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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Delta-v required to get to Medium Earth Orbit?

Does anyone know what's the delta-v you need to get to Medium Earth Orbit (the delta-v for 7,000 km high orbit for example)? I know that to get to LEO you need around 9.5 km/s (including gravity and ...
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55 views

Maneuvering a space shuttle using propulsion systems?

A colleague and I randomly started on this subject, and, not being very good at anything science / physics related we were stumped at how this might work. So the question is: If I park my space ship ...
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225 views

Variable mass dynamics: Particle and Rigid Body

I'm encountering some issues in the understanding of some basic concepts about the dynamics of variable-mass particles and rigid bodies. For what I found, for example reading On the use and abuse of ...
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Would the rotation of a space ship in vacuum slow it down

Firstly , a few disclaimers : English is not my native language so I may use the wrong technical terms. Please notify me and I will correct the question. As a CS major , I've only taken one class ...
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Detecting radioactive material at a distance

I have heard a lot about the failures of even the best-funded anti-ballistic missile technology. The usual explanation is that ABM is very hard after the boost phase because of evasion techniques and ...
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186 views

Burning fuel in space while accelerating and deaccelerating

Is it true that for acceleration in space we need not the same quantity of the fuel than during the deacceleration stage?
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98 views

Why does Philae have only three legs?

Can anyone explain why comet lander Philae has only three legs? Isn't it obvious that it now has problems that it would not have had if it had four legs arranged as a regular tetrahedron - or even ...
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Why didn't all three of my electrical fuses ignite? [closed]

I built a rocket that used 3 x solid fuel motors. To ignite them I used 3 electrical fuses, which are basically a thin filament of wire which heats up when given enough voltage. Only 2 of the 3 fuses ...
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What is a rocket engine thrusting against in space?

I know Newton's third law of motion might be the answer for this but still I am wondering how the rockets could thrust in the empty space and move in the opposite direction. I guess an astronaut ...
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156 views

Will a rocket produce more thrust if fired in air, rather than vacuum?

I've been in an argument with a friend. He claims that when a rocket engine is fired in air, it get significantly more thrust due to the rocket pushing gas into the atmosphere, and the atmosphere ...
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How Earth communicates with Voyager I?

After taking a basic signals & systems class and learning about the frequency domain, I started wondering: How the heck do scientists still communicate with Voyagers I and II??   Do they ...
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106 views

The Law of Conservation of Energy and Time

The Law of Conservation of Energy essentially states that in a given closed system, the total energy at any instance of time should be equal. This includes the kinetic energy, gravitational potential ...
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65 views

Why was the asteroid 101955 Bennu chosen by the NASA OSIRIS-REx sample return mission?

Please explain it in simple terms. Why was THIS asteroid chosen among all the thousand of asteroids?
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Why do rockets jettison fuel tanks? [duplicate]

I'm trying to understand why rockets have multistages releasing their fuel tanks. Say a rocket $R$ has two fuel tanks $A$ and $B$, which respectively have masses $m_a$ and $m_b$, and the mass of the ...
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743 views

What properties would the ideal material for spacecraft construction possess?

Assuming we develop the capability to send a robot to study Gliese 518, or any of the Earth-like planets discovered in the neighbourhood; the spacecraft would need to travel through the Solar System ...
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116 views

spacecraft thrust through means other than liquid propellants

Is there any way of achieving effective thrust in space without using conventional fluid or gas propellants such as rocket-fuels or supercooled material? For instance: gaining thrust through solar ...
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107 views

How much fuel is needed for a constant-acceleration rocket?

My son and I have been discussing the concept of a constant-acceleration rocket, as described here and here. We're willing to assume advanced technology such as a fusion rocket, which, according to ...
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1k views

NASA's “Impossible” Space Engine

Recently, there was some news that said that the researchers at NASA have come across some impossible kind of space engine which does not require any fuel. I have read at a few places like here, here ...
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116 views

What's the point of NASA's impossible space engine? Wouldn't a mirror work better?

My understanding (which is very little) is that the point of NASA's recent virtual-particle engine is to convert solar energy into momentum. That's fine, but what's the point? If the spacecraft is ...
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437 views

Escape velocity of satellites

I know that the equation for it is $$v^2 = \frac{2GM}{r},$$ and with that, the rocket should be launched at that speed. But could it go much slower spending much more fuel to escape from gravity ...
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Is it possible to build a huge spaceship like the one of of Star Trek or Prometheus?

Ok, so theoretically, is it possible to build a spaceship like the ones we see off of Star Trek or Prometheus or will physics not allow it? What are some challenge faces such an task. Also, is there ...
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395 views

How can Excel be used to model the flight of a rocket? [closed]

Firstly, sorry for any silly mistakes or improper use of this website - this is my first time using it! I am trying to use Excel to model the flight of the Apollo 11 Saturn V rocket using the real ...
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53 views

Can we use water as fuel for nuclear thermal space propulsion?

As I know, the working fuel of choice is Hydrogen because of its low molecular mass. When it comes to escape velocity, the estimate vary too much, from $8$km/s to $50$km/s (gas core reactor). ...
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42 views

How did Goddard's rocket reach 41 feet in under 2.5 seconds?

I'm working on a simple rocket flight simulation, and am trying to reproduce aspects of Goddard's first successful rocket flight. My sources put the empty weight at 5.75-6lbs, loaded weight 10.25-10.4 ...
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Is interstellar flight possible in near future in a way that would keep our civilization alive?

