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Questions tagged [rockets]

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

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What determines rocket height/width?

I was wondering what determines the height/width ratio of a rocket? What are factors that influence the choice between a tall skinny rocket like Falcon 9 or a wider shorter (in ratio) like Ariane 5 or ...
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Changes in rocket engine design, based on fuel being used [on hold]

What are the major differences in rocket engine design for different fuel combinations such as H2L+ LOX or Solid fuel or RP-1 + LOX ETC...
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1answer
137 views

Why rockets are not tossed up before launch [duplicate]

Ok, I understand the nature of my question but anyway why the rockets are not tossed up before launch. It could introduce a huge handicap for a rocket in terms of reduced distance it has to travel, ...
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Using weather patterns as a primary criteria, would South America be an ideal place to launch rockets?

I was looking at a map of historic hurricane travel the other day and noticed that South America doesn't really get them. Florida gets a lot of hurricanes. Texas gets them too. It also occurred to me ...
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Use of different fuels for stages of Saturn V

Why were different fuels used for different stages of Saturn V? I read that the first stage used kerosene (RP-1) and LOX combination, but liquid hydrogen and LOX for the second and third stages. With ...
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Why does the Delta 4 Heavy look burned? [duplicate]

When I was looking at pictures of the Delta 4 Heavy rocket, I noticed that closer to the engines, the rocket looks black instead of the orange color it has right after launch. It looks burned to me. ...
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2answers
94 views

Why are exhaust nozzles in space shaped the way they are? [duplicate]

Why are nozzles in space shaped like a cone and not like a tube ensuring all the exhaust is directed strait?
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44 views

How to reach a target apoapsis with a gravity turn?

Ok, here I go. I have as a project to simulate the launch of a payload by a rocket into polar orbit. Since original question was too big, let's get it into separate parts. First of all, trajectory ...
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149 views

Was New Horizons launched on a copper rocket?

Screenshots below are from Brian May's new music video Brian May - New Horizons (Ultima Thule Mix) [Official Music Video] The beginning shows the launch of a rocket. I can't tell for sure if this is ...
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Could rockets launched from the ground use wings in the stages?

Could a slower or smaller rocket take advantage of lift if all the stages had wings? Could the stages reduce splashdown impact forces by using a spinning seedpod-like design (as shown in the image ...
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3answers
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Why is SpaceX not creating its own launch vehicle for small satellites?

With a (predicted) $5.5 Billion dollar market, why isn't SpaceX trying to build its own 'mini launch vehicles'? With the brand and the technology they have, they can easily capture a huge chunk of the ...
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1answer
79 views

Can I able to use RP 1 and LOX in metal tin small size rockets? Is that possible? [closed]

I love rockets. Planning to build a tin rocket but not with water and air pressure. I would like to build a small metal tin rocket using fuel as RP 1 and oxidizer as LOX. I know this is too hazardous ...
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1answer
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Is a Kármán Rocket Possible? [duplicate]

Why are the rockets not razor sharp, skinnier and taper off at both ends farther to cut through air better? Would making a rocket more aerodynamic allow it to be more efficient flying as a "Kármán ...
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What is the best fuel for bottle rocket? [closed]

I want to modify my firework bottle rocket to fly a mile high. What will be the best fuel for this? Could fuel used in space rockets be scaled down to work in a large bottle rocket?
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1answer
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What causes those curtain-like hot and cool spots in the 2nd stage nozzle of this Electron ELaNa 19 launch?

Here is a GIF that I made of the recent Electron Launch from frame grabs in the Rocket Lab video ELaNa 19 Launch - 12/16/2018 It is about 4M, so it won't fit in SE's normal image import. Frames are ...
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0answers
34 views

Conditions and sensors that can be used for parachute deployment?

I'm looking for an explanation on ideal conditions/considered factors when a parachute is deployed (particularly in large competition rockets). Also what sensors should be used to measure these ...
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1answer
117 views

How much propellant is needed for a 1G continuous trip to the moon?

I've seen some calculations of the energy requirements of 1G propulsion, which are obviously huge, but at least theoretically achievable...but what about propellant? Somebody check my math, but it ...
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1answer
81 views

Is there enough energy in a rocket nozzle for fission?

