Soyuz / R-7 Strap-on Booster Sep

[Citabria]

clongton - 24/4/2008  1:58 PM
2. A very pretty landscape with several dead cows lying there. The caption said that the soil is becoming polluted with rocket fuel from the dropped booster tanks.

I wonder what's in the tanks that's so poisonous. The fuel is just kerosene, no? The cryo O2 and N2 would evaporate. There is some Hydrogen Peroxide. Would that linger? What else is in there?

[Jim]

kerosene is poisonous.  Protons and other vehicles land there too.

[Danderman]

Citabria - 24/4/2008  6:15 PM  

clongton - 24/4/2008  1:58 PM 2. A very pretty landscape with several dead cows lying there. The caption said that the soil is becoming polluted with rocket fuel from the dropped booster tanks.

I wonder what's in the tanks that's so poisonous. The fuel is just kerosene, no? The cryo O2 and N2 would evaporate. There is some Hydrogen Peroxide. Would that linger? What else is in there?

 

I can't imagine that any significant amount of kerosene remains from the Soyuz first stage boosters, and certainly no O2 or H2O2 from the turbopumps. But, these land very close to the cosmodrome in flat plains.  The Proton first stage lands a little farther, and that does contain some nasty stuff, but fortunately, its one big piece. The Dnepr first stage, when flown to 65 degrees, would also land in Kazakhstan, and would contain some nasty stuff.

The stuff that lands further downrange, in the Altai, includes the Proton second stage.

So, yes, there are some launches that drop nasty stuff downrange. Not many per year, though, and its hard to imagine that anyone who is not right next to a fallen stage would suffer much from the wisps of propellant that may remain in the tanks. I suspect the automobile traffic from metalworkers is far more dangerous to the local cows.

On the other hand, I have heard rumors that the exhaust from the SRBs is quite nasty, and that NASA is required to drop some lime in the ocean after launches. I can't say that this is true, its only a rumor.

 

[Jim]

Danderman - 24/4/2008  9:35 PM
On the other hand, I have heard rumors that the exhaust from the SRBs is quite nasty, and that NASA is required to drop some lime in the ocean after launches. I can't say that this is true, its only a rumor.>

not true

[Lampyridae]

DarthVader - 26/3/2008  3:25 AM

Citabria - 25/3/2008  9:38 AM

Thanks for replying again. Yes, it's me again with the same question I posted a few months ago and you answered back then. Do you know if there are any tech docs out there about this?

No worries . As for the document(s), well no. I'd love to find any describing this in details, but there's nothing available that I know off.

About the LOX vent push: Watching recent Soyuz launches on NASA-TV, even though the views were low magnification, I've seen the boosters tumble pretty quickly after sep. Could the vent push that hard? Or are aerodynamics helping the tumble?

 

I'm no aerodynamics expert, but yeah I do believe that it will play a role as well as the decaying thrust which is likely offset from the strap-on center of gravity.

I don't know the altitude and velocity where they separate but the drag pressure will be very high, especially once they expose more surface area and poke out of the stagnation and boundary layers around the rocket and into supersonic flow. It is probably after Max Q but still pretty high. Those boosters are like tin cans in a hurricane so they will flip pretty quickly. Burnt-out solids, especially modern composites, also flip pretty quickly and they stage at lower velocities.

The views of booster sep probably aren't all that good because the booster is higher up and further downrange when that happens than for smaller SRBs on, say, Delta II which only burn for 90 seconds or so as opposed to 120s on the Soyuz. IMHO of course.

[icbmfreak]

Has anyone calculated the number of Russian stages that have impacted since 1957? 10,000 for an estimate?

[gospacex]

Lampyridae - 24/4/2008  9:10 PM
I don't know the altitude and velocity where they separate but the drag pressure will be very high, especially once they expose more surface area and poke out of the stagnation and boundary layers around the rocket and into supersonic flow. It is probably after Max Q but still pretty high. Those boosters are like tin cans in a hurricane so they will flip pretty quickly. Burnt-out solids, especially modern composites, also flip pretty quickly and they stage at lower velocities.

Max-Q happens around 70 sec. After max-Q dynamic pressure falls very quickly. I don't think that at 120+ seconds it will be "very high". But still noticeable.

[Citabria]

Finally, rocketcam shows actual sequence (about 2:25 into video). Wow, it's fast.