Author Topic: The Different Variants of Titan Boosters  (Read 48149 times)

Offline Vlong

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Re: The Different Variants of Titan Boosters
« Reply #200 on: 09/18/2016 11:36 PM »
On May 20, 1972, the fourth mission suffered an Agena pneumatic regulator failure during ascent that caused loss of control gas.  A stable orbit was not achieved.  Pieces of the highly classified satellite were subsequently found in England.  The eighth launch on June 26, 1973 ended in much more dramatic fashion when a Titan propellant tank ruptured only 12 seconds after liftoff.  Debris fell into the Pacific Ocean.  For decades, the cause of this failure was hidden.  I've never seen a photo or video of this failure.  Have you? Then again, Titan 24B's numerous successes were also hidden.  After the 1973 failure, 15 of them flew true before the program ended on April 17, 1984. Gambit-3's ground resolution, rumored to be the best ever achieved by the United States, remains classified.

The source for the June 1973 failure is that "History of GAMBIT/HEXAGON" article published by the NRO, however this other document I'm posting cites it as a rupture of the Agena fuel tank rather than the Titan, which seems more consistent with the fact that for years, the launch was always listed an an Agena failure.

Offline Blackstar

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Re: The Different Variants of Titan Boosters
« Reply #201 on: 09/20/2016 11:27 PM »
I'm kinda lazy at the moment, so I'll just ask:

How many Titan IIs were refurbished as SLVs in the latter 1980s? How many got launched? My understanding is that six were originally allocated to classified payloads (SIGINT satellites), but that this got reduced to three, leaving three to launch other payloads. One of those other payloads was Clementine.

Offline Jim

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Re: The Different Variants of Titan Boosters
« Reply #202 on: 09/20/2016 11:32 PM »
I'm kinda lazy at the moment, so I'll just ask:

How many Titan IIs were refurbished as SLVs in the latter 1980s? How many got launched? My understanding is that six were originally allocated to classified payloads (SIGINT satellites), but that this got reduced to three, leaving three to launch other payloads. One of those other payloads was Clementine.

13 flew, 14 produced
« Last Edit: 09/20/2016 11:33 PM by Jim »

Online Skyrocket

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Re: The Different Variants of Titan Boosters
« Reply #203 on: 09/20/2016 11:38 PM »
I'm kinda lazy at the moment, so I'll just ask:

How many Titan IIs were refurbished as SLVs in the latter 1980s? How many got launched? My understanding is that six were originally allocated to classified payloads (SIGINT satellites), but that this got reduced to three, leaving three to launch other payloads. One of those other payloads was Clementine.

see here for all Titan-2 orbital missions: http://space.skyrocket.de/doc_lau/titan-2.htm
« Last Edit: 09/20/2016 11:38 PM by Skyrocket »

Offline Sam Ho

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Re: The Different Variants of Titan Boosters
« Reply #204 on: 09/20/2016 11:43 PM »
I'm kinda lazy at the moment, so I'll just ask:

How many Titan IIs were refurbished as SLVs in the latter 1980s? How many got launched? My understanding is that six were originally allocated to classified payloads (SIGINT satellites), but that this got reduced to three, leaving three to launch other payloads. One of those other payloads was Clementine.

13 flew, 14 produced
The unflown one is at the Evergreen Museum.

http://www.evergreenmuseum.org/popular-exhibits

Offline WallE

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Re: The Different Variants of Titan Boosters
« Reply #205 on: 05/01/2017 12:57 PM »
Years after the final Titan 3E launch, by TC-6 of Voyager 1 on September 5, 1977, JPL's Bruce Murray and others disclosed that the launch had resulted in a "close call".  The Titan 2nd stage had shut down a few seconds early due to a propellant management problem.  Something like 1,200 lbs of propellant "outage" occurred versus the goal of less than 534 lbs at most.  Centaur had to make up the velocity difference to the parking orbit.  It then consumed nearly all of its propellant during its final burn to reach its planned velocity.  In the end, Centaur had 3.4 seconds of propellant (less than 220 lbs) left in its tanks.

In the re-telling since, this story seems to have drifted a bit.  Some versions blame a Titan propellant leak.  Others say that the 1,200 lbs was the extra Centaur propellant burned.  Murray's book and NASA SP-2004-4230 both say it was 1,200 lbs left in the Titan tank and neither mention a leak. 

