Questions tagged [rockets]

Questions regarding the boosters or thrusters used to propel man-made objects. For rockets firing opposite the primaries, see [retrorockets]. See wiki for other related tags.

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17 votes
4 answers
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Is this egg-shaped nose cone a good, aerodynamic design?

So Jeff Bezos has recently travelled to space aboard an Amazon-funded rocket, which has an unusual, egg-shaped nose. However, just about every other rocket I've seen has more of a cone-shaped nose, ...
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2 votes
1 answer
300 views

Calculating total burn time for a rocket under constant acceleration with two propellant consumption rates

I tried posting this question on the Physics side of StackExchange but didn't get any response after a week, presumably because it was lost within the broadness of physics in general, so I'm hoping ...
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2 votes
1 answer
161 views

Which burning of Solid Propellant is best axial burning or radial Burning?

Which Burning is Better Axial or Radial of Solid Propellant grain used in Solid Rocket Motors? How Someone Determines which to choose according to the Mission requirements ?
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2 votes
1 answer
521 views

Does MAX Q during rocket launch only say that rocket experiences max dynamic pressure? [duplicate]

I know that during rocket launch, one main event that occurs is MAX Q where the rocket experiences maximum dynamic pressure which is simply (1/2)ρv^2. I also know that drag coefficient of rocket ...
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14 votes
2 answers
3k views

Could one survive a ride into orbit outside a rocket?

Another question asked whether a Falcon 9 class rocket could reach orbit with a person (-like mass) duct-taped to the outside of it, in spite of the resulting mass asymmetry. The consensus of one ...
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32 votes
1 answer
6k views

Could a Falcon 9 reach orbit with a person glued to the outside of it?

Apologies for asking a dumb question, but I'm going to ask it anyway... I was watching a music video where the singer duct-tapes her ex to the side of a rocket to exile him into space, and it made me ...
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2 votes
1 answer
735 views

Why not use alternative/low-pressure atmospheres in fairings during launch?

For example: using a reduced pressure helium atmosphere. Most fairings are already cleanroom environments. Benefits I can see: Eliminate need for acoustic tiles as low pressure and/or light gasses (...
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18 votes
9 answers
5k views

Would it be practical to catch a rocket's exhaust to reuse it as fuel?

It's been some days that i think that would it be possible to make a ship that looks like this? The idea is to catch the fuel as you go. Would this make any sense or the thrust would be canceled by ...
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31 votes
2 answers
6k views

What are the chances that a spacecraft is hit by space junk?

If a rocket flies into space there is a possibility that it will encounter a piece of space garbage; even a small screw can be fatal. What are the chances that such a collision really takes place? ...
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3 votes
2 answers
116 views

Have any fluids been vented directly from a rocket on a launchpad, instead of through an umbilical?

Rockets on the launchpad often need to release liquids or gases before launch. For example, cryogenic liquids boil off; the vapors need to be released to prevent tanks from bursting. It seems that ...
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3 votes
1 answer
135 views

Attitude control of rockets with RD-107 engines

This question is specifically about the Soviet engine RD-107, (although it can be generalized) a version of which was clustered in Soviet rocket 8K71 which launched their "Sputnik". Each ...
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6 votes
0 answers
193 views

What are the various ways that rockets measure the instantaneous thrust of each engine?

@DavidHammen's answer to Engine failure: how to detect? mentions thruster sensors. This intrigued me and so I thought I'd ask about how this is done. Thrust is a critical parameter to know in real ...
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0 votes
1 answer
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What qualifications and requirements do you need to go to the moon?

I've dreamed of shooting for the moon, but I'm not sure how, if any former NASA Recruitments or scientists see this, please tell me what I need to do. Question: What were the qualifications to be ...
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3 votes
0 answers
81 views

Can we afford to increase rocket launches when we are are in desperate need to cut down emssions? [duplicate]

I love SpaceX and what they are doing with rockets and reusability, but their work is also going to exponentially increase the demand for new launches to orbit. If we are ever going to create a self ...
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3 votes
1 answer
465 views

Conversion of heat into electricity in rocket nozzles

Can we use advanced thermoelectric materials to reduce the temperature of nozzles by converting heat energy to electric energy and reducing the strain on the nozzle material and the coolant while ...
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3 votes
1 answer
269 views

How much fuel could a rocket save by launching from an airship/blimp?

