Questions tagged [propulsion]

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

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Variant of the Tsiolkovsky rocket equation including engine specific power and efficiency, can anyone help me under stand how this works

First of all this code is not mine I am trying to understand how the equation for m_u works. This comes from a master thesis called Trajectory design for a Titan mission using the Direct Fusion Drive ...
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14 votes
2 answers
3k views

Could the Space Shuttle launch with two engines?

In a movie, they need to launch the Space Shuttle, but one engine is not ready to go in time, so they decide to launch with the booster and two of the shuttle's engines - Could the shuttle Launch with ...
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How exactly does depressurization work in a solid rocket motor?

How does the extinction process actually work in a solid rocket motor? Most people initially always read that once a solid rocket fuel is ignited there is no way to actually stop its operation until ...
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4 votes
1 answer
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Can ion propulsion system be used to maintain lunar orbit?

I am doing research on propulsion systems and it was suggested that I use an ion propulsion system for a theoretical satellite I am tasked with designing, I need to maintain orbit for three years ...
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What should be the mission plan in order to reach TITAN (SATURN) by a group of 15 people for Scientific Exploration? [closed]

I am working on a project where we have to design a Mission to TITAN by Digitally construct and document the development of a six-month long human settlement on Titan (Moon), bearing the capability to ...
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Why is monopropellant used?

The most efficent fuel, liquid hydrogen, is a bipropellant. So, why don't we just use bipropellants? Some monopropellants, such as hydrazine, are toxic. Wouldn't it be easier to just use bipropellants ...
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2 votes
1 answer
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Why did the recent Elana41 mission fail?

On February 10, 2022, the Astra LV0008 rocket failed mid-flight, shortly after stage separation. It appeared to ignite and then shut off repeatedly, while also spinning out of control. Do we know what ...
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5 votes
2 answers
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What is wrong with hydrazine as a monopropellant?

While answering a question about if N2O was a practical monopropellant, I found that hydrazine was considerably more efficient. So, why do people want to replace it with N2O, if hydrazine is more ...
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2 votes
0 answers
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Are VASIMR + Arcjet engines feasible for orbital transfers on Mars?

The VASIMR engine is an electric propulsion system that has been lauded for its ability to cut down on interplanetary transfers. While it requires a high power source (in the range of 200kW), it is a ...
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4 votes
1 answer
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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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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 /...
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Why can't you travel to Mars in a straight line?

I had two questions regarding choosing a path to Mars. Firstly: I wanted to have a look at the mathematics behind the reason as to why we choose Hohmann's transfer over a journey that is a straight ...
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What is the equation that relates delta v of a rocket to time taken to complete an orbit?

I wanted to see how the delta-v produced by a rocket affects the time it takes to complete a certain orbit. So what is the equation that relates these two quantities?
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7 votes
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Is it more expensive to send a chemical rocket from surface of Earth to an orbit or from this orbit to Mars?

I was trying to understand how cost-effective it would be to use an ion engine to power a mission. But since these propulsion systems cannot be used to leave Earth's gravitational field due to their ...
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From which NASA publication originates/where can I find a higher resolution version of this SSME flow diagram?

This came up when I was taking a look at Endeavour over in LA. Where can I find a readable version of this full flow diagram (valves, control systems, and everything)?
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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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6 votes
2 answers
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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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What are the forces affecting superconducting MRI-magnet on low-earth orbit and could you accelerate a satellite with these forces?

In superconducting magnetic levitation the magnet levitates on top of the superconducting material (Meisner effect). In space, the electric current of the solar wind should create a magnetic field ...
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Realistic cost of pulse units for nuclear pulse propulsion?

Nuclear pulse propulsion https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion) was believed to be - by it proponents - far superior to chemical propulsion. Either because max. delta v you ...
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7 votes
4 answers
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How are vacuum optimized engines tested without disintegrating them?

SpaceX recently test fired vacuum optimized raptor engines of starship. Doesn't vacuum optimized engines disintegrate when operated in atmosphere? If yes, what additional modifications are made to the ...
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Did the Cygnus Orb-3 failure disable/destroy both engines?

When the Antares 130 rocket carrying the Cygnus Orb-3 mission experienced an explosion in one of its turbopumps, did that lead rapidly (before crashing / before RSO triggered flight termination) to a ...
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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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0 votes
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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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2 votes
1 answer
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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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Standing still to move forward [closed]

If our galaxy is tracking through space at ~1.3mm, couldn’t we arrive at point B if we came to a stop at point A. i.e. decelerate to -1 g
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2 votes
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Was the Isp = 11,000 seconds Neumann Drive tested on the ISS? Did it work? How well did it perform?

In 2018 answers were posted to What is Australia's Bartolomeo platform? When does it arrive at the ISS; when and where will it be attached? Will the Neumann drive start testing aboard the ISS ...
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What orbit-raising propulsion system will Tiangong use, and how does it differ from that of the ISS in terms of performance and technology?

The new Wall Street Journal video China's Answer to the Aging International Space Station: The Tech Behind Tiangong | WSJ emphasizes after 03:26 that Tiangong's ...
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22 votes
6 answers
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Why is it not concerning from a cost perspective to have so many engines on Starship?

Starship is meant to imitate (to a degree) the affordability of passenger jets. This applies to Earth-to-Earth travel as well as space travel. Jetliners started with 4 engines, but have since migrated ...
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What type of main propellant valves are being used in Rutherford Engine?

