Why did Starhopper's exhaust plume become brighter just before landing?Is it possible to create different colors in rocket exhaust?What is it that SpaceX is editing out of their videos after posting them on YouTube?What is the cause of the blue light from LH2/LOX rocket engines?Why did it take so long for methane to be used as a rocket propellant?Why hasn't Dragon been reused before CRS-11?How effective are Falcon 9 1st stage grid fins in the last few seconds before landing?Why does the SpaceX first stage booster boost up and back after separation not just back?Do the SpaceX ASDS orient themselves in a particular direction before a landing? Is there a “landing ellipse”?SpaceX and propulsive landing on Mars — what just happened? (and why?)Why does Merlin 1D Vac turbopump drive exhaust go around the nozzle?Why does the Superdraco exhaust seem so under-expanded in this photo?
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Why did Starhopper's exhaust plume become brighter just before landing?
Is it possible to create different colors in rocket exhaust?What is it that SpaceX is editing out of their videos after posting them on YouTube?What is the cause of the blue light from LH2/LOX rocket engines?Why did it take so long for methane to be used as a rocket propellant?Why hasn't Dragon been reused before CRS-11?How effective are Falcon 9 1st stage grid fins in the last few seconds before landing?Why does the SpaceX first stage booster boost up and back after separation not just back?Do the SpaceX ASDS orient themselves in a particular direction before a landing? Is there a “landing ellipse”?SpaceX and propulsive landing on Mars — what just happened? (and why?)Why does Merlin 1D Vac turbopump drive exhaust go around the nozzle?Why does the Superdraco exhaust seem so under-expanded in this photo?
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$begingroup$
In 2019 Aug 27's test flight, during the final 8 seconds before landing (T+00:45), Starhopper's plume was suddenly much brighter. Why?
The Raptor's thrust can't have changed much then, because Starhopper's speed and trajectory hardly changed. A different fuel mix? (Again, why bother?)
The glow starts about when the visible plume touches the landing pad, which had already started to glow. But how could that touch affect the appearance of the plume itself? Burning concrete dust (or whatever) can't propagate up towards the engine.
spacex raptor
asked 8 hours ago
Camille GoudeseuneCamille Goudeseune
1,2017 silver badges20 bronze badges
$endgroup$
add a comment |
$begingroup$
In 2019 Aug 27's test flight, during the final 8 seconds before landing (T+00:45), Starhopper's plume was suddenly much brighter. Why?
The Raptor's thrust can't have changed much then, because Starhopper's speed and trajectory hardly changed. A different fuel mix? (Again, why bother?)
The glow starts about when the visible plume touches the landing pad, which had already started to glow. But how could that touch affect the appearance of the plume itself? Burning concrete dust (or whatever) can't propagate up towards the engine.
spacex raptor
asked 8 hours ago
Camille GoudeseuneCamille Goudeseune
1,2017 silver badges20 bronze badges
$endgroup$
$begingroup$
Burning metal from inside the engine?
$endgroup$
– Organic Marble
7 hours ago
1
$begingroup$
Interesting question! Just fyi SpaceX edits their YouTube videos after some period of time to remove segments with no activity, so it's always good to include a time from the launch clock as well. I've edited the time in your clip so that the video plays properly now that they've dramatically shortened it.
$endgroup$
– uhoh
7 hours ago
add a comment |
$begingroup$
In 2019 Aug 27's test flight, during the final 8 seconds before landing (T+00:45), Starhopper's plume was suddenly much brighter. Why?
The Raptor's thrust can't have changed much then, because Starhopper's speed and trajectory hardly changed. A different fuel mix? (Again, why bother?)
The glow starts about when the visible plume touches the landing pad, which had already started to glow. But how could that touch affect the appearance of the plume itself? Burning concrete dust (or whatever) can't propagate up towards the engine.
spacex raptor
asked 8 hours ago
Camille GoudeseuneCamille Goudeseune
1,2017 silver badges20 bronze badges
$endgroup$
In 2019 Aug 27's test flight, during the final 8 seconds before landing (T+00:45), Starhopper's plume was suddenly much brighter. Why?
The Raptor's thrust can't have changed much then, because Starhopper's speed and trajectory hardly changed. A different fuel mix? (Again, why bother?)
