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Questions tagged [rocket-science]

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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Is there any graphs that demonstrate the Tsiolkovsky rocket equation? [on hold]

For example can you see the equation from analysis of a graph?
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Why is the onboard trip shorter when riding on a relativistic rocket as compared to a Newtonian rocket? [duplicate]

In the top answer for this question on the Space Exploration StackExchange, it's calculated that a rocket traveling at constant 1g of acceleration over 100,000 light years would, under Newtonian ...
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How fast can we get to Alpha Centauri?

Suppose in the near future we send an Antimatter rocket that is capable of constant $1g$ acceleration to our nearest star, Alpha Centauri, $4.3$ light years away and suppose we want the spacecraft to ...
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Can you predict how much fuel you need to launch a rocket based on conservation of energy?

I was just wondering if there was a way to calculate how much fuel you need for launch, possibly to do with chemical energy to kinetic energy. Thanks
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Mass required to accelerate to relativistic speed

What would the rest mass of a rocket need to be if it carries a payload of 1kg and is accelerated to 1/2 c and then decelerated to a stop. Assume: 1 - energy required is obtained via fusion of ...
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Water from air concept – is this plausible?

Here’s an idea I had: Consider how a rocket stove works.. There is an inlet where wood is fed into the stove and an outlet for which the exhaust can vent. Very simple but very effective. Now apply ...
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Why do cylindrical rockets require a roll and pitch maneuver?

On the space shuttle, I understand that the quick roll and pitch maneuver wins because it increases payload, aligns antennae, etc. But if one looks at the Apollo missions on a Saturn V, why is this ...
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Change of orbit with tangential impulse

I see a similar question: Change of orbit with a radial impulse. The answer to that question seems fine to me. In the answer, mention is made of this similar question, but it is not fully treated. ...
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Why haven't we yet tried accelerating a space station with people inside to a near light speed? [closed]

Is that something we could do if we use ion or nuclear thrusters? Wouldn't people in the station reach 0.99993 speed of light in just ...
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Help with Gravity Assist [closed]

In our scenario, a spaceship of mass 70,000 kg and velocity $v_o$ is planning on slingshotting around Earth and we're supposed to find what the exit velocity will be. The Earth is the origin in our ...
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1answer
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Can satellites stay in orbit when the Earth is being accelerated?

In a TV show I'm watching, the people of Earth have decided to leave the solar system, and take Earth with them, so they've built a large number of powerful rocket engines on one side of the Earth (as ...
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Could one theoretically use the expansion of the universe to travel through it? At least in one direction?

Could one theoretically use the expansion of the universe to travel through it? At least In one direction? That’s it that’s my question. I’m not a physicist but I do get ideas. I also wonder if one ...
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If fuel was provided by an autonomous side ship, how much fuel would be required for a 10 metric tons rocket to reach the ISS?

The point here is that the rocket weight should never include fuel. It can take off from any departure base of your choice. The fuel provided by the side ship would then be used only to lift the ...
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What percentage of a rocket fuel is used to lift fuel itself?

I don't need an exact number, also it can be to travel to the ISS or the moon, it's not important. I just want to get an idea of how much fuel is used in a «recursive» sort of way. Edit: I am asking ...
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How did most of the math and physics formulae that govern our lifestyle and help us in space exploration come into being? [closed]

I realise that this isn't a very academic question, but after watching movies like First Man and Interstellar, it got me wondering: How did all these formulas that we use on a regular basis come into ...
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What is difference between Impulse and Thrust in Physics/Rocket Science?

The question is clear. What is the difference between Impulse and Thrust in Physics/Rocket Science as meaning?
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Why don't we use ionized neon for arc jets?

On a typical arc jet there is a cone in the proppelent stream (ammonia or hydrazine) that acts as an anode and the the nozel itself is the cathode. But why don't we use ionized neon as the cathode and ...
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Nuclear Propulsion

I am watching a video on nuclear rocket engines, specifically the Nerva engine. It has a propulsion efficiency of 750-800 Isp versus chemical rockets which are only 350-400 Isp. The follow on NRX ...
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Model Rocket Stabilisation

I am designing a model rocket and am using 3 B6-4 Engines. Inevitably there will be perturbation of its trajectory by wind and engine/thrust inconsistencies. The way that I currently understand the ...
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1answer
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Is a rocket engine most efficient when its velocity is equal to the exhaust velocity?

I was reading Dale's answer on this question and from the answer I concluded the following: 1- When the rocket is traveling at a velocity much less than the exhaust speed, most of the chemical energy ...
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Rocket Leaving Earth's Gravitational Field

I stumbled across this seemingly simple question that really stumped me on further thought: A rocket is intended to leave the Earth's gravitational field. The fuel in its main engine is a little ...
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1answer
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Chemical energy

A physics problem I am solving has a rocket which launches and releases a certain chemical energy $u$. What is chemical energy? How would I incoporate it into the equations of conservation of energy? ...
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Would it be possible to do a “slow” translunar injection, lasting an hour or more

Part of my sci-fi novel takes place on a spaceship with centrifugal pseudogravity (initially at ~1g), designed to make passengers comfortable on a week-long voyage to the moon. With that being said, I ...
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Rocket propulsion equation

The equation $$V_{rel} \frac{dm}{dt} - mg = ma $$ what is the meaning of m in the given equation is it the mass of the rocket and the point with which we are concerned or is it the initial given ...
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Can the pressure term in the general thrust equation be negative?