How much more energy does the rocket exhaust atom have to have to be before fission can occur to create more thrust? Which exhaust byproduct atom would be the easiest to split? I understand in ...
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3answers
901 views

How is the CG of rocket found after the complete assembly

Using CAD modeling, the center of gravity of a rocket can be easily predicted. But in reality, after the assembly, the CG will not be exactly at the place given by the model because of difference in ...
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0answers
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How large are the advantages to building a Martian spaceport on Olympus Mons? What are the disadvantages?

There are several questions and answers here about a potential advantage to launching from substantially higher altitudes, usually the answers are that while indeed there is some advantage, it is ...
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2k views

How can a rocket approaching the Karman Line then return to earth faster than 53 m/s terminal velocity?

In the book, How to Make a Spaceship: A Band of Renegades, an Epic Race and the Birth of Private Spaceflight the opening chapter details the June 2004 attempt to take SpaceShipOne to the Karman Line. ...
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1answer
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Do launch vehicle companies like SpaceX and RocketLab use magnetometers in their IMU units? If not, why?

I am aware that most launch vehicle companies use strapdown IMU systems, consisting of gyros and accelerometers. I was thinking if one could use a magnetometer and accelerometer to get data (like they ...
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Why doesn't a regeneratively cooled engine crack due to differential expansion induced by thermal gradients?

A liquid rocket engine with regeneratively cooled chamber walls and nozzles would definitely be one among those components experiencing the steepest thermal gradients (Chamber wall inner - $3000 K$ ...
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Why NASA hosts many of their reports public, while ESA/JAXA/ Roscomos doesn't?

There are abundant resources available online in NTRS about the hard earned knowledge of rocket science. But NASA makes them available for free for all. But there does exist some classified ...
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2answers
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Why are LOx plumbing not insulated?(ref: Huzel and Huang)

In the book Modern Engineering for Design of Liquid Propellant Rocket Engines, the following excerpt appear in chapter 9 - Interconnecting Components and Mounts: The liquid-oxygen lines were not ...
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2answers
118 views

Other than He and N as pressurizing gases

To pressurize the liquid propellant tanks Helium is most widely used and after that Nitrogen. Helium is quite costly and Nitrogen is economic but it messes with the O/F ratio of the engine (ref). So, ...
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66 views

At which stage of rocket development does systems engineering become critical/useful? [closed]

Rockets are complicated system and the interaction of the sub-systems are even more complicated. But different subsystems tend to be developed parallels without much interaction but does so when ...
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0answers
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How are the liquid propellant umbilical cord protected from the exhaust?

The launch pad umbilical cords supply propellant to the rocket, and will definitely have some remaining at the time of liftoff. I remember the Saturn V footage wherein a heavy protection door slams ...
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0answers
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Problems with shutting off “torch igniter” during the operation of combustion chamber

With reference to the presentation pp 76, where SSME's Augmented Spark Igniter is said to have their flame "On" even after the main combustion chamber ignition, is to prevent the blowback from the ...
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1answer
147 views

What function did the ribbed portions of the Saturn V exterior serve?

I would like to know what function did the ribbed portions on Saturn V exterior serve, such as the the intertank section and forward skirt on Stage 1. Thank you!
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79 views

Maturity of interplanetary rockets technology with known fuel supply is close?

Considerably, the scale of current jet propulsion rocket technology to leave Earth is closely connected to the target delivery mass, mission goal and the required fuel quantity to lift and deliver ...
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2answers
549 views

Why is there such a large range of stage numbers, including fractional stages?

Falcon 9 clearly has two stages, but the smaller two-stage Electron has a "kick-stage" so some might call that 2.5. The question Quantitative benefits of Atlas II's engine-dropping or 1.5 staging? and ...
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Trying To Understand This Characteristic Velocity To Force Problem

Having problems trying to solve part b of this problem. Rocket Propulsion Elements 8th - Chapter 2 A jet of fluid hits a stationary flat plate in the manner shown below. (a) If there is 50 kg of ...
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Why is Adiabatic wall temperature taken as the driving temperature in rocket engines?

