Questions tagged [propulsion]

Systems for propelling a spacecraft from one place to another, such as rockets.

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1answer
77 views

Can a Mars orbiter mass only 50 kg?

A press release by the SatRevolution consortium says that it plans to send cubesats "as small as 50 kg" to Mars to "conduct a variety of valuable science." So that means orbiting, not just a flyby ...
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1answer
129 views

A question about the feasibility of the Casimir propulsion system [closed]

There is a connection between vacuum energy density and the Casimir effect , see : https://arxiv.org/abs/quant-ph/0204125 Another reference can be found here: https://aapt.scitation.org/doi/10.1119/...
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Are there any staged combustion cycle rocket engines under 1000 kN? Is it easier to produce larger engines with this type of engine cycle?

I found that most engines developed with staged combustion cycles are inherently quite powerful. Are there any engines which was developed with the staged combustion cycle with a thrust under 1 MN. ...
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56 views

Maximum speed of rocket propellant flow?

In reading this question (Limiting factors of liquid rocket engine thrust), it prompts me to ask if there is an upper limit in how fast the propellant/oxidizer can be pumped into a combustion chamber ...
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1answer
114 views

What is the formula to calculate thrust needed to launch from the Moon to Mars?

I want to make a rocket that will travel from Earth then fly from the moon then reach Mars Most of the things are done I just need the formula
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1answer
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Does the moons atmosphere have any amount of human-provided xenon?

Xenon is one of the most widely used propellants for ion engines (sic)- and I also just so happened to stumble on a graph that says the moon could feasibly capture xenon into its atmosphere. Id ...
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2answers
3k views

Could a complex system of reaction wheels be used to propel a spacecraft?

I was think about different ways spacecraft could feasibly move around and I came across Reaction Wheels as a way they can rotate. So I was curious if a complex system of them could be used to propel ...
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1answer
136 views

Magnetic force-driven propulsion system for an interplanetary/interstellar spacecraft

I have come up with a conceptual idea of a magnetic force-driven space propulsion system. What I believe is very unique about this propulsion system concept is that its working principle should not ...
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2answers
102 views

What is the ideal propulsion for an inner solar system spacecraft?

I've seen the X3 ion thruster named as the future for traveling between planets. Would the ideal spacecraft have only one propulsion? Or would it have multiple sources such as hydrazine and solar ...
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2answers
109 views

How is it that “blow-down” propellant storage systems work in micro/ zero-gravity?

A "blowdown" pressure system is something that is extensively utilized on Earth -- with tons of applications ranging from kegs to high-tech hydraulics. This architecture focuses on adding a ...
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Why don't we use Cavea-B

Raiz Aerospace raised an interesting question during one of his KSP Realism Overhaul play throughs. If the RCS propellant Cavea-B is better than hydrazine and less toxic why does no one use Cavea-B, ...
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1answer
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VLEO - ion thrust using atmospheric molecules?

For very low Earth orbit satellites such as the SpaceX Starlink, would it be at all feasible to design an ionic thruster that carries no onboard fuel? Instead it would simply scoop the atoms directly ...
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2answers
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How does a Hall effect ion thruster have a sea-level Isp of 800? Operates at 1 atmosphere?

Astronatix's SPT-100 lists the following: Stechkin electric rocket engine. Used on Meteor and Gals satellites. In Production. 1.35 kW Hall thruster. Thrust variable 2 to 20 kgf. ...
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How does a “hybrid orbital raising system” based on R-4D (N2O4/MMH) + SPT-100 (Hall effect) work exactly? (Intelsat 38 & 39)

Astronatix's Intelsat 39 lists the two engines SPT-100 Stechkin 1.35 kW Hall thruster. R-4D Marquardt N2O4/MMH rocket engine. 490 N. Question: Why is this combination on Intelsat 39 called "hybrid" ...
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Is it possible to get a spacecraft into earth orbit using Linear Eddy Current Braking on an orbital runway?

The "Space Runway" [I have slightly edited this to clarify some issues that have been raised] Luke Parrish mentioned an unusual and novel space launch method to me. The idea is to get a spacecraft ...
8
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1answer
505 views

Sea level static test of an upper stage possible?

