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.

learn more… | top users | synonyms (1)

0
votes
0answers
11 views

How do rockets fly? [duplicate]

Is it that when a rocket loses its mass due to the escaping gases that results in its acceleration due to the same force acting upwards? If so, how is Newton's Third Law associated with it?
-1
votes
0answers
30 views

How can a polar orbit of a satellite be achieved? [on hold]

I mean an orbit in which the satellite is above antarctica on southern hemisphere and above arctic circle in northern hemisphere? I guess it won't be possible to be exactly above the axis but closer ...
8
votes
3answers
108 views

Can we make high acceleration safe to our bodies thanks to this gravity trick?

According to Wikipedia, a human body can resist g-force of about $5 g$. It can be a greater value in some circumstances, but even as low as $2 g$ would be unpleasant after several seconds. This means ...
-2
votes
0answers
42 views

Formula for altitude of an accelerating rocket [closed]

I'm trying to find a formula for a rocket's altitude including the change in the rockets mass due to fuel being consumed. The normal formula I would use would be $\mathrm{ (Thrust/Mass )} \cdot 9.81x^...
0
votes
1answer
25 views

Rocket Propulsion Equation: Meaning of Net Force

Upon deriving the rocket equation, my textbook (Giancoli) states that the meaning of the net force on the final equation is the net force on M. Note that $M$ and $dM$ are used as the rocket (without ...
1
vote
2answers
63 views

Could superconducting magnets be used to form a shield around a spacecraft?

If superconducting magnets could be used in space to form a field around a spacecraft of a similar field strength on the earth 25 to 65 microtesla's? Would the temperature in space at -246c be OK ...
-1
votes
1answer
39 views

Mass ejection to improve trajectory?

Let me start with an example: Suppose I have a long range two stage rocket in pursuit of an agile aircraft of some sort. Once the fuel in the first stage is exhausted it may need to be ejected. Do ...
1
vote
1answer
51 views

Orbiting in space

Background I'm making a game where a spaceship needs to orbit another object in space at a set distance. Space is, unlike other game, like space is in reality. Friction less. (at least to my ...
1
vote
0answers
33 views

How much velocity can a canister of fuel give a spaceship? [closed]

We could approximate a basic solution If we know the mass of the fuel $m$, the mass of the ship $M$ and the amount of energy left in the fuel $E$. So the energy density of the fuel is, $\frac{E}{m} = ...
2
votes
1answer
60 views

Why was the Sputnik rocket's mass over 130 times that of the rocket equation?

From the Sputnik rocket's Wikipedia page, the specific impulse of the boosters and the engine are both ~307 s. Low Earth Orbit requires a Delta V of ~9400 m/s. The mass of Sputnik is ~85 kg. Plugging ...
0
votes
1answer
60 views

Could vacuum chambers lighten the load for space bound technology?

Would cavities of near vacuums in the head (or in the 6 x 6 blocks surrounding the rocket [for reentry temperatures]) of a rocket make it lighter so it can be sent out easier?
0
votes
0answers
58 views

Trouble following an argument about a rocket problem

This is from pages 32-33 of Physics for Mathematicians. A rocket + fuel system of mass $m(t)$ is moving along at velocity $v(t)$, with its fuel being ejected at the velocity (relative to the rocket) $...
-1
votes
1answer
37 views

How is rocket acceleration with flight angle calculated?

I know $a=F/M$ and that if you launch straight up you have to subtract the rocket's weight from the thrust, but what about at an angle? At any angle there's a rearward component that is sine theta of ...
0
votes
3answers
68 views

Space Rocket Ionizing Its Path To Decrease Fuel Consumption [closed]

A beam(maybe multiple beams from ground crossing at, or just some very high alternating potential, something like focused haarp) on tip of rocket targeting at path of it, ionizing just the closest ...
1
vote
2answers
107 views

Relativistic Rocket Fuel Requirements

I am trying to reconcile two different calculations of fuel for a 1g constant acceleration/deceleration trip to Alpha Centauri. One found here (http://math.ucr.edu/home/baez/physics/Relativity/SR/...
34
votes
7answers
6k views

Supergun Launching of Satellites

I should say first that I don't believe this is a feasible launch method, otherwise NASA and other space agencies would be using it by now. It's based on this BBC news story Saddam Hussein's Supergun ...
1
vote
2answers
69 views

Magnetism In Space

I am not an expert when it comes to physics. I was looking at maglev technology the other day and a thought crossed my mind. Would similar systems work for deep space exploration. I understand ...
0
votes
1answer
32 views

How is a rocket mounted w.r.t. gimbal?

Gimbal system is used to balance the rocket from tripping after its launch. But, how is a rocket mounted with respect to the gimbal system?
3
votes
1answer
64 views

2 times the velocity, 4 times the energy, 8 times the heat

In SpaceX's webcast today they talked about the first stage getting back to Earth with twice the velocity as usual. I quote: "So 4 times as much energy means harder on the stage, and 8 times as much ...
1
vote
0answers
19 views

What wavelengths of electromagnetic radiation are emitted by the LH2/LOX reaction?

