NASA Titan Booster launch question

Hello everyone. I would love to pick the collective brain on this forum to answer a couple of questions I have about the Titan booster.

Every time I watch some footage of a Titan Booster launching I wonder what that sound is just before the rocket motors ignite. It sounds a lot like someone turning over a starter on a riding motor and then you start to see some action. I also am curious as to the rust colored cloud the bellows out from underneath the rocket just before ignition. Is this a fuel rich or oxidizer rich situation or something else entirely.

Thanks for your input. Maybe I can at last, know the answer to these questions.

David

I think the first part is the turbo pumps spooling up. They feed the fuel/oxidizer to the motor. And I believe the rust colored cloud is rust being blown off the steel components exposed to the salt air at Kennedy.

Dave is right. It is the turbo pumps. Here is a very good description of the sequence:

https://www.techbastard.com/missile/titan2/startsequence.php

The rust colored cloud is oxidizer, Nitrogen Tetroxide (N204).

The rust colored cloud is the oxidizer nitrogen tetroxide, chemically N2O4, which is a brown colored toxic liquid and gas with a vapor pressure of 1 atmosphere.

The Titan missile launcher was derived from the Titan ICBM developed in the 1960s. It employs a very nasty, toxic hypergolic propellant system using Aerozine 50 fuel and nitrogen tetroxide oxidizer.

Bob

...well, I was half right

The nitrogen tetroxide N2O4 is a clear liquid, but can readily (probably with a little bit of energy like heat or catalysis) into nitrogen dioxide NO2, which is a reddish brown gas. Both nitrogen tetroxide are toxic and can be corrosive especially if water is absorbed forming nitric acid. If you have ever smelled nitrogen dioxide, you will not forget it. It is pungent and can you get a person into coughing spasms. A simple way to make nitrogen dioxide in the laboratory is to drop copper into high strength nitric acid.

I worked with N2O4 and NO2 for 6 months as an undergrad. I've only seen it as a yellow-brown liquid which is how NIOSH describes it. https://www.cdc.gov/niosh/npg/npgd0454.html

N2O4 is simply a dimer of NO2 which is a brown toxic gas. It takes very little energy to go from the dimer to the monomer and back. It boils at 70 F and if you are in an air conditioned room, you can have puddles of liquid in your gas line where the air is slightly colder than 70 F. The liquid is corrosive and toxic. Regardless of what the color is, it's really nasty stuff.

It has a relatively high odor threshold, and you rapidly become desensitized to the smell. This is not good because you think it's gone away but it hasn't. The first sign of overexposure is a splitting headache followed by a nose bleed. Don't ask be how I know. After looking at the potential effects, you take 2 aspirin and go to bed. https://www.cdc.gov/niosh/idlh/10102440.html

If you wake up in the morning you're fine......:blush:

Bob

aerostadt said:

The nitrogen tetroxide N2O4 is a clear liquid, but can readily (probably with a little bit of energy like heat or catalysis) into nitrogen dioxide NO2, which is a reddish brown gas.

Click to expand...

I worked with N2O4 and MMH for years in the Shuttle Program. N2O4 always had the reddish brown color in both its liquid and gaseous state when we were handling it.

The Aerozine 50 fuel is 50% hydrazine, also really nasty stuff.
But it works good.

M

Isn't the Titan retired now? I didn't think NASA had flown those for several years.

2005

https://www.youtube.com/watch?v=modul24YyN0