The glow starts about when the visible plume touches the landing pad, which had already started to glow. But how could that touch affect the appearance of the plume itself? Burning concrete dust (or whatever) can't propagate up towards the engine.
spacex raptor
spacex raptor
asked 8 hours ago
Camille GoudeseuneCamille Goudeseune
1,2017 silver badges20 bronze badges
asked 8 hours ago
Camille GoudeseuneCamille Goudeseune
1,2017 silver badges20 bronze badges
edited 5 hours ago
Camille Goudeseune
asked 8 hours ago
Camille GoudeseuneCamille Goudeseune
1,2017 silver badges20 bronze badges
asked 8 hours ago
Camille GoudeseuneCamille Goudeseune
1,2017 silver badges20 bronze badges
asked 8 hours ago
Camille GoudeseuneCamille Goudeseune
1,2017 silver badges20 bronze badges
1,2017 silver badges20 bronze badges
$begingroup$
Burning metal from inside the engine?
$endgroup$
– Organic Marble
7 hours ago
1
$begingroup$
Interesting question! Just fyi SpaceX edits their YouTube videos after some period of time to remove segments with no activity, so it's always good to include a time from the launch clock as well. I've edited the time in your clip so that the video plays properly now that they've dramatically shortened it.
$endgroup$
– uhoh
7 hours ago
add a comment |
$begingroup$
Burning metal from inside the engine?
$endgroup$
– Organic Marble
7 hours ago
1
$begingroup$
Interesting question! Just fyi SpaceX edits their YouTube videos after some period of time to remove segments with no activity, so it's always good to include a time from the launch clock as well. I've edited the time in your clip so that the video plays properly now that they've dramatically shortened it.
$endgroup$
– uhoh
7 hours ago
$begingroup$
Burning metal from inside the engine?
$endgroup$
– Organic Marble
7 hours ago
$begingroup$
Burning metal from inside the engine?
$endgroup$
– Organic Marble
7 hours ago
1
1
$begingroup$
Interesting question! Just fyi SpaceX edits their YouTube videos after some period of time to remove segments with no activity, so it's always good to include a time from the launch clock as well. I've edited the time in your clip so that the video plays properly now that they've dramatically shortened it.
$endgroup$
– uhoh
7 hours ago
$begingroup$
Interesting question! Just fyi SpaceX edits their YouTube videos after some period of time to remove segments with no activity, so it's always good to include a time from the launch clock as well. I've edited the time in your clip so that the video plays properly now that they've dramatically shortened it.
$endgroup$
– uhoh
7 hours ago
add a comment |
2 Answers
2
active
oldest
votes
$begingroup$
Indeed it is due to contaminants — dust! — in the plume.
Did you notice all the dust being kicked up around the landing site? Some of that dust cloud, a very small and low-dust-density part of it (so it's really hard to see), flows upward, then back toward the rocket, and then is entrained in the rocket's exhaust plume. It's just like the toroidal flow around a helicopter hovering near the ground.
The nice, clean blue plume from the Raptor engine results from efficient burning, not producing a lot of hydrocarbons in the exhaust. The reaction is essentially complete when the exhaust exits the nozzle, so you get the blue of the relaxation emission from excited-state water, and the invisible IR emissions from CO2. When dust is entrained in the plume you get a wide range of chemical species — hydrocarbons, silicates, all the stuff in Texas dirt! — reacting in the plume, and they emit light all over the visible spectrum. Hence the change in color, and conversion of more of the plume's energy to visible light, so the plume brightens.
edited 5 hours ago
Camille Goudeseune
1,2017 silver badges20 bronze badges
answered 7 hours ago
Tom SpilkerTom Spilker
12.1k32 silver badges59 bronze badges
$endgroup$
2
$begingroup$
Sounds plausible, but do you have a reference?
$endgroup$
– Russell Borogove
7 hours ago
$begingroup$
@RussellBorogove, No, this is based on knowledge gleaned from working with folks who did past robotic Mars landings: the behavior of plumes and the airflow around them during landings.
$endgroup$
– Tom Spilker
7 hours ago
1
$begingroup$
So that's why the plume isn't bright on launch also. Then, the vehicle's ascent needs more thrust, so the toroidal vortex is spreading out too fast to reconnect with the plume.
