Questions tagged [propulsion]

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

69 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
10 votes
1 answer
478 views

Has a rocket engine with LOX as the oxidizer ever fired beyond the GEO belt?

Intuitive Machines' Nova-C lunar lander is scheduled to launch in mid-February of this year. Notably, the lander uses liquid methane as fuel and liquid oxygen as the oxidizer, and it will rely on this ...
quinnkenri's user avatar
  • 1,130
8 votes
0 answers
542 views

Is thermal soakback from the engine a problem for rocket stages? Especially ones that complete several burns over several hours (e.g. S-IVB, Centaur)?

Thermal soakback is a phenomenon whereby a hot, operating engine transfers heat into the spacecraft, usually conduction through the engine mounts. I've only ever seen this problem discussed with RCS ...
dasvitek's user avatar
  • 111
7 votes
0 answers
118 views

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.
yekanchi's user avatar
  • 275
7 votes
0 answers
193 views

Why aren't injector pumps used in rockets?

Is there something that makes injectors unsuitable as oxidizer pumps? Seems to me that rockets would benefit significantly from a pump with no moving parts that runs off its own exhaust.
Bob Hopeldorf's user avatar
6 votes
0 answers
122 views

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?
RNG's user avatar
  • 385
6 votes
0 answers
1k views

Potential improvement to BFR or New Glenn if equipped with aerospike exhaust on their engines?

Aerospikes basically tackle the issue of the variability in required expansion ratio for a rocket engine to be efficient at a given altitude. A recent example though mired in legal issues is a small ...
bob dash's user avatar
6 votes
0 answers
152 views

Relationship between part dimensions and performance of ion electrospray thruster

I got the relationship between power, thrust and specific impulse for an ion electrospray thruster as follows: $$P/T= 1/2 \times g_o \times I_{\mathrm{sp}}$$ Where: $P$ = power required (in Watts), $...
Romean's user avatar
  • 367
5 votes
0 answers
379 views

Do cold gas thrusters fueled by supercritical CO2 have a higher Isp than those fueled by liquid CO2?

The private space company Pixar has developed an autonomous space vehicle (Wall-e) propelled by a cold gas thruster Hand-Held Maneuvering Unit as demonstrated in this press release: From https://...
Woody's user avatar
  • 21.6k
5 votes
0 answers
435 views

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 ...
Mat NX's user avatar
  • 237
5 votes
0 answers
303 views

Purging process of a rocket engine

Does spacex purge Falcon 9 engines after landing ? If so, which gas is used for purging?
Vasanth C's user avatar
  • 1,161
5 votes
0 answers
212 views

What is the droplet size that is desirable for pintle injectors?

The pintle injectors tend to generate droplets after impingement of the fuel and the oxidiser stream and I understand that the droplets will be premixed. In such a case, even a larger premixed ...
karthikeyan's user avatar
  • 4,469
5 votes
0 answers
683 views

Pulse Rocket Engine

How feasible would a rocket engine that ignited fuel in fast, high pressure pulses be. This type of engine would be especially applicable for low thrust burns such as for the raising of a small ...
Benjamin Bridger's user avatar
5 votes
2 answers
327 views

Thrust to weight of large solid fuel boosters

I have been looking at examples of large solid fuel rocket boosters or first stages used for space launch, such as P80, the Space Shuttle SRB, the various versions of Graphite-Epoxy-Motor, the solid ...
Ögmundur Eiriksson's user avatar
4 votes
0 answers
173 views

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 ...
spacegirl98's user avatar
4 votes
0 answers
209 views

Where can I read about Lucy's complete propulsion system?

Wikipedia's /Lucy (spacecraft) says nothing of propulsion, and it's SWRI home page for the spacecraft http://lucy.swri.edu/mission/Spacecraft.html gives specification and enumerates what's on Lucy’s ...
uhoh's user avatar
  • 149k
4 votes
0 answers
149 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 ...
Milwrdfan's user avatar
  • 2,798
4 votes
0 answers
112 views

Electromagnetic engines in heavy radiation regions

What sorts of peculiarities might affect an electromagnetic rocket (VASIMR or Magneto-Inertial Fusion) crossing Jupiter's radiation belts? Could all of that energy fry a magnetic thrust chamber and ...
PHChilly's user avatar
  • 326
3 votes
0 answers
133 views

How can I derive Starlink specs looking at the incident of February 2022?

