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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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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Why does the RD-0110 Injector have a larger cone spray angle in the outer element rather than the inner element?

Wouldn't a large cone spray angle in the inner element (oxidizer) impinge with the outer element spray cone (fuel) and facilitate better atomization and mixing? Here are the RD-0110 Injector specs:
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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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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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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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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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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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1answer
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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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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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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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Injector design

I want to design a coaxial swirl injector for a bipropellant liquid rocket engine. I've tried to search a lot but can't find many references for the same. Has anyone worked on a coaxial swirl injector ...
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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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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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What will be the final Starship prototype?

So far, Spacex has made and destroyed/launched Starhopper,MK1-MK4, and SN1-SN10. They also have SN11 on the launchpad and BN1,BN2, and SN15-SN20 under construction. What will be the final Starship ...
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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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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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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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1answer
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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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1answer
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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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2answers
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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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404 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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1answer
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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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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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1answer
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If a company/agency has already developed a kerolox/hydrolox rocket, is it wise for them to switch to an all-methalox rocket? (to lower costs)

Multiple rockets, such as the Atlas V or Saturn V, have used the combination of a kerosene/liquid oxygen (kerolox) lower stage for higher density and thrust within the atmosphere and a liquid hydrogen/...
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What happens to the debris of a rocket that exploded or crashed? Is there a dedicated effort to cleaning the debris?

Assuming that everything is not vaporized, one would think that all waste is collected and incinerated. Does SpaceX, NASA, etc have a dedicated team/effort to cleaning up this debris?
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Most open source spaceflight missions revealed unintentionally

As of 2021 there are few fully open source satellites (OSSI-1, UPSat, FossaSat-1, Oresat, some more?) and numerous student groups building and documenting rockets. These projects are intended to be ...
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Rocket engine with lowest Isp to reach orbit

Which engine with the lowest possible specific impulse has reached orbit propelling a given rocket? There is a page at Wikipedia that compares orbital engines but some engines are missing Isp value ...
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What if we launched rockets from space using the slingshot method and centripetal force? Would that be possible?

Would we have to build a orbiting launch station that uses centripetal force to launch the rockets? Or a station that freely floats through space not in a planets orbit? Would something like this ...
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What is the inlet and outlet pressure of Merlin LOX/RP-1 turbopump?

I got the inlet and outlet pressure of Saturn V engines turbopumps here, but I couldn't find the turbopump pressure of the Merlin engine of Falcon 9.
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Are there any hand-sized rocket engines?

Are there any rocket engines that are small and light enough to be held in one or both hands? Gas, liquid and hybrid designs are fine but solid motors are excluded (with the exception of solids that ...
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2answers
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How big is an orbit of “X by Y miles”?

While reading the NASA overview of Apollo 11, says: Apollo 11 launched from Cape Kennedy on July 16, 1969, carrying Commander Neil Armstrong, Command Module Pilot Michael Collins and Lunar Module ...
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Rocket fuel cost to launch 1 kg to orbit

I have 2 questions about the cost of liquid rocket fuel to launch (anything) to LEO orbit. Let's assume we use fuels used in commercial spaceflight today (probably LOX+LH2 or LOX+RP-1 etc.). What is ...
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What are the implications of North Korean black and white patterns on missiles?

Black and white patterns on rockets were originally intended as roll patterns. They helped as a visual back-up for acceleration sensors measuring the roll, as discussed in this previous question What ...
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Calculating Pressure Inside Combustion Chamber

I am trying to calculate the pressure inside a combustion chamber of a rocket candy. My "engine" is made out of PVC with an internal diameter of 1/2 in. Are there ways for me to calculate ...
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2answers
502 views

Pressure levels inside rocket liquid oxygen tanks?

What is the pressure levels inside rocket liquid oxygen tanks, at launch time? The question is for the minimum and maximum (known) levels of pressure inside such tanks. I am asking for any rocket ...
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Longest static fire?

What is the longest duration for a static fire of a complete rocket stage? Initially I wanted to ask this for Falcon 9 and Falcon Heavy I found a 10 second static fire for Falcon Heavy - https://...
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How big could a rocket get?

What are the practical limitations on the size of Earth based, orbital rockets? How tall/heavy might we make a rocket? For the purposes of this question, I'm mostly interested in rockets using ...
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Is steam a good gas to use for a small RCS thruster on a small rocket?

Is steam a reasonable tradeoff from other hot/cryogenic gases in order to have safety and have it easily obtainable? Thanks
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1answer
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Is there a distinct flame-front in a liquid-fuelled rocket combustion chamber?

Liquid fuel and liquid oxidizer are injected at high pressure through small orifices into the 'top' of a rocket's combustion chamber. The intention is that these mix quickly and then burn completely ...
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How do they determine dynamic pressure has hit a max?

Max-Q is a key event during launch, and dynamic pressure is closely monitored so they know when a max is hit. But how exactly do they know when Q hits a max? If you track the rate at which Q is ...
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How to make a model rocket that doesn't spin?

I'm attempting to build a rocket with 8 fins (four on bottom and four smaller ones towards the top). The four fins near to the top will be attached to servo motors and programmed to stabilize or guide ...
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How important is the convergence angle of a liquid bipropellant rocket engine

So I can't exactly find out what angle should the converging part of the rocket chamber be or why different angles are chosen for engines (varies by about 15°). Are there any guidlines on the angle or ...
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Does the displacement angle change after burnout?

I came across the above image on Nakka's page about fins and what I understood is that rockets will turn into the wind during the thrust phase, and will drift slightly with the wind after burnout. But ...
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1answer
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Why are some rockets painted black? [duplicate]

Why are Rocket Lab's and other rockets painted Black? Shouldn't they be painted white to reflect most light and therefore absorb less heat from sunlight?
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Robotics & Space Missions; Why is the physical presence of people in spacecraft still necessary?

Robotics is now well developed. Many programming languages allow you to work in real-time. Also, a new era of space missions and research is in full swing. So here's the question: Why is the physical ...
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1answer
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Payload Capacity definition

Does the payload capacity of a rocket include the satellite and the adaptator or is it just the satellite ?
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How many times is a single rocket engine tested?

When a rocket engine is loaded into a test stand is it tested once before removal or is it allowed to cool and then tested again. Is every liquid-fueled rocket motor that flies to space first tested ...
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Why doesn't NASA release all the aerospace technology into public domain?

NASA is a publicly funded US governmental agency, yet it does not seem to release all the technology it develops into public domain for people being able to study it and learn from it. For instance, ...
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Can liquid rocket engines have the same thrust as solid rocket engines?

Take the Vega rocket launcher for example. Its first three stages are solid rocket engines and burn at a relatively short time. If I were to change its first stage into a liquid rocket engine, can ...
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When has hydrogen peroxide been used in rocketry?

Peroxide is apparently a very good propellant, but I can't seem to find any instance of it being used. Has it ever been used and if not, why hasn't it? What's its downsides?

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