$endgroup$
– Camille Goudeseune
5 hours ago
add a comment |
$begingroup$
The bright yellow light from RP-1 burning engines is from carbon soot built up from already-complex carbon molecules in kerosene. However the single-carbon methane molecules quickly oxidize to CO2 and H2O and are not conducive to soot growth. When we cook using natural gas (methane) we rarely see soot produced, and so the flame is blue mostly due to diatomic molecular carbon C2 (see the vibronic spectrum in this answer and this answer) and possibly excited water as @TomSpilker mentions and as discussed in What is the cause of the blue light from LH2/LOX rocket engines?.
I like his explanation that the bright yellow light is from dust being entrained in the plume, but I don't think the light is chemical in nature.
Instead, it's probably blackbody thermal radiation from the dust (bits of rock) either solid or melted, that's instantly heated to the exhaust's temperature. The exhaust gas can not efficiently radiate because it's not a blackbody, but the moment the particles enter the plume they can readily glow.
That's why its so bright and so uniform in the same rocket-exhaust yellow color we see from soot-producing LOX/RP-1 plumes.
answered 7 hours ago
uhohuhoh
50.8k23 gold badges201 silver badges657 bronze badges
$endgroup$
$begingroup$
I agree, it's not all from chemical reactions, a good fraction of it is indeed blackbody radiation. It's a mix: there's a fair portion of biologically-produced species in the Texas soil, and at those temperatures they react like crazy, yielding some species with discrete emission spectra, and some (like soot) that also radiate via blackbody radiation.
$endgroup$
– Tom Spilker
7 hours ago
2
$begingroup$
@RussellBorogove oh no, I've accidentally revealed my newly-invented LOX/LCO engine to the world!
$endgroup$
– uhoh
6 hours ago
$begingroup$
Wait'll you see my newly-invented monopropellant monatomic-hydrogen engine! I just have to figure out how to stabilize the propellant... ;-)
$endgroup$
– Tom Spilker
6 hours ago
1
$begingroup$
If only one could accept two answers! Yes, soot blackbody radiation explains the color, but Tom explained why the plume gets brighter at all.
$endgroup$
– Camille Goudeseune
5 hours ago
add a comment |
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2 Answers
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active
oldest
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2 Answers
2
active
oldest
votes
active
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votes
active
oldest
votes
$begingroup$
Indeed it is due to contaminants — dust! — in the plume.
Did you notice all the dust being kicked up around the landing site? Some of that dust cloud, a very small and low-dust-density part of it (so it's really hard to see), flows upward, then back toward the rocket, and then is entrained in the rocket's exhaust plume. It's just like the toroidal flow around a helicopter hovering near the ground.
The nice, clean blue plume from the Raptor engine results from efficient burning, not producing a lot of hydrocarbons in the exhaust. The reaction is essentially complete when the exhaust exits the nozzle, so you get the blue of the relaxation emission from excited-state water, and the invisible IR emissions from CO2. When dust is entrained in the plume you get a wide range of chemical species — hydrocarbons, silicates, all the stuff in Texas dirt! — reacting in the plume, and they emit light all over the visible spectrum. Hence the change in color, and conversion of more of the plume's energy to visible light, so the plume brightens.
edited 5 hours ago
Camille Goudeseune
1,2017 silver badges20 bronze badges
answered 7 hours ago
Tom SpilkerTom Spilker
12.1k32 silver badges59 bronze badges
$endgroup$
2
$begingroup$
Sounds plausible, but do you have a reference?
$endgroup$
– Russell Borogove
7 hours ago
$begingroup$
@RussellBorogove, No, this is based on knowledge gleaned from working with folks who did past robotic Mars landings: the behavior of plumes and the airflow around them during landings.
$endgroup$
– Tom Spilker
7 hours ago
1
$begingroup$
So that's why the plume isn't bright on launch also. Then, the vehicle's ascent needs more thrust, so the toroidal vortex is spreading out too fast to reconnect with the plume.
$endgroup$
– Camille Goudeseune
5 hours ago
add a comment |
$begingroup$
Indeed it is due to contaminants — dust! — in the plume.
Did you notice all the dust being kicked up around the landing site? Some of that dust cloud, a very small and low-dust-density part of it (so it's really hard to see), flows upward, then back toward the rocket, and then is entrained in the rocket's exhaust plume. It's just like the toroidal flow around a helicopter hovering near the ground.
