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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 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?

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 question the 'Summerfield criterion' is mentioned. Saying that 'Historically, the Summerfield criterion was used, where the minimum pressure in a nozzle must be greater than 0.35...0.4*...
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Why do the shapes of these two exhaust plumes from an Atlas V 411 look different?

The Atlas V 411 configuration is interesting because there is a single SRB on one side of the first stage, requiring the main engines to vector substantially to keep the thrust mostly axial. The ...
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Max Q vs Prandtl-Meyer Fan

Does Max Q occur before or after the Prandtl–Meyer expansion fan? The shape, nature's way of avoiding a single shock wave (per Wikipedia) is visible on the Apollo launches for example. Apollo 11, ...
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Why are rocket launches so loud?

In reading an answer here: How close can I get to a rocket launch and not get killed?, the comment is made that noise from the launch can be tremendous. This isn't a big surprise to anyone who's ...
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Does the luminous blue shockwave from the RS-25 engine appear to be rectangular?

Here is a photo of a test firing of the Space Shuttle main RS-25 engine from 1981 from here: The top of the blue luminous area (a static shock wave?) looks like it has a corner. Here is a screen ...
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What is the cause of the blue light from LH2/LOX rocket engines?

Below are some screen shots from circa June 2016 launch (or re-launch) videos by Blue Origin (video link) and SpaceX (video link). The New Shepard burns $\text{H}_2$/$\text{O}_2$, while the Falcon 9 ...
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What is the electromagnetic spectrum profile of rocket flame/exhaust?

...from common observation, I can easily conclude there is a lot of infrared (from burning, superheated fuel), ending somewhere near yellow of visible spectrum; there should be next to none of UV and ...
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Why were the Titan II's Flames Clear?

I've seen multiple sources attribute the clear flames to the use of hypergolic fuels for propulsion, but I have been unable to find any explanation for why hypergolic fuels burn clearly. (Image ...
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Strongbacks vs Launch towers: Difference and definition?

What's the difference between a launch tower and a strongback?
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Do strongbacks/launch towers have to be repainted or refurbished after a launch?

Videos of rocket launches often show exhaust flames engulfing at least the upper parts of a launch tower or strongback. Do these towers need to be reconstructed or at least repainted after a launch? ...
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What does the exhaust plume of a rocket look like in vacuum?

There are plenty of photos of rocket tests and launches in atmosphere, and in these the exhaust plume tends to be a long thin flame. Is this true for when rocket engines operate in a vacuum? My guess ...
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In space, how far from the nozzle is the exhaust from a space-craft capable of causing damage?

I suspect the question may be a trifle subjective; dependent upon the nature of the propulsion system, the energy levels, as also the nature of the object impinged The exhaust from a space-craft is ...
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Are rocket exhaust flames ever opaque?

The flame exiting the space shuttle main engine is obviously transparent. But, you can't see objects through either the Saturn V booster flame or that of the space shuttle solid rocket boosters. Is it ...
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Why are the exhaust plumes exiting the nozzles of SpaceShip Two segmented along their length?

Here is a photo of SpaceShip 2's exhaust shortly after ignition during the test flight in January Why do they have that segmented structure, and how does it affect thrust?