What could the Kozlov’s Aerosmena project blimp add to fuel saving if space rockets were launched from it? Where would you place the rocket and airship on this chart?
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2 votes
1 answer
96 views

What permission do I need to build a rocket that goes to space? [closed]

I wanted to build a rocket that goes to the karman line at 340000 feet which is technically space. I know the rules and what I need to get to launch the rocket such as faa clearance and more but I ...
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2 votes
1 answer
93 views

Rocket propellant control

In a liquid propellant rocket, how is the quantity of propellant controlled? - for two purposes. One for achieving the required "ratio" of propellants, and 2nd, to control the thrust of the ...
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0 votes
0 answers
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How could I find the pressure and/or the Isp at the exit of a rocket nozzle if I have data for the throat and comb. chamber?

I've been looking at this for some time and working with CEA which will only give me data points for the pressure, temperature, Isp, etc. for the Injection, Combustion Chamber End, and the Throat; but ...
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3 votes
2 answers
397 views

Livery on rockets?

Aircraft are normally painted with colorful livery---swoops, checkers, etc. Has this ever been done on a rocket? I can imagine the motivation hasn't been there because rockets are out of sight within ...
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10 votes
2 answers
1k views

How does a command sent to a rocket or rover look like?

I think the question is quite clear. Let's say when Mission Control decides to let Perseverence move forward for 3 seconds with a speed of 10 (whatever..) What syntax would this command have? Im ...
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4 votes
1 answer
242 views

What does 'a nudge' mean in the context of rocketry?

The following paragraph is from a wired.com article: When I visited this past fall, SpinLaunch employees were still unpacking from the move. As we walked among giant sheets of steel, Yaney explained ...
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24 votes
2 answers
4k views

Why are Starship landings so difficult when SpaceX has landed so many boosters?

Per Wikipedia, SpaceX has landed boosters successfully 79 out of 90 times. Yet Starships seem to be reliably exploding upon landing. What is so different about the two that Starships are so much more ...
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3 votes
5 answers
578 views

Why is hydrogen better than helium as remass?

I just watched a very good YouTube video on why nuclear engines might be useful, and it also goes into why Hall Effect thrusters are super good at squeezing obscene ISP out of things. During the video,...
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4 votes
1 answer
251 views

Why are propellant tanks filled from the bottom?

It seems that the norm is to (fast-) fill fuel and oxidiser tanks from the bottom. For example, on this drawing of the Saturn S-IC stage you can see the LOX and RP-1 fill valves at the bottom of the ...
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3 votes
1 answer
132 views

Clustering of liquid fueled rocket engines

Which rocket first used clustering of liquid fueled rocket engines on their first stage?
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1 vote
0 answers
28 views

Apogee estimate starting from simplified one-dimensional numerical simulations

I asked a question on pen and paper apogee estimation and got an answer from @tom-spilker that called my attention: He said that he quickly estimated an inclined launch apogee from the results of a 1-...
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2 votes
1 answer
190 views

Why the max dynamic pressure might not happen at maximum drag instant?

I understand that is that when a rocket accelerates the drag force grows dramatically since the force is related to velocity squared. But, at the same time, the density is decreasing, so the force is ...
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  • 65
1 vote
2 answers
96 views

Pen and paper apogee estimation

I have calculated the apogee of a 2.5kN avg. thrust sounding rocket once ignoring drag and then assuming maximum constant (magnitude and direction) drag after burnout. Here are the figures I used in ...
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1 vote
0 answers
61 views

Pressurant gas line design considerations

I am trying to understand the constraints on pressurant gas line sizes and lengths. For a static volume, the lines can be small in diameter because there is no significant flow velocity and therefore ...
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10 votes
1 answer
1k views

Rocket engine test bed structure

Rocket engine thrust will eventually "lift" a certain amount of weight, to a certain height. For Saturn V, they used 5# F1 engines, each of which produced a thrust sufficient to lift ...
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3 votes
1 answer
314 views

Pendulum rocket fallacy - so why *do* skyrockets have sticks?

This question is inspired by two, linked questions. Skyrockets (of the pyrotechnic/firework kind) have guide sticks, which are (according to internet sources) to enhance stability: "The guide ...
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18 votes
4 answers
6k views

What is the "pendulum rocket fallacy" as it relates to analogizing a pencil balanced on a finger to maintaining attitude of a hovering rocket?

I've received comments that explain to me that the analogy between rocket attitude control during a hovering maneuver and the act of balancing pencil on the end of a finger is a helpful and good one; ...
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  • 148k
3 votes
1 answer
540 views

Is streamline body shape essential for propagation in the vacuum of space?