The nice, clean blue plume from the Raptor engine results from efficient burning, not producing a lot of hydrocarbons in the exhaust. The reaction is essentially complete when the exhaust exits the nozzle, so you get the blue of the relaxation emission from excited-state water, and the invisible IR emissions from CO2. When dust is entrained in the plume you get a wide range of chemical species — hydrocarbons, silicates, all the stuff in Texas dirt! — reacting in the plume, and they emit light all over the visible spectrum. Hence the change in color, and conversion of more of the plume's energy to visible light, so the plume brightens.
edited 5 hours ago
Camille Goudeseune
1,2017 silver badges20 bronze badges
answered 7 hours ago
Tom SpilkerTom Spilker
12.1k32 silver badges59 bronze badges
$endgroup$
2
$begingroup$
Sounds plausible, but do you have a reference?
$endgroup$
– Russell Borogove
7 hours ago
$begingroup$
@RussellBorogove, No, this is based on knowledge gleaned from working with folks who did past robotic Mars landings: the behavior of plumes and the airflow around them during landings.
$endgroup$
– Tom Spilker
7 hours ago
1
$begingroup$
So that's why the plume isn't bright on launch also. Then, the vehicle's ascent needs more thrust, so the toroidal vortex is spreading out too fast to reconnect with the plume.
$endgroup$
– Camille Goudeseune
5 hours ago
add a comment |
$begingroup$
Indeed it is due to contaminants — dust! — in the plume.
Did you notice all the dust being kicked up around the landing site? Some of that dust cloud, a very small and low-dust-density part of it (so it's really hard to see), flows upward, then back toward the rocket, and then is entrained in the rocket's exhaust plume. It's just like the toroidal flow around a helicopter hovering near the ground.
The nice, clean blue plume from the Raptor engine results from efficient burning, not producing a lot of hydrocarbons in the exhaust. The reaction is essentially complete when the exhaust exits the nozzle, so you get the blue of the relaxation emission from excited-state water, and the invisible IR emissions from CO2. When dust is entrained in the plume you get a wide range of chemical species — hydrocarbons, silicates, all the stuff in Texas dirt! — reacting in the plume, and they emit light all over the visible spectrum. Hence the change in color, and conversion of more of the plume's energy to visible light, so the plume brightens.
edited 5 hours ago
Camille Goudeseune
1,2017 silver badges20 bronze badges
answered 7 hours ago
Tom SpilkerTom Spilker
12.1k32 silver badges59 bronze badges
$endgroup$
Indeed it is due to contaminants — dust! — in the plume.
Did you notice all the dust being kicked up around the landing site? Some of that dust cloud, a very small and low-dust-density part of it (so it's really hard to see), flows upward, then back toward the rocket, and then is entrained in the rocket's exhaust plume. It's just like the toroidal flow around a helicopter hovering near the ground.
The nice, clean blue plume from the Raptor engine results from efficient burning, not producing a lot of hydrocarbons in the exhaust. The reaction is essentially complete when the exhaust exits the nozzle, so you get the blue of the relaxation emission from excited-state water, and the invisible IR emissions from CO2. When dust is entrained in the plume you get a wide range of chemical species — hydrocarbons, silicates, all the stuff in Texas dirt! — reacting in the plume, and they emit light all over the visible spectrum. Hence the change in color, and conversion of more of the plume's energy to visible light, so the plume brightens.
edited 5 hours ago
Camille Goudeseune
1,2017 silver badges20 bronze badges
answered 7 hours ago
Tom SpilkerTom Spilker
12.1k32 silver badges59 bronze badges
edited 5 hours ago
Camille Goudeseune
1,2017 silver badges20 bronze badges
edited 5 hours ago
Camille Goudeseune
1,2017 silver badges20 bronze badges
edited 5 hours ago
Camille Goudeseune
1,2017 silver badges20 bronze badges
1,2017 silver badges20 bronze badges
answered 7 hours ago
Tom SpilkerTom Spilker
12.1k32 silver badges59 bronze badges
answered 7 hours ago
Tom SpilkerTom Spilker
12.1k32 silver badges59 bronze badges
answered 7 hours ago
Tom SpilkerTom Spilker
12.1k32 silver badges59 bronze badges
12.1k32 silver badges59 bronze badges
2
$begingroup$
Sounds plausible, but do you have a reference?
$endgroup$
– Russell Borogove
7 hours ago
$begingroup$
@RussellBorogove, No, this is based on knowledge gleaned from working with folks who did past robotic Mars landings: the behavior of plumes and the airflow around them during landings.