I am trying to calculate and speculate the specifications of Starlink satellites (mainly related to propulsion) based on the accident on the 3rd of February 2022. There are multiple sources that ...
Playstation_waifu's user avatar
3 votes
0 answers
36 views

Effect of delaying electron ion recombination in ion engine plumes; is a tiny additional thrust component available?

I have a follow-up question in response to this answer by @uhoh, basically asking about higher order effects alluded to in their answer. If the ion exhaust plume coming off an ion engine remain ...
alessandro's user avatar
3 votes
0 answers
90 views

Where are Falcon 9 1st stage GN2 tanks located?

Is nitrogen propellant for the two cold gas thrusters pods contained in the interstage? The view we have from the B5-B1050 recovery shows several small COPV(s) pic1 Here you can see where the cold gas ...
redshiftseven's user avatar
3 votes
0 answers
50 views

Are there substances that can effectively mined from asteroids that can be used for ion thrusters?

The most popular ion thruster design seems to use Xenon. Unfortunately, due to it's low boiling point Xenon isn't easily available in space. Are there other materials from which ion thrusters could ...
Christian's user avatar
  • 292
3 votes
0 answers
129 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 ...
Kai's user avatar
  • 31
3 votes
0 answers
99 views

How is supersonic rocket exhaust able to match sea-level pressures?

I understand that the diverging portion of a rocket nozzle speeds up the flow and also expands it, in order to best match ambient pressure outside. However, doesn't higher speed flow lower the ...
redshiftseven's user avatar
2 votes
0 answers
68 views

Would (Dual Spool and Concentric Powerhead) FFSC Cycle engine be possible to engineer

I,ve been wondering if it was possible engineer and how we would we work it out DUAL SPOOL FFSCC ENGINE with concentric core and individual concentric turbine inside one another and maybe it could ...
ALPHA X FUTUR COMPANY AEROSPAC's user avatar
2 votes
0 answers
77 views

Are there any proposals for propulsive debris deorbiting which address basic requirements for efficiency?

This illustration shows many of the challenges using propulsive deorbiting: https://www.smithsonianmag.com/air-space-magazine/34_aug2017-cleaning-up-space-junk-180963932 The trust line of the tug is ...
Woody's user avatar
  • 21.6k
2 votes
0 answers
112 views

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 ...
FontFamily's user avatar
2 votes
0 answers
52 views

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. ...
D. Hodge's user avatar
  • 165
2 votes
0 answers
42 views

Anyone know of a "N71" Hall Effect Thruster currently in production or development?

In a NASA Goddard Q&A transcript for an upcoming proposal, the NASA representative mentioned that the mission designers were considering the "N71" Hall Effect Thruster as an option for an upcoming ...
Terrance Yee's user avatar
  • 2,284
2 votes
0 answers
36 views

Do colloid thrusters generate thrust by using only droplets or pure ions as well? If they only use droplets, how are they the same as electrospray?

In all of the research literature I have read so far, I've seen colloid thrusters explained as devices that gain thrust by releasing only charged droplets from ionic liquids as the exhaust mass. ...
Tonu's user avatar
  • 21
2 votes
0 answers
64 views

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. ...
Rajath Pai's user avatar
  • 1,251
2 votes
0 answers
116 views

Could a Soyuz-MS deorbit after a failure of its deorbit engine?

The scenario: A Soyuz-MS spacecraft is on-orbit and ready for its deorbit burn. The crew then discover that there is a fault in the propulsion system and the deorbit engine can't fire. The craft is ...
Alex Hajnal's user avatar
  • 1,971
2 votes
0 answers
95 views

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 ...
karthikeyan's user avatar
  • 4,469
2 votes
0 answers
66 views

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 ...
Muze's user avatar
  • 1
2 votes
0 answers
86 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.
ARK's user avatar
  • 21
2 votes
0 answers
107 views

Is there a use case describing the need to perform xenon propellant offloading?

