Questions tagged [propulsion]

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

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1answer
162 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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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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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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1answer
78 views

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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1answer
98 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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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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1answer
204 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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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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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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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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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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1answer
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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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156 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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668 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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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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1answer
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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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127 views

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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1answer
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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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293 views

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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164 views

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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103 views

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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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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1answer
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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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83 views

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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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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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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1answer
129 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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2answers
135 views

Can Pyroxene and other silicon compound be used as a theoretical spacecraft fuel?

I have been reading this patent : https://patents.google.com/patent/US3137599A/en This lead me to this paper: https://www.jstor.org/stable/44682837?seq=1 The first uses Polysilane, which basically ...
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423 views

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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2answers
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Science Contest Topic (space exploration)

I'm thinking of entering the Breakthrough Junior Challenge. It is a global science video contest in which participants have to explain a hard science/math topic in a 3 min video. Right now I'm ...
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1answer
80 views

Kinetic reaction from emission of electromagnetic radiation

If an object is emitting 1 watt of electromagnetic radiation directionally and has negligible black body radiation, how much thrust is produced? How can you calculate this generally?
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225 views

Specific impulse and delta-v in Tsiolkovsky's rocket equation

According to Tsiolkovsky's rocket equation, it is possible to calculate the delta-v of a multistage rocket if you know the characteristics of each stage of the rocket. In my case, the only ...
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1answer
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Does better satelite propulsion help selling secondary payloads?

Generally orbital inclination change is said to be (fuel) expensive so everyone is trying to reach their final orbit straight from the launch vehicle. Small launch vehicles (Rocket Lab etc.) reach ...
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How do you "make" a soliton? (recent peer-reviewed theoretical work in FTL travel)

I've just read an Article on the new approach on Warp Drives Dr. Erik Lentz describes. Instead of creating a bubble with negative energy density, he describes a Soliton in spacetime, which he ...
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36 views

Powering pulsed Ion Thruster

The thrust of an Ion Thruster is directly proportional to the Input power. I've done some experimenting with DIY versions, and I was wondering: Since Power is simply Energy/Time, if I shot incredibly ...
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1answer
105 views

Attitude control with cold gas thrusters

Consider the cold gas thrusters on a Falcon 9. There are two thruster pods on stage 1 and two on stage 2. Each pod has four orifices to fire along the x, y, and z axes of the scacecraft. By varying ...
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Why are the rocket plumes on SN10 different colors?

At about 7:53 (T+2:30) in this official video of the SpaceX Starship SN10 test flight, the engines are shown in the lower right, with clearly different colors in the plumes. The one on the right is ...
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2answers
156 views

Using lasers to reach the Karman line

I've just seen this Anton Petrov video: New Type of Laser Levitation Could Help Us Explore the Mesosphere. It's about this new form of levitation that uses lasers to heat up the air underneath a craft,...
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1answer
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How long can the dawn probe‘s ion thrusters burn?

The title pretty much summarizes the question. Weirdly, googling „dawn spaceprobe burn time“ and similar things didn‘t turn up anything useful (at least for me), so I was wondering if maybe someone ...
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157 views

launch rocket like bullet from steam/air rifle?

I've included an image depicting how exhaust energy from a rocket launch can be recouped by turning it into a large scale pressure cooker by the use of some kind of platform=sabot (thanks @...
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1answer
85 views

How do I calculate thermochemical properties of mixed gases?

I'm working on a rocket project, and my design of engines is stalled. I need to be able to calculate the Cp, Cv, and R for mixtures of O2/CH4 (stoichiometric or fuel-rich mix) and CO2/H2O (result of ...
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270 views

If a company/agency has already developed a kerolox/hydrolox rocket, is it wise for them to switch to an all-methalox rocket? (to lower costs)

Multiple rockets, such as the Atlas V or Saturn V, have used the combination of a kerosene/liquid oxygen (kerolox) lower stage for higher density and thrust within the atmosphere and a liquid hydrogen/...
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1answer
152 views

How much power do radiation-based engines produce

I heard that the Voyager satellites used a radioactive source to power the computer and sensor systems. How much power can this technique produce nowadays? Could it power, say, a fighting robot? ...
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1answer
118 views

nozzle throat area calculation for choked flow

I am quite confused for my sugar propellant rocket nozzle. I have designed a CD nozzle by hit and trial method. It worked but produced so less amount of thrust .I have used 2.3 kg propellant which ...

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