$endgroup$
– Tom Spilker
7 hours ago
1
$begingroup$
So that's why the plume isn't bright on launch also. Then, the vehicle's ascent needs more thrust, so the toroidal vortex is spreading out too fast to reconnect with the plume.
$endgroup$
– Camille Goudeseune
5 hours ago
add a comment |
2
$begingroup$
Sounds plausible, but do you have a reference?
$endgroup$
– Russell Borogove
7 hours ago
$begingroup$
@RussellBorogove, No, this is based on knowledge gleaned from working with folks who did past robotic Mars landings: the behavior of plumes and the airflow around them during landings.
$endgroup$
– Tom Spilker
7 hours ago
1
$begingroup$
So that's why the plume isn't bright on launch also. Then, the vehicle's ascent needs more thrust, so the toroidal vortex is spreading out too fast to reconnect with the plume.
$endgroup$
– Camille Goudeseune
5 hours ago
2
2
$begingroup$
Sounds plausible, but do you have a reference?
$endgroup$
– Russell Borogove
7 hours ago
$begingroup$
Sounds plausible, but do you have a reference?
$endgroup$
– Russell Borogove
7 hours ago
$begingroup$
@RussellBorogove, No, this is based on knowledge gleaned from working with folks who did past robotic Mars landings: the behavior of plumes and the airflow around them during landings.
$endgroup$
– Tom Spilker
7 hours ago
$begingroup$
@RussellBorogove, No, this is based on knowledge gleaned from working with folks who did past robotic Mars landings: the behavior of plumes and the airflow around them during landings.
$endgroup$
– Tom Spilker
7 hours ago
1
1
$begingroup$
So that's why the plume isn't bright on launch also. Then, the vehicle's ascent needs more thrust, so the toroidal vortex is spreading out too fast to reconnect with the plume.
$endgroup$
– Camille Goudeseune
5 hours ago
$begingroup$
So that's why the plume isn't bright on launch also. Then, the vehicle's ascent needs more thrust, so the toroidal vortex is spreading out too fast to reconnect with the plume.
$endgroup$
– Camille Goudeseune
5 hours ago
add a comment |
$begingroup$
The bright yellow light from RP-1 burning engines is from carbon soot built up from already-complex carbon molecules in kerosene. However the single-carbon methane molecules quickly oxidize to CO2 and H2O and are not conducive to soot growth. When we cook using natural gas (methane) we rarely see soot produced, and so the flame is blue mostly due to diatomic molecular carbon C2 (see the vibronic spectrum in this answer and this answer) and possibly excited water as @TomSpilker mentions and as discussed in What is the cause of the blue light from LH2/LOX rocket engines?.
I like his explanation that the bright yellow light is from dust being entrained in the plume, but I don't think the light is chemical in nature.
Instead, it's probably blackbody thermal radiation from the dust (bits of rock) either solid or melted, that's instantly heated to the exhaust's temperature. The exhaust gas can not efficiently radiate because it's not a blackbody, but the moment the particles enter the plume they can readily glow.
That's why its so bright and so uniform in the same rocket-exhaust yellow color we see from soot-producing LOX/RP-1 plumes.
answered 7 hours ago
uhohuhoh
50.8k23 gold badges201 silver badges657 bronze badges
$endgroup$
$begingroup$
I agree, it's not all from chemical reactions, a good fraction of it is indeed blackbody radiation. It's a mix: there's a fair portion of biologically-produced species in the Texas soil, and at those temperatures they react like crazy, yielding some species with discrete emission spectra, and some (like soot) that also radiate via blackbody radiation.
$endgroup$
– Tom Spilker
7 hours ago
2
$begingroup$
@RussellBorogove oh no, I've accidentally revealed my newly-invented LOX/LCO engine to the world!
$endgroup$
– uhoh
6 hours ago
$begingroup$
Wait'll you see my newly-invented monopropellant monatomic-hydrogen engine! I just have to figure out how to stabilize the propellant... ;-)
$endgroup$
– Tom Spilker
6 hours ago
1
$begingroup$
If only one could accept two answers! Yes, soot blackbody radiation explains the color, but Tom explained why the plume gets brighter at all.