Is interstellar flight possible in the near future in a way that would keep our civilization alive? I mean is it practically possible to obtain technology that would enable us to travel to nearby ...
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69 views

Ziolkowsky Rocket Equation

I've looked at multiple sources on the internet and just can't wrap my mind around it. If I reference the wikipedia page on it; http://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation I am getting ...
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Terrestrial Space Elevator Construction - Plausability

Framework If there was a cable constructed at the equator about the circumference of the Earth, and if this cable had sufficient strength to remain intact while erect, call this tensile strength T. ...
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When a planet has a high gravity, is it impossible to build and launch a successful chemical rocket to space?

Just recently a a large rocky planet has been discovered. "Astronomers have discovered a new type of rocky planet beyond the solar system that weighs more than 17 times as much as Earth while being ...
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How to calculate launch angle for tangentially launched satellites?

What is the value of theta for a satellite not falling back to the Earth if it is launched from the direction tangent to the surface of the Earth? I have found the escape velocity which is 11.18km/s, ...
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635 views

Is there an upper limit to a rocket's size/payload? [duplicate]

It's obvious that as you increase the payload of a rocket, you need to also increase the amount of rocket fuel. Yet, as you increase the amount of rocket fuel, you are also increasing the overall mass ...
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695 views

Would a craft travelling increasingly close to the speed of light appear to be decelerating?

I've been pondering the implications of time dilation. Is it right to assume that if a craft was travelling at a speed very close to the speed of light (>= 0.9999c for example), that to an external ...
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496 views

Rocket propelled by a giant monochromatic laser

I am preparing for my quals and stumbled across the following problem, and although it only requires undergraduate-level physics, I feel I can't piece everything together. "A rocket of mass $m_0$ is ...
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250 views

How should I throttle my rocket to reach highest altitude? [closed]

"Real world" problem. Suppose we want to launch a rocket equipped with an engine which can be throttled as we prefer. Suppose also that the amount of fuel burnt per time is directly proportional ...
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298 views

How much time passed for the passenger traveling with at speed-of-light spaceship? [duplicate]

Let's suppose we have a spaceship with the exact speed of light. If a traveller takes this spaceship to go to proxima centauri (approximately 4 years light away from Earth) and come back, we (as ...
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105 views

Why speed of Mangalyan is constant?

I have learned in school regarding the relationship between speed,acceleration and distance is $$v^2-u^2=2as $$ The initial velocity of India's Mars Orbiter Mission, MOM, is 32 km/s source and now ...
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thrust-bursting towards a destination in space

<--burst of thrust------|ME in a ship>----->>--<<--laser radar--<<---->>---||destination In the above, I imagine myself in a ship, marking my speed to a far off destination with laser ...
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Would it be economical to add a counterweight to rocket launches?

It seems a large amount of rocket fuel during launches is spent to get the mass moving; indeed according to QuickLaunch, Inc. it takes 40% of the rocket fuel to get to Mach 1.3. It seems as though the ...
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Launching a unpropelled rocket

I have read about the application of railguns and other ground powered launch, where there is no need to carry any propellant in the rocket. I am wondering, to what velocity should the vehicle ...
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73 views

Calculating a spacecraft's deflection angle [closed]

There is a spacecraft with mass $M_1$ moving in a certain trajectory with a constant speed $V_r$. To modify its trajectory, a engine is turned on and starts ejecting gas at a speed $V_g$, which is ...
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102 views

Do I need to take weight of the rocket into account when calculating escape velocity?

Here there is the old problem. I know from the old problem that the work $W_v$ that I need to make a rocket fast enough to reach the escape velocity is $$W_v= G \frac{mM}{r}$$ therefore because ...
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How long would it take me to travel to a distant star?

Suppose I wanted to travel to one of the recently discovered potentially Earth-like planets such as Kepler 186f that is 490 light years away. Assuming I had a powerful rocket and enough fuel, how long ...
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334 views

Travel duration from Earth to a star at 9.8 m/s² acceleration

How much time would it take for a traveler (in traveler's perspective) to reach a star at distance $d$, if it accelerates at 9.8 m/s² (for a comfortable travel)? I understand that $V = V_0 + a\times ...
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About the speed of light

If Mr. E is aboard a spaceship traveling near the speed of light the usual reason for the spaceship not going faster than $c$ is the (relativistic) mass of the ship increases without bound, I think. ...
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Why do rocket engines have a throat?

Diagrams of rocket engines like this one, (source) always seem to show a combustion chamber with a throat, followed by a nozzle. Why is there a throat? Wouldn't the thrust be the same if the ...
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3k views

Why don't rockets tip over when they launch?

Rockets separate from the launch pad and supporting structures very early in flight. It seems like they should tip over once that happens. Why don't they tip over? Is it due to a well designed ...
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458 views

How do I calculate the time it would take for a space craft launching from earth to reach another planet?

I am making a matlab program the my final project for my programming class in college. I have chosen this problem, but I am bashing my head against the wall trying to figure out the equations and how ...
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95 views

Is a scaled-up aircraft carrier 'ski-ramp' a viable system to impart enough velocity to significantly assist a spacecraft to orbit? [duplicate]

Not a boost straight up to escape velocity, just sufficient added momentum to make a significant economic saving on fuel cost, mass and complexity of a standard launch. It seems ludicrous to me how ...
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How to calculate the velocity needed for a rocket to get to a L1 point (escape a body without orbiting)?

I'm looking to calculate parameters around launching, say, a model rocket STRAIGHT to the moon. This does not mean through orbital insertion into a stable ~17,000 MPH relative to earth's surface and ...
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651 views

Max altitude of rocket [closed]

A rocket is launched perpendicularly with an initial acceleration of 10 m/s2, if the fuel runs out after 1 minute, what will be the maximum height reached by the rocket?
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101 views

What is the cheapest way to land a grain of sand on the moon? [closed]

I have a payload that is the size and density of a grain of sand. I want to land it intact on the moon, but I am not particular about location beyond that. What is the least expensive way to get it ...