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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1answer
2k views

What is this South Korean rocket and why does it have separate yellow and blue exhaust plumes?

The BBC's Watching North Korea from a supersonic fighter jet (screenshot from YouTube) shows the launch of a South Korean rocket. I notice that it has both a very long, nicely expanded blue exhaust ...
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2answers
660 views

Are In-Flight Electrically Heated Steam Rockets Possible?

I wonder if a rocket that uses electricity from internal batteries to heat water in its tanks to high pressure would be able to use that pressure to take off. Is it possible? I've researched here and ...
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1answer
103 views

Are Interplanetary mission trajectory computations based entirely on Newtonian mechanics?

I am wondering if the application of General Relativity is ever needed(?) I assume that Newtonian mechanics is sufficient with some trajectory corrections applied as needed on route. I also assume ...
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76 views

How is a desired chamber pressure achieved in a liquid rocket engine

Before everyone responds that this has been asked before, I have read through every relevant post I could find here and believe my question has not been clearly covered. I also understand that "...
3
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1answer
97 views

Specific impulse of a rocket engine

Keeping other things (fuel, oxidizer, their ratio, mass flow rates, throat diameter, other hardware like pump, injector nozzles & impinging pattern etc.) same, if I changed only the geometry (...
3
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1answer
177 views

Where do the numbers 101,972 and 3,600 come from in terms of Thrust-Specific Fuel Consumption (TSFC or SFC)?

Online, on sites such as Wikipedia's for Specific Impulse and Thrust-specific fuel consumption, there are these units: 101,972/x g/(kN·s) and 3,600/x lb/(lbf·hr) Perhaps 3600 comes from the number of ...
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1answer
106 views

Where is Webb Space Telescope?

In this NASA application page Where is WEBB? about the recently launched Webb space telescope the information provided tracking the cruising speed of the telescope widely changes (i.e. dropped from 0....
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0answers
60 views

Regulations relating to setting up a liquid rocket engine test site in the UK?

I am an aeronautical engineering student and with a few other students we are developing a liquid engine for a rocket. We would like to test our liquid engine. We will need a lot of testing. So we are ...
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0answers
50 views

Multiple rocket nozzless vs single rocket nozzle?

I am an aeronautical engineering student and at university with a group of friends we are are working on building a rocket aimed at getting past the Karman Line (boundary to space). We will be ...
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0answers
105 views

What is the benefit of an inverted rocket stage?

For example the Chinese rocket Jielong 1 has an inverted 4th (final) stage. So the payload sits between 3rd and 4th stage. When 3rd stage separates it has to do a 180 degree turn before igniting the ...
4
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1answer
703 views

Why did the James Webb Space Telescope briefly lose altitude during its launch? [duplicate]

As shown in the center panel of this screenshot from NASA's livestream of the James Webb Space Telescope's launch, the telescope briefly lost altitude during its launch trajectory (and this was ...
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0answers
61 views

How to estimate total CO2 emission per year due to rocket manufacture?

I'm working on a study on greenhouse gas emissions related to rockets. While I have the post-launch (atmospheric) emissions, I need data for emissions related to production. For example, according to ...
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1answer
133 views

Calculating time for several transfer orbits

I was watching a video that displayed how the time to get to Mars varied with the production of varying delta-v and was looking for the mathematics behind such a calculation. Here is the link to the ...
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0answers
58 views

Thrust needed for Ion Thruster Lift off from Earth surface

I've been calculating the needed mass flow rate for a hypothetical ion rocket, lifting off from Earth's surface and propelled with a Dual-Stage 4-Grid ion thruster. Data given: mass of the spaceship /...
2
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1answer
94 views

electric depositing on rocket engine

I saw a video from Everyday Astronaut in which he mentioned electric depositing on a rocket engine. How can thin depositing stand for high pressures?
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1answer
78 views

How is delta-v calculated for an interstellar journey?

Just recently I have been learning about orbital mechanics and I came across the following article: https://blogs.scientificamerican.com/life-unbounded/why-chemical-rockets-and-interstellar-travel-...
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1answer
140 views

What limits pressure buildup in SRB's?

According to st. Robert's Law, propellant burn rates increase with pressure. When an SRB is ignited, propellant starts to burn, making the pressure rise in the combustion chamber. The flow through the ...
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6answers
4k views

Why do rockets have multiple stages?

