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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Prove thrust is double the dynamic pressure across area A [on hold]

Hey, I would be really thankful if someone could answer this for me. Prove that the value of the reaction thrust F equals twice the total dynamic pressure across the area A for an incompressible ...
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30 views

If humanity was to send a probe to Proxima Centauri, how long would the travel last?

[Feb 3 2016] (I am including the date I asked this as a reference, since technology evolves with time, this question's answer will change in time...) If humanity was to send a probe to the nearest ...
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1answer
48 views

Optimal time for satellite rocket launch considering moon gravity [closed]

As per this The Gravitational Force of the Earth and Moon on Each Other Moon is pulling us with a force equal to 1/300,000th of our weight. I have read this Is the fuel burn for a satellite launch ...
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32 views

Aircraft Thrust to weight ratio contradiction with energy conservation

Usually, airliners have (Thrust/Weight) T/W ratio in the range of 0.2 to 0.8 and for steady flight W = lift My question is, for example, that Antonov 225 has Thrust/weight: 0.234 for max takeoff ...
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1answer
47 views

rocket vertical landing [closed]

SpaceX has published a couple of videos that show one of their heavy-lift rockets landing vertically in a highly specific location. How is it possible that they are able to control so many ...
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36 views

Can outgassing produce a significant thrust on a space ship?

There are a variety of materials that outgas in the atmosphere, and I imagine they would do so even more in the vacuum of space. I imagine an object in space would experience a small force as ...
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2answers
104 views

Violation of the Newton's first law of motion in the movement of spacecrafts in the vacuum of space [closed]

Suppose a rocket at rest in space where there is a complete vacuum and no force to influence the rocket: In the left we have the rocket with a metal ball in it. After the ball is thrown out of the ...
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2answers
184 views

At What Point Does Mass Cease to Matter?

I know very little about physics so I naturally have a lot of simple minded questions. Assuming I am piloting a rocket and want to obtain the fastest speed possible. At what point does mass more ...
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1answer
64 views

How to calculate the thrust of a rocket with relativistic exhaust

The general thrust equation is $F = \frac{dm}{dt}\cdot v$, where $m$ is propellant's mass and $v$ is the exhaust velocity, is the equation right? What if the propellant is highly relativistic? One ...
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1answer
85 views

Understanding rocket equations [closed]

I'm doing a science project where I have to explain the physics behind a trip to an exoplanet and I also have to explain about rocket equations while doing so. I know that a trip to an exoplanet is ...
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1answer
57 views

Conservation of energy during the flight of a fire cracker [closed]

We say that energy is neither created or destroyed. It can only be transformed. I hope this principle is applied in the flight of a fire cracker. The chemical energy is converted into physical energy ...
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17 views

Motion in Spaces [duplicate]

How does a shuttle move in the space as, the whole mechanism of a rocket is based on 3rd law of newton but, we can not apply 3rd law of newton in space because there is no reactive force in space?
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109 views

Explain this contradiction of violation of “ energy conservation ” using classical mechanics

Consider a rocket moves upward with some acceleration for a very small time say '$dt$' then the kinetic energy increases (for acceleration). as well as as the potential energy increases (due to height ...
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2answers
178 views

The NERVA had to use liquid H2… But why?

The NERVA engine, developed at the late 60ies, was a nuclear thermal rocket developed for vacuum use in space craft. It was supposed to use Liquid Hydrogen, a cryogenic fuel with quite a few issues ...
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4answers
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Could we launch a missile from a planet with the mass of Jupiter?

