Author Topic: Thor Booster Variants  (Read 24322 times)

Offline edkyle99

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Thor Booster Variants
« on: 07/18/2016 03:45 AM »
This is going to take awhile, given the numerous Thor and Delta variants.

In 1955 the U.S. began Thor IRBM development as a stop-gap until Atlas could enter service.  Thor would use Atlas-derived propulson and warhead and an existing inertial guidance system.  It would have 2,400 km range to reach the Soviet Union from Western Europe.   Douglas Aircraft Company won the SM-75 Thor contract in December 1955.  The company delivered its first Thor from Santa Monica, California to Cape Canaveral on October 26, 1956. 

The early R&D Thors, named Douglas Missile 18, or DM-18, were powered by 135,000 lbf Rockeydyne MB-1 engines and topped by dummy nose cones. Thor 101 blew up on its LC 17B launch pad on January 25, 1957.  This was followed by three more failures.  Finally, on September 29, 1957, still less than two years after the program began, Thor 105 flew a successful long-range flight from the Cape.  One month later, Thor 109 flew the first full-range flight down the Atlantic Missile Range.   

All-inertial guidance system test flights began in December, 1957.  Reentry vehicle test flights began in February 1958 with Thor 120, which also debuted a new, less-tapered guidance section. 

Thor DM-18A, the operational variant without fins, numbered Thor 138 and higher, began flying in 1958.  The first crew training launch from Vandenberg, which was also the first long-range launch from that West Coast base, took place on December 16, 1958, when Thor 151 flew successfully over the Pacific Ocean.

Thor became operational in Great Britain during December 1959.   There, 60 Thors were deployed at four former airfield bases.  A total of 1,000 personnel manned each base.  Thors were stored horizontally in retractable steel shelters on an erector-launcher mount.   Missiles could be launched within 15 minutes of an order, in theory.   

Thors were retired from IRBM duty in August 1963 and returned to the United States where nearly all would be assigned to other duties.

 - Ed Kyle
« Last Edit: 07/18/2016 03:52 AM by edkyle99 »

Offline kevin-rf

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Re: Thor Booster Variants
« Reply #1 on: 07/18/2016 05:11 AM »
Ed. I am looking forward to learning new things. Given the volume that needs to be covered, this will be a long thread!
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Offline kevind

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Re: Thor Booster Variants
« Reply #2 on: 07/18/2016 06:08 PM »
10 months from signing contract to delivery of first vehicle.  Probably could never be done that quickly today.

Offline gwiz

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Re: Thor Booster Variants
« Reply #3 on: 07/18/2016 06:46 PM »
It's debugging the software that takes the most time with today's vehicles.

Offline Old Space Dude

Re: Thor Booster Variants
« Reply #4 on: 07/24/2016 12:46 AM »
 During the first quarter of 1960, there were three Thor launchings from the cape which were said to be testing an
improved engine. Each flew what was called at the time an experimental low-drag fairing covering the Mk 2
re-entry vehicle. These looked very much like a Jupiter re-entry vehicle. Can anyone enlighten me on this?

Offline edkyle99

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Re: Thor Booster Variants
« Reply #5 on: 07/24/2016 03:50 AM »
During the first quarter of 1960, there were three Thor launchings from the cape which were said to be testing an
improved engine. Each flew what was called at the time an experimental low-drag fairing covering the Mk 2
re-entry vehicle. These looked very much like a Jupiter re-entry vehicle. Can anyone enlighten me on this?
DM-18C.  Had MB-3 Block 2 165 Klbf engine.  This was a test vehicle meant to demonstrate longer range.  It had a low drag fairing and a GE Mark 2 RV.  The fairing would not have shared anything with the Jupiter RV, because the Jupiter RV was a conical ablative reentry vehicle.  The Thor fairing was just a jettison-able fairing to reduce drag, while the stumpy heat-sink Mark 2 RV used by the operational Thors still lurked beneath.  All three launches were from LC 18B, which had a tactical launcher setup.  I'll add details later.

 - Ed Kyle
« Last Edit: 07/24/2016 02:12 PM by edkyle99 »

Offline edkyle99

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Re: Thor Booster Variants
« Reply #6 on: 07/24/2016 09:54 PM »
"Thor-Able" (orginally proposed as "Thor-Vanguard") was a Thor first stage topped by Vanguard second, and in some cases, third stages.  The second ("Able") stage was a pressure-fed nitric acid/UDMH stage powered by an Aerojet AJ-10 series engine. The third stage was a spin-stabilized Allegany Ballistics Lab X-248 "Altair" series solid motor.

