Riding the booster
- Thread starter teqniq
- Start date
TitanSound
Mr Beardy Drummer
If you smoke weed/hash, I implore you to have a spliff before you watch that with decent headphones on. Quality 
2hats
Dust.
Just more detail than I've seen from on board cameras in the past...
Tyvek shower caps torn from nose RCS thrusters between 4.8 and about 6 seconds (by the MET clock in the top right hand corner). This is just a plastic paper used to protect the manoeuvring jet thruster assemblies from being contaminated with moisture whilst the vehicle sits out on the pad. They are designed to fall off quickly and get incinerated in the exhaust plume before the shuttle gets to any speed at which they can cause damage. Similar covers on thrusters lower down the shuttle get torn away by the acoustic over-pulse at solid rocket booster ignition. Lots of launch vehicles use similar to protect rocket motor assemblies that have to sit out on a launch pad for days.
At the subsonic/supersonic boundary, great pressure differences cause the condensate to form (it's a physical manifestation of the Prandtl Glauert transformation which describes the flow regime at a given Mach number - at Mach 1 that would become infinite, except that's non-physical and in reality other factors come to dominate). In the lower pressure region around the craft atmospheric temperature drops momentarily causing moisture in the air to condense out into a fleeting cloud. You can see similar in high performance aircraft and in other situations where there are sudden changes in pressure (vortices off commercial aircraft wing tips, compression waves in the atmosphere due to nuclear explosions, say, and it's the process that forms many 'everyday weather' clouds). Here you see it from 42-48 seconds. (Note it's still pretty much vertically over the launch pad throughout this time).
Wing flutter (weakest parts of the orbiter) due to vehicle loading in the dense lower atmosphere can be seen from 36 seconds to about 75 seconds where it tails off. The main engines and solid motors throttle back during this time to avoid over-stressing the assembly. This is Max-Q the period of maximum dynamic stress (coincides with the transonic regime).
Having cleared the dense part of the atmosphere, from about 75-79 seconds, you can clearly see it's pitching over backwards more dramatically (the horizon line climbs in the background of the camera field of view), the angle of ascent is gradually reduced so the vehicle can now accelerate to orbital velocity (from launch to solid rocket separation it changes from 90 degrees to about 57 degrees to the horizontal). The imperative is to gain speed, even at the expense of some altitude (it will naturally gain altitude as orbital mechanics take over at the end of powered flight, with little atmospheric drag). The ascent profile actually looks like:
which is not untypical for a lot of launch vehicles. Powered flight ends around 900km downrange in that diagram (well after the end of the film excerpt), just after the dip in altitude, but the vehicle is now travelling so fast it naturally climbs out to orbital altitude (there are no engines running from 900km through to the end of that diagram).
Will that do you?
e2a: forgot to mention Max-Q.
Tyvek shower caps torn from nose RCS thrusters between 4.8 and about 6 seconds (by the MET clock in the top right hand corner). This is just a plastic paper used to protect the manoeuvring jet thruster assemblies from being contaminated with moisture whilst the vehicle sits out on the pad. They are designed to fall off quickly and get incinerated in the exhaust plume before the shuttle gets to any speed at which they can cause damage. Similar covers on thrusters lower down the shuttle get torn away by the acoustic over-pulse at solid rocket booster ignition. Lots of launch vehicles use similar to protect rocket motor assemblies that have to sit out on a launch pad for days.
At the subsonic/supersonic boundary, great pressure differences cause the condensate to form (it's a physical manifestation of the Prandtl Glauert transformation which describes the flow regime at a given Mach number - at Mach 1 that would become infinite, except that's non-physical and in reality other factors come to dominate). In the lower pressure region around the craft atmospheric temperature drops momentarily causing moisture in the air to condense out into a fleeting cloud. You can see similar in high performance aircraft and in other situations where there are sudden changes in pressure (vortices off commercial aircraft wing tips, compression waves in the atmosphere due to nuclear explosions, say, and it's the process that forms many 'everyday weather' clouds). Here you see it from 42-48 seconds. (Note it's still pretty much vertically over the launch pad throughout this time).
Wing flutter (weakest parts of the orbiter) due to vehicle loading in the dense lower atmosphere can be seen from 36 seconds to about 75 seconds where it tails off. The main engines and solid motors throttle back during this time to avoid over-stressing the assembly. This is Max-Q the period of maximum dynamic stress (coincides with the transonic regime).
Having cleared the dense part of the atmosphere, from about 75-79 seconds, you can clearly see it's pitching over backwards more dramatically (the horizon line climbs in the background of the camera field of view), the angle of ascent is gradually reduced so the vehicle can now accelerate to orbital velocity (from launch to solid rocket separation it changes from 90 degrees to about 57 degrees to the horizontal). The imperative is to gain speed, even at the expense of some altitude (it will naturally gain altitude as orbital mechanics take over at the end of powered flight, with little atmospheric drag). The ascent profile actually looks like:
which is not untypical for a lot of launch vehicles. Powered flight ends around 900km downrange in that diagram (well after the end of the film excerpt), just after the dip in altitude, but the vehicle is now travelling so fast it naturally climbs out to orbital altitude (there are no engines running from 900km through to the end of that diagram).
Will that do you?
e2a: forgot to mention Max-Q.
Top Tip!If you smoke weed/hash, I implore you to have a spliff before you watch that with decent headphones on. Quality
Crispy
The following psytrance is baṉned: All
You work in aerospace, 2hats?
