Regan Brown
Space shuttles require a lot of fuel to launch and propel themselves into orbit. The shuttle has three main parts: an orbiter that holds the crew and payload, an immense external fuel tank, and two solid rocket boosters. The shuttle's three built-in liquid-fuel engines and two solid-fuel rockets produce a combined 6.6 million pounds of thrust. The fuel used in the solid rockets is made of aluminium powder, ammonium perchlorate, and a polymer binder. The shuttle's main engines use liquid hydrogen and liquid oxygen, which create the most efficient thrust of any rocket propellant. However, slowing down and landing don't require fuel; instead, the shuttle glides back to Earth, using the atmosphere as a source of friction to slow down.
Explore related products
What You'll Learn
The weight of fuel impacts the amount of fuel needed
The weight of the fuel itself impacts the amount of fuel needed for a space shuttle. This is due to Tsiolkovsky's rocket equation, which states that any craft heading into space must boost "excess" mass in the form of fuel—most of which is the fuel required for transporting the fuel it will burn later in the journey. This creates a cycle that increases the amount of fuel needed.
The weight of the fuel also impacts the amount of fuel needed because, in order to lift off, the shuttle must generate enough thrust to counteract the weight of the fuel. The more the fuel weighs, the more thrust is needed, and thus the more fuel is needed to generate that thrust.
Additionally, the weight of the fuel impacts the shuttle's ability to slow down and stop in space. To slow down, the rocket nozzles must be turned backward and ignited, using more fuel. The heavier the fuel load, the more fuel is needed to slow down.
The weight of the fuel also affects the shuttle's ability to reach orbit. The shuttle must carry enough fuel to generate the necessary thrust to overcome the force of gravity and achieve orbital speed. The weight of the fuel contributes to the overall weight of the shuttle, requiring more fuel to achieve the necessary thrust.
To address the challenge of fuel weight, space shuttles are designed with multiple stages, allowing parts of the shuttle to be dropped off sequentially as their fuel is exhausted. This reduces the weight of the shuttle and allows the remaining fuel to be used more efficiently.
The Cost of Fuel Injector Cleaning Services
You may want to see also
Explore related products
Fuel is required to slow down and land
A space shuttle requires a lot of fuel to slow down and land because of the immense velocity it builds up during its journey in space. As a general rule, the heavier the craft and the higher its velocity, the more fuel is required to slow it down.
A space shuttle in orbit travels at hypersonic speeds of about 17,300 mph, and this speed must be reduced to about 250 mph at landing. To slow down, the shuttle must counteract the force that kept it in motion: its engines must provide long and sustained braking thrust, which requires a lot of fuel.
The amount of fuel required to slow down a space shuttle is so significant that it would cost significantly more to launch a shuttle with enough fuel for a powered descent. Instead, NASA exploits the Earth's atmosphere as a "free" energy source to slow down the shuttle. The shuttle glides back to Earth unpowered, using the atmosphere to create friction that slows the shuttle down.
However, this method of slowing down results in a hot re-entry, where the friction with the Earth's atmosphere heats up the shuttle. This can be dangerous, but NASA has the process under control. In the future, with advancements in technology, it may be possible to have a cold re-entry with nearly unlimited thrust that does not require significant additional fuel.
Fuel Consumption of Boeing 777-300: By the Hour
You may want to see also
Explore related products
Fuel is needed to escape Earth's gravity
A space shuttle requires a lot of fuel to escape Earth's gravity. The power needed to lift a space shuttle into orbit comes from two solid-fuel rockets, each 12 ft (4 m) wide and 149 ft (45.5 m) long, and from the shuttle's three built-in, liquid-fuel engines. The fuel used in the solid rockets is made of aluminium powder, ammonium perchlorate, and a special polymer that binds the other ingredients into a rubbery matrix. This mixture is moulded into a long prism with a hollow core that resembles an 11-pointed star in cross section. This shape exposes the maximum possible surface area of burning fuel during launch, increasing combustion efficiency. The two solid-fuel rockets each contain 1.1 million lb (500,000 kg) at ignition, together producing 6.6 million pounds (29.5 million N) of thrust, and burning out only two minutes after the shuttle leaves the launchpad.
The shuttle's three main engines turn off at approximately 522 seconds, when the shuttle has reached an altitude of 50 mi (105 km) and is 670 mi (1,426 km) down range of the launch site. At this point, the external fuel tank is also jettisoned. The shuttle's main engine, which must work above the atmosphere, uses 385,000 gallons of liquid hydrogen and 143,000 gallons of liquid oxygen.
