A question for those more knowledgeable about these things:
Are the components of Rocket Fuel scarce?
I'm asking the question because it occurred to me that there might be a limit on the number of space-based missions we can launch due to the availability of these components, and I'm wondering at what kind of point we'll reach the stage where we'll be unable to explore space based on these limits.
Full Version: Rocket Fuel
As far as I know they use Hydrogen and Oxygen in liquid form. Don't think we'll run out of those soon. Also solid rocket boosters are used , but I don't know what they use for those.
I just never could understand why they have not started using nuclear rockets which are far more powerful than liquid rockets.
I just never could understand why they have not started using nuclear rockets which are far more powerful than liquid rockets.
From Wiki
"""Solid propellants (and almost all rocket propellants) consist of an oxidizer and a fuel. In the case of gunpowder, the fuel is charcoal, the oxidizer is potassium nitrate, and sulfur serves as a catalyst. (Note: sulfur is not a true catalyst in gunpowder as it is consumed to a great extent into a variety of reaction products such as K2S. The sulfur acts mainly as a sensitizer lowering threshold of ignition.) During the 1950s and 60s researchers in the United States developed what is now the standard high-energy solid rocket fuel. The mixture is primarily ammonium perchlorate powder (an oxidizer), combined with fine aluminium powder (a fuel), held together in a base of PBAN or HTPB (rubber-like fuels). The mixture is formed as a liquid, and then cast into the correct shape and cured into a rubbery solid. Solid fueled rockets are much easier to store and handle than liquid fueled rockets, which makes them ideal for military applications. In the 1970s and 1980s the U.S. switched entirely to solid-fuelled ICBMs: the LGM-30 Minuteman and LG-118A Peacekeeper (MX). In the 1980s and 1990s, the USSR/Russia also deployed solid-fuelled ICBMs (RT-23, RT-2PM, and RT-2UTTH), but retains two liquid-fuelled ICBMs (R-36 and UR-100N). All solid-fuelled ICBMs on both sides have three initial solid stages and a precision maneuverable liquid-fuelled bus used to fine tune the trajectory of the reentry vehicle."""
Wiki entry: rocket propellant
"""Solid propellants (and almost all rocket propellants) consist of an oxidizer and a fuel. In the case of gunpowder, the fuel is charcoal, the oxidizer is potassium nitrate, and sulfur serves as a catalyst. (Note: sulfur is not a true catalyst in gunpowder as it is consumed to a great extent into a variety of reaction products such as K2S. The sulfur acts mainly as a sensitizer lowering threshold of ignition.) During the 1950s and 60s researchers in the United States developed what is now the standard high-energy solid rocket fuel. The mixture is primarily ammonium perchlorate powder (an oxidizer), combined with fine aluminium powder (a fuel), held together in a base of PBAN or HTPB (rubber-like fuels). The mixture is formed as a liquid, and then cast into the correct shape and cured into a rubbery solid. Solid fueled rockets are much easier to store and handle than liquid fueled rockets, which makes them ideal for military applications. In the 1970s and 1980s the U.S. switched entirely to solid-fuelled ICBMs: the LGM-30 Minuteman and LG-118A Peacekeeper (MX). In the 1980s and 1990s, the USSR/Russia also deployed solid-fuelled ICBMs (RT-23, RT-2PM, and RT-2UTTH), but retains two liquid-fuelled ICBMs (R-36 and UR-100N). All solid-fuelled ICBMs on both sides have three initial solid stages and a precision maneuverable liquid-fuelled bus used to fine tune the trajectory of the reentry vehicle."""
Wiki entry: rocket propellant
QUOTE (heinrich1858 @ May 27 2008, 07:55 AM) 
As far as I know they use Hydrogen and Oxygen in liquid form. Don't think we'll run out of those soon.
* Grins *
Fair enough - I guess we should be okay for the foreseeable future, then.
And this one from NASA
The solid-propellant motor is the oldest and simplest of all forms of rocketry, dating back to the ancient Chinese. It's simply a casing, usually steel, filled with a mixture of solid-form chemicals (fuel and oxidizer) which burn at a rapid rate, expelling hot gases from a nozzle to achieve thrust.
Solids require no turbopumps or complex propellant-feed systems. A simple squib device at the top of the motor directs a high-temperature flame along the surface of the propellant grain, igniting it instantaneously.
Solid propellants are stable and easily storable. Unlike liquid-propellant engines, though, a solid- propellant motor cannot be shut down. Once ignited, it will burn until all the propellant is exhausted.
Solids have a variety of uses for space operations. Small solids often power the final stage of a launch vehicle, or attach to payload elements to boost satellites and spacecraft to higher orbits.
Medium solids such as the Payload Assist Module (PAM) and the Inertial Upper Stage (IUS) provide the added boost to place satellites into geosynchronous orbit or on planetary trajectories.