The Titan storable engines were "hydraulically balanced" and did not use active propellant utilization systems.  Propellant management was by statistical analysis that determined how much fuel and oxidizer should be loaded for given ambient temperatures and expected system performance (mixture ratios and tank pressures especially).  The goal was usually to run to oxidizer depletion with only 100 or 200 lbs of usable second stage fuel left as "outage".  The expected second stage propellant burn rate was 323.42 lbs/second, but this usually varied a bit.  Perhaps the TC-6 propellant loading was off for the conditions, or the engine mixture ratio shifted, or tank pressurization (autogenous) shifted.  I would love to see an official flight report to confirm the cause.

The version I heard was that the Titan second stage suffered from low thrust and was short on velocity at cutoff. This may have been due to a pressurization problem or perhaps the LR-91 engine used on TC-6 didn't have enough performance for the mission--individual rocket engines do vary slightly in their performance levels, as you noted, second stage performance on each Titan launch was a little different.

This was a recurring problem on Titan second stages; mostly Titan II ICBM tests, but a few orbital launches as well, for example one GAMBIT satellite was lost when its second stage underperformed and drove it into the Pacific Ocean. According to the flight report for the first Titan Centaur (TC-1), the second stage also underperformed slightly.

Offline edkyle99

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Re: The Different Variants of Titan Boosters
« Reply #206 on: 06/26/2017 03:03 PM »
At long last I have "finished" a Titan history page as part of the Titan variant compilation.  Let me know if you see typos, etc.
http://www.spacelaunchreport.com/titan.html
http://www.spacelaunchreport.com/library.html

 - Ed Kyle

Offline WallE

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Re: The Different Variants of Titan Boosters
« Reply #207 on: 06/26/2017 04:05 PM »
At long last I have "finished" a Titan history page as part of the Titan variant compilation.  Let me know if you see typos, etc.

Seems ok except that the 6/26/73 accident was not a first stage explosion, it was a failure of the Agena main fuel valve which resulted in no orbital insertion, and there are declassified KH-8 docs correlating this. Hence the amusing postcard.

Offline edkyle99

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Re: The Different Variants of Titan Boosters
« Reply #208 on: 06/26/2017 05:03 PM »
At long last I have "finished" a Titan history page as part of the Titan variant compilation.  Let me know if you see typos, etc.

Seems ok except that the 6/26/73 accident was not a first stage explosion, it was a failure of the Agena main fuel valve which resulted in no orbital insertion, and there are declassified KH-8 docs correlating this. Hence the amusing postcard.
My description of that failure came directly from the official Gambit history (Robert Perry "A History of Satellite Reconnaissance, Volume IIIA - Gambit"), Page 314.

It read as follows.

"The last mission of fiscal year 1973, mission 4339, was begun on 26 June 1973.  It proved to be a disappointing anticlimax to the high achievement of 4338.  Some 12 seconds after the early morning launch from Vandenberg Air Force Base, the main fuel tank of the Titan ruptured.  The debris fell into the Pacific Ocean south of Vandenberg."

 - Ed Kyle
« Last Edit: 06/26/2017 05:06 PM by edkyle99 »

Offline WallE

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Re: The Different Variants of Titan Boosters
« Reply #209 on: 06/26/2017 05:54 PM »
My description of that failure came directly from the official Gambit history (Robert Perry "A History of Satellite Reconnaissance, Volume IIIA - Gambit"), Page 314.

It read as follows.

"The last mission of fiscal year 1973, mission 4339, was begun on 26 June 1973.  It proved to be a disappointing anticlimax to the high achievement of 4338.  Some 12 seconds after the early morning launch from Vandenberg Air Force Base, the main fuel tank of the Titan ruptured.  The debris fell into the Pacific Ocean south of Vandenberg.

However, "The GAMBIT Story" includes this item. Also if a failure occurred 12 seconds after liftoff, the booster would still be directly above the pad, it would not have performed the pitchover maneuver yet and hence debris could not have fallen into the ocean in this situation, it would land around the pad area. Contemporary newspaper accounts also make no mention of such a failure, while they do mention the 2/17/71 Corona failure which exploded shortly after launch.
« Last Edit: 06/26/2017 06:05 PM by WallE »

Offline edkyle99

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Re: The Different Variants of Titan Boosters
« Reply #210 on: 06/26/2017 06:33 PM »
My description of that failure came directly from the official Gambit history (Robert Perry "A History of Satellite Reconnaissance, Volume IIIA - Gambit"), Page 314.

It read as follows.

"The last mission of fiscal year 1973, mission 4339, was begun on 26 June 1973.  It proved to be a disappointing anticlimax to the high achievement of 4338.  Some 12 seconds after the early morning launch from Vandenberg Air Force Base, the main fuel tank of the Titan ruptured.  The debris fell into the Pacific Ocean south of Vandenberg.

