Questions tagged [exhaust]
Resultant reaction mass, usually a gas or plasma, released from a rocket or thruster, including chemical, cold gass, ion and other types of engines.
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What happens when the exhaust goes mach one
To create thrust and enough lift, you need a lot of mass thrown out at high velocities from a rocket engine. Most of the time this mass (exhaust) reaches over mach 1. I'm just curious whether this ...
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What is the dark brown gas emission seen during the ascent of Starship?
During the video (see below) of Starship IFT-4 there is a lot of brown smoke or gas in the Superheavy exhaust from near the start for almost 30 seconds. Is this NO2? If so roughly how much is produced?...
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How well does a sea-level engine operating in a vacuum perform compared to a vacuum-optimized engine operating in a vacuum?
A sea-level rocket engine generally has a smaller bell than the equivalent model vacuum-optimized engine - and is perhaps a little bit lighter because of that. I assume that there could be other ...
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Is the rocket exhaust plume at liftoff of a liquid fuled rocket cold? Can it condense? [duplicate]
I try to understand what the exhaust cloud on the ground from the start of Starship consists of.
Of course it was unusually mineral-rich, but I try to understand whether we saw much else, apart from ...
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What is the exhaust temperature of a liquid oxygen + liquid hydrogen vacuum engine?
Ideally the exhaust of stochiometric liquid oxygen + liquid hydrogen rocket would be fast moving chunks of ice at zero kelvin. In this way all the potential chemical energy in the fuel/oxidizer is ...
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What color would the exhaust of an antimatter rocket be?
For the purpose of this question assume that the problems associated with antimatter drives have been solved.
Let's say my spaceship is using a Matter-Antimatter rocket that reacts Antihydrogen with ...
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Inconsistencies in calculating exhaust velocity
I'm quite sure this is either a small or just plain stupid mistake but my anxiety is getting the better of me. when calculating exhaust velocity this is the equation used:
however I keep getting ...
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Do engines in the middle of an engine cluster get impulse benefits?
Presumably the rocket engines in the center of an engine cluster would be surrounded by lower-pressure exhaust from the outer engines so essentially the "atmospheric pressure" around the ...
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Why does this sounding rocket have black sooty exhaust with mach-diamond-like oscillations? Is this unusual?
File footage of a sounding rocket with a dark, non-luminescent, sooty exhaust with mach-diamond-like oscillations is shown in the video 1957-1959 IBM 704 Computer - Vanguard Satellite Program "...
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What is this South Korean rocket and why does it have separate yellow and blue exhaust plumes?
The BBC's Watching North Korea from a supersonic fighter jet (screenshot from YouTube) shows the launch of a South Korean rocket.
I notice that it has both a very long, nicely expanded blue exhaust ...
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Why is Ariane-5's upper stage appear to vent exhaust post engine cut off?
I was surprised to see, with unaided eyes, a rocket like object in the skies on Dec 25, 2021 (Indian time) around the same time as JWST launch. My coordinates were approximately ...
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Silane as a rocket fuel
At about 6:55 into the video Why Moon Mining Will DEFINITELY Be A Thing it is stated that lunar silica (SiO2) could be turned into silane (SiH4), which is the silicon analogue of methane. It also ...
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How did the kerosene-burning Black Arrow have transparent exhaust? (seems to just "hover" in photos)
Kerosene + LOX rockets have big, bright exhaust plumes, at least in the atmosphere; second stages are are a different matter: Why is the flame of the Falcon 9's 2nd stage (nearly) invisible?
But ...
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Can kerolox or SRB soot particles grow too large too quickly; not accelerated in expanding exhaust leading to a loss of mass-specific impulse?
In this answer to Is methyl silane CH6Si ever considered as fuel in rocketry? I argue that there's no huge loss in mass-specific impulse (Isp) when producing sand (and by extension soot) in the ...
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ISP losses associated with exhaust vane TVC
What is the impact of exhaust vanes, such as those in the A4 and Redstone rockets, on exhaust velocity and overall ISP? As well as this, what is the relationship between ISP losses and the width of ...
