What explanation can you offer for the fact that practical space vehicles are lauched by multi stage rockets..

Question

What explanation can you offer for the fact that practical space vehicles are lauched by multi stage rockets, fired in intervals along the trajectory, rather than by a single rocket ignited at the earth's surface?

Why is it incorrect to call g(=9.8ms^-2) ,which is acceleration due to free fall, to be "gravity"?

why is it more costlier to build a single rocket with all the needed fuels for the flight into space than a multistage rocket system.

Any space experts ut there?

Answer 1

First, 9.8ms^-2 is correctly called acceleration due to GRAVITY, not free fall. Free fall is the condition wherien something falls under the influence of gravity alone, nothing else.

Anyway, gravity is neither acceleration nor a force, but the property of a material body that maskes it attract and be attracted by another material body.

As for the rockets, As you go higher, you experience less gravity. meaning less force needed to make the rocket fly.

A multistage assembly has these advantages over single stages:

1. You release unnecessary mass as you go higher. Since F=ma, less mass, more acceleration (for the same amount of force). Fuel efficiency is the result. Just lie having extra fuel tanks for your car that you can remove once they are empty.

2. Costwise, a multistage is cheaper to make. Consider the sizes of launch vehicles. Lots of smaller parts are easier and cheaper to build (along with the equipment needed to build them), as well as easier to assemble. Assembly ease equals cost efficiency.

3. Staging puts the fuel of the rocket in compartments. So if something goes wrong (minor) , it would be contained more easily.

Answer 2

As a rocket ascend, a great fraction of its mass is expended, as fuel gets burned. As the rocket gets lighter, the power of its engine is needlessly high compared with the mass that is left to accelerate. Big engines and big empty fuel tanks are just dragging the rocket down, and if they are not required anymore, would be better being thrown away than used all the way up.
Rockets engines have a rather narrow area of peak efficiency. Running at say 20% power would make them extremely inefficient. At the same time, if the engine were to be used from lift off at full power all the way to orbit, their much higher than needed thrust would accelerate the then much lighter rocket at a much higher rate, perhaps uncomfortably high.

A final aspect to consider is the nozzle expansion ration. At sea level, when the rockets starts, the gasses coming out of the rocket engine have to be at a pressure that is a bit higher that the ambiant air pressure (so that the gasses would go out). But at altitude where the air pressure gets lower, that pressure would be too high and would reduce the rocket efficiency. Engines used on second and 3rd stage therefore have proportionally larger nozzles, to exhaust gasses at a lower pressure, more adapted to those conditions.

As for the second part of your question, gravity is a phenomenon that CAUSE acceleration. 9.81 m/s^2 is the acceleration given by Earth's gravity at sea level. Gravity of the moon causes a different level acceleration, and so does Mars and so on.


Additonal stuff: single stage to orbit rockets are envisioned. However to be economically sound, they have to be cheap enough to operate that the cost of maintening and refurbishing them between missions is small. If you have a reusable rocket that you have to totally dismantle and have each part examined each time, the cost to do so would be almost the same as assembling another rocket from all new components; plus you would have to make up for the extra weight that you bring to space and back (instead of throwing out) with a more efficient engine system. It is a very delicate balance, one that the Space Shuttle showed was not reached already.

Answer 3

For me its for economic reason, it is much costlier to build a single rocket with all the needed fuels for the flight into space than a multistage rocket system.

Answer 4

simply by fact as quickly as the gasoline is ignited, the area and shape which contained it and the autos themselves are ineffective and purely upload weight to the vehicle which slows down its destiny acceleration. via dropping the tiers that aren't any further functional, the rocket will become lighter, so the thrust of destiny tiers could be waiting to supply greater acceleration than if the faster point have been nonetheless related, or a unmarried super rocket could be in a position to.

Answer 5

Space shuttle is a single stage rocket.