Author Topic: Thor Booster Variants  (Read 14920 times)

Offline the_other_Doug

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Re: Thor Booster Variants
« Reply #20 on: 08/28/2016 04:47 PM »
...The guidance system, which was on the Ablestar stage and was described as a "lightweight" guidance system assembled under the guidance of Space Technology Lab (later The Aerospace Corp), would have taken control after the first couple minutes of flight, or perhaps not until after staging...

Just one minor request for clarification -- I thought that STL later became TRW, not The Aerospace Corp.  Was the latter a separate spin-off from STL that concentrated only on DoD projects, or somesuch?
-Doug  (With my shield, not yet upon it)

Offline Jim

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Re: Thor Booster Variants
« Reply #21 on: 08/28/2016 05:21 PM »
STL of the Ramo Woolridge Company became The Aerospace Corporation.  Ramo Woolridge became TRW.

Online Space Ghost 1962

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Re: Thor Booster Variants
« Reply #22 on: 08/28/2016 07:05 PM »
STL of the Ramo Woolridge Company became The Aerospace Corporation.  Ramo Woolridge became TRW.
FWIW, Thompson is the "T".

Offline Blackstar

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Re: Thor Booster Variants
« Reply #23 on: 08/29/2016 12:05 AM »
The Air Force required that Ramo Wooldridge (note the extra "d" in the name) not make hardware. This was because the company was going to be privy to the detailed information from the hardware developers on the ICBM and other missiles. Ramo Wooldridge agreed to this provision, but they soon realized that building stuff is where the money was to be made.

STL, if I remember correctly, started off as an analysis group within Ramo Wooldridge that was going to build hardware. When Ramo Wooldridge became TRW, they wanted to build hardware, so they spun off STL as the analysis organization, becoming The Aerospace Corporation. So TRW became a hardware developer and The Aerospace Corporation (which was often called "Circle A" by others because of their logo) just did analysis, although it occasionally built instruments for spacecraft.

I'm doing all that from memory, which might be faulty. You can look here:

https://en.wikipedia.org/wiki/TRW_Inc.

« Last Edit: 08/29/2016 12:05 AM by Blackstar »

Offline Blackstar

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Re: Thor Booster Variants
« Reply #24 on: 08/29/2016 12:10 AM »
And on the subject of STL, I think their story has not really been told. There is an official Aerospace Corp history, which I think has a chapter on STL. But STL also did intelligence analysis of Soviet missiles for the CIA, and they did work on satellite reconnaissance. That stuff was classified and never made it into the unclassified history.

Offline edkyle99

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Re: Thor Booster Variants
« Reply #25 on: 08/29/2016 12:13 AM »
Two Thor DSV-2D vehicles launched suborbital "Big Shot" missions from Cape Canaveral in 1962.  They boosted 135 foot diameter Echo balloons above the atmosphere to test balloon deployment methods for subsequent planned orbital launches. This was NASA's Applications Vertical Test Program (AVT), better known as "Big Shot".  A cylindrical Equipment Section, topped by a DA-92 shroud built by Douglas, were added to the now-standard DM-21 Thor, which was also used as the first stage for Thor Ablestar and Thor Agena B.  After the boost phase, the shroud and a balloon deployment canister were jettisoned at an altitude of about 250 nmi.  During the coast to 1,000 nmi, the balloon inflation experiment was performed while TV and film camera's in the Equipment Section recorded the result.  During the first launch, the balloon ruptured during inflation.  The second launch produced a successful inflation.

 - Ed Kyle

Offline gwiz

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Re: Thor Booster Variants
« Reply #26 on: 08/29/2016 10:34 AM »
The April 1964 Thor Ablestar failure (Thor 379) is listed in Peter Hunter's records as having been caused by an incorrect switch position that caused "erroneous guidance signals to be sent to Thor".  This led to loss of control at some point during the ascent...Thus If it was radio guidance, the "incorrect switch position" could have been at a ground-based guidance computer.  One description of this failure states basically that the wrong program was run.
According to my notes, the switch could be set to "ground test" or "flight" mode, so a "ground test" setting could indeed be running something other than flight software.