The PAM-DII provides a boost for Delta and Space Shuttle payloads. The IUS goes on the Space Shuttle and the Titan III and Titan IV class of launch vehicles.
Only one of the nation's launch vehicles, the Scout, uses solids exclusively. This four-stage rocket launches small satellites to orbit.
Titan, Delta and Space Shuttle vehicles depend on solid rockets to provide added thrust at liftoff.
The Space Shuttle uses the largest solid rocket motors ever built and flown. Each reusable booster contains 1.1 million pounds (453,600 kilograms) of propellant, in the form of a hard, rubbery substance with a consistency like that of the eraser on a pencil. The four center segments are the ones containing propellant. The uppermost one has a star-shaped, hollow channel in the center, extending from the top to about two thirds of the way down, where it gradually rounds out until the channel assumes the form of a cylinder. This opening connects to a similar cylindrical hole through the center of the second through fourth segments. When ignited, the propellant burns on all exposed surfaces, from top to bottom of all four segments. Since the star-shaped channel provides more exposed surface than the simple cylinder in the lower three segments, the total thrust is greatest at liftoff, and gradually decreases as the points of the star burn away, until that channel also becomes cylindrical in shape. The propellant in the star-shaped segment is also thicker than that in the other three.
A solid propellant always contains its own oxygen supply. The oxidizer in the Shuttle solids is ammonium perchlorate, which forms 69.93 percent of the mixture. The fuel is a form of powdered aluminum (16 percent), with an iron oxidizer powder (0.07) as a catalyst. The binder that holds the mixture together is polybutadiene acrylic acid acrylonitrile (12.04 percent). In addition, the mixture contains an epoxy-curing agent (1.96 percent). The binder and epoxy also burn as fuel, adding thrust.
The specific impulse of the Space Shuttle solid rocket booster propellant is 242 seconds at sea level and 268.6 seconds in a vacuum.
The solid-propellant motor is the oldest and simplest of all forms of rocketry, dating back to the ancient Chinese. It's simply a casing, usually steel, filled with a mixture of solid-form chemicals (fuel and oxidizer) which burn at a rapid rate, expelling hot gases from a nozzle to achieve thrust.
Solids require no turbopumps or complex propellant-feed systems. A simple squib device at the top of the motor directs a high-temperature flame along the surface of the propellant grain, igniting it instantaneously.
Solid propellants are stable and easily storable. Unlike liquid-propellant engines, though, a solid- propellant motor cannot be shut down. Once ignited, it will burn until all the propellant is exhausted.
Solids have a variety of uses for space operations. Small solids often power the final stage of a launch vehicle, or attach to payload elements to boost satellites and spacecraft to higher orbits.
Medium solids such as the Payload Assist Module (PAM) and the Inertial Upper Stage (IUS) provide the added boost to place satellites into geosynchronous orbit or on planetary trajectories.
The PAM-DII provides a boost for Delta and Space Shuttle payloads. The IUS goes on the Space Shuttle and the Titan III and Titan IV class of launch vehicles.
Only one of the nation's launch vehicles, the Scout, uses solids exclusively. This four-stage rocket launches small satellites to orbit.
Titan, Delta and Space Shuttle vehicles depend on solid rockets to provide added thrust at liftoff.
The Space Shuttle uses the largest solid rocket motors ever built and flown. Each reusable booster contains 1.1 million pounds (453,600 kilograms) of propellant, in the form of a hard, rubbery substance with a consistency like that of the eraser on a pencil. The four center segments are the ones containing propellant. The uppermost one has a star-shaped, hollow channel in the center, extending from the top to about two thirds of the way down, where it gradually rounds out until the channel assumes the form of a cylinder. This opening connects to a similar cylindrical hole through the center of the second through fourth segments. When ignited, the propellant burns on all exposed surfaces, from top to bottom of all four segments. Since the star-shaped channel provides more exposed surface than the simple cylinder in the lower three segments, the total thrust is greatest at liftoff, and gradually decreases as the points of the star burn away, until that channel also becomes cylindrical in shape. The propellant in the star-shaped segment is also thicker than that in the other three.
A solid propellant always contains its own oxygen supply. The oxidizer in the Shuttle solids is ammonium perchlorate, which forms 69.93 percent of the mixture. The fuel is a form of powdered aluminum (16 percent), with an iron oxidizer powder (0.07) as a catalyst. The binder that holds the mixture together is polybutadiene acrylic acid acrylonitrile (12.04 percent). In addition, the mixture contains an epoxy-curing agent (1.96 percent). The binder and epoxy also burn as fuel, adding thrust.