The rocket, in two-stage form, was created by Ramo-Wooldridge Space Technology Laboratories (as the prime contractor) to test ICBM ablative reentry vehicle techology before Atlas and Titan were ready.  In 1958 it flung GE Advanced Reentry Test Vehicles more than 10,000 km to prove the ablative technology.  It was the first time that a big USAF liquid fueled rocket had staged successfully.  The two-stage rocket was controlled by an autopilot rather than an active guidance system.

Someone at STL quickly realized that Thor-Able could be turned into an ICBM (briefly named "Thoric") - that it would be able to carry the lighter RVs and warheads soon to appear.  The idea was rapidly quashed by the chain of command, which also removed STL from the Thor-Able prime contractor role in favor of Douglas.

Thor's first orbital attempts were part of ARPA's "Operation Mona", better known as "Pioneer" - the name assigned by NASA when it assumed control after the first launch.  Pioneer was the first U.S. attempt to reach the Moon.  Adding radio guidance to the Able second stage and an ABL X-248 third stage created the "Thor-Able 1" variant to do the attempt.  Three attempts in 1958 failed to reach the moon, but did manage to loft Pioneer 1 to record altitude where it collected data on the Van Allen belts.

"Thor-Able 2" was a two-stage variant with BTL guidance in the Able stage that boosted GE "RVX-1" (or "Precisely Guided Reentry Test Vehicle") scaled ablative reentry vehicles on multiple ICBM-distance flights  in 1959.  RVX-1 looked a lot like the Mark 3 and 4 RVs that later topped Atlas and Titan ICBMs.  The Navy managed to recover some of these, proving the design.

Thor-Able 2 with a third stage orbited NASA TIROS 1, the first weather satellite, in 1960.  Thor-Able's 3 and 4 orbited NASA's Explorer 6 and Pioneer 5 in 1959 and 1960, respectfully.  These used an improved AJ10-101A second stage engine.

Thor-Able served as the starting point for NASA's highly successful Thor-Delta, which first flew in 1960.

 - Ed Kyle
« Last Edit: 07/24/2016 10:01 PM by edkyle99 »

Offline Antilope7724

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Re: Thor Booster Variants
« Reply #7 on: 07/25/2016 12:42 AM »
From the Defense Technical Information Center website, this pdf:

"A Satellite and Space Vehicle Program for the Next Steps Beyond the Present Vanguard Program. - Dec 10, 1957 - Naval Research Laboratory. - 130 pages

Diagrams in PDF:

pg 110 - Fig. 30 - Thor-Vanguard vehicle
pg 114 - Fig. 34 - Improved Thor-Vanguard three-stage vehicle.
pg 117 - Fig. 37 - Improve Thor-Vanguard four-stage vehicle


http://www.dtic.mil/dtic/tr/fulltext/u2/339967.pdf

Offline Antilope7724

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Re: Thor Booster Variants
« Reply #8 on: 07/25/2016 01:11 AM »
From the Defense Technical Information Center website, this pdf:

"Preliminary Plan for Operation Fish Bowl (Atomic Test using Thor missile). - Nov 1961 - Air Force Special Weapons Center, Kirtland Air Force Base, New Mexico"


Diagram in PDF:

pg A10 - Fig. 4 - (Thor) Typical Launch Emplacement and Control Area


http://www.dtic.mil/dtic/tr/fulltext/u2/a469481.pdf

Offline Antilope7724

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Re: Thor Booster Variants
« Reply #9 on: 07/25/2016 01:36 AM »
From Archive.org:

"Design feasibility report: Thor test booster for the NASA manned space capsule"
Douglas Aircraft Company - Dec 1958

Diagrams in PDF:

Pg 13 - Figure 1 - Thor Test Booster for NASA Capsule - Outboard Profile

Pg 14 - Figure 2- Thor Test Booster for NASA Capsule - Detail of Adapter Section

https://archive.org/details/nasa_techdoc_19780072545

Offline edkyle99

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Re: Thor Booster Variants
« Reply #10 on: 07/31/2016 12:34 AM »
At the dawn of the Space Age the highest priority U.S. space program was U.S. Air Force Weapons System 117L, also known as the Advanced Reconnaissance System. One component of WS-117L was the "Corona" photographic "spy" satellite, which returned exposed film in small "satellite recovery vehicles".

