One thing no one can disprove...

[spacemaverick]

If Rockets do not work in space...

...how do they get back down from orbit?


If rockets do not work in space...

...then there are NO ANOMALIES in the Moon and Mars photos...

...because they could not have taken those photos on the Moon or Mars

Touche'....good one "Z"......

[spacemaverick]

If you can disprove a "positive" can you prove a negative?  I had that question offered to me at one time...

[The Matrix Traveller]

Hi spacemaverick ,

I believe you may be more informed about Solid rocket fuels than myself i.e. Missiles etc.   

ArMap seems to be having some difficulty in understanding Rocket Engines.   

Can you explain the 'theory' to him please.   

Many thanks.

[ArMaP]

A Rocket engine is a 'Thermal Converter' !   

I know, but when I said "only interested" I meant that I see talking about jet and automobile engines as irrelevant, as they do not work in the same way.

The Nitrogen is IN the FUEL !   

Example in Solid Fuel ......    C6H6N6(NO2)6

Not if the fuel is hydrogen, and that's what I was talking about.

[The Matrix Traveller]

Not if the fuel is hydrogen, and that's what I was talking about.

Oh but it isn't !

Hydrogen is only ONE 'Component', of the Make up of WHAT propels a human designed Space vehicle.

Hydrogen is ONE of the Components of the 'Heat Source' ONLY !   

The other Component of the 'Heat Source' is the Oxidiser !   

Another 'Component' is The 'Expansion Media', (Gas)    the Heat Source i.e. Hydrogen and Oxidiser Heat
through their Chemical interaction. (Burning)


Look at the Compound C6H6N6(NO2)6 (Solid Rocket Fuel) see it has Hydrogen, Carbon and Nitrogen ...   


Liquid based Rocket fuels also contain their Expansion Media within the recipe ....   

It's a huge area of 'Chemistry' and Thermal Dynamics ...

[spacemaverick]

Hi spacemaverick ,

I believe you may be more informed about Solid rocket fuels than myself i.e. Missiles etc.   

ArMap seems to be having some difficulty in understanding Rocket Engines.   

Can you explain the 'theory' to him please.   

Many thanks.

I have no background in rockets or chemistry.  The only background I have is in munitions which includes missiles (just checking out the systems and that is all.  High school science should do the trick though.  I will attempt to find the information in video form which may help explain.  All I know is that propellants be they solid or liquid have all the appropriate chemicals contained in the propellant to do the job.  In the case of a rocket/missile fired from a submarine...the tube is filled with air which propels the missile out of the tube into the air and then the propellant is ignited above the water after the rocket has been turned sideways at an angle.   The exiting thermal energy from the rocket motor pushes against the rocket motor casing which in turn causes the rocket to move.

Now take the small handheld instrument the astronauts used to move around during Gemini which did not have flammable propellant but merely a non-flammable gas contained there-in.  As the gas was released by the astronaut from the unit it would push the astronaut to where he wanted to go in the opposite direction of where it was pointed.  Nothing thermal about that.

Like I said...I will find a video to explain it better.

[spacemaverick]

Here you go...the basics...

[spacemaverick]

Submarine launch of rocket....motor ignited after just leaving the water...





This is a cruise missile launch:

[ArMaP]

Oh but it isn't !

On what I'm talking about it is, as I asked about an oxygen+hydrogen rocket, not about any other oxidizer+fuel.

Or is it not possible to make an oxygen+hydrogen rocket?

[spacemaverick]

Beyond my knowledge level ArMap....

[ArMaP]

Beyond my knowledge level ArMap....

Thanks anyway.

[spacemaverick]

http://www.nasa.gov/topics/technology/hydrogen/hydrogen_fuel_of_choice.html

From NASA

Despite criticism and early technical failures, the taming of liquid hydrogen proved to be one of NASA's most significant technical accomplishments. . . . Hydrogen -- a light and extremely powerful rocket propellant -- has the lowest molecular weight of any known substance and burns with extreme intensity (5,500°F). In combination with an oxidizer such as liquid oxygen, liquid hydrogen yields the highest specific impulse, or efficiency in relation to the amount of propellant consumed, of any known rocket propellant.

Because liquid oxygen and liquid hydrogen are both cryogenic -- gases that can be liquefied only at extremely low temperatures -- they pose enormous technical challenges. Liquid hydrogen must be stored at minus 423°F and handled with extreme care. To keep it from evaporating or boiling off, rockets fuelled with liquid hydrogen must be carefully insulated from all sources of heat, such as rocket engine exhaust and air friction during flight through the atmosphere. Once the vehicle reaches space, it must be protected from the radiant heat of the Sun. When liquid hydrogen absorbs heat, it expands rapidly; thus, venting is necessary to prevent the tank from exploding. Metals exposed to the extreme cold of liquid hydrogen become brittle. Moreover, liquid hydrogen can leak through minute pores in welded seams. Solving all these problems required an enormous amount of technical expertise in rocket and aircraft fuels cultivated over a decade by researchers at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory in Cleveland.