I am confused about the main fuel and oxidizer valves used in Rutherford engine by Rocket Lab's Electron Launch Vehicle (as shown in video link attached). It looks like angle valves but I don't see ...
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3 votes
4 answers
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Of all propulsion devices that could reach near-C speeds, which one is closest/most practical?

With even the most efficient chemical fuel we have to reach Alpha Centauri(closest star system to our own) in a human lifetime, you would need a fuel tank millions of lightyears across. So we need to ...
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Which burning of Solid Propellant is best axial burning or radial Burning?

Which Burning is Better Axial or Radial of Solid Propellant grain used in Solid Rocket Motors? How Someone Determines which to choose according to the Mission requirements ?
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2 votes
1 answer
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Can ion Thrusters be used for Reaction Control System?

As RCS (Reaction Control System) mainly required less thrust than regular rocket engine can ion Thrusters be used for attitude determination in spacecraft(Orion, Dragon), satellites or even during ...
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4 votes
1 answer
182 views

Why did Apollo missions open the propulsive Hydrogen vents during the coast phase?

According to Figure 2-1 of the SA-503 flight manual the LH2 continuous vent was opened during the coast phase, and closed during the ullage stage of the S-IVB restart T_6 + 0:00:42.0 (but open for ...
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4 votes
1 answer
728 views

Rocket propulsion question help

I've attempted this question but once again got this wrong. Here is what I did I knew that the thrust equation was mass flow * (Vj - V0). I also knew that the mass ...
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7 votes
0 answers
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What's The Gas Discharge After Landing Finished For SpaceShip2?

What's the gas discharge after landing finished For SpaceShip2? Why did they did it right after landing finished while crew were on board.
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2 votes
1 answer
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Can external plasma enter the chamber of an ion thruster?

Suppose a satellite in LEO wich have a ion thruster, this ion thruster have a grid accelerator and in LEO there are a high density of plasma by the ionosphere, thus the particles of the ionosphere can ...
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2 votes
1 answer
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Has Demonstrator-1 2021-006BX demonstrated a hydrogen-oxygen combustion engine fueled by electrolysis yet?

NASA's NASA CubeSat to Demonstrate Water-Fueled Moves in Space says: A NASA CubeSat will launch into low-Earth orbit to demonstrate a new type of propulsion system. Carrying a pint of liquid water as ...
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2 votes
1 answer
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Navigating to moon from orbit [closed]

In short: My goal is to get knowledge about general travel in space and navigating to a certain object - with literally "low cost" tech. My primary interest is how to control and move a ...
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5 votes
3 answers
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Is the ejection of matter one way to get pushed the other way the only propulsion method we have?

I do mean propulsion (not gravity assist or the like). All the "rocket" engines I've seen (chemical, nuclear, ion, etc) seem to eject material one way to get the craft pushed the other way. ...
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3 votes
1 answer
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Estimating thrust and kg fuel for a generation ship's journey to Alpha Centauri

Premise: A generation spaceship leaves Earth around the year 2060 on a journey to colonize Alpha Centauri A (ACA). In this fiction, fusion power is achieved in 2040, improved over 20 years, and used ...
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1 vote
1 answer
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Joint between actuators and structure in thrust vector control systems

I've been wondering how exactly it is that actuators are joined to the structure of a thrust vector control system. The reason I'm confused may be illustrated by the following image of a Vernier ...
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2 votes
0 answers
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Prop feed with Anhydrous Ammonia in Microgravity

Considering contributing to an SBIR through my PhD where we're looking at NH3 as a green prop solution. Need to figure out how to feed vapor from a liquid/mixed phase tank to the a prop system. ...
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Other than safety qualifications, was there any technical/engineering reason why propulsive landing was cancelled for the DragonV2?

The Dragon V2 cannot perform a propulsive landing. But the Starship will be making propulsive landings. Why?
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14 votes
1 answer
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Why did each F-1 engine have dual fuel feedlines?

Each F-1 engine had two fuel feedlines connecting it to the fuel tank as shown in these contemporary photographs and drawings. The corresponding LOX system only had one feedline. The engine had a ...
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1 vote
1 answer
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Looking for a ballistic projectile technology development company I'd read about a few years(?) ago

I recall reading a few years(?) ago about a ballistic projectile technology development company that expressed interest in launch capability as well as applications closer to Earth. In a comment below ...
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4 votes
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What equation is being used- chamber pressure v.s. mass flow rate? (Cold-gas thruster)

I am doing a project on cold gas thrusters and have seen a couple of graphs relating chamber pressure against mass flow rate. I can't seem to find the equation that relates these two parameters to ...
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0 votes
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How could I find the pressure and/or the Isp at the exit of a rocket nozzle if I have data for the throat and comb. chamber?

I've been looking at this for some time and working with CEA which will only give me data points for the pressure, temperature, Isp, etc. for the Injection, Combustion Chamber End, and the Throat; but ...
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2 votes
1 answer
192 views

What are all the kinds of electric propulsion that don't qualify as ion propulsion in standard spaceflight lingo?

Comments on the meta question We have both electric-propulsion and ion-thruster tags, are they distinct? What would be good usage guidance for electric-propulsion? indicate that the term "...
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3 votes
2 answers
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Can pyroxene and other silicon compounds be used as a theoretical spacecraft fuel?

I have been reading this patent, which led me to this paper. The first uses polysilane, which basically replaces the $\text{C}$ in a $\text{-R-C-R-}$ group, making an $\text{-R-Si-R-}$ group. I also ...
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how does the direct fusion drive generate electric power?

According to its Wikipedia page, about 30% of the power "generated" by the DFD reactor can be used for electrical power. But wouldn't that make it have net positive energy? Since we are ...
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