For the program, Lockheed Missiles and Space Company developed a new upper stage named "Hustler", later renamed "Agena".  Agena A was more than a rocket stage, it was an orbiting platform for Corona - a spacecraft in its own right.  It was powered by a Bell 8048 UDMH/IRFNA turbopump-fed engine.  The engine was not restartable, so after separating from Thor the stage would coast for a couple of minutes to apogee before beginning its burn.  Agena's forward section housed an inertial guidance system that used horizon sensors to provide updates.  Cold-gas thrusters located in its aft section provided flight control. 

Fifteen Thor-Agena A launches occurred between February 28, 1959 and September 13, 1960.  All launched toward near-polar orbits from converted Thor IRBM pads 75-3-4 and 75-3-5 at Vandenberg AFB.   The missions were given the "Discoverer" cover name.  Discoverer was said to be a scientific research effort, but it was actually a Corona development program.   

Development was hard-won.  One Agena A stage was destroyed even before the first flight in the "Discoverer Zero" pad accident on January 21, 1959. *   Six of the 15 Thor-Agena A launches failed to reach orbit, and a seventh launch failed to achieve the proper orbit due to a guidance system failure.  Brand-new Agena was most-often the culprit.  Not until Discoverer 13, flown in August 1960, would a capsule be orbited and successfully recovered - the first man-made object recovered from space.  Discoverer 14 returned film containing images taken by the spacecraft's Keyhole camera.  The images covered 1.5 million square miles of Warsaw Pact territory and revealed the presence of 64 previously unknown airfields, 26 surface to air missile sites, and a previously unknown launch center at Plesetsk.

 - Ed Kyle

* A sneak circuit triggered during a pre-launch test caused the stage to fire its ullage rockets. Agena 1019 was subsequently scrapped, but the Thor 160 booster was refurbished and used on the Discoverer 12 flight in 1960.
« Last Edit: 07/31/2016 03:16 PM by edkyle99 »

Offline edkyle99

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Re: Thor Booster Variants
« Reply #11 on: 08/02/2016 04:33 PM »
Thor DM-18C was a special test vehicle that was powered by an upgraded Rocketdyne MB-3 Block 2 (LR-79-NA-11) engine that produced 165,000 pounds thrust.  A GE low drag fairing topped the missile, covering the standard GE Mark 2 reentry vehicle.  DM-18C tested the improved, higher thrust engine and demonstrated modest range improvement.  Three launches, all from Cape Canaveral LC 18B, took place during January-February, 1960 (Thors 256, 259, and 263).  All were successful.

MB-3 Block 2 would soon begin to power Thor space launch variants.

 - Ed Kyle
« Last Edit: 08/02/2016 07:19 PM by edkyle99 »

Offline edkyle99

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Re: Thor Booster Variants
« Reply #12 on: 08/05/2016 12:34 AM »
In 1960, ARPA and the U.S. Air Force began flying Thor-Able-Star, originally named "Thor-Epsilon" which used the Aerojet General "Able-Star" pressure-fed hypergolic second stage powered by an AJ10-104 series engine.  Developed for primary customer the U.S. Navy, Able-Star was the world’s first re-startable stage.  It was a fat version of the Able stage, carrying more than twice as much propellant. 

Thor's tapered guidance section was replaced by a stepped interstage adapter.  MB-3 Block 1 150 Klbf engines apparently powered the initial Thor boosters, with MB-3-2 165 Klbf engines replacing them at some point.  A lightweight STL guidance system topped the second stage.  Nitrogen jets provided three-axis flight control of the stage during coast periods. 

Thor-Able-Star flew 19 times during 1960-65, including 11 launches from the Cape and 8 from Vandenberg AFB.  It performed the first in-space stage restart during its first flight on April 13, 1960.  After the stage completed its initial 258 second burn, it and its Transit 1B payload coasted for 19 minutes before the stage performed a second, 13 second long burn to raise the orbit. 

Early flights orbited the U.S. Navy's initial Transit (navigation) and U.S. Army's Courier (communications) satellites, along with Solrad/GRAB electronic intelligence radar signal "spy" satellites flown piggyback with Transit.  The final two of six Cape-launched Transit satellites were powered by SNAP 3B nuclear power sources (radio-isotope thermoelectric generators or "RTGs") - the first time that RTGs were launched into orbit.  Thor-Able-Star also orbited ANNA 1B (Army, Navy, NASA, Air Force) a satellite that carried beacons for use in ground surveying.   