The specific impulse of the Space Shuttle solid rocket booster propellant is 242 seconds at sea level and 268.6 seconds in a vacuum.
theyll soon scrap rocket fuel one day and use nuclear power
QUOTE (dr alien @ May 27 2008, 11:51 PM)
theyll soon scrap rocket fuel one day and use nuclear power
it's much safer to use RF than go nuclear.
QUOTE (Legatus Legionis @ May 27 2008, 03:58 PM)
it's much safer to use RF than go nuclear.
that is very true but most of the time satelites and robots are being sent up to space and using nuclear power would make the journey quicker and it would save energy.
QUOTE (dr alien @ May 27 2008, 04:49 PM)
that is very true but most of the time satelites and robots are being sent up to space and using nuclear power would make the journey quicker and it would save energy.
Dr alien just a thought though.You have seen the amount of stages the Arian rocket the European space agency uses have you not.Those stages are all liquid fueled which produces a lot of power in the motors.The truth is that there just is not a nuclear motor which can match power of the liquid fueled motors.Safety wise.If a liquid motor blows up only it and the things around it gets damaged.If a nuclear motor for instance goes it radiates everything its components come into contact with.Health hazard is a major problem here.
QUOTE
using nuclear power would make the journey quicker and it would save energy
That my friend is not possible and simply would not work at all.To put it simply a nuclear motor does not have the thrust to even lift itself of the ground.
Google the kiwi type-A nuclear rocket motor and see for yourself.
But there is one thing that can work for this type of motor.If you can get it into space,you could actually have a good source of propulsion for say a spaceship
I find that you will understand yes.
As simple answer (but totally unsatisfactory one) to Tiggs question would be.. depends on the type of fuel you use.
Each of the types of fuel have advantages and disadvantages. The liquid oxygen (LOX) / liquid hydrogen (LH2) fuelled rockets are the environmentalists dream. The exhaust product is pure water. The fuel is also plentiful. The down side is that LH2 and LOX is horrible stuff to store, the rockets must be fuelled immediately before launch and need to be continuously topped up as the fuel boils off, and it there is a delay then the fuel must be unloaded from the vehicle. Such cryogenic fuels require very complicated (and therefore expensive) engines.
Solid fuel is mush easier to store. Many (if not most) nuclear missiles use this type of fuel as the rockets are permanently fuelled and read to go. Solid fuel rockets are also very simple in comparison to other designs.The down side is that they can be highly polluting (not really an issue if you are about to nuke a hundred cities but not always great for a space agency). They are also impossible to shut of if they suffer a problem (once the shuttle SRBs ignite the vehicle is committed to just over 2 minutes of powered flight, even if it suffers a problem in the first second). Although they tend to be reliable, when a solid fuelled rocket suffers a problem it tends to be a catastrophic failure.
Many other types of liquid fuel and oxidiser tend to be rather nasty. They are often corrosive and or toxic. Difficult to handle when fuelling your rocket and highly environmentally damaging in the event of an accident. Indeed Russia is aiming to move it's main launch complex from Baikonour in Kazakhstan to Vostochny in the Amur region of Russia. One of the main reasons for this is the cost of compensating Kazakhstan for the pollution caused by the residual fuel in their vehicles stages when they hit the ground in Kazakh territory and after launch accidents.
Each of the types of fuel have advantages and disadvantages. The liquid oxygen (LOX) / liquid hydrogen (LH2) fuelled rockets are the environmentalists dream. The exhaust product is pure water. The fuel is also plentiful. The down side is that LH2 and LOX is horrible stuff to store, the rockets must be fuelled immediately before launch and need to be continuously topped up as the fuel boils off, and it there is a delay then the fuel must be unloaded from the vehicle. Such cryogenic fuels require very complicated (and therefore expensive) engines.
Solid fuel is mush easier to store. Many (if not most) nuclear missiles use this type of fuel as the rockets are permanently fuelled and read to go. Solid fuel rockets are also very simple in comparison to other designs.The down side is that they can be highly polluting (not really an issue if you are about to nuke a hundred cities but not always great for a space agency). They are also impossible to shut of if they suffer a problem (once the shuttle SRBs ignite the vehicle is committed to just over 2 minutes of powered flight, even if it suffers a problem in the first second). Although they tend to be reliable, when a solid fuelled rocket suffers a problem it tends to be a catastrophic failure.
Many other types of liquid fuel and oxidiser tend to be rather nasty. They are often corrosive and or toxic. Difficult to handle when fuelling your rocket and highly environmentally damaging in the event of an accident. Indeed Russia is aiming to move it's main launch complex from Baikonour in Kazakhstan to Vostochny in the Amur region of Russia. One of the main reasons for this is the cost of compensating Kazakhstan for the pollution caused by the residual fuel in their vehicles stages when they hit the ground in Kazakh territory and after launch accidents.
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