I guess, almost all the rockets have multiple stages. But, I was wondering, why do they have multiple stages? Couldn't they have just 1 stage? With more stages, they would require more engines (...
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1answer
53 views

Designing of CD nozzle with respect to Mass flow rate of propellants

How do I calculate the flow rate of exhaust gases required at the throat of a CD nozzle, with given throat diameter of "D", so as to achieve a "Choked flow condition" (velocity of ...
3
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1answer
65 views

How we can relate rotary inverted pendulum to a rocket system?

Initially I posted this question on EE Stack Exchange but I am also posting it here in Space Stack Exchange so I may get attention from a much related audience. I am interested in control systems ...
2
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2answers
216 views

Why aren’t vacuum engines turned on after Mach 1?

In rockets, smaller nozzles are used at lower altitudes because atmospheric pressure would cause problems by pushing air into nozzles with higher expansion ratios. However, it seems to me that once ...
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2answers
2k views

Is it possible to propulsively land an SRB?

I am wondering if it is possible to propulsively land a solid rocket booster after it detaches from the core booster. I know you could use thrust termination ports to stop thrust, but it would drop ...
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6answers
7k views

How much has fuel efficiency increased in rockets since the Apollo missions?

I have been talking with a friend of mine and the subject turned to modern rockets versus Apollo era rockets and fuel efficiency. My friend stated that today’s rockets use half the fuel of the rockets ...
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1answer
119 views

How do kick motors distance themselves from their payload after their burn, if at all?

I saw Space News' An object is now orbiting alongside China’s Shijian-21 debris mitigation satellite recently about a "new object" orbiting near a relatively newly launched satellite. The ...
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0answers
57 views

Rocket equation with Drag factor

For the avg Thrust of 2 kN, burn time = 3.5 s, burn rate= 1.4, over the time diff of dt = 0.1 sec Isp = 140 sec Cd for the Ogive nose cone C-section = 0.75 Cross-sec Area of the ogive nose cone = 0....
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2answers
506 views

Calculating the projectile of rocket using RCS to tilt the flight path

If I have main solid rocket with 800 N Thrust, 9 kg in total and has RCS thrusters 0.5 m from the center mass. Mid flight the RCS with 1 N force is activated for 2 sec. How does it affect the flight ...
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1answer
156 views

How could Shuttle orbiter with internal airlock dock with ISS or other space stations and were internal airlocks used for missions with spacelabs?

As you can see in this animation time 11:45 >, during latter Shuttle missions EVA airlock was placed in payload bay and used both for docking with ISS (with orbital ...
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2answers
680 views

What novel tank designs and ideas are out there to prevent fuel in a rocket tank from "sloshing around"?

After seeing all the Starship failures, having something with a membrane keep things in place seems like an obvious solution. Bladder tanks and "balloons" have been discussed here: Why is an ...
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0answers
121 views

High latitude launch sites

I have two questions: What is the hype about launching rockets from high latitude launch sites? For references: Andoya Space (Norway) and ESRANGE (Sweden) received grants of > 20 M EUR. Wouldn’t a ...
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0answers
55 views

Do fins with slightly different masses but the same surface area affect the stability of a rocket?

Each of four fins of a rocket are of slightly different masses like( 0.204, 0.2, 0.199 and 0.19 kg). If they have the same surface area, will that severely affect the stability (spin) during flight? I ...
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65 views

What is the best place on the internet to learn basic physics needed for rocket engineering? [closed]

Does anyone know a site where everything is in one place and it teaches equations and pricipals from the basics?
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1answer
171 views

Pressure inside Starship CH4 and LOX header tanks during entire Earth-Mars trip and landing on Mars?

What should be the pressure inside Starship CH4, LOx header tanks during the entire Earth-Mars trip and landing on Mars ? The main CH4, LOx tanks should be under 6 bar pressure, because that is the ...
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1answer
207 views

The thrust in the calculation of specific impulse

In calculating the specific impulse using the thrust generated as one of the parameters, do we take the total thrust generated or the average thrust over the period of the burn? $I_{sp} = \frac{F_{...
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170 views

How many turbine blades, engine seals and bearings do reusable rocket engines have and how are they inspected?

