# Questions tagged [acceleration]

Questions regarding acceleration - the rate and/or direction by which an object's speed or velocity vector changes with respect to time.

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### Why did the space shuttle's altitude go down after reaching 108,000m?

I recently took a look at this little data sheet by NASA: Math and Science @ Work; Space Shuttle Ascent Time Altitude Velocity Acceleration Comment (s) (m) (m/s) (m/s^2) 20 1244 139 18.62 40 5377 ...
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### Term disambiguation: acceleration with/without gravity

I'm ashamed to ask this. But a free-falling accelerometer in a gravitational field will read a nice round zero. And if that accelerometer is given some thrust, it will read the acceleration produced ...
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### Which nD accelerometer symmetric configurations on a cubical LEO spacecraft can serve as a makeshift 3D gyro resolving tumbling from tidal forces?

As they often do @DavidHammen's comment has got me thinking about the following question, which is a mathematical exercise rather than a realistic scenario. On a hypothetical large cubical spacecraft ...
676 views

### What do ISS astronauts do while the ISS gets reboosted? [duplicate]

For its orbit to not decay, the ISS reboosts itself to higher altitudes once in a while. During the reboost, I wonder how much gravity is felt by the astronauts onboard, and what do they do to avoid ...
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### Average acceleration of a rocket given average mass and thrust

If we assume that a small scale rocket is launched perpendicularly to the ground and ignore the drag, how can I calculate the average acceleration given that I know the burn time, the average thrust, ...
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### Lagrange coefficients orbit acceleration

I have an initial position, velocity and acceleration (in x,y,z coordinates) for a certain orbit, and I need to compute the next position, velocity and acceleration after a certain time interval (I ...
203 views

### How much anti-matter is needed for an anti-matter propelled rocket to reach $P$ % ($P\lt{100}$) of the speed of light (c)?

I think this is a tough one. Imagine a rocket is produced which is propelled by a matter-anti-matter device. Its sole purpose is to reach high velocity. Which means the mass can be kept low, say $m$ ...
166 views

### Fastest rocket to reach space?

Spaceloft XL can reach space - 100 km - in 60 seconds So I wonder which rockets can reach that limit fastest Balloon-launched sounding rockets count but separately (from the moment they launch from ...
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### Did the Perseverance rover's Atlas 5 really “leap off the pad”? If so, was it because the payload is tiny, or because it's going to Mars?

Spaceflight Now's ULA’s Atlas 5 is NASA’s go-to rocket for nuclear-powered space probes quotes Tory Bruno, president and CEO of United Launch Alliance: “This rocket is going to leap off the pad with ...
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### How to calculate the maximum heliocentric speed during a flyby?

The following graphs are related to the Voyager 2 / Jupiter flyby occurred on July 1979 (I did the calculation with the SPICE library and NAIF’s data files). We see that the maximum speed relative to ...
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### Supersonic flow of non-compressible fluids

Will the non-compressible fluids, travelling at Mach 1, at the throat of a CD nozzle, accelerate after they leave the throat?
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### Is centripetal acceleration around an ellipse with constant tangential velocity always pointed towards the center of the ellipse? [closed]

I've tried to find answers online but surprisingly couldn't find any.
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### Did any spacecraft ever use the Sun's gravity for acceleration?

Space probes often use planets to accelerate onto a trajectory towards their goal(s) without having to consume too much fuel. But the fastest acceleration would be made through the Sun's gravity if ...
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### How much is a typical reentry vehicle decelerated by heatshield ablation?

Most spacecraft (or parts thereof) intended to survive atmospheric (re-)entry use an ablative heatshield, which, when exposed to the strong aerodynamic heating of (re-)entry, gradually ablates away, ...
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### calculating the terminal velocity of a theoretical solar sail when reaching a distance d where acceleration is insignificant

I am trying to calculate the terminal velocity of a solar sail starting at distance 1AU. I know that my sail will accelerate and its acceleration will be inversely proportional to the distance squared....
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### Tacking a solar sail to increase duration of acceleration

Because the utility of a solar sail diminishes the further it travels away from the sun (max. distance ~50 AU), the longer it can stay in closer proximity to the sun the longer it can accelerate. Is ...
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### Average acceleration of a rocket

Given a rocket has a minimum acceleration with full tanks of say 1 g and a max acceleration with empty tanks of 3g, what's the average acceleration? Is it just 2
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### Could Breakthrough Starshot proposed propulsion system be used in a regular size probe to accelerate it faster than any probe has been before?

Supposedly Breakthrough Starshot project wants to accelerate a capsule of the size of a mobile phone - according to one source - and of the size of the chip of a mobile phone - according to another ...
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### What lateral and rotational accelerations can a spacecraft achieve?

I've found information like the Space Shuttle Orbiter has so many thrusters each generating so much force to maneuver "with redundancy" in orbit. But without knowing something like how many thrusters ...
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### What precisely was the character of the non-gravitational acceleration of Oumuamua?

