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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Resources for Rocket propulsion

I am a Mechanical Engineering student who is very much interested in Rocket propulsion. Lately I have been searching for good resources to learn concepts about rocket propulsion. I'd be glad to get ...
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How to determine the Delta-v for orbital changes around a Kerr black hole?

What's the Delta-v required to change between the Marginally bound orbit and the innermost stable circular orbit around a Kerr black hole.
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Delta v of a trans-Mars injection (TMI)

Why does it only take about 600 m/s more than Earth's escape velocity to have an encounter with Mars while it takes much more Delta v (about 3 km/s) from a solar orbit (same as Earth orbit) to have an ...
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Would an ICBM be visible? [closed]

From the ground, would an ICBM warhead on terminal approach be visible to the naked eye before it detonated? I'm thinking it would be at reentry speed so would look like a big fireball.
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Why does a rocket engine that produces a constant thrust over a set period of time have less energy if it has more mass? (Zero-$g$) [closed]

A rocket engine with the thrust of 1N working for 10 seconds will add more kinetic energy to the rocket if it is attached to a 10kg rocket and less if it is attached to a 20kg rocket. The rocket ...
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Momentum of the exhaust of a rocket

I was set out to derive the equation of motion of a rocket under the influence of a uniform gravitational field. The equation is as follows $$m\frac{dv}{dt}=-v'\frac{dm}{dt}-mg$$ where $v$ is the ...
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$\Delta v$ to raise the apogee of an orbit?

I was just wondering why it takes more delta v to increase the apogee of an orbit from 1000 km to 11000 km than to increase the apogee of an orbit from 200000 km to 210000 km (from a fixed perigee at ...
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How does the thrust achieved in my model differ from a rocket engine?

I am experimenting with a design that looks this, using both straight and 90 degree curved pipes: I am supplying compressed air marked by yellow arrows and the pipe is producing a very small force in ...
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Would metallic hydrogen be powerful enough to fuel a 1g rocket?

I have read that the issue with a 1g rocket is that no fuel in existence is powerful enough to provide a constant acceleration of 9.8 meters per second for years on end, and it would take hundreds of ...
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Can a rocket be taken to the edge of space with balloons so it can fly from there? [duplicate]

Can we have a (I assume very large) airship or balloon to take a rocket ship all the way to the upper atmosphere so it can use a lot less fuel from there to go to space/other planets. We could even ...
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Relativistic Rocket with Constant Acceleration [duplicate]

How long does it take to (constantly) accelerate to a relativistic velocity? Inspiration from [0] and [1]. Assume you are sitting in a spaceship. To make you feel home, the spaceship accelerates such ...
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Newton's 3rd law and rocket nozzles

For a given solid propellent charge the energy given off by the charge is equivalent in all cases. Yet by varying the throat of the nozzle, the rocket velocity will be different for each individual ...
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How to calculate deltaV due to residual thrust

I'm trying to script a hover slam in a simulated environment using generic kinematic equations to calculate the correct throttle values I should be matching. I cut the throttle of my engine when my ...
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Projection of the force beams on the missile

We know that $∑F = ma$ and the forces that affect the rocket is drag and weight and thrust and lift. I need to know what is the projection of these forces on the three-dimensional world
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Why does burning propellants off of the stoichiometric ratio improve performance?

According to Page 91 of Ignition!: An Informal History of Liquid Rocket Propellants by John D. Clark in the Chapter 7: Performance: "If you're burning a hydrocarbon with oxygen, or if you're ...
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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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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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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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