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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Need help finding a clean expression for exit velocity

I'm trying to calculate a engine burning LOX and ethanol (96%) and for that I am using both CEAgui, a GUI for NASA's CEA (Chemical Equilibrium with Applications) code Sutton's Rocket Propulsion ...
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759 views

Getting back from the Moon

This link describes the way back from the Moon surface to the orbiting spacecraft. But how could that spacecraft get back to the Earth? It is a long journey. How much rocket fuel would be needed, in ...
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Efficiency of rocket stages and converging/diverging nozzle

It is a fact (to the best of my knowledge) that for optimum thrust from a rocket engine, one of the most important factor is the design of its converging/diverging Nozzle - the diverging cone to be ...
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Did rockets use turbopumps prior to the V-2?

Did the liquid propellant rockets before V-2 use turbopumps or were their fuel tanks pressurized with gas? Or perhaps were their engines gravity-fed?
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Why was the Delta Clipper cancelled?

Delta Clipper (McDonnell Douglas DC-X) achieved vertical landing two decades before Falcon 9. And its cost was very small - 60 million dollars. Why was such an awesome Rocket cancelled? How is NASA ...
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1answer
78 views

how does the open expander cycle seperate the fuel for the pump and combustion chamber

I'm designing a single open cycle expander rocket engine using propane. However, I've been unable to find out whether or not the fuel is split into the turbine and combustion chamber before or after ...
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1answer
82 views

Rocket staging by use of strap on Boosters

Will it be advantageous to have multiple (say-3) stages of a rocket, arranged in a "strap-on" type SRBs' assembly, geometrically well distributed around the circumference w.r.t. their ...
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Can Chemical Engineer work on something related to space?

I am an undergraduate student (scientific section) living in Qatar. I have a big interest in astronomy and astrophysics and have participated in the IOAA (International Olympiad on Astronomy and ...
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Design of propellant tanks of a rocket [duplicate]

I understand that the propellants (e.g. LOX & LH2) are stored in a rocket tank which is pressurized by Helium or a neutral gas, so as to push the propellants towards the tank outlet, to the turbo-...
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Why are spin-stabilized rockets stable?

Spinning rigid bodies are stable about their axes of smallest and largest moments of inertia. When there are energy dissipation modes, such as bending and propellant slosh, only the largest moment of ...
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Federal Limitations on Model Rocketry in India

I am hoping to find information on the rules regarding model rocket launches in India. How high can I fly? How heavy can a custom rocket be? Can I legally make and fly custom engines/motors?
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1answer
158 views

Does thrust depend on rocket chamber shape?

I mark with green part of rocket which produce forward thrust and with red backward thrust. integration of pressure around rocket walls gives total thrust,which always act in forward direction.. Does ...
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Does thrust depends on rocket chamber shape? [duplicate]

i mark with green part of rocket which produce forward thrust and with red backward thrust. integration of pressure around rocket walls gives total thrust,which allways act in forward direction.. Does ...
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2answers
81 views

What stage of a Scout G-1 rocket enters orbit?

Last night I saw a Scout G-1 rocket body part called 1986-088B (according to COSPAR) with my binoculars. I researched a little and found that these rockets had 4 stages, called Algol, Castor, Antares ...
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1answer
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Will the Mars 2020 rocket be visible in the night sky?

When a Space X rocket was launched towards the ISS this year, the rocket could be seen in the night sky in Europe. The information as to where and when to look in the sky was even easily available ...
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If rocket engines only need fuel and oxidizer, then why there are so many pipe lines on the engines?

If fuel and oxidizer are pumped by turbines to the combustion chamber, then why there are so many pipes around? It should only have a two-cylinder shaped turbine assembly. I doubt there are other ...
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1answer
152 views

Which are good resources to learn more about the components of a rocket engine?

A detailed and annotated image of a SpaceX raptor engine (found on a SpaceX website) illustrates that in addition to the major components (e.g. pumps, inlets, combustion chamber, nozzle), there are ...
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Why there are small holes just at the ending of RS-25 rocket engine? [duplicate]

I have seen these holes in many pictures and I can't understand what are these and why are they used?
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2answers
189 views

Best shape for Orion nuclear pulse-propelled ships?