When exactly did Oumuamua accelerate, when did it begin, when did it end, was it uniform across that period, and at what vector did it occur? I've seen some vague references to it lasting 100 days, ...
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### Apply forces such that a satellite reaches a given point in space

I'd like to find out a strategy for solving the following simplified problem. A small spherical craft at $t=0$ has a position and velocity vectors $\mathbf{x_0}, \mathbf{v_0}$ in a zero gravity ...
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### How was InSight's vertical seismometer (accelerometer) tested in Earth's stronger gravity?

The BBC article InSight Diary: The silence of space tells an interesting story and has an interesting audio recording of InSight's seismometer signals sped up to audio frequency, made while in ...
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### Ion thrusters trip time

Suppose we had a fully equipped nuclear powered ion thruster starship. If it had a constant rate of acceleration of 1g, taking into account the fact that at the half way point you would have to turn ...
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### How long will it take me to get to Mars?

I am a spaceship travelling from Jupiter under constant acceleration of 1g (9.8meters/sec2) provided by fusion drive to Mars. I departed at exactly the same time as an identical ship, travelling the ...
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### Orbital Railgun for launching deep space probes

I've perused some of the articles and questions on magnetic acceleration using rail guns and they all seem to say that it's possible just not practical. I wanted to know what are the drawbacks to ...
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### Outgassing as a viable explanation of Oumuamua acceleration excess

A recent paper on Oumuamua claims the following: 'Oumuamua (1I/2017 U1) is the first object of interstellar origin observed in the Solar system. Recently, Micheli et al. (2018) reported that '...
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### What forces and motion would astronauts experience in a spacecraft in Earth-Moon L1 & L2 Lissajous orbit?

What is the maximum velocity they would experience? Would they be aware of the movement based on the positions of the Earth, Moon, or stars, or would it be too slow to notice? Would they feel any G ...
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### What could possibly happen if an object accelerates 9.81 m/s^2 upwards if it started from the ground ? [closed]

Will the acceleration of the object and the acceleration due to gravity cancel each other and that object remains at the same space coordinate?
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### Is there an optimal accelaration for first stage going in LEO?

I know every engineering works is based on compromises, and rocket design is no exception. A rocket should go as quickly as possible to high altitude to avoid flying for a long time and at high speed ...
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### How do I calculate a rockets burn time from required velocity?

Say my rocket could produce F newtons of thrust while consuming M1 kilograms of fuel per second. It's mass at start is M0, and it keeps burning until it reaches V velocity. How would I find out the ...
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### Gravitational forces affecting acceleration on a space ship with artificial gravity [closed]

I and my brother are having an argument on gravity on a space ship. For this argument lets say, you are in a void. There are no outside gravity forces, ie planets or solar systems in the near region. ...
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### What is a non-propulsive vent?

I just hear the term "non-propulsive vent". Is it a thing, a vent that does not cause propulsion? Or is it an event, where a vent of some unwanted gas has occurred which did not result in a ...
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### How much acceleration g-force can prevent pilot from moving their arms?

Assuming that the craft’s engine is capable of any amount of acceleration, how much g-force would prevent the pilot from being able to move their limbs in order to control the space craft? There is ...
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### Theoretical Max G forces on Shuttle Launch?

Reading this question Why are rocket engines operating above 100% often considered nominal? leads me to a question about throttling back the SSMEs in the later stages of a Shuttle Launch to limit G ...
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### Soyuz seat - return

Every astronaut launching on a Soyuz has a seat custom-made (source). However, I don't believe astronauts typically return on their original Soyuz, and I know that they don't always. In this case, are ...
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### SpaceX rocket strange velocity

In SpaceX launch on May 1st, 2017, we get to see the full flight path of the first stage rocket of the falcon 9 from launch to land: It accelerates to around 1685m/s ...
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### Challenging the Kármán line from above

The initial conditions of the thought experiment is (very) LEO / reentry. capsules, space shuttle and other spacecraft can generate lift in upper atmosphere during reentry, in order to reduce ...
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### Why does not the ISS turn when accelerating?

When spasecraft accelerates its center of masses should be on the line of force vector otherwise it will start to spin. How does ISS hold its orientation when accelerating? Do gyros hold station ...
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### On determining nominal speed of reaction wheel

As part of a project, I am designing a reaction wheel system for a nano-satellite. I am now researching on how to determine the nominal speed of the reaction wheel. I have characterized the deadzone ...
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### Is it possible, using known acceleration laws, to drastically lower force required to leave Earth's Gravitational pull?

Just a silly theory to illustrate my question. If we were to build a globe (or a detached runway, could be any structure really as long as it goes around earth and meets on both ends) around the earth,...
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### Amount of fuel for accelerating a spaceship

Suppose I have a spaceship and fire up its engines, accelerating to 10000 km / h. Now I turn off my engine and see I have consumed 10 % of my fuel (90 % left). How much fuel does it take to ...
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### Are we actually that close to techniques of accelerating probes to speeds like a quarter $c$?

As recent research has been started by a team around Stephen Hawking under the name Breakthrough Starshot they are going for accelerating little probes up to 0.2~0.25$c$. There isn't that much ...