Thor-Able-Star flew from Vandenberg AFB Complexes 75-1-1 and 75-1-2 during 1963-65.  The sites were later renamed Space Launch Complex (SLC ) 2 East and 2 West, respectively.  All eight Vandenberg launches carried Transit navigation satellites, aimed toward near-polar orbits.  They used SNAP 9A RTGs, which were loaded with more Plutonium 238 than the SNAP 3B RTGs.  The SNAP 9A design was discontinued after the Transit 5-BN-3 flight failed to reach orbit due to an Able-Star stage failure.  The RTG disintegrated in the atmosphere releasing about 1 kg of Plutonium 238.  The final five Transit-O ("Oscar")  missions, all successful from a launch vehicle perspective, used solar powered satellites.

Thor Able-Star's early flight record was spotty, with five launch vehicle failures, two by Thor and three by Able-Star, during the first 10 flights.  But only one of the final nine Thor Able-Stars, the one that carried the last nuclear powered Transit, failed, and the Thor first stage itself flew successfully during the final 14 flights. 

Although August 13, 1965 saw the last flight of Thor-Able-Star, the basic stage structure would subsequently migrate to NASA's ever-improving Delta launch vehicle.  Today's Delta 2 second stage still uses the basic design. 

 - Ed Kyle
« Last Edit: 08/06/2016 02:59 AM by edkyle99 »

Offline edkyle99

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Re: Thor Booster Variants
« Reply #13 on: 08/17/2016 11:49 PM »
NASA’s Milton Rosen coined the rocket name "Delta".  He chose “Delta” because it would be the fourth Thor-based space launch vehicle after Thor Able, Thor Able-Star, and Thor Agena.  Rosen had led the Naval Research Laboratory’s Viking sounding rocket and Vanguard satellite programs.  He transferred to NASA in October 1958 along with 157 NRL Vanguard program employees to form the Agency’s new Goddard Space Flight Center. 

Thor-Delta was an adaptation of Thor-Able 2 (originally "Thor-Vanguard").  It was meant to serve as an "interim" launch vehicle for NASA, until larger Atlas launch vehicles (Atlas Vega and Atlas Centaur were the plan at the time) were brought on line.  A cold gas-jet attitude control system was added to the previous Able second stage to create Delta.  With this system, Delta could coast and reorient itself in space after its pressure-fed AJ-10-118 engine had performed its burn.  This improved the accuracy of solid fuel third stage spin-up insertions.  Both upper stages were tweaked and weight was shaved from Thor itself.  A Bell Telephone Laboratories BTL-300 radio guidance system was added in an equipment compartment atop the second stage to control the vehicle. Typical missions saw the second stage coast for several minutes after its burn before aiming and spin/separating the ABL X-248-A5 third stage.

Goddard ordered 12 Thor-Deltas from Douglas Aircraft and the other stage contractors in April 1959.  The first, carrying Echo 1 from Cape Canaveral’s Complex 17A on May 13, 1960, failed.  A re-try in August with Echo 1A succeeded.  So did the third, and fourth, and so on until all of the final 11 were successful.  They orbited five Tiros, two Explorer, one Orbiting Solar Observatory, Ariel 1 the first U.K./U.S. satellite, Echo 1A, and Telstar 1 the famous experimental AT&T active repeater communications satellite. With such unprecedented success, NASA removed the "interim" label and ordered more, improve Thor-Deltas, about which more later. 

 - Ed Kyle
« Last Edit: 08/18/2016 02:49 AM by edkyle99 »

Offline edkyle99

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Re: Thor Booster Variants
« Reply #14 on: 08/24/2016 06:32 PM »
More-capable Thor Agena B began flying on October 26, 1960.  It launched 43 times, failing eight times, during its five-years of service.  It used an upgraded DM-21 Thor first stage powered by an MB-3 Block 2 (initially) or Block 3 engine that produced 165 to 170 Klbs of liftoff thrust.  The original Thor guidance section was replaced by a shorter, lighter adapter section.  The Agena B second stage, which was powered by the restartable 16 Klbf thrust Bell 8081 (initially) or 8096 engine engine, was 60 inches in diameter and weighed about 14,770 lbs fueled.  It carried two times more propellant than Agena A and used a more powerful, more efficient engine that also gained payload capability by being able to restart.  Like Agena A, Agena B was a spacecraft in its own right, able to maintain attitude while operating on batteries for up to two weeks. 

