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Questions tagged [rockets]

Questions regarding the boosters or thrusters used to propel man-made objects.

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4answers
12k views

Effect of atmospheric drag on rocket launches and benefits of high altitude launch sites

What is the approximate influence of atmospheric drag on the cost of rocket launches? Is it beneficial to have launch sites located at higher altitudes? Cape Canaveral is at sea level, but I've ...
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4answers
5k views

How much bigger could Earth be, before rockets would't work?

hint: Apparently the Tsiolkovsky rocket equation does not actually say that you can launch a conventional rocket into orbit around an arbitrarily large and massive body. Question: "How much bigger ...
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2answers
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Launch Accelerations: Values, history

This topic: What G-forces do different launchers cause? indicates that current satellite launchers are limiting peak acceleration to about 4g. I'm pretty sure the STS (Shuttle) did the same. My ...
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4answers
14k views

What is the purpose of having a countdown during a rocket launch?

Every rocket launch has a countdown. But what purpose does it serve?
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5answers
33k views

Is it possible to reach space using home-made rocket?

The first stage would be a high altitude balloon, which could reach 30km. Then start a rocket-candy from that high. Without cargo, is it possible to reach the edge of space (Kármán line - 100km), or ...
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3answers
1k views

Is it normal for thrusters to “ice up”?

Towards the end of the JSSAT-14 webcast (around T+32:58), we see a thruster firing. Over the space of around 20 seconds, you can see it "icing up": What is this that's forming? Is this a normal ...
16
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1answer
700 views

Cause of apparent plume deflection on SES-10?

While watching the SES-10 flight, starting a little after T+1:30, I noticed that the direction of the first-stage exhaust plume started to diverge from the alignment of the rocket body. The ...
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3answers
2k views

On a Super-Earth 1.5x the volume and mass of Earth, would our rocket technology allow us to reach orbit? [duplicate]

To try and make parameters clear, can we say we are talking about 50% 'more Earth'? As in, Earth, but 1.5 times as big and heavy? And let us include the atmosphere. If there is 50% more of it by ...
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2answers
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Could I build my own spaceship?

We all know that for most people access to space is currently pretty limited because space flight services are expensive, as they are in short supply. Suppose I wanted to bypass an expensive service ...
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3answers
12k views

Why are hydrogen-fluorine fuels not used for rockets more frequently?

Many rockets use hydrogen- and oxygen-based propellants as fuel. Why are hydrogen-fluorine fuels not used? It has a specific impulse of 390 seconds, higher than hydrogen-oxygen combustion (360 ...
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6answers
9k views

Why do rocket nozzles open near the end?

Question: Why do rocket nozzles open wider at the end than, let's say, get narrower? Let me explain: I recently learned from random internet sources, that a jet engine works by having this amazing ...
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2answers
42k views

What is the vapour/smoke that comes from a rocket before launch?

While a rocket is waiting on the platform during the final countdown, it often seems to have clouds of steam or something similar escaping from it. Is this normal, and what are these clouds?
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1answer
413 views

How do rocket propellant combinations rank in terms of “brightness”?

While a booster on the shuttle had a bit more than twice the thrust of the shuttles engines at take-off, I'd venture a guess that it produced on the order of a thousand time more visible light. In ...
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3answers
3k views

Is this a correct understanding of Tsiolkovsky's rocket equation?

When I graph the rocket equation, substituting arbitrary values for v(exhaust) and m1, so m0 because m1 - m0, the graph implies that increasing propellant mass past a certain point does not increase ...
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3answers
4k views

Could 3D printing be used to achieve perfect grain geometry of solid and hybrid rocket motors?

Solid cores, either for solid-fueled of hybrid rocket motors, use various propellant grain geometries to achieve thrust curve needed. For example, some of these could look like:    &...
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1answer
980 views

How would the Saturn V have differed if the first stage was also LH2/LOX?

Since both Kerosene (RP-1) and liquid hydrogen (LH2) continue to be important liquid fuels used with liquid oxygen (LOX), something can be learned by comparing how they are used. This is covered well ...
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4answers
9k views

Why is there a hole in solid rocket engines?