2hats
Dust.
Thought I'd pop this figure I spotted the other day in here since it's relevant:
and after watching the Ariane 5 launch I thought it would be amusing to compare:
e2a: last diagram - to clarify, the coloured portions are powered flight, the various black lines being the coast portions of each ascent (ballistic trajectory).
and after watching the Ariane 5 launch I thought it would be amusing to compare:
e2a: last diagram - to clarify, the coloured portions are powered flight, the various black lines being the coast portions of each ascent (ballistic trajectory).
beesonthewhatnow
going deaf for a living
The job done by Skywalker Sound on that is utterly stunning. If anyone has a link to more info on that I'd love to see it...
beesonthewhatnow
going deaf for a living
I'm guessing they use some sort of PZM/boundry mic, but as to what I have no idea. The only thing I'd be sure of is that they won't come cheap
2hats
Dust.
Interesting. The cameras are RocketCams made by Ecliptic Enterprises. Ruggedised industrial video cameras with built in microphones which actually get completely overloaded at times - you can hear the original sound (different launch) here (albeit with the air-to-ground audio as well):
So clearly they are mixing the sound from various sources.
Thinking about it a bit more it makes sense that there's bound to be some sort of sound throughout this video since booster separation is typically around 45 km and they continue on a ballistic trajectory to about 65 km altitude. There is still a significant degree of atmosphere at these altitudes - not enough for you or I to breathe, obviously, but enough to propagate some sorts of sounds. For comparison, the protective fairings covering satellites on nearly every expendable rocket launch are not jettisoned till just over 100 km altitude as the aerothermal fluxes are considered too high until then (ie above 100 km is considered close enough to vacuum as makes no difference so the extra weight of the fairing, which protects the payload from environmental exposure, air drag, aero-heating, etc in the lower atmosphere, can now be shed, improving the overall ascent performance).
More in-rocket porn here. They even tried to get video from the external tank up to the point of re-entry over the Pacific.
A couple more videos worth watching for the detail and some physics if you look carefully...
This one including detailed engineering images and commentary:
(both are available in 720p).
So clearly they are mixing the sound from various sources.
Thinking about it a bit more it makes sense that there's bound to be some sort of sound throughout this video since booster separation is typically around 45 km and they continue on a ballistic trajectory to about 65 km altitude. There is still a significant degree of atmosphere at these altitudes - not enough for you or I to breathe, obviously, but enough to propagate some sorts of sounds. For comparison, the protective fairings covering satellites on nearly every expendable rocket launch are not jettisoned till just over 100 km altitude as the aerothermal fluxes are considered too high until then (ie above 100 km is considered close enough to vacuum as makes no difference so the extra weight of the fairing, which protects the payload from environmental exposure, air drag, aero-heating, etc in the lower atmosphere, can now be shed, improving the overall ascent performance).
More in-rocket porn here. They even tried to get video from the external tank up to the point of re-entry over the Pacific.
A couple more videos worth watching for the detail and some physics if you look carefully...
This one including detailed engineering images and commentary:
(both are available in 720p).
2hats
Dust.
One other 'realistic' audio (and video) that I've just found again - shot from the ground:
One should note that the 'sound' level at solid rocket motor ignition at the launch pad is around 220 dB and the sound suppression system (water poured over the pad prior to ignition) cuts this back to about 140 dB for the reflected acoustical energy in order to minimise damage to the vehicle and occupants. I've seen a figure of ~200 dB for death arising from internal organ failure (most of the energy of the rocket motors is at low frequencies, around 20 Hz). At ~100 m from the pad a human will succumb to the heat of the exhaust and the sound levels are still sufficient to kill the unprotected out to about 300 m. You have to be almost 2 km away to avoid permanent hearing damage without ear protection (about 130-140 dB). So clearly someone has taken a bit of artistic license with the audio in the enhanced sound video.
Other than being in the cockpit, about 1 mile is the closest that anyone on the ground gets, as best as I know. Lots of local wildlife gets cooked.
One should note that the 'sound' level at solid rocket motor ignition at the launch pad is around 220 dB and the sound suppression system (water poured over the pad prior to ignition) cuts this back to about 140 dB for the reflected acoustical energy in order to minimise damage to the vehicle and occupants. I've seen a figure of ~200 dB for death arising from internal organ failure (most of the energy of the rocket motors is at low frequencies, around 20 Hz). At ~100 m from the pad a human will succumb to the heat of the exhaust and the sound levels are still sufficient to kill the unprotected out to about 300 m. You have to be almost 2 km away to avoid permanent hearing damage without ear protection (about 130-140 dB). So clearly someone has taken a bit of artistic license with the audio in the enhanced sound video.
Other than being in the cockpit, about 1 mile is the closest that anyone on the ground gets, as best as I know. Lots of local wildlife gets cooked.
secondedGreat vids there 2hats, thanks
2hats
Dust.
Just to mention the Ariane 5 on board camera from the flight on Friday. Booster separation 1m50s into this video and then the fairing seen gently dancing away at about 2m20s:
This video has the lower stage separation at about 27m20s:
Video quality not as good as from the shuttle boosters but then this was live from the vehicle in flight whilst the (high quality) shuttle videos were stored on board and recovered from the SRBs later.
This video has the lower stage separation at about 27m20s:
Video quality not as good as from the shuttle boosters but then this was live from the vehicle in flight whilst the (high quality) shuttle videos were stored on board and recovered from the SRBs later.
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