$endgroup$
– Camille Goudeseune
5 hours ago
add a comment |
$begingroup$
The bright yellow light from RP-1 burning engines is from carbon soot built up from already-complex carbon molecules in kerosene. However the single-carbon methane molecules quickly oxidize to CO2 and H2O and are not conducive to soot growth. When we cook using natural gas (methane) we rarely see soot produced, and so the flame is blue mostly due to diatomic molecular carbon C2 (see the vibronic spectrum in this answer and this answer) and possibly excited water as @TomSpilker mentions and as discussed in What is the cause of the blue light from LH2/LOX rocket engines?.
I like his explanation that the bright yellow light is from dust being entrained in the plume, but I don't think the light is chemical in nature.
Instead, it's probably blackbody thermal radiation from the dust (bits of rock) either solid or melted, that's instantly heated to the exhaust's temperature. The exhaust gas can not efficiently radiate because it's not a blackbody, but the moment the particles enter the plume they can readily glow.
That's why its so bright and so uniform in the same rocket-exhaust yellow color we see from soot-producing LOX/RP-1 plumes.
answered 7 hours ago
uhohuhoh
50.8k23 gold badges201 silver badges657 bronze badges
$endgroup$
$begingroup$
I agree, it's not all from chemical reactions, a good fraction of it is indeed blackbody radiation. It's a mix: there's a fair portion of biologically-produced species in the Texas soil, and at those temperatures they react like crazy, yielding some species with discrete emission spectra, and some (like soot) that also radiate via blackbody radiation.
$endgroup$
– Tom Spilker
7 hours ago
2
$begingroup$
@RussellBorogove oh no, I've accidentally revealed my newly-invented LOX/LCO engine to the world!
$endgroup$
– uhoh
6 hours ago
$begingroup$
Wait'll you see my newly-invented monopropellant monatomic-hydrogen engine! I just have to figure out how to stabilize the propellant... ;-)
$endgroup$
– Tom Spilker
6 hours ago
1
$begingroup$
If only one could accept two answers! Yes, soot blackbody radiation explains the color, but Tom explained why the plume gets brighter at all.
$endgroup$
– Camille Goudeseune
5 hours ago
add a comment |
$begingroup$
The bright yellow light from RP-1 burning engines is from carbon soot built up from already-complex carbon molecules in kerosene. However the single-carbon methane molecules quickly oxidize to CO2 and H2O and are not conducive to soot growth. When we cook using natural gas (methane) we rarely see soot produced, and so the flame is blue mostly due to diatomic molecular carbon C2 (see the vibronic spectrum in this answer and this answer) and possibly excited water as @TomSpilker mentions and as discussed in What is the cause of the blue light from LH2/LOX rocket engines?.
I like his explanation that the bright yellow light is from dust being entrained in the plume, but I don't think the light is chemical in nature.
Instead, it's probably blackbody thermal radiation from the dust (bits of rock) either solid or melted, that's instantly heated to the exhaust's temperature. The exhaust gas can not efficiently radiate because it's not a blackbody, but the moment the particles enter the plume they can readily glow.
That's why its so bright and so uniform in the same rocket-exhaust yellow color we see from soot-producing LOX/RP-1 plumes.
answered 7 hours ago
uhohuhoh
50.8k23 gold badges201 silver badges657 bronze badges
$endgroup$
The bright yellow light from RP-1 burning engines is from carbon soot built up from already-complex carbon molecules in kerosene. However the single-carbon methane molecules quickly oxidize to CO2 and H2O and are not conducive to soot growth. When we cook using natural gas (methane) we rarely see soot produced, and so the flame is blue mostly due to diatomic molecular carbon C2 (see the vibronic spectrum in this answer and this answer) and possibly excited water as @TomSpilker mentions and as discussed in What is the cause of the blue light from LH2/LOX rocket engines?.
I like his explanation that the bright yellow light is from dust being entrained in the plume, but I don't think the light is chemical in nature.
Instead, it's probably blackbody thermal radiation from the dust (bits of rock) either solid or melted, that's instantly heated to the exhaust's temperature. The exhaust gas can not efficiently radiate because it's not a blackbody, but the moment the particles enter the plume they can readily glow.
