# Tagged Questions

Colloquially referred to as one of the hardest professions, rocket science is actually a common name for spacecraft/space-systems engineering. However, one can also generalize this to include all forms of rocketry, including rockets that are not capable of space travel.

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### How many days it takes to travel to Cygnus? [duplicate]

BACKSTORY I read today newspaper and made discovery of planet Cygnus (in news paper of course :v) that human can live there! The distance is 1400 Lightyear. Assuming I travel with the world fastest ...
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### Saturn V F-1 engines and beyond

I read that the F-1 engine from the 1st stage of the Saturn V rocket is the most powerful engine ever created by mankind, delivering ~200 gigawatts of power. Thus, I have got two questions: Will ...
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### Can we escape Earth's gravity slowly?

I had a recent conversation with my girlfriend, who is a physics grad student. She was kind enough to listen to me rant about an idea concerning escape velocity. Unfortunately, I am still thinking ...
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### How to find a condition that ensures that the rocket immediately takes off?

For the rocket in a constant gravitational field, how to find a condition that ensures that the rocket immediately takes off? Update: I apologize. Let's try again. So my question: For the rocket in ...
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### Rocket in constant gravitational field [duplicate]

A Rocket in a constant gravitational field, what are the conditions required for the rocket to take off immediately? (in terms of $m_0,μ,g,v_r$), where $m_0$ = mass of the rocket at $t=0$ $μ$ = mass ...
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### Rocket/Thrust/Gas/Free Expansion of Gas

We know, the rockets in space use Newton's 3rd law to increase their velocity and hence move. What I don't understand is how it is possible in space aka vacuum-state without air? From what I know, ...
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### How does the space shuttle move in a vacuum? [duplicate]

If there is no friction in space, then how does the space shuttle boost? According to Newton's law we move by pushing something; in space, there is vacuum, so how the space shuttle moves without ...
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### Which is the right explanation for rocket motion? [duplicate]

What actually causes a rocket to move? Is it the pressure in the rocket engine or the amount and velocity of mass that is being ejected out. The reason I am asking is, I found these two explanations ...
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### Understanding of the $m v^2/2$ formula for kinetic energy

I have some problem to intuitively understand why the kinetic energy grows quadratically with the velocity (at least in non-relativistic case). Assume the following experiment: we launch an unmanned ...
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### Do objects launched from Earth retain the Earth's lateral inertia (67,000mph)

We've probably all heard of the gun on a train theory. Fire a bullet that would normally travel 500mph on a train that's moving 200mph (in the same direction the train is moving) and you've now got a ...
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### What are the preferred height and diameter proportions for a rocket model?

I'm pretty sure, that if you make a rocket that's relatively small in height compared to diameter, it will most likely not fly very high and probably spin out of control. What about a rocket that is ...
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### Does lunar module need the same amount of fuel for landing and take off?

Let's assume there is no atmosphere and let's assume there is no change in weight due to fuel consumption, will reactive rocket need the same amount of fuel for landing on a planet as for take off? ...
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### What would have been required to boost Mir into a stable orbit?

In 2001, the Russian space station Mir was deorbited and burned up in the atmosphere, after \$4.2 billion in expenditures. As it was orbiting within the thermosphere, it was encountering perpetual drag ...