I have been doing research on Project Orion. There was this big expensive canceled NASA program to build armored spaceships that had to be blasted into space by exploding nuclear charges underneath ...
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Why does kerosene need inducer?

We see inducers before the main kerosene turbopump in engines such as F1 and RD180. Given the property of kerosene having extremely low vapor pressure (~0.007 bar around room temperature), is this ...
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3answers
200 views

What (if anything) limits the efficiency of a rocket engine?

Humans have developed lots of rockets. I observe that in most cases to increase the payload capacity we just increase the amount of fuel. Is it not possible to exponentially increase the efficiency ...
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Full Flow Staged Combustion Benefits vs Closed Staged Combustion [duplicate]

I am aware that the RS-25 space shuttle engine was a closed staged combustion engine, and used two preburners (both fuel rich) to drive the turbines and pumps to pump the LOX and fuel into the ...
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2answers
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What is the maximum practical deltaV obtainable from a chemical rocket launched from earths surface?

What is the maximum practical deltaV obtainable from a chemical rocket launched from earths surface? Not an exact number as there are too many variables but an approximate maximum assuming a 10,000kg,...
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1answer
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Do converging-diverging engine nozzles need to be bell-shaped?

Many rockets designed after the V2 but prior to Saturn V, do not show the typical "Bell" shaped diverging nozzle. Why is it so? Do they achieve supersonic speeds for the exhaust gases in any other way?...
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81 views

Pump Power related queries

I know that pump power can be calculated using this formula $$P_p = \frac{\rho \ Q \ \Delta H \ g_0}{\mu_p}$$ Source: Rocket Propulsion Elements by Sutton 8th Ed. Equation 10-16, Chapter 10. Page ...
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Falcon 9 launch process - perception of launch speed

One of the things that drew attention from my local group of rocket-watchers with the Falcon 9/Crew Dragon launch is the perceived speed of the actual launch process. We have been conditioned for ...
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1answer
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why do under-expanded engines have less than ideal thrust?

I've been looking into rocket propulsion a bit and got stumped on something. I read that the thrust generated by an engine can be determined by the following: $$ F = \frac{w}{g}v_{e}+A_{e}(P_{e}-P_{a})...
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How was Demo-2's Falcon 9 booster different from any other F9?

According to The Sum Of All Knowledge, the Falcon 9 has only twice (including the 2016 ground fire destroying the payload) failed to put the primary payload in orbit. Thus, the May 30 2020 Demo-2 ...
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1answer
111 views

How much LOX is vented / wasted while loading?

We're all aware of the recently aborted SpaceX Demo-2 launch... While talking with friends we discussed the venting of LOX pre-launch. I presume that the reason for this venting is largely to achieve ...
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2answers
217 views

single thrust vs. multiple thrust

Does using one 5000 pound thrust engine give the same amount of thrust as five 1000 pound thrust engines? I am asking in terms of effectiveness not efficiency. Do the two different configurations ...
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1answer
63 views

Why would one assume chamber pressure instead of chamber volume when designing a rocket engine?

Most modern rocket analysis methods can base calculations on either Gibbs free energy or the Helmholtz free energy when computing what the exhaust products (and hence, the exhaust velocity) will be (...
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2answers
117 views

Why aren't rockets launched in movement? [duplicate]

Rockets launched to reach orbit usually start from a stationary position, engines are started and the rocket slowly gain acceleration upwards, eventually reaching orbit. What I'm thinking is that the ...
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1answer
119 views

For F1 rocket engine, why propellant holes were not in proportion to the fuel to oxidizer ratio?

I understand that the F1 rocket engine had (approximately) 1428 Oxidizer holes and (approximately) 1404 Fuel (RP1) holes in the injector plate. Since the Oxidizer to fuel ratio was 2.27:1 for the F1 ...
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1answer
155 views

Are rocket tanks being filled up until the last seconds before liftoff?