That's why its so bright and so uniform in the same rocket-exhaust yellow color we see from soot-producing LOX/RP-1 plumes.
answered 7 hours ago
uhohuhoh
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edited 7 hours ago
answered 7 hours ago
uhohuhoh
50.8k23 gold badges201 silver badges657 bronze badges
answered 7 hours ago
uhohuhoh
50.8k23 gold badges201 silver badges657 bronze badges
answered 7 hours ago
uhohuhoh
50.8k23 gold badges201 silver badges657 bronze badges
50.8k23 gold badges201 silver badges657 bronze badges
$begingroup$
I agree, it's not all from chemical reactions, a good fraction of it is indeed blackbody radiation. It's a mix: there's a fair portion of biologically-produced species in the Texas soil, and at those temperatures they react like crazy, yielding some species with discrete emission spectra, and some (like soot) that also radiate via blackbody radiation.
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– Tom Spilker
7 hours ago
2
$begingroup$
@RussellBorogove oh no, I've accidentally revealed my newly-invented LOX/LCO engine to the world!
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– uhoh
6 hours ago
$begingroup$
Wait'll you see my newly-invented monopropellant monatomic-hydrogen engine! I just have to figure out how to stabilize the propellant... ;-)
$endgroup$
– Tom Spilker
6 hours ago
1
$begingroup$
If only one could accept two answers! Yes, soot blackbody radiation explains the color, but Tom explained why the plume gets brighter at all.
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– Camille Goudeseune
5 hours ago
add a comment |
$begingroup$
I agree, it's not all from chemical reactions, a good fraction of it is indeed blackbody radiation. It's a mix: there's a fair portion of biologically-produced species in the Texas soil, and at those temperatures they react like crazy, yielding some species with discrete emission spectra, and some (like soot) that also radiate via blackbody radiation.
$endgroup$
– Tom Spilker
7 hours ago
2
$begingroup$
@RussellBorogove oh no, I've accidentally revealed my newly-invented LOX/LCO engine to the world!
$endgroup$
– uhoh
6 hours ago
$begingroup$
Wait'll you see my newly-invented monopropellant monatomic-hydrogen engine! I just have to figure out how to stabilize the propellant... ;-)
$endgroup$
– Tom Spilker
6 hours ago
1
$begingroup$
If only one could accept two answers! Yes, soot blackbody radiation explains the color, but Tom explained why the plume gets brighter at all.
$endgroup$
– Camille Goudeseune
5 hours ago
$begingroup$
I agree, it's not all from chemical reactions, a good fraction of it is indeed blackbody radiation. It's a mix: there's a fair portion of biologically-produced species in the Texas soil, and at those temperatures they react like crazy, yielding some species with discrete emission spectra, and some (like soot) that also radiate via blackbody radiation.
$endgroup$
– Tom Spilker
7 hours ago
$begingroup$
I agree, it's not all from chemical reactions, a good fraction of it is indeed blackbody radiation. It's a mix: there's a fair portion of biologically-produced species in the Texas soil, and at those temperatures they react like crazy, yielding some species with discrete emission spectra, and some (like soot) that also radiate via blackbody radiation.
$endgroup$
– Tom Spilker
7 hours ago
2
2
$begingroup$
@RussellBorogove oh no, I've accidentally revealed my newly-invented LOX/LCO engine to the world!
$endgroup$
– uhoh
6 hours ago
$begingroup$
@RussellBorogove oh no, I've accidentally revealed my newly-invented LOX/LCO engine to the world!
$endgroup$
– uhoh
6 hours ago
$begingroup$
Wait'll you see my newly-invented monopropellant monatomic-hydrogen engine! I just have to figure out how to stabilize the propellant... ;-)
$endgroup$
– Tom Spilker
6 hours ago
$begingroup$
Wait'll you see my newly-invented monopropellant monatomic-hydrogen engine! I just have to figure out how to stabilize the propellant... ;-)
$endgroup$
– Tom Spilker
6 hours ago
1
1
$begingroup$
If only one could accept two answers! Yes, soot blackbody radiation explains the color, but Tom explained why the plume gets brighter at all.
$endgroup$
– Camille Goudeseune
5 hours ago
$begingroup$
If only one could accept two answers! Yes, soot blackbody radiation explains the color, but Tom explained why the plume gets brighter at all.
$endgroup$
– Camille Goudeseune
5 hours ago
add a comment |
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$begingroup$
Burning metal from inside the engine?
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– Organic Marble
7 hours ago
1
$begingroup$
Interesting question! Just fyi SpaceX edits their YouTube videos after some period of time to remove segments with no activity, so it's always good to include a time from the launch clock as well. I've edited the time in your clip so that the video plays properly now that they've dramatically shortened it.
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– uhoh
7 hours ago