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What were/are the stingiest and most generous vacuum nozzle? (records for the smallest and largest expansion ratios)
Vacuum nozzles are huge compared to their sea-level or atmospheric counterparts, as can be seen by comparing the first stage engines on an Electron or Falcon-9 to their second stages, where a big ...
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Merlin 1-D Vacuum - Side Exhaust Noted in Flight Videos
During the Falcon 9 second stage firing of the Merlin 1D Vac engine, the video shows an exhaust plume ejecting from near the top of the nozzle bell, and canted outward (say 10 degrees) from the bell. ...
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During ascent, can SPACE-X ever be seen from Long Island, NY?
At night I have seen Space Shuttles' engine exhaust from Long Island NY, in the southeast sky 7 minutes after liftoff from the Cape. Does Space-X ever launch in a direction that it can be seen from ...
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Apollo 4 vs Apollo 8 plume
I was recently browsing photos of early Apollo missions and noticed that the plume of the Apollo 4 during launch is significantly bigger than that of Apollo 8. Wondering why is that?
Apollo 4 (top) ...
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Confusion about reactive force of a rocket
I am confused about the equation describing the reactive force of a rocket. I read from this source this equation:
where M is mass of the rocket, u is the velocity of exhaust gas in an inertial frame ...
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What will happen to the rocket exhaust particles fired by spacecrafts?
During the launch, when the rocket is itself yet to attain a stable orbit, the exhaust from the launch vehicle is directed approximately in the opposite direction of its velocity. So, there is no ...
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Why should the velocity through the nozzle throat be sonic?
I have read (even on this site), that exhaust gas velocity is (normally?) sonic (exactly Mach 1) through the choke point of a De Laval, or convergent-divergent, nozzle:
At the "throat", where the ...
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Do liquid propellant rocket engines experience thrust oscillation?
I know SRBs have a quite bit of thrust oscillation, and it's pretty much part and parcel of burning solid propellant. Do liquid-propellant engines experience something similar albeit at a much smaller ...
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What factors determine the altitude at which rocket exhaust plumes start blooming hugely?
The images below are from a much larger set of photos in Spaceflight Now's August 8, 2019 article Photos: Atlas 5 paints the sky with spectacular sunrise launch.
They show several effects related to ...
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What is the velocity distribution of the exhaust for a typical rocket engine?
The exhaust velocity figure of a given engine is an average value. I'm curious to know how the distribution of velocities of the exhaust particles look.
From a qualitative perspective, how does the ...
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Is it possible to create different colors in rocket exhaust?
Would it be feasible in any rocket engine (liquid or solid) intended for flight above the atmosphere to add one of the following elements: barium, lithium, sodium, copper, or calcium to create ...
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Why does the Electron rocket throw sparks; especially at SECO?
The RocketLab YouTube video STP-27RD Launch - 05/05/2019 shows the exhaust plume from the second stage engine evolve as the atmospheric pressure drops. During this time there are frequent outbursts of ...
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Are these two length scales in FH exhaust plumes real, understood, and distinct?
The Ars Technica article We can admit it—we’re dazzled by the controlled fury of the Falcon Heavy includes a beautiful photo of the exhaust plume produced by the 27 engines of a Falcon Heavy launch.
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What propulsion system would not pollute the surface when landing on a pristine celestial body?
A robotic lander on a science mission, especially to an airless body, would like to avoid disturbing the surface it is landing on with rocket exhausts. MSL Curiosity used a Sky Crane to somewhat ...
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Why does the PSLV first stage's exhaust plume turn to bluish at high altitude?
After few seconds, post liftoff(anywhere between 60s and 90s), the exhaust plume of PSLV turns into a bluish colour. This is quite evident in night launches than day launches(obviously because the ...
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Why does the exhaust plume apprear to be throbbing?
Here is a cropped video of the space shuttle exhaust. There appears to be some throbbing/oscillatory behaviour to the exhaust plume.
It is often visible along with an intensity changes/fluctuation ...
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What causes these plume features on Delta IV Heavy?
Just catching up on the Jan 19th launch of NROL-71 on board the Delta IV Heavy and I noticed these very prominent features in the exhaust plumes, beginning around the time the centre core is throttled ...
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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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How does the camera make the exhaust of the Electron's RP-1/LOX exhaust transparent?