Liquid hydrogen and liquid oxygen have a very high specific impulse and are used for the upper or second stages of a rocket. Hydrogen has the lowest molecular weight of any known substance, making it ideal for keeping the weight of a rocket relatively small. When combined with liquid oxygen, hydrogen creates the most efficient thrust of any rocket propellant.
The amount of fuel needed to escape Earth's gravity is also due to the larger fuel tanks necessary to contain a lower-density propellant and the atmospheric drag that acts on the tanks when the rocket attempts to power beyond Earth's gravity. As a result, different propellants are used for different missions and differ among the stages of any given rocket. Solid propellants have higher density and therefore thrust. They are also storable, transportable, reliable, less complex, and can also contain their own oxidizer.
Fuel Transportation: Placard-Free Quantity Rules
You may want to see also
Explore related products
Liquid fuel is more efficient for space travel
Space shuttles require a lot of fuel because they must carry all the fuel needed for the entire journey, as well as an oxidizer, unlike airplanes that draw oxygen through their engines. The fuel load must be heavy enough to not only lift the shuttle but also to return it safely to Earth.
Liquid hydrogen, for example, is well-suited for upper-stage use where Isp (specific impulse) is at a premium and thrust-to-weight ratios are less relevant. Vehicles with dense-fuelled booster stages reach orbit earlier, minimizing losses due to gravity drag and reducing the effective delta-v requirement. However, liquid hydrogen has a low density, which means that the fuel tankage, plumbing, and pump must be larger, increasing the vehicle's dry mass and reducing performance.
Liquid methane and ammonium dinitramide (ADN)-based propellants have also been found to be optimal fuels for space travel in terms of efficiency, cost, and environmental impact.
Ethanol Content in Canada's 94 Octane Fuel Explained
You may want to see also
Explore related products
Solid fuel is denser and provides more thrust
Space shuttles require a lot of fuel to launch and reach orbit. The power needed to lift a space shuttle into orbit comes from two solid-fuel rockets and the shuttle's three built-in liquid-fuel engines. Solid rocket boosters generate 85% of the thrust needed to get the shuttle off the ground. Solid-fuel rockets have a higher density than liquid-fuel rockets, and they provide more thrust.
Solid rocket fuel is denser than liquid rocket fuel. This high propellant density makes for a compact size. Solid rocket motors combine fuel and oxidizers when the motor is cast, and the propellant combustion occurs inside the motor casing. Solid-fuel rockets typically have higher thrust, shorter burn times, and a higher mass than liquid-fuel rockets. The higher mass is due to the higher density of solid rocket fuel.
The higher density of solid rocket fuel means that solid-fuel rockets can produce more thrust than liquid-fuel rockets. Thrust is produced by expelling mass rearward at high velocity. The thrust produced can be calculated by multiplying the mass flow rate of the propellant by its exhaust velocity relative to the rocket. The higher density of solid rocket fuel means that it has a higher mass flow rate, resulting in more thrust.
Solid-fuel rockets are also simpler, more reliable, and more cost-effective than liquid-fuel rockets. They are easier to store and handle, and they have been used in missiles and ICBMs. Solid-fuel rockets are ideal when large amounts of thrust are needed, and cost is an issue. For these reasons, solid-fuel rockets have been used as the initial stages in rockets, including the Space Shuttle.
The Perfect Ratio: Understanding Oil in Fuel
You may want to see also
Frequently asked questions
The power needed to lift a space shuttle comes from solid-fuel rockets and the shuttle's built-in liquid-fuel engines. The shuttle must carry not only the fuel but an oxidizer as well, which is necessary for combustion. The shuttle's main engine, which must work above the atmosphere, uses 385,000 gallons of liquid hydrogen and 143,000 gallons of liquid oxygen.
The shuttle must carry a large amount of fuel because there are no "gas stations" in space. If there were, a smaller engine could be used, requiring less fuel.
Unlike airplanes, which burn fuel by drawing oxygen through their engines, spacecraft must bring the whole chemical equation along with them. The oxidizer is kept separate from the fuel until valves bring them together for ignition.
The shuttle glides back to Earth unpowered, exploiting the planet's atmosphere to slow it down. This means that less fuel is required overall.
As things fall towards the Earth, they accelerate. The only things that can slow them down are friction with the atmosphere and a reaction engine, both of which would require a large amount of fuel.
