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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Lift force equation of a rocket and Lift curve slope

I'm trying to determine the lift curve slope of a rocket to get the lift coefficient, using L/qA . the lift equation I'm using is thrust-drag-mgsin(alpha). to me this seems correct as it essentially ...
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Is there a function or equation that can trace the trajectory of a space rocket's motion on the three coordinate axes $(x ,y ,z)$?

To be honest I'm working on a project at the university which is a simulation of launching a rocket into space The problem here is that this simulation needs to be realistic enough for my programming ...
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Will a spacecraft with angular momentum have to course correct if it thrusts along the same axis as its rotation?

For the sake of illustration, let's say you have a cylindrical spacecraft, sitting "at rest" in space, relatively speaking. It has a thruster on one end. If it fires the thruster, it goes ...
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For someone staying on Earth, what is the minimum possible time to send a spaceship to Alpha Centauri and have it back?

Suppose we want to send a spaceship to Alpha Centauri and calculate the minimum possible time it will take for us here on Earth to have the spaceship back. We are not interested in how fast the time ...
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Can a balloon start from Earth and fly to the Moon, using Helium for lift to the top of the atmosphere and then as propellant?

The JP Aerospace's Tandem airship achieved a record-breaking 28,982 meters for the highest airship flight. After reaching this height, can the helium balloon be used as a propellant, the same way if ...
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Quantifying how much would Jupiter heat up if you accelerate Jupiter out of orbit around the sun using fusion candles? [closed]

So, I responded to a post of someone saying that you could turn Jupiter into a spaceship using fusion candles. I mentioned that doing so would dramatically heat up the planet, especially if you were ...
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Questions about the derivation of the rocket equation

Let us derive the final velocity of a rocket facing straight up that is attempting to leave the earth's surface. Basically, we are deriving Tsiolkovsky's rocket equation. We can see that initially, ...
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Energy to momentum

Is there anyway to convert energy to motion IN SPACE? Let's say a satellite collects electric energy from sun using solar panel. Is it possible to convert it to Linear motion? The only way I know to ...
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How fast would a rocket have to go to maintain in the earth orbit without falling down? And how frequent would rocket boosters be needed? [closed]

I was thinking how fast would a rocket have to go to maintain in the in earth orbit? I was thinking of the ISS going 7000kph with rocket boosters every 6 months. What is the most efficient way to ...
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What would happen if a spaceship would pass near a completely stationary astronomical object?

Imagine a completely stationary astronomical object (e.g a planet) and assume it has no movements of any kind (no rotation, no orbits around a star or even a galaxy... a completely still planet) If a ...
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Linear acceleration, gravity, and flipping 180° to slow down

In The Expanse ships use linear acceleration for gravity with the decks placed perpendicular to the thrust vector, this creating a "floor." When it comes time to decelerate a ship would need ...
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How can satellites change direction without any medium in space? [duplicate]

How can satellites change direction without any medium in space? How do spaceships move in space if there is no medium? How does Newton's third law of motion work in space?
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Thrusters in space

Suppose we propel ourself using thrusters in space. If we have two thrusters pushing against each other like this: Nothing will happen. We can imagine the "strain" on the vehicle chassis; ...
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Rocket Rotation due to air resistance

I am currently working on a rocket simulation in Python. After the rocket engine stopped firing, the rocket is in free fall. My problem is that I cannot figure out how to calculate the air resistance ...
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How can I calculate the intercept direction of a constant accelerating missile?

I'm simulating missiles in 3d space and want the missiles to intercept a target which has constant velocity. Given the targets velocity is "u" a vector and the missiles acceleration rate is &...
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Can a rocket travelling in free space really travel arbitrarily far, with fixed fuel, by slowing down the rate of emission? Intuition vs calculation

$\newcommand{\d}{\mathrm{d}}$So for A-level physics we were given some very basic Newton's third law rocket thrust questions. I noticed that one of the formulae involved the natural log, and I reverse ...
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What is the extra kicks to accelerate a spacecraft during gravity assist?