As we know that for the upper stages of the rocket, we need high propulsion efficiency thereby high specific impulse. For that we employ a nozzle with higher expansion ratios. Now, if we conduct the ...
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1answer
158 views

Why is the thrust to weight ratio of ion thrusters so low?

The more power we feed an ion thruster, the more thrust it generates. In theory, if we could give it, let's say 10 gigawatts of power, it could generate pretty high thrust. In the example I calculated ...
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1answer
138 views

In theory, how much thrust could an ion thruster generate?

Ion thrusters require a lot of electrical power, while their thrust is incredibly low. However, the more power is available, the more thrust can be achieved. What would be the theoretical limit to ...
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1answer
215 views

Could a CubeSat be propelled by this low-tech electromagnetic propulsion system?

I have come up with a conceptual idea for a low-tech electromagnetic propulsion system for a CubeSat, and I would like to know if it would create (on a theoretical basis) a net force strong enough to ...
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75 views

How do you calculate burns needed to land?

Assume I was landing a rocket and wanted to do calculations on how to correctly land. How do you determine at what time you fire the engine and at what power to successfully land on a predetermined ...
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Exit pressure for Rocket Lab Curie engine

What do you think the exit pressure for rocket lab curie engine could be?and the area ratio as well? its a kickstage engine and it is said that it has about 25lbf thrust.
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60 views

Exit pressure value for vacuum nozzle [duplicate]

What value of exit pressure should I use in the design equations for a small liquid rocket engine nozzle for 200km-500km operating conditions? Since using zero as a value is not possible or else ...
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Apollo SM RCS specific impulse?

What is the specific impulse of the RCS thrusters on the Apollo Service Module? This document cites 281 seconds for the LM's RCS thrusters, but I cannot find similar specs for the SM.
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1answer
124 views

Under-expanded nozzle at sea level - is it a problem?

I'm designing a solid rocket motor with a fixed pressure in the combustion chamber $p_{cc} = 70~bar$. When it comes to the choice of the right nozzle, I have to consider the proper expansion ratio, in ...
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2answers
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Apollo CSM RCS maximum number of simultaneously active engines?

Reading the RCS subsystem manual, it seems like each RCS quad of the Apollo SM consisted of four hypergolic engines. Am I correct in saying that all four engines of each of the four quads could be ...
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ECI to LVLH transformation [duplicate]

I am working on a transformation of ECI coordinates to LVLH (Local Vertical Local Horizontal) coordinates in order to calculate satellite maneuvers. Does anybody know how should I approach the problem?...
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1answer
218 views

Why we don't use cyclotron for ion thrusters?

We know that the advantage of thruster is high efficiency and 'everlasting' propulsion. Which It can not provide a sudden huge propulsion during launch like chemical fuel is its biggest problem. I ...
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103 views

What if GOCE rolled 90°?

Reading this question: Is GOCE a satellite or aircraft? I wondered what would happen if GOCE rolled 90° in either direction, so that it's solar panels become parallel to Earth's horizon, and then ...
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1answer
104 views

Ambient pressure for vaccum nozzle design

How do I find out the ambient pressure for designing a vaccum rocket engine? I am using the propellant combustion charts from the braeunig website. But I cannot figure out the ambient pressure for ...
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155 views

What is a mixture ratio of propellant?

I am a little confused, is the mixture ratio of a propellant Fuel/Oxidizer or Oxidizer to Fuel ratio?
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Can a reaction wheel decelerate to add momentum in the same direction? [closed]

Can a reaction wheel shed weight to gain speed? Could a reaction wheel at its max spin be flipped or rearranged around 180 degrees then slowed to add to its velocity?
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What is the difference between “Air-augmented rocket propulsion” and “integral rocket-ramjet propulsion”?

While going through the topic called "Combinations of Ducted Jet Engines and Rocket Engines" in Chapter 1 of Sutton & Biblarz's Rocket Propulsion Elements, 9th Ed I found the section below. Line ...
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1answer
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Will a spacecraft accelerate in a gravitational field via the use of a powered rotating mass?