I would like to find out why there is a straight hole down the middle in all solid rocket engine motors. I thought it only makes sense in hybrid engines where pure oxygen needs to be blown down the ...
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3answers
4k views

Why do the exhaust flames from cryogenic stage engines appear to be separated from the nozzle?

Why do the exhaust flames from cryogenic stage engines appear to be separated from the nozzle?
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3answers
8k views

What is the purpose of the black-and-white patterns on some rockets?

Some rockets have black-and-white patterns painted on them. For example, the Saturn V has them at the bottom of the upper stages and the SLS block 2 is supposed to have them below the payload. In ...
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1answer
6k views

Why did Apollo use roll and pitch maneuvers similar to Space Shuttle to establish ascent trajectory?

When the Space Shuttle launched, it would perform a roll and then pitch to establish its ascent trajectory. There is fairly straightforward rationale for this. The vehicle's aerodynamic shape, the ...
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3answers
2k views

How small could an orbital rocket be?

To what extent might a booster designed to place an extremely light weight "micro" satellite with radio transmitter, say 100 grams for the sake of argument, be scaled down before factors such as ...
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2answers
4k views

Is it possible for the Space Shuttle Solid Rocket Boosters (SRB) to hit the Space Shuttle after jettison?

We all know that the Space Shuttle Solid Rocket Boosters (SRB) were the pair of large solid rockets used by the United States' NASA Space Shuttle during the first two minutes of its powered flight. ...
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1answer
3k views

Where is the optimal location to launch payloads to outer space?

Imaginary scenario: The US, Russia, China, Europe, India, and all the private space companies in between combine resources for a sustained space exploration program beyond Earth. They can choose any ...
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3answers
2k views

Is there a maximum Isp for “exothermic chemical reaction rockets”?

The question Is there a maximum $\text{I}_{sp}$? reminded me that I once read somewhere that the maximum possible $\text{I}_{sp}$ for a rocket engine based on expansion driven by exothermic, ...
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1answer
2k views

Why do the Shuttle's external tanks appear to be rusted?

Wikipedia article states as STS-1 at liftoff. The External Tank was painted white for the first two Space Shuttle launches. From STS-3 on, it was left unpainted. I wonder why the ...
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3answers
676 views

Why do we use the gravitational acceleration at the Earth's surface when calculating the specific impulse of an engine?

So one of the ways of calculating Isp is: Isp = Ve/g0 You divide the effective exhaust velocity by acceleration at earth's surface. This gives you a number in seconds, and is generally considered ...
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3answers
945 views

Is aerodynamic lift ever useful in rocket flight?

When a rocket is traveling through an atmosphere, the component of the aerodynamic force in the direction of motion is called drag, and the component perpendicular to that is called lift. Usually a ...
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1answer
2k views

How can I estimate the Coefficient of Drag on a Saturn V rocket, a simulator or some data would be pretty awesome

I'm trying to get some information on this and its proving difficult as the information is usually acquired experimentally from what I've found. A single number at a specific altitude and speed would ...
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1answer
3k views

Do all launches include self-destruct mechanisms?

Do all launches involve self-destruct mechanisms? How do they usually work? Is it just the boosters that are required to self-destruct? In the case of the space shuttle, how about the external tank? ...
28
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1answer
2k views

Why do the Russians use these fence-like interstage fairings?

When we look at various Russian rockets we often see a metal structure looking like a kind of garden fence separating some stages. To my knowledge, only the R7 family (Vostok, Voshkod, Soyuz) and N1 ...
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4answers
7k views

How big would a manned ascent stage for Mars need to be?

For a manned mission to Mars that isn't a one-way trip, we'll need an ascent stage that can reach orbit from Mars' surface. How big would this need to be to transport e.g. 3 astronauts to orbit? We've ...
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2answers
3k views

What limits the number of times that a liquid fueled rocket can restart?

I know the upper stage of the Falcon 9 can be restarted once, thus allowing an additional thrust for some circumstances that might require it. However, I don't really understand the mechanism that ...
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2answers
7k views

Does launching a device into orbit change earth's orbit?

Does launching a space shuttle or rocket change the earth's orbit? After all, to get momentum in space you need to throw something out.
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4answers
4k views

How does a simple construction keep a firing rocket on the ground?