In the general thrust equation, it looks like the pressure term can be negative if the ambient pressure is greater than the nozzle exit pressure: $$F=\dot m\cdot V_\mathrm e+\left(p_\mathrm e-p_\...
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Is there a minimum range for an Intercontinental Ballistic Missile? [closed]

To be more concrete: Would it be possible to fire a ICBM Minuteman III from Malmstrom Air Force Base in Montana (USA) to hit Helena (the capital of Montana) about a hundred kilometers away? If not, ...
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Lagrangian of Rocket [closed]

While solving equation of rocket motion with Newton's law in 1-d,I pondered to apply Lagrangian method on this. However, I didn't get correct result. Because I can eliminate last 2nd equation using ...
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How do rocket engines work in EMPTY space? [duplicate]

So I just read this and it didn't make any sense It is not necessary for the rocket exhaust to push against anything EXCEPT THE SHIP ITSELF. You see, when the combustion of fuel takes place ...
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1answer
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Optimal trajectory of rocket with variable specific impulse and constant power

I am trying to derive trajectory of rocket with variable specific impulse and given power of engines $P$ that minimizes the total time. The specific impulse is given as time-variable effective exhaust ...
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1answer
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How was the equation for a gravitational assist derived?

Im currently writing a paper about a hypothetical probe meant to escape our solar system and I want to analyse how gravitational assists would be beneficial for its mission. I found a website with an ...
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1answer
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How do ion thrusters create a force against the spacecraft?

I recently saw an old thread, How do reaction engines create a force against the rocket?, get bumped up, and it asks a good question: in a chemical rocket, the fact that the rocket exhaust gets ...
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How do reaction engines create a force against the rocket?

I'm fairly new to physics, so please forgive me if I lack basic understanding. I'm wondering how rocket engines actually work. I know the answer of "actio est reactio", but I feel like this is a ...
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What would happen if I used a jet pack that accelerates at $g$ but always upward?

I'm trying to imagine what would happens if gravity is cancelled. I assume that without air, if the effect of gravity were to disappear I would fly off Earth on a tangential line. But with the air ...
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How does a rocket gimble work?

I'm trying to understand how a rocket Gimble turns a rocket using unbalanced resultant forces . For simplicity lets say a compressed air rocket. If the rocket is straight ahead the escaping gas ...
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Standing waves in raptor rocket engine test

Stopping the video of the recent test of the raptor rocket engine, one can see a standing wave forming in the exhaust gases: https://youtu.be/MAAzbjG_Duc?t=23 I was wondering what might cause a ...
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How this equation happens and what it describes?

I'm having some trouble with Momentum and Impulse, In this equations, Thrust = F = m * a = dp / dt = m * (dv / dt) + v * (dm / dt) How is the, m * (dv / dt) + v * (dm / dt) Happens, and what it ...
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Aerospike Nozzle Geometry

I have searched the site and my search for the results I want yielded 16 results, none of which seemed to be very helpful. I have searched the internet several times but I do not have the knowledge or ...
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I'm travelling near the speed of light. Do I need to brake before using a super-massive black hole to turn around?

I'm taking one of those new fusion drives for a trip to nearby supermassive black hole. At a comfortable 1 G, it'll take me about 7 months of proper time to accelerate to 95% the speed of light. I'm ...
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Does Oberth Effect work in free space or it works only in gravitational field (gravitational well)?

From Wikipedia article about Oberth Effect it is not clear if it works in free space (no gravity, no air, etc). For example, in very far space between 2 galaxies, gravity is almost zero. There are 2 ...
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2answers
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Why cannot we go in outer space with constant speed?

Sorry if this question is very childish for experts here. This was the question I had in school and years later it has resurfaced. I did some google search but getting the same equations of ...
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Generic Differential Equation for Oberth Effect

In Wikipedia article about Oberth Effect there is an example of calculation in a simple case when the differential equation is not required. In non-English versions of this article (for example, ...
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1answer
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How can China put artificial moon if they're not in equator?

China plan to put artificial moon. I suppose the moon would have to be geo stationary in orbit. However, a geostationary orbit would be on equator and china is not on equator. So how would it work? ...
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1answer
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Rocket equation and drag formula

i originally posted this question over at the math section but a guy told me to switch it to here instead. i'm writing an assignment on firework rockets and their trajectory. Now of course im doing ...
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1answer
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Solving the rocket differential equation

I'm trying to derive the rocket equation. I'm pretty sure that the differential equation for the rocket equation is $$v(t)\delta t =\frac{m(t)\delta t }{m(t)} V_e$$ where $v(t)\delta t$ is the ...
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1answer
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Is it possible to use an accelerator/collider as a space engine? [closed]

I was just trying to get a discussion going about physics that we can already create. I did not realize that I would have to write a paper to ask a simple question. Is it possible to use an ...
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1answer
52 views

Work-Energy Theorem for Non-Constant Mass

"The net work done on an object is equal to its change in kinetic energy." Let's say that a rocket is moving upwards while expelling gas and is thus losing mass. (Non-constant mass) As the object ...
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2answers
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Rocket speed (Is the equation my choose is the correct one and is my (asumption) and calculation is correct with regard to Hawking's sentences

Hawking wrote, Exhaust speed of chemical rockets is 3 kilometer/second. By dropping 30 percent of their mass, they can achieve speed of about 0.5 kilometer per second and then slow down again. ...
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Are there two action-reaction pairs operating in a rocket

I'm confused about the action-reaction pair in a rocket. is it 1 The action of the explosion of gases in the combustion chamber on the rocket, and the reaction of the rocket on the gases, or 2 The ...
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Where does the momentum exchange happen in a rocket? [duplicate]

Where does the momentum exchange happen in a rocket. Is it in the combustion chamber alone?