From previous year statements of SpaceX representatives, the most difficult and longest part of used F9 booster refurbishment are inspections of the most volatile parts of the booster's nine Merlin ...
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1answer
92 views

Tilted exhaust gases from the rocket nozzle after sonic boom [closed]

Our solid propellant rocket, on test, produces sonic boom. Right after, the plume of exhaust tilts sideways. This will definitely have a gimbal effect during flight. The propellant chamber has one ...
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0answers
198 views

SpaceX Inspiration4 mission cost breakdown

It is believed that SpaceX Inspiration4 total mission cost was more than 100 million USD. https://twitter.com/DJSnM/status/1439470685064073219 What could be cost breakdown for this mission ? After ...
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1answer
65 views

Lift and Drag of a Model Rocket

Talking about aerodynamic forces in a model rocket, I believe that Lift and Drag are the components of a net force which acts on the Center of pressure. Knowing this, could I affirm that the net ...
2
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1answer
102 views

Why are my empirical and theoretical value of mass flow rate in solid propellant rockets not similar?

For a rocket of: fuel mass $m_f$ = 6 kg, Thrust = 3.1 kN, (vs 4k using reducing catalyst to delay burn time) total powered burn time, $t_b$ = 3.5 s, (using reducing catalyst vs 1.8 sec) This ...
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0answers
46 views

Mass production rate vs mass consumption rate in solid rockets

Do the two terms mean the same? mass production rate, mass flow rate and mass consumption rate in a solid propellant rockets.
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0answers
121 views

SpaceX estimates for Starship and Super-heavy heat shields maximum heating during their orbital and suborbital reentry

Did SpaceX made public their estimates for Starship orbital vehicle heat shield maximum heating (and overall reentry heating profile) during orbital reentry on Earth and same for Super-heavy booster ...
3
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1answer
127 views

Can the cryogenic expansion of liquid oxygen and liquid hydrogen be used to pump a rocket engine?

A common fuel amongst rockets is that of the combination of cryogenic liquid hydrogen and liquid oxygen. I looked at the design of a simple rocket using this cocktail that is the propellant and found ...
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1answer
108 views

How does the Falcon 9 upper stage settle its propellants?

I understand the upper stage separates with the use of pneumatic pushers, but what settles the propellants in the upper stage tanks so that the propellant is pushed back to the intake? The pushers ...
2
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1answer
206 views

What is the max height I can achieve with my solid prop rocket?

For a rocket of: mass, $m$ = 25kg, dry mass $m_f$ = 19 kg, Thrust = 2.1 KN, total powered burn time, $t_b$ = 3.5 s, $I_{sp}$ = 129 I get powered burn height = 549 m and total time to max ht of 5506 ...
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2answers
243 views

How are upper stage engines chilled down?

To chill down an engine, cryogenic propellant is pushed through the engine. This is fine for the first stage because the chill down propellant can just flow out the nozzle and on to the ground/the ...
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0answers
158 views

Trussed strongback or hollow shell strongback?

I noticed that rocket Lab has a hollow rectangular section strongback made of steel, while few strongbacks like that of Astra [similar size] has a trussed structure for a strongback. is there any ...
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1answer
373 views

Why do recent launch vehicles like that of Space X and Rocket Lab have far fewer umbilicals than before? What has changed?

Launch vehicles using mobile launch pads have many umbilical connections, whereas the ones using TEL launch structure with strongback, don't. Why is that? As seen in the picture, Electron has just one ...
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1answer
232 views

Why will the final version of Starship be almost empty after its first launch?

It has been announced that SpaceX Starship SuperHeavy will need 16 launches with the tankers to refuel Lunar Starship. Why is the Starship going to be empty after reaching orbit, since the booster is ...
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0answers
133 views

Silane as a rocket fuel

At about 6:55 into the video Why Moon Mining Will DEFINITELY Be A Thing it is stated that lunar silica (SiO2) could be turned into silane (SiH4), which is the silicon analogue of methane. It also ...
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2answers
2k views

Does going to Mars take the same energy as making a rendezvous with something going to Mars?

I think I found a mathematical error in the 2015 movie The Martian1. Warning, there will be spoilers. The final plan they settle on to rescue Mark Watney is to have the Tiayang Shen rendezvous with ...
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1answer
114 views

Does anyone know the stay time, or what characteristic length should be used, for a LOX/LCH4-fuelled rocket engine?

Just what it says on the tin. I need to know either the "stay time" (Ts) or characteristic length (L*) that would be used to figure combustion chamber dimensions used with a LOX/LCH4-...

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