The improved launch vehicle orbited Keyhole 2 through 5 (mostly) film return spysats and three "Ferret" electronic intelligence satellites.  It also flew several times for NASA, orbiting second generation weathersat Nimbus 1, Canadian ionespheric satellites Alouette 1 and 2, and NASA's Echo 2 and Explorer 31.  Alouette 1, the first non-U.S. or U.S.S.R. built satellite, operated for a then-unheard-of decade.

Thor Agena B flew from three VAFB pads, flying 17 times in 1961 and 18 times in 1962.

Most of the NASA launches took place a year or two after Thor Agena B was done with its Pentagon work.  The NASA launchers appeared to use Agenas that were similar to the three Ferret launchers, with longer cylindrical equipment sections rather than the partially tapered sections used by the KH Agenas.

 - Ed Kyle
« Last Edit: 09/10/2016 02:50 PM by edkyle99 »

Offline Blackstar

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Re: Thor Booster Variants
« Reply #15 on: 08/24/2016 07:53 PM »
I think that the Agena B could restart only once or twice. When they developed the Agena D it had a multi-start capability.

Offline edkyle99

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Re: Thor Booster Variants
« Reply #16 on: 08/25/2016 02:11 AM »
I think that the Agena B could restart only once or twice. When they developed the Agena D it had a multi-start capability.
Yes.  As near as I can tell, most of the Thor Agena B missions, which either went to LEO or to slightly elliptical orbits with low perigees, used a single restart for a total of two Agena burns.  The first burn was usually something like 234-ish seconds duration, while the second burn at first apogee would only last a few seconds.  Agena B was the second stage to restart in orbit (Able Star was first), but it was the first turbopump powered stage to restart.

 - Ed Kyle
« Last Edit: 08/25/2016 02:14 AM by edkyle99 »

Offline Old Space Dude

Re: Thor Booster Variants
« Reply #17 on: 08/28/2016 12:51 AM »
  As I understand things, the Thor-Delta used an improved first-second stage separation system that was tested on the last two Thor-Able launchings.

  The Thor-Ablestar launch failure of April 1964 has always seemed to be something of a mystery as to what
exactly went wrong.

  I have always thought that the Thor-Agena -D launch of the Star-rad payload of October 1962 must have looked like the 1962 Ferret vehicles, with just a simple nose cone atop  the Agena.

  Any comments?

Offline gwiz

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Re: Thor Booster Variants
« Reply #18 on: 08/28/2016 09:45 AM »
That's what the pictures in the Peter Hunter collection show.

Offline edkyle99

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Re: Thor Booster Variants
« Reply #19 on: 08/28/2016 03:09 PM »
  As I understand things, the Thor-Delta used an improved first-second stage separation system that was tested on the last two Thor-Able launchings.

  The Thor-Ablestar launch failure of April 1964 has always seemed to be something of a mystery as to what
exactly went wrong.

  I have always thought that the Thor-Agena -D launch of the Star-rad payload of October 1962 must have looked like the 1962 Ferret vehicles, with just a simple nose cone atop  the Agena.

  Any comments?
The Star-rad shroud had a similar conical section, but it sat straight upon the equipment section of the Agena.  The Ferret shrouds included a short cylindrical section (maybe 15-20 inches tall) below the cylindrical section.  Both shrouds had a similar brass color.

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.  I don't know enough details about the guidance system to understand exactly what happened.  My understanding is that the Thor phase of flight was under the control of an autopilot rather than a guidance system.  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.  At that point, it would have been sending "guidance signals ... to Thor".  It was a may have been radio guidance or it may have been a simplified inertial system.  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.

EDIT:  A bit more information.  Guidance was a Space Technology Lab radio guidance system that used a Burroughs J-1 computer on the ground to integrate trajectory based on doppler shift measurements from a transponder on the vehicle.  Trajectory corrections were transmitted to the vehicle during the second stage of flight. 

I'm adding a couple of low resolution trims from the high resolution Peter Hunter images that are being steadily added to L2.  The Ferret example used an Agena B while Star Rad rode on an Agena D.

 - Ed Kyle
« Last Edit: 08/28/2016 07:46 PM by edkyle99 »

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.

Offline 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."

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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.

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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

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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 »

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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.

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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.

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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

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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.

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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.

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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 »

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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."

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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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Offline edkyle99

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Re: Thor Booster Variants
« Reply #40 on: 09/08/2016 02:39 AM »
Thor-Agena D used a "standardized" Agena D upper stage that was designed to fly atop Thor, Atlas, and Titan with minimal changes.