I believe that a powered rotating mass on board a spacecraft should result in the spacecraft being propelled in a continuous increasing velocity towards the source of the gravitational field. To help ...
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1answer
189 views

Could this satellite wobble in orbit creating additional orbital angular momentum?

This question asks if this type of steam engine would work: Could a steam Engine outperform other electric producing devices in space? this not a sterling engine since it has far less moving parts. ...
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1answer
120 views

What is the nozzle extension of merlin engine and rutherford engine made of?

It is clear from the pictures, that the nozzle extension of Merlin and Rutherford vacuum engine aren't actively cooled. What is the material of construction for those nozzle extension to withstand ...
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9answers
6k views

Would a grinding machine be a simple and workable propulsion system for an interplanetary spacecraft?

I am wondering if any space agency has ever considered using a grinding machine as a propulsion system for an interplanetary spacecraft. This system would not be used to lift the spacecraft off of a ...
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1answer
292 views

Could a “nuclear turbo-jet” be built?

Being familiar with jet engines myself, I wonder whether a similar device could be built to provide high $I_{\text{sp}}$ and high thrust in vacuum and space. Using the tried-and-true turbojet formula ...
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1answer
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What differences exist between the pressurants and their associated systems between a pressure fed and pump fed liquid rocket engine

There is an apparent need to have pressurants in both pressure fed and pump fed systems. However, since pump fed systems can create the necessary pressure, they can work with less pressurants and ...
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1answer
218 views

Efficiency of a nuclear thermal rocket

I am trying to calculate the specific impulse and thrust of a nuclear thermal engine, given the thermal power of the reactor, the maximum working temperature and the propellant. I'm calculating the ...
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2answers
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Could a cubesat propel itself to Mars?

I wrote the answer below to the question Could a cubesat be propelled to the moon? before realizing that it said Moon and I'd written it for Mars, so I've cloned that question and moved the answer ...
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Could a cubesat be self propelled to the moon from LEO?

Is it possible with current technologies to propel a cubesat, which is launched from Earth, to the moon? If current propulsion systems are able to do so, how do I continue the research in this topic ...
4
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1answer
153 views

What kind of “jet engine-like propulsion” does HyperSciences use to accelerate projectiles to sub-orbital altitudes?

The Teslarati article For HyperSciences, geothermal energy builds a path to space describes the use of technology which has been applied to drilling to launching projectiles to sub-orbital altitudes ...
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1answer
226 views

How do you determine what the temperature will be in the combustion chamber of a rocket engine?

I am guessing it is dependent on the fuel and oxidiser and the chamber pressure but is there an equation that would calculate the chamber temperature?
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Weight Flow Rate

I read in the book INTRODUCTION TO ROCKET SCIENCE AND ENGINEERING by T.S.T that Rocket Engineers design how big the throat of the nozzle should be based on the Weight Flow Rate. So my question is HOW?
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350 views

What could go wrong if someone overpowered an ion engine?

The X-3 ion engine is the most powerful ion engine ever made, and puts out an astounding 5.4 N of force, using 103 kW. It's fuel is inert xenon gas, ionized and heated to a plasma. Now, what would ...
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1answer
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What type of propellant does Spacex plan to use in Starship for long duration missions?

For long duration missions such as ones to mars what type of propellant would be best suited?
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1answer
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What happens when LOX and H2 are injected into the combustion chamber of a rocket?

I can't seem to find an answer on this. I thought that when oxygen and hydrogen get injected they collide and break bonds etc. to form water vapour which because of the pressure in the combustion ...
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How to calculate the force drop due to multiple thrusters firing?

When multiple thrusters are connected to one pressurized propellant tank and multiple thrusters are fired simultaneously, this will cause a pressure drop in the supplying pipes and as such a drop in ...
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Very Low Gravity Bicycle

There are a couple of existing questions about riding bicycles off of Earth. Designing a bicycle for Mars? Can you ride a bicycle on Deimos? Bicycles are lightweight and proved a reliable method ...
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1answer
628 views

Advantage of full-flow staged combustion vs conventional staged combustion engine

Referring to the question in this thread. What is the advantage of full-flow staged combustion (FFSC) vs conventional staged combustion rocket engine? In FFSC we feed the full volume of fuel and ...