Rocket engines such as the Rocketdyne Rocket System 68 and the Space Shuttle Main Engine use liquid hydrogen and liquid oxygen as propellants. The exhaust from this type of engine is notable in ...
1
vote
1answer
41 views

Can an accelerometer be used to determine orientation of a rocket under power?

I saw a project on Hackaday featuring a model rocket with moveable fins to stabilize the rocket's trajectory: Hackaday. The goal was to arc the rocket to a horizontal trajectory and keep it there. In ...
1
vote
2answers
62 views

Can AMO physics be applicable for space travel? [closed]

I know it sounds very stupid question. I am working on the AMO physics (Quantum Optics). I recently saw articles about the Spacex, and I thought it is really amazing, and thinking about the possible ...
-1
votes
1answer
37 views

Question about Thrust; am I correct?

Basically, here's what I understand about Thrust: Thrust is a force. You get it by doing $v\times\frac{dM}{dT}$. Pretty basic, because that's the formula you're given. However, because I'm trying to ...
1
vote
2answers
85 views

How does rocket thrust work?

I can't seem to find a specific answer to this anywhere. I understand that in a rocket there is a chemical reaction that causes gas particles to leave the rocket at high velocity. By Newton's third ...
1
vote
1answer
54 views

Force of Gravity of a stationary object acting on another object moving through space

Story: I have x and y positions of a spaceship as it moves through space to some goal location at [1000, 700]. A record of its movement is given by: ...
0
votes
2answers
27 views

Model velocity as function of distance in object subject to drag and propulsion

Given an initial speed $v_0$ and acceleration $\frac{dv}{dt}|_0=a_0$, I need to find velocity as a function of distance knowing that Drag is $ D = Av² $ Propulsion is $P = Bv + C$ I already found $...
0
votes
3answers
147 views

Why can't space become fuel for spaceships? [closed]

I read somewhere that space is constitued mostly of hydrogen. So why can't space and its constituants (not only hydrogen) serve as fuel for future spaceships? The dreamer I am simply imagine a ...
0
votes
0answers
35 views

Rocket launch from equator

I am trying to simulate a rocket launch from the equator. I know that the earth's rotation around its axis will give the rocket an initial speed of $466$ m/s in the x axis. How much speed will the ...
0
votes
0answers
42 views

Velocity of rocket as a function depended of time and emitted gas?

First of all I'd like to say sorry if this question may seem be written weird in English. I got the original question in German and I have not the required vocabulary to translate it 100% correctly. ...
0
votes
1answer
98 views

Rocket equation derivation mistake by my professor

In one of my lectures our physics professor gave a derivation of the ideal rocket equation as follows: Let $v_G > 0$ be the velocity at which the gas is emitted from the rocket. Let $m$ and $v$ be ...
0
votes
1answer
48 views

Motion in space

Does a space shuttle travelling in space experience any resistance to its motion? If a body in space is applied constant force, does it attain speed of light after sufficient time?
0
votes
1answer
92 views

Fallacious derivation of the rocket equation

Consider a rocket in free space of initial mass (including fuel) of $m_0$ using up/ejecting fuel at a constant rate $r$ (mass per time). That means that at time $t$ the rocket has mass $m=m_0-rt$. The ...
6
votes
5answers
329 views

How does constant thrust avoid quadratic kinetic energy accumulation?

I haven't found the right search terms for this question, so if it has been answered, references would be welcome. Suppose we start from experimental station in deep space (interstellar space if need ...
0
votes
0answers
63 views

Solving propulsion force of water rocket

As a note, I am not a physics student, although I am familiar with many physics concepts and calculations. I am trying to calculate the force of the thrust of a water rocket. I started with the ...
0
votes
0answers
20 views

Air Powered Vs. Water Powered Rockets [duplicate]

I was looking online to find a comparison between purely air powered rockets, and water/air powered rockets, but could not find any. To clarify, a "water rocket" is filled partially with water and ...
0
votes
1answer
32 views

How much force would an explosive decompression really provide?

In science fiction, explosive decompression is occasionally used to slow down or provide a nudge for very large spacecraft (for instance, recently in the 2015 movie The Martian, and in this old Star ...
-3
votes
1answer
114 views

My theory to travel near the speed of light. Why will this theory not work? [closed]

Why can't a spacecraft travel near the speed of light? Here's my theory. We assemble the spacecraft in the Earth's orbit just like the International Space Station, each time, equipping it with lots ...
0
votes
0answers
51 views

Finding the distance a spaceship would travel given a time of departure and velocity

Let's say a spaceship leaves Earth at a day t and with velocity v. Is there a way to know how many kilometers it will cover to arrive on Mars? This would be a trivial question were it not by the fact ...
0
votes
0answers
64 views

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

If humanity was to send a probe to the nearest star: Proxima Centauri, at a distance of 4.24 light years from our sun, what would be the optimal propulsion technology to reach the destination as soon ...
0
votes
1answer
64 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 ...
0
votes
1answer
48 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 ...
0
votes
1answer
82 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 ...
1
vote
2answers
45 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 ...
0
votes
2answers
145 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 ...
1
vote
2answers
189 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 ...
0
votes
1answer
90 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 ...
2
votes
1answer
105 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 ...
0
votes
1answer
104 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 ...
1
vote
0answers
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?
-2
votes
1answer
134 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 ...