Offline edkyle99

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Re: Thor Booster Variants
« Reply #27 on: 08/30/2016 03:18 PM »
DSV-2E Thors were DM-18A IRBM Thors modified to perform live exoatmospheric thermonuclear warhead launches from Johnston Island in the Pacific Ocean as part of Operation Fishbowl during 1962.  The Thors carried instrumented "pods" attached to the side of their propulsion sections.  The pods were released at intervals during the boost phase to gain differential separation from the exploding W49 or W50 warhead.  After reentering, the contaminated pods floated beneath parachutes to the Pacific and were recovered.  The Thors flew from a pair of tactical launchers (Launch Emplacements 1 and 2) set up near one corner of the tiny island.  During launches, most Johnston Island personnel had to be evacuated to ships standing offshore. 

The tests taught the U.S. about the effects of exoatmospheric nuclear explosions, both on orbiting satellites and on ground-based communications and power systems.  The project produced dazzling nuclear effects, but it also suffered a series of disastrous failures.  There were eight DSV-2E launches, seven with live warheads.  Four of the seven "live" launches failed. 

The first Fishbowl launch was a successful R&D flight with no warhead.  The second launch, carrying an active warhead, was "lost" by a defective range safety tracking radar and had to be destroyed 10 minutes after liftoff.  Three subsequent Thors, all carrying nuclear warheads, suffered propulsion system failures and had to be destroyed by range safety.  Two of those destructions occurred downrange, a minute or more into flight, dropping some radioactive contamination on and near Johnston Island.  The third failure, on July 25, 1962, was a true Cold War disaster. 

Thor 180, the missile for that "Bluegill Prime" shot attempt, was fitted with a W50 thermonuclear warhead capable of producing a 400 kiloton explosion.  A  propellant valve stuck at ignition, causing a leak that fed a rapidly expanding fireball that enveloped Thor on its launch pad.  The range safety officer fired the destruct system, destroying the Thor, the warhead, and the launch emplacement, which burned for some time, contaminating the island.  Despite several subsequent cleanup efforts, Johnston Atoll, managed by the U.S. Fish and Wildlife Service since 2000, is still affected.

In the end, Operation Fishbowl only produced three successful high altitude explosions.   One of these, Starfish Prime on July 9, 1962, was a 1.4 megaton explosion, created by a W49 warhead at an altitude of  400 kilometers.  It created a fireball and artificial aurora visible in Hawaii, along with an electromagnetic pulse that disrupted power and communications.  It also pumped enough radiation into the Van Allen belts to destroy or seriously degrade seven orbiting satellites. 

Two attempts took place during the midst of the Cuban Missile Crises, on October 16 and 26, 1962.  The latter Bluegill Triple Prime shot, which detonated a W50 warhead at 48 km, almost unbelievably took place while SAC was at DEFCON 2.

The final Fishbowl launch carried the "Kingfish" 400 kiloton warhead up to its 98 km detonation altitude.  Kingfish was one of the last above-ground U.S. nuclear tests, because the U.S. and the Soviet Union signed an atmospheric test ban treaty shortly thereafter.

 - Ed Kyle
« Last Edit: 08/30/2016 03:35 PM by edkyle99 »

Offline Chrup4

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Re: Thor Booster Variants
« Reply #28 on: 09/06/2016 11:36 AM »
Thorad-Agena was a Thor with an extended tank and three SRB motors topped by an Agena D. All missions launched from VAFB and carried DoD payloads, mostly the KH-4A/B Corona satellites. Forty-three launches took place in 1968-72 and three of those were unsuccessful. The first failure on May 9, 1967 merely left its KH-4A payload in an incorrect orbit when the Thor failed to cut off on schedule and burned to propellant depletion.

The second failure on May 5, 1968 was a major debacle. Shortly after liftoff, the Thor began to drift off its flight path when the pitch and roll sequence was to start, leading to an RSO destruct. It might have ended there, but the payload on this launch (a Nimbus weather satellite) included two SNAP isotopic power generators. The generators had very sturdy casings just for this occasion--if a launch failure occurred, the radioactive contents of them would not escape.

A major effort was made to locate the SNAP generators and eventually, in the last week of September, they were found intact along with the Nimbus satellite off the Santa Barbara islands in 300 feet of water. The generators were retrieved from the sea bottom and the plutonium removed and placed in a different set of generators for a later launch.

SNAP generators were also used to power scientific instruments on the Apollo missions and played an important part during the final day of Apollo 13 when it was decided to have Aquarius reenter the atmosphere in an area that would ensure the SNAP generators would land in the Tonga Trench, one of the deepest points in the ocean, so that in the event their casings ruptured during reentry, impact, or on the ocean floor, there was almost no chance of harmful radiation affecting anything. The exact spot where Aquarius's SNAP generators landed is unknown, nor if they ruptured, but it could be at least safely assumed 13,000 feet of water is enough to keep their contents far away from human contact.