Suppose a spacecraft coming from behind a planet during a flyby, it gets a boost in speed and also change in direction of travel but where does this extra kicks come from? Now that I understand ...
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Would a relativistic rocket need more fuel if it were powered externally?

If a relativistic rocket is pushed by a laser sail, in the frame of reference from which the laser is being fired, the ship is gaining mass and needs more and more energy to accelerate it any further, ...
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Past a certain speed $v_\text{rocket} > v_\text{exhaust}$, why don't rockets slow down with more prograde thrust?

Let's say that you're a stationary observer in a zero-G environment. From your perspective, you measure the speed of a rocket at different points in time. In the first frame, $t = 0$, the rocket is ...
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Shear stress in Interstellar docking scene [closed]

The movie Interstellar has a scene where a huge spaceship (64 meter diameter ring) called Endurance is spinning out of control after an explosion. The protagonist slows its angular velocity down by ...
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Why does the ion thruster trust not assume a simpler form?

Consider the thrust of an ion thruster in a vacuum as described by Dan M. Goebel and Ira Katz, Fundamentals of Electric Propulsion: Ion and Hall Thrusters. From the conservation of momentum, the trust ...
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Theoretical rocket engine based on plasma shock waves particle acceleration

Credits for the article - https://www.quantamagazine.org/cosmic-map-of-ultrahigh-energy-particles-points-to-long-hidden-treasures-20210427 Can this mechanism be used to speed up gas particles to ...
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4 votes
6 answers
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Origin of the thrust force in jet engine

I am reading a lot about the jet engine operation and I meet mostly explenation that the thrust is generated thanks to the exhaust nozzle that "accelerates" the air. However the nozzle ...
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On Conversation of Momentum in Variable-Mass Systems

I am wondering how you would exactly calculate the velocity change in an object that changes mass for whatever reason, such as a rocket leaving behind parts of itself. Is this a simple case of m1v1 = ...
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Why cant there be a sonic velocity inside the convergent part of a nozzle? (ie upstream of the throat)

A convergent-divergent nozzle is typically used for accelerating or decelerating airflow to or from supersonic speeds. The typical configuration for such a nozzle is the de Laval nozzle that is ...
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Why is the JWST orbit only taking 30 days?

Presumably the Ariane 5 rocket launched the James Webb Space Telescope into an elliptical orbit with its apogee at the L2 point. Such an orbit’s period is about 70 days, i.e. the journey to L2 should ...
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Could a relativistic rocket use elliptical orbits for faster deceleration and acceleration?

The biggest hurdle with relativistic rockets seems to be their acceleration and deceleration times. If 1 g propulsion were possible, it would still take over a year to get up to relativistic speeds, ...
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What physics could be applied to accelerate a person from zero to 8000 m/s if you want to: a) Minimize the time, and b) Not kill or hospitalize them? [closed]

My thoughts on this are that you would: Immerse the person facing forwards in a neutral buoyancy fluid, Slew the acceleration up and down just enough to avoid shock waves in their body, Increase air ...
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What limit rocket final speed if there is no drag?

If thrust is constant and drag dont exist, speed goes to infinity or in relativistic physics to speed of light. Even in relativistic theory mass of rocket increase with speed that will just reduce ...
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Project Hail Mary - Does relativity cause us to need more fuel or less fuel for interstellar travel?

In the book, project Hail Mary, Eridians were not aware of relativity. It is claimed that, due to this, they calculated that they would need much more fuel than actually needed for interstellar travel....
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The accelerate from an elliptical orbit to a circular orbit

If there is a satellite and it is in an elliptical orbit. At the aphelion, it accelerates from its elliptical orbit to a circular orbit. The thing that confuses me is that when the satellite is at ...
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Can you calculate kinetic energy with the rocket equation?

Is it possible to calculate kinetic energy with the rocket equation? I am doing a quick school project on the efficiency of a rocket. What if we write velocity with the kinetic energy formula. $E_k=\...
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Can drag be neglected, although the object is in motion?