Agena D used an improved Bell 8096 restartable engine, still producing 7.26 tonnes thrust but now with higher specific impulse.  It also used a Bell Telephone Laboratories (BTL) 600 radio guidance system. 

Thor-Agena D flew 21 times during 1962 to 1967 from Vandenberg AFB pads 75-1-1, 75-1-2, 75-3-4 and 75-3-5, carrying Keyhole 4 and 5 film return spysats, DSAP Block 1 military weather satellites, Poppy electronic intelligence satellites, and experimental U.S.Navy satellites among others.  Four launches failed, and a fifth placed Poppy 1A/1B in a too-high orbit when Agena failed to cut off as planned.  The satellites still functioned, but the orbit limited data collection.

 - Ed Kyle
« Last Edit: 09/08/2016 02:40 AM by edkyle99 »

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Re: Thor Booster Variants
« Reply #41 on: 09/08/2016 02:25 PM »
Thor-Agena D used a "standardized" Agena D upper stage that was designed to fly atop Thor, Atlas, and Titan with minimal changes.

Yes, the Agena A and B were all custom built for the mission and launch vehicle they were used with; Agena D was an attempt to create one standard configuration. It did improve overall reliability even though quite a few Agena failures still occurred in the mid-to-late 60s.

The Atlases were also custom built for each space mission, although the basic design of them was derived from the Atlas D missile. After the failure of Mariner 1 and five consecutive Ranger probes (plus a string of failed DoD launches from the West Coast), a board of inquiry was established that recommended one standardized Atlas for all space launches, as well as better assembly, checkout, and prelaunch procedures. NASA frequently complained about the poor quality control on Atlases and the numerous repairs and hardware modifications they needed before launch, though some of that no doubt went hand-in-hand with the hapless Convair technicians having to memorize the technical details for about 20 different flavors of Atlas. This eventually led to the Atlas SLV-3, which arrived in 1965 as the Atlas ICBM program was ending and replaced the multitude of earlier Atlas variants. The SLV-3 was basically an Atlas D core with thicker tank walls to support the weight of upper stages, as well as uprated engines.

The Soviet program did the same thing with the R-7; after it was retired from ICBM use, they settled on one standardized model instead of the numerous R-7 models flying pre-1965.
« Last Edit: 09/08/2016 05:06 PM by Chrup4 »

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Re: Thor Booster Variants
« Reply #42 on: 09/08/2016 02:57 PM »
The SLV-3 was basically an Atlas D core with thicker tank walls to support the weight of upper stages, as well as uprated engines.

There was more to it.  Standardized avionics with different guidance systems for each coast. Standardized electrical interfaces for upper stage or payloads. 

Offline edkyle99

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Re: Thor Booster Variants
« Reply #43 on: 09/13/2016 04:20 PM »
NASA/Goddard couldn't ignore the success of the original twelve Thor-Deltas, so it ordered more.  These featured incremental improvements, introduced pretty much "one at a time".  The method worked.  Only 2 of these 24 Deltas would fail outright.

Delta A introduced MB-3 Block 2 engines that produced 170 klbf liftoff thrust.  Delta A, which flew twice in 1962, also featured a shorter interstage between Thor and Able to shave weight.  The improved Delta actually stood 4 to 5 feet shorter than the original Thor-Delta. 

Delta B, which flew nine times during 1962-64, introduced a 36 inch second stage stretch and improved AJ-10 engine performance.  This variant launched Explorer 17, TIROS 7 and 8, Relay 1 and 2, Telstar 2, and Syncom 1 and 2.  Syncom 1 was the first launch to GTO, though the satellite was lost during its apogee motor firing.  Syncom 2 succeeded, reaching an inclined geosynchronous orbit.     

Delta C added a more powerful ABL X-258 “Altair 2” third stage during its 11 flight, 1963-67 run.  It orbited more Explorers and a string of early solar observatories and weather satellites.  Remarkably, Delta boosted the TIROS 9 and 10 and ESSA 1 weathersats into near sun synchronous orbits - from Cape Canaveral, Florida!  The flight paths doglegged south, crossing Cuba and Panama before the third stage fired over the equator just northwest of South America to complete the insertion. (Delta would not fly from Vandenberg AFB until 1966.)