I can understand hydrazine offloading and the hazards associated, but I'm wondering if there is such a need for xenon offloading.
Iridium's user avatar
  • 21
2 votes
0 answers
184 views

Optimal Thruster Layout For Cubesat

I am working on a simulation of a Cubesat for rendezvous. Using the Clohessy-Wiltshire equations I calculate delta-v. Now that I know the thrust needed for operation, I would like to know how to ...
Buzz92's user avatar
  • 21
2 votes
0 answers
287 views

thrusters, force torque, distribution matrix , orbit maneuver

I have a few questions about computing torques and forces. I use the same configuration as in the thesis titled An Attitude Control Sysytem Design Based on the Turksat-1b Geostationary Satellite. ...
khouane boulanouar's user avatar
2 votes
0 answers
52 views

Attitude and orbit thrusters catalog

Typically, when trying to adjust simulation parameters (of orbit control, attitude control...) to real world values in order to validate algorithms with comparisons with past and current mission ...
Julio's user avatar
  • 1,772
2 votes
0 answers
74 views

Switching off the magnetic coils in a Hall Effect Thruster

Talking about Hall Effect Thrusters (HET), we can say that the presence of a hollow cathode is relevant to reach a good operation of the thruster. We also can plot the potential-x (trajectory of ...
Panri93's user avatar
  • 201
2 votes
0 answers
79 views

Preliminary design of Propellant ducts

I'm trying to roughly estimate dimensions and masses of propellant and pressurant ducts for conventional upper- & transfer stages. My basic approach follows Barlow's formula for cylindrical ...
cl10k's user avatar
  • 351
2 votes
0 answers
280 views

What are non-rocket-based reaction mass drives called?

There's plenty of talk out there about a certain type of propulsion system, but I don't know the proper name for it. You gather up / buy / otherwise acquire some kind of non-rocket material, like ...
Joe's user avatar
  • 3,940
1 vote
0 answers
33 views

Thrust Impulse graph for specific engine type

I've seen many graphs for nuclear, chemical and airbreathing engine. However I have not seen a good depiction of electric engines such as xenon ion engines, argon thrusters, lithium, etc. This ...
AnarchoEngineer's user avatar
1 vote
0 answers
101 views

What kind of propulsion did/does the Raytheon EKV vehicle use?

Raytheon has developed an Exoatmospheric Kill Vehicle, designed to intercept an ICBM and destroy it through a collision. Here are some related links: Wikipedia page YouTube video about the project, ...
Steve's user avatar
  • 1,174
1 vote
0 answers
114 views

What are better ways to deliver heat directly to propellant in a Thermal Rocket design for use in launch than UV such as in the Nuclear Lightbulb?

Most advanced, high-power engine concepts that I came across aren’t suited for atmospheric launch, so I got curious about what kinds of engines could launch a very heavy craft from the surface of a ...
PedrohSpaceWolfy's user avatar
1 vote
0 answers
134 views

Is there any major difference between acceleration of solid propelled and liquid propelled rockets during launch

Few days ago, ISRO launched its PSLV-C53, which had solid first stage. (Clip here) Also, the SpaceX's starlink launched on 24th July, 2022, having liquid first stage. (Clip here) Is there any major ...
Priyansu Tank's user avatar
1 vote
0 answers
94 views

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 ...
Akhil Sharma's user avatar
1 vote
0 answers
69 views

Sources for values for realistic thrust calculation exercise?

I want to use this simplified equation to calculate the thrust of multiple different real engines: $$F = \dot{m} V_e + (p_e - p_0) A_e$$ Source: https://www.grc.nasa.gov/www/k-12/airplane/rockth....
JKamue's user avatar
  • 11
1 vote
0 answers
259 views

Technological challenges to sending a high altitude balloon to space and orbit from 50 km?

Below At what altitude would I have to go in a lighter than air balloon to be above all wind and just have the earth rotate underneath me? there is a comment: If you want to be above all winds, you ...
uhoh's user avatar
  • 149k
1 vote
0 answers
98 views

How to send a 6-km mirror close to the Sun to propel a light sail?

I have written a paper about a crewed interstellar spacecraft that I propose. I suggest to use either a laser, a Fresnel lens or a mirror to propel the sail of the spacecraft with sunlight. I have ...
Albert's user avatar
  • 29
1 vote
0 answers
30 views

Injectors Diameter and Numbers

how would you determine the diameter and the number of injectors if unlike doublets elements are used? The Data given is: Isp =286 s Chamber pressure= 25 bars Propellant pair: Fuel= Hydrazine and ...
Adeel Ahsan's user avatar