Streamline body shape is essential for reducing friction during motion in fluids like liquid and gas, including our dense atmosphere. Is streamline body shape also essential for propagation in the ...
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6 votes
0 answers
72 views

Why does SpaceX use Methane instead of Butane? [duplicate]

Genuinely, curious on why they use Methane as it's much harder to compress and liquefy whereas butane liquefies easily and is highly compressible.
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0 votes
1 answer
239 views

Flying saucer shape rocket vs cylindrical shape rocket

Here's my hypothesis- Cylinder shaped large rocket is not suitable for vertical landing due to its high center of mass and bulky weight. However an equally weighing saucer shape rocket has more ...
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5 votes
1 answer
216 views

Is it possible to launch a rocket with steam by using a fission reactor?

The idea is to use a fission reactor to turn water into steam pumping it outside the reaction chamber through heat pipes.
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5 votes
1 answer
333 views

Static Fire Tests: How is the rocket prevented from flying?

In rockets like Starship, if 35 Raptors are firing at same time, then in a full-duration static fire test there would be enormous loads being exerted from 35 raptors, on the clamps holding the rocket. ...
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11 votes
2 answers
3k views

What is this line, what is it called, what is the reason behind it?

I started following SpaceX recently. I used to read the updates but now I am diving deeper to learn new things. SpaceX is fascinating and I really like everything about it. But I have question, I don'...
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24 votes
4 answers
4k views

Can someone explain the SN10 landing failure in layperson's terms?

The things I can't understand from what Elon tweeted are: "engine was low on thrust due (probably) to partial helium ingestion" There are only tanks for liquid oxygen and CH4 - where did ...
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5 votes
1 answer
245 views

What will be the final Starship prototype?

So far, SpaceX has made and destroyed/launched Starhopper, MK1-MK4, SN1-SN19, BN1-BN3, and BN5. They also have SN20 on the launchpad stacked on BN4. The are stacking SN21-SN22, and SN23-SN24 are under ...
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1 vote
0 answers
156 views

Will i be able to see the SpaceX tonight launch from Ocala, Fl?

Im currently in Ocala, FL and SpaceX launches a rocket tonight (March 9th) from Cape Canaveral. Will I be able to see it given the proper conditions?
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41 votes
5 answers
15k views

Why did the SpaceX Starship SN10 explode?

Much to everyone's relief. The SpaceX Starship SN10 successfully completed its flight and landed..... But, sometime later, It exploded! Why? And did it have anything to do with the fire near the ...
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7 votes
5 answers
1k views

Earth Launch System with Water Propellant

Water based thrusters have been proposed (and possibly tested by now) for use in satellites and other in-space vehicles - see this NASA article. The idea is to perform electrolysis on the water to ...
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0 votes
1 answer
143 views

Use of SRB for Saturn V [duplicate]

In 1967, a solid fuel rocket motor with 260 inch diameter and 89 inch throat dia, was tested, and it was found to generate 5.8 million pounds of thrust. This was much higher than the F1 engines used ...
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  • 3,422
3 votes
1 answer
197 views

Why don't silo-launched Minuteman missiles incinerate themselves at launch?

Whilst cobbling together an answer for this question, I found myself thinking about the effects of hot rocket exhaust on a rocket launching from a confined space. I assumed it would be generally ...
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7 votes
2 answers
344 views

What happened to tripropellant rockets?

IIRC, tripropellant rockets can deliver superior performance compared to bipropellant rockets (at the cost of added complexity). Now, I know that there is the Li/H/F combo, but it isn't used because ...
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6 votes
2 answers
510 views

Solid state thrust vectoring

Usually thrust vectoring for the whole rocket is done by changing the orientation of individual engine(s) by hydraulic/electric actuators. So in this system the engine simply moves and with it the ...
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3 votes
1 answer
96 views

How do I calculate thermochemical properties of mixed gases?

I'm working on a rocket project, and my design of engines is stalled. I need to be able to calculate the Cp, Cv, and R for mixtures of O2/CH4 (stoichiometric or fuel-rich mix) and CO2/H2O (result of ...
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  • 301
5 votes
1 answer
180 views

How to select appropriate orbital rocket stage thrust?

I’ve been working on a preliminary design of a small-lift launch vehicle capable of sending a small satellite into LEO. Given the required $\Delta v$ (~9 km/s for LEO), the mass distribution, ...
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