Going by the definition of convective heat transfer coefficient from Wikipedia (which I have started to doubt; reason follows): $h=\frac{q}{\Delta T}$, where the $\Delta T$ is taken as the difference ...
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1answer
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What's the actual oxidizer/fuel ratio in the combustion chamber of the Vulcain?

I'm working on a simple exercise on the Vulcain, but I'm having a hard time figuring out what the real O/F ratio is, in the combustion chamber. I need the mixture ratio in the chamber to calculate the ...
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1answer
120 views

Does a rocket sound louder to the astronauts as it leaves the atmosphere?

Rocket launches are LOUD, even to nearby observers on the ground. However, once in space, the vacuum does not transmit sound, so any sound produced by the engines will be contained to the spacecraft. ...
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Reliability of self pressurization of propellant tanks for liquid engines

In a cryogenic propellant tank, the liquid always continuously changes into gas which pressurizes the tank. To pressurize the tank more we can run the liquid through the pipes along the outer wall and ...
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Pressurization line (Helium to LOX tank line) chilling while pressurizing LOX tank

I have read that in rockets and launch vehicles Helium is used for the pressurization of propellant tanks. What temperature Helium is stored at? If Helium is stored at room temperature then while ...
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1answer
224 views

How does falcon-9 engine survive while re-entry burn without chilling ?

I've often seen that in launch sequence, "engine chilldown". I've learnt that chilling is done to avoid thermal cracking in plumbing lines and also to avoid cavitation. While re-entry, do they ...
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2answers
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If I wanted to try to terraform Mars, who would have the authority to stop me?

Let’s say hypothetically I could fund a rocket ship and pack it with lots of biomaterial. Biomaterial that would hopefully survive the impact, reproduce and potentially alter the atmosphere of Mars. ...
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1answer
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Can VTVL rockets use dampers like high rise buildings to provide stability?

VTVL with long and thin body have a difficult time in obtaining stability during landing. Watch this failed SpaceX rocket landing for example: Why can't they use "...
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Gimballing angle consider for liquid rocket engines [duplicate]

I went through the documents for gimbaling of liquid rocket engines and saw that there is about 20 degrees per second of gimbaling rate (in comments). But I am not able to get, what is the maximum ...
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Effect of the location of igniter in starting liquid rocket engine

What will be the effect of off axis igniter, say a Spark igniter has to be used along with a pintle? Will the igniter being off axis have any effect on engine start? Also, will an off-center igniter ...
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0answers
79 views

What is meant by chamber pressure in rocket engines?

Is "chamber pressure" the pressure at the tip of the injector, or the pressure before combustion inside the chamber, or the pressure after combustion inside the chamber?
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1answer
102 views

What is the typical mach number at which the peak dynamic pressure occurs?

Is there any mach number range (say 0.8-1.4) where the maximum Q of the rocket should occur?
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0answers
66 views

How much would mass-production impact the cost of solid-fuel rockets?

Let's imagine that, for some arbitrary reason, solid-fuel rocket stages were needed and built en masse in factories, like planes or even like cars. How much would it drive down the cost of an ...
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3answers
6k views

Why not keep the engine for multi-stage rockets?

Rocket engines are a huge weight in a multi-stage rocket. and they are stacked like so: Fairing/Payload Fuel Engine -- Seperator -- Fuel Engine and so on, which means multiple engines. Is there ...
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0answers
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How to make a orbital launch tube work?

Normal rockets would not work in a pressurized tube, but could a stage be made for the diagonal launch tube to save fuel and weight? Can the bottom stage be nuclear powered? Unlike the piston launch ...
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0answers
265 views

Why is the exhaust plume of Falcon 9 upper stage shaped the way it is?

The (single) Merlin 1D vacuum engine's exhaust plume has a symmetric shape, comprising of six distinct "inner" plumes. Why does it have this shape? Is it due to the shape/configuration of fuel ...
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0answers
54 views

Is it feasible to take liquid Helium in a Pressure Fed System?

Can liquid Helium be flowed through a heat exhanger to increase its temperature and pressure which will further pressurize fuel-oxidizer tanks.