its weight is at a maximum and a huge amount of thrust is needed just to get it moving. As the rocket gets underway it sheds mass through its exhaust, so its weight is reduced and the same amount of thrust will have a greater effect in terms of accelerating the rest of the rocket.

Tsiolkovsky came up with various rocket designs and concluded that the most efficient setup was a vertically launched vehicle with several 'stages' — each a self-contained rocket that could carry the stages above it for a certain distance before exhausting its fuel, detaching and falling away. This principle, still widely used today , reduces the amount of dead weight that needs to be carried all the way into space. Tsiolkovsky devised a complex equation that revealed the necessary thrust force needed for any given rocket maneuver, and the "specific impulse" — how much thrust is generated per unit of fuel — needed for a rocket to reach space.

He realized that the explosive rocket propellants of his time were far too inefficient to power a space rocket, and argued that liquid fuels and oxidants, such as liquid hydrogen and liquid oxygen, would ultimately be needed to reach orbit and beyond. Although he did not live to see his work recognized, Tsiolkovsky's principles still underpin modern rocketry. Rockets must delicately balance and control powerful forces in order to make it through Earth's atmosphere into space.

A rocket generates thrust using a controlled explosion as the fuel and oxidant undergo a violent chemical reaction. Expanding gases from the explosion are pushed out of the back of the rocket through a nozzle. The nozzle is a specially shaped exhaust that channels the hot, high-pressure gas created by combustion into a stream that escapes from the back of the nozzle at hypersonic speeds, more than five times the speed of sound.

Isaac Newton's third law of motion states that every action has an equal and opposite reaction, so the "action" force that drives the exhaust out of the rocket nozzle must be balanced by an equal and opposite force pushing the rocket forward. Specifically, this force acts on the upper wall of the combustion chamber, but because the rocket motor is integral to each rocket stage, we can think of it acting on the rocket as a whole.

Although the forces acting in both directions are equal, their visible effects are different because of another of Newton's laws, which explains how objects with greater mass need more force to accelerate them by a given amount.

So while the action force rapidly accelerates a small mass of exhaust gas to hypersonic speeds each second, the equal reaction force produces a far smaller acceleration in the opposite direction on the far greater mass of the rocket.

As the rocket gains speed, keeping the direction of motion closely aligned with the direction of thrust is critical. Gradual adjustments are needed to steer the rocket towards an orbital trajectory, but a severe misalignment can send the rocket whirling out of control. Most rockets, including the Falcon and Titan series and the Saturn V moon rocket , steer using gimballed engines, mounted so that the entire rocket motor can pivot and vary the direction of its thrust from moment to moment.

Other steering options include using external vanes to deflect the exhaust gases as they escape the rocket engine — most effective with solid-fueled rockets that lack a complex motor — and auxiliary engines, such as small thruster rockets mounted on the sides of the rocket stage. Modern rocket motors have come a long way from fireworks, the first in rocket history. There may or may not be extra side boosters to help out, too. Because this initial stage must carry the weight of the entire rocket with payload and unspent fuel , it is usually the biggest and most powerful section.

As the rocket accelerates, it initially encounters an increase in air resistance -- which it must also overcome through brute thrust. But, as it moves higher, the atmosphere becomes thinner and the air resistance lessens. This means that the stress experienced by the rocket during a typical launch rises initially, to a peak and then falls back down. The peak pressure is known as max q. For the SpaceX Falcon 9 and the United Launch Alliance Atlas V , max q is usually experienced at between 80 and 90 seconds of a launch, at an altitude of between seven miles 11 km to nine miles Once the first stage has completed its duty, rockets usually drop that section and ignite their second stage.

The second stage has less work to do because it has less mass to move and has the advantage of having a thinner atmosphere to contend with. For this reason, the second stage often only consists of a single engine.

Most rockets will also jettison their fairings at this stage too this is a pointed cap at the rocket's tip that protects the payload. In the past, discarded lower sections of the rocket would simply burn up in the atmosphere.

But starting around the earlys, engineers began designing these sections to be recoverable and reusable. Private companies like SpaceX and Blue Origin have taken this principle further and have designed them to be able to return to Earth and land themselves. This is beneficial, as the more parts that can be reused, the cheaper rocket launches can become. Modern rockets tend to use either liquid, solid, or hybrid fuels. Liquid forms of fuel tend to be classified as petroleum like kerosene , cryogens like liquid hydrogen , or hypergolics like hydrazine.

In some cases, alcohol, hydrogen peroxide, or nitrous oxides can also be used. Solid propellants tend to come in two forms: homogenous and composite. Both are very dense, stable at room temp and are easily stored. The former can be either a simple base like nitrocellulose or a double base like a mixture of nitrocellulose and nitroglycerine.

Composite solid propellants, on the other hand, use a crystallized or finely ground mineral salt as the oxidizer. In most cases, the actual fuel tends to be aluminum-based.

The fuel and oxidizer may be held together with a polymeric binder that is also consumed during combustion. Launchpads, as the name suggests, are platforms from which rockets are launched. They tend to form part of a larger complex, facility, or spaceport. A typical launchpad will consist of a pad or launch mount, which will usually be a metal structure that supports the rocket in an upright position prior to blastoff. These structures will have umbilical cables that fuel the rocket and provide coolant prior to launch, amongst other functions.

They will also tend to have lightning rods to protect the rocket during lightning storms. Launch complexes will vary in design, depending on the rocket's design and the operator's needs.