I know this doesn't belong in this forum, but this tends to be where the rocketry experts hang out, so I apologise in advance...

I have been watching the Spacecraft Films Gemini DVD's (with a huge amount of nostalgic pleasure, but that is by the by).

Just prior to each launch of the Titan launch vehicle, there is a short, sharp noise similar to a giant intake of breath. It is just prior to ignition and presumably is associated with the ignition process.

Can anyone tell me what it is precisely?

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"I'd take the awe of understanding over the awe of ignorance any day." - Douglas Adams

I'm pretty sure that's the starter cartridge, a solid fuel gas generator that provided the high pressure gases required to get the turbopump assembly turbines going. Its burn was of really short duration, about a second.

Once the hypergolic propellants started flowing and burning, they also provided fuel to the gas generator which supplied the continuing pressure to keep the system running.

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Thanks mate. Now you mention it, it does sound a little like the starter cartridge used in diesel rigs. That makes sense to me now!

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"I'd take the awe of understanding over the awe of ignorance any day." - Douglas Adams

Apogee has a new book out on that other launch vehicle

Atlas: The Ultimate weapon.

More dramatic than accurate. Howzabout "Atlas: A Good First Try"?

Oddly enough, just last week I drove by an old Atlas-E coffin launcher about 50 miles outside of Spokane, Washington.

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"Transport of the mails, transport of the human voice, transport of flickering pictures - in this century, as in others, our highest accomplishments still have the single aim of bringing men together." St. Exupery

The weapon so deadly, it launches coffins for its victims!

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"Earth diameter is 7,900 miles, and Moon diameter is 2,160 miles. It takes on average 90 minutes to complete one Earth orbit, so one Moon orbit should take roughly 25 minutes." - Sam "NasaScam" Colby

Bearer of the highly coveted "I found Venus in nine Apollo photos" sweatsocks.

DataCable^2008 A+

A broom and a dust-pan would be more useful!
For those of you who don't know, before the advent of vertical silos, the missiles were kept in horizontal "coffins". When the time came to teach the dirty, rotten, commie pinkoes a lesson, the missiles would be elevated to vertical, fueled, and then, well...

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"Transport of the mails, transport of the human voice, transport of flickering pictures - in this century, as in others, our highest accomplishments still have the single aim of bringing men together." St. Exupery

Titan wasn't much bigger. The Soviet SS-9 SCARP (R-36-O) Tsyclon--and its twin brother the SS-18 SATAN (R-36M--or voevoda), which became the Dnepr launch vehicle--both outclass the Titan II. When the Soviets wanted larger payloads, they didn't stretch their R-36 series out to the point of absurdity--they just used a big dedicated rocket like R-7 or their version of Saturn IB--the UR-500 Proton. That hypergolic vehicle--like the Saturn 1-B, had a central oxidizer drum surrounded by fuel tanks--though Saturn used a Lox-filled Jupiter surrounded by kero-or-lox filled Redstone cores--all bolted together to form one stage.

But the Air Force didn't want that Army rocket--so they nixed it and stretched out the Titans--overoptimised them out the wazoo--and what started off smaller than an SS-9 wound up in Proton's class--but was a lot more expensive. Sticking with the cheaper Saturn 1-B (which had more room for upgrades and lent itself to further development) would have made a lot more sense.


But the AF wanted Titan III and IV, the latter costing a billion a shot including Milstar payloads--more than a Saturn V moon shot.


That's our Air Force for you. The Soviets were smarter. They kept their space program far away from their Air Force--and were a lot better off for having done so. Pilots often become the heads of any nations air force. Just ask Pete Worden about how our AF is little but a fighter-pilot's union. This is why they found money for $200 billion JSF programs and F-22s, but don't care much about how many of their rockets are as old if not older than their B-52s.

As I work in TV I have limited knowledge of Rocket technology. In the case of the Gemini DVD set, I referred to that sound as the "d**n cool noise right as the engines fired!!"

Another "d**n cool noise right as the engines fired!!" noise can be heard on the Hubble Service mission DVD from Mark as the STS launches. That one brings chills down my back, it sounds so !"§$&% powerful.

Having said all that, nothing beats the excitement of a Saturn V launch.

Dwight

ps the naughty words arent that bad, but I thought I'd edit them just in case