In rocket launch videos, we often observe liquid propellant rocket engines running at full thrust for several seconds before actual liftoff. We understand that liquid propellant rockets consume a ...
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Relating Rocket Propellant Selection to Specific Impulse

Is it possible to directly relate a fuel/oxidizer selection to specific impulse at vacuum? I have tried a few different methods, but cannot seem to directly relate the two.
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2answers
91 views

Using heated water as propellant for a DT-He3 fusion thruster

Not sure if this would be best placed here or in World building SE, but I'll try here. Let's say I have a Dueterium-Helium 3 fusion pulse engine (similar to what is in the Expanse) that will use ...
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Rocket Performance

I am just trying to do a simple rocket performance analysis. I want to determine specific impulse (vacuum isp) as a function of oxidizer to fuel ratio (O/F) for a LOX/LH2 engine and LOX/CH4 engine. I ...
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1answer
66 views

Pressure withstanding capability

As you can see in this pic, F-1 rocket engine consists of 15 main components. Now, how is it possible to keep all the components together intact in high pressure situations like when the rocket is in ...
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1answer
112 views

Nozzle Exit Pressure Too High?

I've been doing some simple rocket science for fun, and I wanted to calculate the specifications of the Lunar Module Descent Engine (LMDE). The LMDE uses Aerozine-50 (UDMH) and Dinitrogen Tetroxide($...
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2answers
233 views

What to do with money?

Suppose I raise $10 million from venture capitalists for my rocket startup, what are the initial steps I must take (as a person with no experience of making rockets before) to ensure my companies ...
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1k views

Encryption in radio system

We know that radio waves are used in communication with rockets, space crafts and satellites. Now, radio system basically consists of transmitter and receiver. If there is frequency match between ...
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4answers
1k views

High altitude stage separation

Normally, at high altitude above Earth's surface, there are stage separation of a rocket. If we consider unmanned rockets, at high altitudes, how does human operators of a rocket who are here on Earth ...
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3answers
4k views

Why doesn't the USA use structurally stronger rockets for the more important launches?

Russia uses the R-7 ICBM-derived Soyuz launch vehicle for most of its space launches. The advantage of it is that there's no concern on what the weather is like on launch day and Soyuz launches almost ...
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613 views

Why does this formula say rocket efficiency depends on velocity?

Wikipedia gives the following equation for the efficiency $\eta_p$ of an engine here: $$\eta_p= \frac {2\, (\frac {v} {v_e})} {1 + ( \frac {v} {v_e} )^2 }$$ where $v$ is the rocket speed and $v_e$ ...
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5answers
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Why do space rockets not start from an angle? Why go straight up? [duplicate]

I know that they used to have this idea, back in the day, of a "space gun" to fire somebody into space, and I understand why that was not safe or practical/feasible. However, once they had come up ...
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2answers
825 views

Is it correct that the Saturn V RP1 tank was pressurized by high pressure helium and the LOX tanks were pressurised by oxygen?

I understand from many sites that in the first stage of the Saturn V, the RP1 tank was pressurized by high pressure Helium tanks, but the LOX tanks were pressurized using gaseous oxygen. Is this ...
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5answers
1k views

Could moon ice be used to fuel a steam powered jetpack for EVA in space or high altitude exploration on the moon?

For long term moon operations, would it be practical to have a jetpack that used steam as a source for EVA on the moon surface and above it in orbit? I imagine a scenario where lunar ice deposits ...
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1answer
98 views

rocket engine design

Do we need to preheat both the fuel e.g. LH2, and the oxidizer e.g. LOX, by running conduits around the nozzle? I presume both being cryogenic, preheating would be a must otherwise, engines will have ...
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1answer
161 views

Fat as hydrocarbon rocket fuel?

Have fat/grease or fatty acids ever been studied as a liquid rocket fuel? (I don't expect it to be a good rocket fuel, but I wonder if anybody has ever burned it in an engine or made a serious study ...
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504 views

Could a thermal nuclear propulsion double as a nuclear reactor?

Nuclear thermal propulsion takes hydrogen and introduces it to enriched uranium that then heats up the gas and expels it to create thrust. Could you use also use the uranium to heat up water instead ...

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