A slightly modified SNAP generator has been used to power all outer planetary probes.

The story of Thor 520 gets still more interesting--apparently the control loss during launch was caused by a rate gyro being improperly installed. The technician responsible was said to be a rather burly individual who ended up breaking off the alignment pins on the gyro while installing it. There was also rumored to be an audio recording of him saying "I can't get the gyroscope to fit properly. Let's try moving it around a bit."

Offline Chrup4

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Re: Thor Booster Variants
« Reply #29 on: 09/06/2016 12:00 PM »
The other failed Thorad-Agena launch was Thor 537 and Agena 1659, which launched a KH-4B satellite from SLC-3W on February 17, 1971.

Because the Thor/Delta family had the LOX tank on the bottom (as opposed to the top like on most launch vehicles), the thrust section would become extremely cold. To prevent this, extra plumbing was used to recirculate hot gas from the gas generator to keep the thrust section warm. On the morning of launch, the recirculation system in Thor 537 was found to have sprung a leak, allowing hot air to escape from the thrust section. Thor chief engineer Ed Dierdorf insisted that this was of no concern and the cold temperatures would not affect anything.

The problem was that the Thor vehicles he was referring to used a different engine variant than the one in the Thorad-Agena, which required a special fuel additive known as Orinite. Prior to launch, a technician proceeded to add a shot of Orinite into the RP-1 tank. Unsure if the Orinite actually went in, he pumped a second shot just to be sure.

That second shot of Orinite cracked an output valve that was only intended to be broken by turbopump pressure during launch. The Orinite dripped down the crack and into a tube that fed lubricant oil to the turbopumps. It then froze there and formed a plug, obstructing the flow of lubricant oil.

At 12:04 PM PST, the Thor lifted from SLC-3W carrying its top secret eye-in-the-sky payload. All went normally until 18 seconds into the launch, when the turbopump bearings seized up from lack of lubrication. The turbopump gears then proceeded to shred themselves, shooting debris through the thrust section. The Thor's engine shut down and the rocket crashed into Bear Creek Canyon in an enormous fireball. Ultimately, the cause of the accident was ruled to be loss of turbopump lubrication.

Although the full details of Thor 537's errant flight have been known for years, we have yet to see any photos or video of it.

Offline Jim

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Re: Thor Booster Variants
« Reply #30 on: 09/06/2016 12:45 PM »
There was also rumored to be an audio recording of him saying "I can't get the gyroscope to fit properly. Let's try moving it around a bit."

There would be no such recording. Vehicle assembly has no need for voice network much less recording

Offline Jim

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Re: Thor Booster Variants
« Reply #31 on: 09/06/2016 12:47 PM »

Because the Thor/Delta family had the LOX tank on the bottom (as opposed to the top like on most launch vehicles),

It wasn't most.  Redstone, Jupiter, Titan I second stage, S-IV, S-IVB, S-II, Centaur, Delta IV HDCSS and DCSS.  All have LOX tanks on the bottom

To prevent this, extra plumbing was used to recirculate hot gas from the gas generator to keep the thrust section warm.

Please show a diagram with this, where the gas generator exhaust goes else where than the turbopump or turbopump exhaust.
« Last Edit: 09/06/2016 01:12 PM by Jim »

Offline Chrup4

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Re: Thor Booster Variants
« Reply #32 on: 09/06/2016 02:02 PM »
There would be no such recording. Vehicle assembly has no need for voice network much less recording

http://www.thespacereview.com/article/1768/1

There was a post in the comment section here by a fellow who claimed to have worked on the Thor program that mentions there being a recording of it, although his account of how the gyro alignment pins got broken is slightly different from the one in the main article. He also claims the yaw gyro was accidentally installed in the pitch axis and all three of them had broken pins.

Offline Chrup4

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Re: Thor Booster Variants
« Reply #33 on: 09/06/2016 02:04 PM »
It wasn't most.  Redstone, Jupiter, Titan I second stage, S-IV, S-IVB, S-II, Centaur, Delta IV HDCSS and DCSS.  All have LOX tanks on the bottom.

I was mainly referring to first stages rather than upper stages and yeah, I know Jupiter had the LOX tank on the bottom.

Offline Jim

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Re: Thor Booster Variants
« Reply #34 on: 09/06/2016 02:25 PM »
There would be no such recording. Vehicle assembly has no need for voice network much less recording

http://www.thespacereview.com/article/1768/1

There was a post in the comment section here by a fellow who claimed to have worked on the Thor program that mentions there being a recording of it, although his account of how the gyro alignment pins got broken is slightly different from the one in the main article. He also claims the yaw gyro was accidentally installed in the pitch axis and all three of them had broken pins.