Delta C1 added an even more potent United Technologies FW-4D third stage motor during its two launches.  Delta 64, the 38th and final Thor-Delta with the 32 inch diameter Vanguard-derived second stage, orbited NASA’s fifth Orbiting Solar Observatory (OSO 5) on January 22, 1969.  This was the final Thor-Delta to fly without strap-on solid motors.  The old Vangaurd stage scored its 37th consecutive "Delta" orbital success on that flight, a relic of the early Space Age surviving to fly even after NASA had launched astronauts atop massive Saturn V boosters a few miles up the Florida coast.

 - Ed Kyle
« Last Edit: 09/13/2016 06:23 PM by edkyle99 »

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Re: Thor Booster Variants
« Reply #44 on: 09/19/2016 02:44 PM »
Thrust Augmented Thor Agena B/D

Thor-Agena was beefed up with the addition of three Thiokol Castor 1 solid rocket motors beginning in 1963.  These "Thrust Augmented Thor" (or TAT) boosters lifted two Agena B, and 61 Agena D, stages with payloads toward orbit from 1963 until 1968.  The Castor 1 motors, derived from the Sergeant missile motor, nearly doubled the liftoff thrust compared to Thor-Agena.  The solids burned for about 40 seconds, with the last dozen seconds comprising a tailoff.  They were jettisoned at T+65 seconds to reach a safe drop zone.  The boosters augmented the upgraded MB-3 Block 3 Thor first stage engine, which itself burned for nearly 150 seconds.

TAT-Agena D would become the most-oft flown U.S. Air Force Thor space launch vehicle.  It could lift roughly 1.5 tonnes to polar orbit, including the Agena stage.  The vehicle's busiest year was 1964, when 20 launches occurred from Vandenberg.

Five pads, 75-1-1, 75-1-2, 75-3-4, 75-3-5, and PA-1-1, a former Atlas Agena pad on the U.S. Navy test facility at Point Arguello (incorporated into Vandenberg as South Vandenberg after 1964), handled TAT Agena D launches. 

For the first time, Keyhole 4A imaging satellites equipped with two film return "buckets" were flown, accounting for the majority of launches.  TAT-Agena D also orbited electronic intelligence satellites, the Quill 1 experimental radar mapping satellite, and three NASA payloads (OGO 2 and 4 and PAGEOS).  TAT-Agena B orbited NASA's NIMBUS 2.   

 - Ed Kyle
« Last Edit: 09/19/2016 08:02 PM by edkyle99 »

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Re: Thor Booster Variants
« Reply #45 on: 09/20/2016 01:50 AM »
Ed might like to know that I found a couple of mistakes/omissions on his Space Launch Report failure list.

1. Pioneer launch 8/17/58--"Thor turbopump T+28 seconds, RSO"

This event happened at 77 seconds and there was no RSO action; the Thor destroyed itself.

2. Corona 67 3/24/64--"Failed to orbit"

The Agena suffered a power failure (this happened several times on T-A launches).

3. Corona 99 R&D 9/2/65--"Agena failed, RSO"

This was the famous failure where high wind pushed the booster off its flight path and debris fell on a trailer. The payload, a mishmash of scientific experiments dubbed MPRV, had nothing to do with the Corona program.

4. Corona 108 5/2/66--"Failed to orbit"

The Agena failed to separate from the Thor and the entire vehicle fell into the Pacific Ocean.

5. Corona 141 2/17/71--"Failed to orbit"

This was the launch mentioned earlier in the thread where an improper prelaunch procedure resulted in the Thor experiencing turbopump failure shortly after liftoff.

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Re: Thor Booster Variants
« Reply #46 on: 09/20/2016 03:54 AM »
Ed might like to know that I found a couple of mistakes/omissions on his Space Launch Report failure list.

1. Pioneer launch 8/17/58--"Thor turbopump T+28 seconds, RSO"
[etc.]
Definitely need to update those lists.  I started that project in 1998.  Much of that information has been updated by declassification, etc., since.

 - Ed Kyle

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Re: Thor Booster Variants
« Reply #47 on: 09/20/2016 04:26 AM »
Definitely need to update those lists.  I started that project in 1998.  Much of that information has been updated by declassification, etc., since.

The Air Force was vague about DoD mission failures before the '80s, sometimes not even admitting they happened at all. Which makes it all the more strange that the February '71 Thor failure was widely known for years and Astronautix had the full details about it. However, the fact that it was a low-altitude failure would have made it harder to hide than an event that occurred late in the launch.