If the Earth had the mass of Jupiter, would we be able to launch a space missile ? Is there a formula to calculate how the launch of 1-Kg payload increases with gravity?
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43 views

Finding position with respect to time along a trajectory across a sphere (orbital mechanics)

When trying to find an object's position with respect to time on a ballistic trajectory along a curved surface, what equation should I use? I know that when adding force to an object to achieve ...
4
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1answer
89 views

The Lagrangian of a Rocket

I am trying to understand how to write the Lagrangian of a system which consists of a rocket losing gas mass in a rate of $\frac{dm}{dt}$, the gas moving in a velocity of $u_0$ in the rocket's view? ...
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1answer
78 views

How much fuel do I need to send cubesat 1kg from Earth orbit to Moon orbit? [closed]

How much fuel do I need to send cubesat 1kg from Earth orbit to Moon orbit? And how much stages? For i.e. C12H22O11 + KNO3, polyethylene + oxygen or kerosene + oxygen.
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37 views

Is it possible to use stainless steel for 3d printed liquid rocket engine powered by kerosene and oxygen? [closed]

There is no possible to print from copper at this moment, so, I need a replacement material. There is rocket engine with regenerative cooling system. It's cooling by liquid propellant (it uses gaseous ...
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38 views

Earth to LEO, gravity drag and potential energy

A lot of references indicate takes about 9.4 km/s of delta-v to reach LEO. https://en.wikipedia.org/wiki/Low_Earth_orbit#Orbital_characteristics The delta-v needed to achieve low Earth orbit ...
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3answers
2k views

Where does the energy go in a rocket when no work is done?

While playing Kerbal Space Program, I wondered where my chemical energy would go when fired at 90° to the motion. It would do no work on the rocket, but all that energy has to go somewhere, right? ...
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1answer
180 views

Rocket projectile motion problem [closed]

I'm not really sure where to start with this question: In a brisk wind from the south-east of $14.1\:\mathrm{m/s}$ a rocket pointed due north is launched from a cliff that is $500\:\mathrm{m}$ above ...
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1answer
80 views

Constant Jerk Relativistic Rocket [duplicate]

A quick google search will give many helpful pages and calculators regarding constant acceleration relativistic rockets, but my question is somewhat different. What if jerk is the parameter to be ...
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1answer
40 views

Reading about liquid propellant rocket design

I was reading NASA's manual on liquid propellant rocket design from 1971. It makes the following statement. The rocket or, in a more general sense, the reaction motor presently is the only ...
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2answers
132 views

How to calculate thrust from opening a pressure vessel in space?

One popular trope in science fiction is the astronaut who (deliberately or inadvertently) punctures an air tank or something and goes rocketing off. How would we calculate the amount of force that ...
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3answers
873 views

Does an ion thrust engine consume more energy as it speeds up?

This question goes to a very basic non-understanding of mine that I have had in the back of my mind for ages - I just read the following here: ion thrusters are capable of propelling a spacecraft ...
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1answer
37 views

Molecular analysis of Rocket propulsion

Newton's third law states,For every action exerted by an object A on object B,there will be an equal and opposite reaction on A. In case of rockets,during ejection of hot gases with high ...
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269 views

Why are rockets launched vertically?

Why the rockets mostly used for space missions are launched vertically upwards and not horizontally like an airplane carrier, gradually increasing its altitude, wouldn't that be more efficient?
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1answer
2k views

Using nuclear devices to terraform Mars: Elon Musk's nuclear proposal? [closed]

Elon Musk has recently suggested Using nuclear devices to terraform Mars. In the past, comet related ideas were mooted, but Musk seems, to me anyway, to be a man in a hurry and perhaps his idea has ...
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3answers
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Why do we launch rockets during the day?

The clips that I have seen of rockets launching all seem to be carried out during daytime. However, we learnt at school that rockets are fired closer to the equator and towards the east to take ...
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1answer
236 views

Water bottle rocket: Where does the energy go without water?

In Portland's OMSI there is a hands-on water bottle rocket station. (https://www.youtube.com/watch?v=cdtmVY76_PQ). The rockets are normal PET bottlers. The visitors fill their bottle with an amount of ...
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2answers
67 views

Rockets and distance [closed]

I am trying to create an equation which allows for me to change the aspects of the rocket so i can calculate the distance traveled vertically. My idea is for a rocket that only moves vertically; ...
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2answers
156 views

Thrust in space without expelling mass

The classic rockets move losing their mass in one direction and moving to the other direction. Thinking about an alternative engine where we lose very small mass. This is how the engine works The ...
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1answer
53 views