That was during checkout (which would be done on a voice net) and they had the tech shove the vehicle so they could see a response

Offline Jim

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Re: Thor Booster Variants
« Reply #35 on: 09/06/2016 02:29 PM »
It wasn't most.  Redstone, Jupiter, Titan I second stage, S-IV, S-IVB, S-II, Centaur, Delta IV HDCSS and DCSS.  All have LOX tanks on the bottom.

I was mainly referring to first stages rather than upper stages and yeah, I know Jupiter had the LOX tank on the bottom.

So in that timeframe: Thor, Redstone and Jupiter vs Titan I and Atlas.  Saturn I and Titan II: no test, different tank arraignment and propellants.

Offline Chrup4

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Re: Thor Booster Variants
« Reply #36 on: 09/07/2016 12:20 PM »
Early Agena stages were essentially custom-built for the mission they were on. In addition, the Agenas used with the Thor differed from the ones used with the Atlas. After the almost incredible Agena failure rate of the early years, it was decided to adopt one standardized configuration for all launches. This would emerge as Agena D, a workhorse for 16 years, but one which remained relatively obscure to the public as most of its launches were secret DoD payloads.

Agena D made her debut on the Thor in the summer of 1962 and on the Atlas a year later.  Thor-Agena Ds were flown until being replaced by the enhanced Thorad-Agena in 1968, all from VAFB, and mostly for DoD payloads. A few NASA payloads were also launched.

In addition, the so-called "Thrust-Augmented" Thor made its debut during this time. This consisted of three Castor SRB motors and would soon become the standard Thor-Agena configuration, although a few were still flown without strap-ons (including the MPRV launch mentioned below). The TAT made its debut on February 28, 1963, carrying Corona 60 aloft and predictably, the unproven booster malfunctioned when one of the SRBs failed to separate following burnout. The excess weight of the spent SRB dragged the booster off its flight path, leading to a Range Safety destruct 100 seconds after launch.

There were several failures of Thor-Agena Ds mostly caused by the Agena, which continued to be a tough beast to tame.

The most (in)famous failure was Thor 401 on September 2, 1965. The payload was known as Multiple Payload Research Vehicle, or MPRV, a jumble of scientific instruments. On launch day, high winds were blowing in from the Pacific Ocean. This was not a concern on the ground, but aloft was a different story. The Thor lifted from SLC-1 at high noon and began the pitchover maneuver, taking it on a southbound arc. However, the strong winds quickly pushed it east, back towards land. Eventually, it exceeded the allowable safety margins on the Range Safety Officer's chart and he sent the destruct command about 40 seconds after launch.

Some pieces of debris fell on a trailer park at the outskirts of VAFB, and one trailer was literally sliced in half. A pregnant woman and her two small children were inside, but miraculously unharmed. It was said that the frightened woman went into premature labor.

Apparently the mishap was caused by failing to take into account the effect of wind shear on Thor 401, which had a longer and less aerodynamically stable payload shroud than the one used by Corona satellites. The Range Safety Officer may also have waited longer than he should have to destroy the vehicle.

One of the fuel cells from MPRV was recovered largely intact, cleaned up and refurbished, and reused for over 400 hours. Its performance was said to have been better after the launch accident than before.

Offline Jim

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Re: Thor Booster Variants
« Reply #37 on: 09/07/2016 01:14 PM »
This is not the place for launch descriptions.  Ed has a thread for each classic launch vehicle where he describes each launch individually.   This thread is just about the configurations. 

Here is the Thor thread

http://forum.nasaspaceflight.com/index.php?topic=31405.0
« Last Edit: 09/07/2016 01:19 PM by Jim »

Offline Chrup4

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Re: Thor Booster Variants
« Reply #38 on: 09/07/2016 03:31 PM »
Here is the Thor thread

http://forum.nasaspaceflight.com/index.php?topic=31405.0

"The topic or board you are looking for appears to be either missing or off limits to you."

Offline zubenelgenubi

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Re: Thor Booster Variants
« Reply #39 on: 09/07/2016 03:48 PM »
Here is the Thor thread

http://forum.nasaspaceflight.com/index.php?topic=31405.0

"The topic or board you are looking for appears to be either missing or off limits to you."

It's a L2 thread: L2 Photo and Imagery Section/Thor Hi Res Images
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