Today I have seen this report of a SpaceX Falcon 9 rocket test firing. The force of a burning rocket is tremendous, and in the video we see an apparently simple construction keeping the rocket (or ...
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4answers
2k views

Why are rocket mass on the launch pad and payload mass to LEO not strongly correlated?

What explains the relation between how much a launcher weights on the launch pad, and how much mass it can lift to orbit? I had expected that more payload requires more fuel to be launched and that a ...
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1answer
2k views

How are rocket nozzles made?

How are rocket nozzles made?? Is it a huge chunk of metal that they cut down or is it a "pipe" that they reshape? Or something else??
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1answer
793 views

Do rocket exhaust plumes really provide a pathway for lightning?

This Wikipedia article states that Rocket exhaust plumes provided a pathway for lightning when it was witnessed striking the Apollo 12 rocket shortly after takeoff. My question is whether this ...
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5answers
15k views

Why does a rocket engine provide more thrust in a vacuum than in atmosphere?

According to NASA Each Space Shuttle Main Engine operates at a liquid oxygen/liquid hydrogen mixture ratio of 6 to 1 to produce a sea level thrust of 179,097 kilograms (375,000 pounds) and ...
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2answers
6k views

Can a rocket be launched while it rains?

All videos of rocket launches I ever saw were performed in clear weather conditions. I also read many reports about launches which were delayed because of bad weather conditions. What are the ...
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2answers
1k views

Has SpaceX re-used a first stage twice yet?

SpaceX has re-used a first stage once, several times now. Has it re-used the same first stage twice yet? If not, has a particular mission been named that will be the first second re-use?
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1answer
812 views

Why are rocket launches so loud?

In reading an answer here: How close can I get to a rocket launch and not get killed?, the comment is made that noise from the launch can be tremendous. This isn't a big surprise to anyone who's ...
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2answers
7k views

What does the exhaust plume of a rocket look like in vacuum?

There are plenty of photos of rocket tests and launches in atmosphere, and in these the exhaust plume tends to be a long thin flame. Is this true for when rocket engines operate in a vacuum? My guess ...
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3answers
987 views

What exactly causes stranded upper stages to explode?

Usually if an upper stage experiences a failure before it can "passivate" itself (empty tanks, drain batteries, etc.), it's only a matter of time before it explodes. For recent examples, see any of ...
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1answer
2k views

Why the non-symmetric design of rocket nozzles?

Although I have seen many perfectly symmetric nozzles, I have also seen designs such as this (Virgin Galactic) which is only symmetrical about one axis: Why is this?
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1answer
826 views

What was the purpose of the small red tank attached to the Titan-Centaur launcher?

Watching a documentary on the Viking missions, I noticed the launcher had a small red tank/rocket attached to one of the solid boosters. It struck me as an odd feature/placement, as I thought you'd ...
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4answers
2k views

Do rocket engines have shock absorbers?

With a million pounds of thrust and many g of acceleration and a significant fraction of a g of vibration, connecting the engine to the rocket can't be trivial. At launch the mass is very high and ...
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5answers
3k views

What is the function of the hypersonic grid fins on SpaceX's booster?

In Musk is testing x-wing style fins, spaceport drone ship there is mention of two Musk tweets: Testing operation of hypersonic grid fins (x-wing config) going on next flight. and Grid fins ...
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6answers
8k views

Can a miniature Saturn V get to the moon and back?

If the Saturn V rocket along with its Apollo spacecraft was miniaturized, for example to 1/72 scale so it was five feet tall, could it still perform a moon landing like the Apollo missions and get ...
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2answers
7k views

How does a single rocket place multiple satellites into orbit?

Nowadays, many rockets transport more than one satellite in orbit. But how does a single rocket place multiple satellites into their orbits? Do all rockets which place multiple satellites into orbit ...
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4answers
2k views

What are the criteria to put the oxygen tank above or below the fuel tank for a given stage of a rocket?

Inside a rocket, tanks are put one above the other. This make sense as it may be a good compromise between tanks shape and the aerodynamicity of the whole rocket. In some rocket stage, the oxygen tank ...