The Real Rocket

Suppose we have a Rocket with initial mass $M_o$ and we want to sent it into space. The equation of motion is (i think... please tell me if there is something i forgot) $$\frac ...
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1answer
89 views

What are the biggest reasons that Cars get higher Land Speed Records than motorcycles'? [closed]

What are the biggest reasons that Cars get higher Land Speed Records than motorcycles'? It is because cars have a more streamlined frame than than motorcycles? But, from pictures, it seems that ...
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1answer
61 views

Rocket thrust over time [closed]

I have calculated the thrust of a rocket, and it's burn time for an orbital manoeuvre. I need to know how much force is applied on the rocket every half-second. How would I go about doing this? ...
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1answer
49 views

Asteroid as a “free slingshot?”

The question Halley's Comet as a "Free Taxi" had an interesting thought, even though it didn't work out. I was wondering about a variation on the idea. Use a cable, as illustrated below. Could this be ...
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Halley's Comet as a “Free Taxi”

Now that the ESA has landed a probe on a comet, namely Rosetta's Philae Probe, could we possibly land a probe on Halley's comet? Fuel seems to be a limiting factor for interstellar expeditions - could ...
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1answer
70 views

Rocket velocity during fuel burn [closed]

I know the formula for the velocity of a rocket after the on board fuel has been used up: $$ \Delta v = v_{ex} \ln\left( \frac{m_i}{m_e} \right) - gt $$ where: $v_{ex}$ is the exhaust velocity ...
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432 views

How does a rocket's exhaust gas' momentum propel a rocket?

During the launch of a rocket into space, the exhaust gases from the engine possess momentum. Outline, with the help of an equation, how this causes the rocket to be propelled upwards. Can ...
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213 views

Can a nozzle increase the thrust of a water rocket?

First of all, what is the correct equation to determine the thrust produced by a water rocket? $$ F_T = \dot{m} V_e \tag{1} $$ $$ F_T = \dot{m} V_e + (p_e - p_0)A_e \tag{2} $$ Using the first ...
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1answer
154 views

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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76 views

Saturn V horizontally attached to Earth

If the Saturn V rocket were attached to the ground facing in the opposite direction of the Earth's spin, would it in anyway slow the Earth's spin on its axis? How significant of an impact would it ...
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71 views

How does NASA determine the position of their probes?

I'm currently following New Horizons visit to Pluto. I'm just wondering how does the Probe/NASA determine the Position of the Probe? I would assume using earth's GPS wouldn't have the necessary ...
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1answer
84 views

Rocket equation derivation, question about signs

My question is about signs in the derivation of the rocket equation. Considering a rocket of mass $m$, its momentum at time $t$ is $p(t)=mv$. At time $t+dt$ it ejects a quantity $dm$ so its momentum ...
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67 views

What's the fastest you can slingshot from one black hole to another? [closed]

Let's say you have your spaceship orbiting around a black hole. Its orbital velocity is arbitrarily close to the speed of light (or you can just set it to c*0.99 if it makes it easier.) There is ...
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46 views

What factors are influencing a woosh rocket?

Not sure if this is too much chemistry, but I'll try: If I fill a plastic bottle with a small amount of rubbing alcohol, shake it around and hold a match to the bottle neck, I'll get a flame wooshing ...
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60 views

Rotational dynamics equation for a variable mass system?

I'm searching for the formulation of Euler's rigid body dynamics in the case of a variable mass system. I'm reading the book Mechanics of Flight by Warren F. Phillips (2nd edition) and unfortunately ...
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2answers
301 views

Velocity of Rocket Exhaust

i recently learned a bit of rocket propulsion.It wasn't much complex but was explained in simple terms.The only problem i had understanding it was that in calculating the thrust of rocket the velocity ...
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2answers
339 views

“Suicide Burn” rocket problem [closed]

THIS IS NOT HOMEWORK. I'm actually in Physics I atm, and am an avid player of Kerbal Space Program. I hope to do my CS masters thesis several years from now on something space related. But none of ...