In this 20-Nov-2018 Tweet from Rocket Labs XXX Peter Beck there is an image of the nine Rutherford engines of an Electron rocket burning. What is unusual is that the exhaust is luminescent but at the ...
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What flame is SpaceX's Hans Koenigsmann describing in his presentation?
At 35:46 in part 1 of this recording of SpaceX's Hans Koenigsmann's talk at IAC 2018, he says something like:
The green stuff that you see is TEA-TEB, that’s the ...
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Temperature and pressure of rocket exhaust
What is the temperature and pressure of the exhaust that comes out of the rocket during the last three seconds of countdown (smoke that stays near ground)?
How much carbon dioxide is there in that ...
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How do rockets "blow" smoke rings? Did "smashing through Max-Q" really do this?
The Teslarati article SpaceX delivers largest commercial satellite in kick off of Falcon 9 marathon includes several beautiful photos, of the Telstar 19V launch, including the one below.
It shows ...
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Is the unusual pattern/shape of SpaceX exhaust due to atmospheric pressure?
This morning's launch of an ISS resupply mission by SpaceX happened in a beautifully clear sky just before dawn. As hoped, the not-yet-risen sun illuminated the entire flight path from just after ...
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Is spacecraft propulsion observable in space? [duplicate]
There are questions on this site about minimal sound in space. But I was very surprised by Russell Borogove's answer to "Why did the Saturn V stage faring appear to burn after separation?" that "...
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What makes exhaust from aluminum-based SRB propellant so bright?
The brightness and color of the extremely bright light produced by the Space Shuttle SRB's is discussed in this answer and in comments below it, though the main subject there is the dim blue light ...
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Why does Merlin 1D Vac turbopump drive exhaust go around the nozzle?
In Merlin 1D Vac engine:
the turbopump drive exhaust goes around the nozzle. Why is that so?
The feature also seems to be missing in the first stage engine, as seen here:
(screenshot taken from ...
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Do spacecraft ever release unneeded gases into space?
My child is learning about the human body and frequently wants to know whether his favorite things work the same way. He asked me if spaceships fart (we've talked about Firetrucks and tailpipes, to ...
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Does "What happens beyond Kármán, stay beyond Kármán"?
The title refers to the promotional slogan "What happens in Vegas, stays in Vegas."
The question How much CO2 would city-to-city rocket flight produce compared to airliners? seems to be focused on ...
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Why are exhaust flames "jumping around" the bases of the Falcon-9 engine nozzles; NROL-76? [duplicate]
I see something interesting the webcast of the NROL-76 launch. At around T+00:00:55 it looks like flames from the exhaust start jumping around the bases of the ring ...
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Does velocity of the exit gasses of a rocket affect visibility of the plume?
A rocket moves under the conservation of linear momentum, where the gases formed inside it, exit through the nozzle, and in turn, the rocket moves forward. What I want to ask about is that: is it true ...
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Orbital ATK’s Cygnus 2nd stage exhaust plume
In watching this video:
of the recent Orbital ATK’s Cygnus launch, I noticed that when the 2nd stage engine fires (after the ullage engine finishes firing), that there ...
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Why does the shock wave in this new 2017 RS-25 test also have a "bump" on one side? [duplicate]
In last year's question Why does the luminous blue shockwave from the RS-25 engine appear to be rectangular? I showed images of an RS-25 engine test from 2015, and what I believe to be a test of the ...
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Were the Space Shuttle's Main Engines ever off while the Solid Rocket Boosters were firing?
I always though the Space Shuttle needed a combination of its solid rocket boosters and its main engines to remain stable while launching. The following diagram found on Wikipedia seems to agree: ...
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What is this yellow light on the side of the 2nd stage nozzle - Shenzhou-11 launch
According to Wikipedia the single engine on the 2nd stage is a YF-20 series engine.
What is causing the faint yellow light on the side of the nozzle where there is a tube wrapped around it?
above: ...
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What is the 'Summerfield criterion' regarding rocket exhaust expansion
In this answer to Why do the shapes of these two exhaust plumes from an Atlas V 411 look different? the 'Summerfield criterion' is mentioned, saying:
Historically, the Summerfield criterion was used, ...
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