I was researching more about drag and why two things fall at the same time, and I came across Nasa's website (and quite a few more website) which said that, When drag is equal to weight, there is no ...
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2 votes
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Does light (photons) exert reaction force on it's source? [duplicate]

I know that photons/ light when incident on a surface exerts forces on it (aka radiation pressure) and it is also used for applications such as solar sails or laser propulsion. This phenomenon is ...
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Scaling difficulty of landing a rocket

I am wondering whether it is more difficult to land (as spaceX does) a rocket of height $k L$ than landing a rocket of height $L$? Is there some scaling law? Or at least is there a way to see in the ...
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How is momentum conserved in a rocket?

My teacher told me that conservation of momentum is always applicable to a rocket because the system, which consists of the rocket and the exhaust from the rocket, is isolated. But how is momentum ...
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Will a rocket need the same fuel and energy going 1 g upwards on Earth as a rocket 1 g in space?

Will the gravity of Earth change the result (making the rocket on earth need more fuel and energy than the one in space)? Or it is the same?
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How do satellites accelerate in space with thrusters?

In my space exploration topic we are learning about satellites. We need to know a bit about thrusters and what they do. However I don’t know how the thrusters accelerate the satellite in space. It ...
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1 vote
4 answers
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Could we move a spaceship by moving a Black Hole?

What if a spacecraft were dragged by a black hole, and the black hole were pushed by continuously firing lasers into it? Would this allow the ship to be accelerated faster than laser propulsion, which ...
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3 votes
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Why does gas that's been choked accelerate when the area it's passing through increases? [duplicate]

The throat of a rocket engine gets it up to sonic flow, and the bell of the engine gets it flowing even faster. But why does this happen? In subsonic flow the gas would slow back down, so why does ...
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How to calculate impulse from pressured gas?

Let's say we have a 1L bottle filled with compressed air at 10 atm. If the bottle is opened, how can we calculate the impulse applied by the releasing gas? I'm guessing the diameter of the opening ...
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5 votes
3 answers
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Basic question about orbital speed

I was reading a Sci-Fi book recently and had a weird thought: I know that objects closer to a gravitational well need to move faster to stay in orbit and objects further away move slower. But if you ...
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1 vote
2 answers
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Can we make a rocket with acceleration 17-40 $g$?

I have read that humans can survive 17g for several minutes, and 40g for a few fractions of a second. There has been much talk about a 1g rocket and its relativistic capabilities, but even with that a ...
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Is the vertical velocity of a orbital spacecraft at apogee is zero relative to earth's surface?

When I throw a ball up, it goes up and then at its highest point, its instantaneous vertical velocity is zero relative to me. is this same for an orbital spacecraft at it highest point in orbit (...
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Significance of a close system propulsion [closed]

I have an idea of a close system propulsion powered by electricity. It can move mass in space without expelling anything. If this shall be proven to work, is this significant to the space flight ...
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Conservation of Momentum - Rocket

I was wondering why the mass of the fuel is regarded as -dm and the mass of the rocket as m+dm? I understand that the total mass has to be unchanged (ie m). Why can't I say that the rocket's mass is m-...
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Would Bessel beam laser propulsion create true constant acceleration?

I've heard that Bessel beams don't diffract. If Bessel beams continuously bombarded a laser sail, would it keep the ship constantly accelerating from our frame of reference?
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Would a laser sail change a relativistic rocket?

All the relativistic rocket equations I've seen include an onboard fuel mass lessening during the journey. If the ship were instead propelled by a Bessel beam laser sail, would that change things? How?...
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Rocket equation derivation confusion

I've been trying to derive the rocket equation, and I've faced a minor confusion regarding a certain intuition. I've no problem deriving the equation mathematically though. There are two ways, one can ...
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Doubt regarding derivation of rocket equation

I'm having quite some issues deriving the ideal rocket equation, and I suspect it is due to lack of identifying scalar terms and vector terms. Here is how I derive it : Let $v$ be the velocity of the ...
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