Today, liquid hydrogen is the signature fuel of the American space program and is used by other countries in the business of launching satellites. In addition to the Atlas, Boeing's Delta III and Delta IV now have liquid-oxygen/liquid-hydrogen upper stages. This propellant combination is also burned in the main engine of the Space Shuttle. One of the significant challenges for the European Space Agency was to develop a liquid-hydrogen stage for the Ariane rocket in the 1970s. The Soviet Union did not even test a liquid-hydrogen upper stage until the mid-1980s. The Russians are now designing their Angara launch vehicle family with liquid-hydrogen upper stages. Lack of Soviet liquid-hydrogen technology proved a serious handicap in the race of the two superpowers to the Moon.4 Taming liquid hydrogen is one of the significant technical achievements of twentieth century American rocketry.

The above excerpt is from the Introduction to Taming Liquid Hydrogen: the Centaur Upper Stage Rocket, 1958-2002 ?. This report details why the Centaur was so important in NASA history as an upper stage rocket -- the critical link between its booster stage (Atlas or Titan) and the mission's payload (satellite or spacecraft).

http://history.nasa.gov/SP-4404/ch8-1.htm

[spacemaverick]

ArMap...does this help?

[ArMaP]

ArMap...does this help?

Thanks, it does, as it shows at least that there are hydrogen+oxygen rockets that, apparently work in space or in a very rarefied atmosphere.

[The Matrix Traveller]

This might help.

http://en.wikipedia.org/wiki/Liquid_rocket_propellants

The highest specific impulse chemical rockets use liquid propellants.

Approximately 170 different liquid propellants have undergone lab testing.

This estimate excludes minor changes to a specific propellant such as
propellant additives, (Often Nitrogen) corrosion inhibitors, or stabilizers.   


In the U.S. alone at least 25 different propellant combinations have been flown.

However, there has not been a completely new propellant used in flight for nearly 30 years.

Many factors go into choosing a propellant for a liquid propellant rocket engine.

The primary factors include ease of operation, cost, hazards/environment and performance.

Bipropellants can be either hypergolic or nonhypergolic. A hypergolic combination of oxidizer
and fuel will start to burn upon contact.

A nonhypergolic needs an ignition source.


Hydrogen

Many early rocket theorists believed that hydrogen would be a marvelous propellant
since it gives the highest specific impulse.

It is also considered the cleanest when used with a liquid oxygen oxidizer because the only by-product is water.


As hydrogen in any state is very bulky, for lightweight vehicles it is typically stored
as a deeply cryogenic liquid.

This storage technique was mastered in the early 1950s as part of the hydrogen bomb
development program at Los Alamos.

It was then adopted for hydrogen fueled stages such as Centaur and Saturn upper stages
in the late 50s and early 1960s.

Even as a liquid, hydrogen has low density, requiring large tanks and pumps, and the extreme cold
requires tank insulation.

This extra weight reduces the mass fraction of the stage or requires extraordinary measures
such as pressure stabilization of the tanks to reduce weight.

Pressure stabilized tanks support most of the loads with internal pressure rather than with solid structures.

Most rockets that use hydrogen fuel use it in upper stages only.

Gaseous hydrogen is commercially produced by the fuel-rich burning of natural gas.

Carbon forms a stronger bond with oxygen so the gaseous hydrogen is left behind.

Liquid hydrogen is stored and transported without boil-off because helium, which has a lower boiling point
than hydrogen, is the cooling refrigerant.

Only when hydrogen is loaded on a launch vehicle (where there is no refrigeration) does it vent
to the atmosphere.


NOTE:  IF only Hydrogen & Oxygen is used in a Combustion type Rocket Engine This can NOT Work !

This is a fact of Physics ...   

Simply because the by-product is WATER which is far denser than Hydrogen and Oxygen Gas !

In this case an Implosion would take place !   


But if another (Inert) gas is Added, the whole Scenario changes, to that of Expansion !   


Because the Oxidising Hydrogen heats the Inert gas and thus this Inert gas, because it can't burn easily,
expands rapidly which then pushes against the 'Exhaust Cone' and as it is a Law of physics,

"To every Action there is an opposite and equal reaction"

The Rocket is pushed forward, in the opposite direction the 'Exhaust Cone' is pointing !

Thrust can also be obtained from Non chemical Jets. In other words NOT involving Combustion,
as spacemaverick pointed out.

The same applies re.

"To every Action there is an opposite and equal reaction"

So Rocket Engines are based on this LAW of Physics ....   

Any Rocket Engine involving Combustion is a 'Thermal Converter', a simple Scientific Fact ...