However, "The GAMBIT Story" includes this item. Also if a failure occurred 12 seconds after liftoff, the booster would still be directly above the pad, it would not have performed the pitchover maneuver yet and hence debris could not have fallen into the ocean in this situation, it would land around the pad area. Contemporary newspaper accounts also make no mention of such a failure, while they do mention the 2/17/71 Corona failure which exploded shortly after launch.
A ruptured fuel tank might mean a leak that didn't cause an immediate failure. 

Perry's account is quite specific.  I can't dismiss the report in this official history without more information.

 - Ed Kyle

Offline WallE

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Re: The Different Variants of Titan Boosters
« Reply #211 on: 06/26/2017 08:32 PM »
Perry's account is quite specific.  I can't dismiss the report in this official history without more information.

In another thread, we had debated the cause of failure in Titan 34D-7, which failed from a propellant leak. It was speculated that a piece of cork broke off the SRBs at liftoff and ruptured a fuel line, but then it could just as easily have been a start transient. The Titan 3B didn't have SRBs so obviously that can be ruled out here, leaving the possibility of a similar start transient here causing a fuel leak. Otherwise I can't think of any other reason why something like this would happen. The Titan family (meaning the core vehicle, not strap-ons) were very reliable LVs, especially the first stage.

However, although that is an official history you cited, the source I used was an equally official history which provides an entirely different account. Another interesting thing to consider is that there were two other Titan 3B/Agena failures during this period, one a Gambit launch, the other a Jumpseat. Therefore one could make the guess that a defective batch of Agenas got out during 1972-73. Or perhaps faulty prelaunch procedures or other equipment failures did them in, there are instances of this happening in other programs (eg. two Samos launches lost due to improper installation of pad umbilicals).

I also just noticed that KH-8 39 was launched exactly 44 years ago today.
« Last Edit: 06/26/2017 08:37 PM by WallE »

Offline edkyle99

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Re: The Different Variants of Titan Boosters
« Reply #212 on: 06/27/2017 04:10 AM »
Here's another bit of information, from January 1981 by Martin Marietta.  It says that there had been 62 Titan IIIB launches by then with 61 successes.  There had in fact been 62 Titan IIIB launches by then, and four failures, but at least two, and maybe three, involved Agena rather than Martin's Titan stages.  The April 26, 1967 failure is typically listed as due to the second stage not developing sufficient thrust.  Two 1972 failures involved Agena.  That leaves June 26, 1973, which, if the 1967 failure did involve Stage 2, Martin Marietta did not report to be a failure involving the Titan stages.

That leaves very puzzling questions.  Where did Robert Perry get the story about the Titan tank leaking at T+12 sec?  And why did he record that as a historical fact?  (Could Titan have had a small leak and Agena failed to start?)

 - Ed Kyle
« Last Edit: 06/27/2017 01:29 PM by edkyle99 »

Offline WallE

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Re: The Different Variants of Titan Boosters
« Reply #213 on: 06/27/2017 05:15 PM »
Here's another bit of information, from January 1981 by Martin Marietta.  It says that there had been 62 Titan IIIB launches by then with 61 successes.  There had in fact been 62 Titan IIIB launches by then, and four failures, but at least two, and maybe three, involved Agena rather than Martin's Titan stages.  The April 26, 1967 failure is typically listed as due to the second stage not developing sufficient thrust.  Two 1972 failures involved Agena.  That leaves June 26, 1973, which, if the 1967 failure did involve Stage 2, Martin Marietta did not report to be a failure involving the Titan stages.

That sounds about right. They only list failures involving the core Titan stages, and just one is indicated for the Titan 3B, which of course be the 4/27/67 launch. Also FWIW they list two Titan 3C failures in 29 launches, which would be the 8/26/66 launch (although I don't know why that counts since it was a payload shroud failure) and the 3/25/78 launch, while excluding the four Transstage failures.

Low thrust was a recurrent problem on Titan second stages since the ICBM test program and it notably happened on the launch of Voyager 1, therefore the failure cause for KH-8 5 should be correct, and there are no alternative explanations for it floating around. The exact reason for it was not determined, possibly a fuel line obstruction or a pressurization problem.

That leaves very puzzling questions.  Where did Robert Perry get the story about the Titan tank leaking at T+12 sec?  And why did he record that as a historical fact?  (Could Titan have had a small leak and Agena failed to start?)

Apparently he got it from the same place as the story about Atlas-Able 3 experiencing a premature Able ignition and Atlas-Centaur 1 exploding when the LH2 contacted the engines, both of which we now know to not be true.

If there was a Titan propellant leak, it must have been at best incidental and not the main contributing factor to the failure.
« Last Edit: 06/27/2017 07:32 PM by WallE »

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