Also as one more addition, Gambit 20 on 7/12/65. This was reported for years as an Atlas control failure and RSO destruct shortly after liftoff, but it has since been revealed that the sustainer engine accidentally shut down due to a computer malfunction, causing the Atlas to plunge into the ocean some 680 miles downrange.

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Re: Thor Booster Variants
« Reply #48 on: 09/25/2016 06:59 PM »
Thors lofted six ASSET (Aerothermodynamic/elastic Structural Systems Environmental Tests) lifting body reentry experiments on suborbital flights from Cape Canaveral/Cape Kennedy during 1963-65.  These were U.S. Air Force missions that evaluated reusable, maneuverable, re-entry vehicle designs that might be able to fly to a precise landing point on earth.  McDonnell Aircraft of St. Louis built the ASSET vehicles.  The original reason for the program was to support X-20 development, but ASSET continued after X-20 was cancelled.  One of the ASSET reentry vehicles was recovered after parachuting to an ocean landing.  Two other recoveries were attempted.  Significant telemetry hauls were made even when the vehicles were not recovered. 

Single-stage Thors, retired UK IRBMs returned to Tulsa, Oklahoma for refurbishment, performed three of the flights as "DSV-2F" variants.  Two-stage vehicles that also used retired Thor first stages topped by what were essentially Delta B type second stages performed the other three flights, as "DSV-2G/Delta" vehicles.  The Delta second stage was only partially loaded with propellant for a relatively short 50-60 second burn.  The only mission failure occurred during the first DSV-2G launch when the second stage failed to ignite.  The final ASSET launch on February 22, 1965 was the last U.S. Air Force Thor flown from Cape Canaveral.

 - Ed Kyle
« Last Edit: 09/25/2016 07:05 PM by edkyle99 »

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Re: Thor Booster Variants
« Reply #49 on: 09/26/2016 01:43 PM »

3. Corona 99 R&D 9/2/65--"Agena failed, RSO"

This was the famous failure where high wind pushed the booster off its flight path and debris fell on a trailer. The payload, a mishmash of scientific experiments dubbed MPRV, had nothing to do with the Corona program.
 

Well, it wasn't a standard recoverable CORONA but the launch is included in the declassified CORONA documents
as being officially part of the CORONA program, as was 1962's still-very-poorly-documented STARAD. I agree
they had little to do with the rest of the CORONA program.
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Re: Thor Booster Variants
« Reply #50 on: 10/05/2016 01:24 AM »
Thor DSV-2J vehicles were retired Thor DM-18A IRBMs that were refurbished for use in ASAT Program 437 and its follow-ons.  A total of 17 of these Thors performed suborbital flights between 1964 and 1975.  The launches were from two Johnston Island launch emplacements originally built for Operation Fishbowl. 

Program 437 Thors were designed to pass within 3 nmi of an orbiting satellite where the missile's 1.44 mT W49 warhead would destroy the satellite.  Test launches were performed with dummy warheads against orbiting U.S. upper stages and satellites.  A total of nine launches took place.  During the initial tests, two Thors would be counted down simultaneously to ensure that at least one would meet the short launch window.  (A sizable staff was required.  Personnel rotated between Johnston Island and a training pad at Vandenberg AFB.)  The ASAT system stood active watch from 1964 until 1970 (longer than Thors had stood IRBM duty), then was placed on disassembled standby until 1975.

Program 437AP (Alternate Payload) carried a camera system rather than a warhead, to photograph orbiting satellites.  The camera and film reentry vehicle was adapted from Corona KH-4.  Only four launches took place during 1965-66, two of which apparently succeeded in photographing orbiting U.S. objects.

After the ASAT program stood down, two one-off launches took place in 1970.  The first, for Program 922 (former 437Y) was an ABM sensor test against a Minuteman 2 RV launched toward Kwajalein.  The Thor shut down 6 seconds early, preventing an intercept, which would not have occurred regardless because, first, the payload and Thor collided after separation and, second, the Minuteman RV failed to separate from its upper stage!  I haven't seen any photos of this Thor, but it was said to have a separable maneuvering payload. 

The second launch, for the High Altitude Program (HAP), was completely successful.  This Thor's heavy payload, which created a simulated nuclear explosion for an on-board X-ray detector to sense, was housed in an Agena-like shroud, which required installation of a special service tower at LE-2.  (I wonder if the tower might also have supported the 922 launch.)  A reentry pod returned film or data or both.

After four years of non activity, Johnston Island hosted two final Thor launches in 1975.  These BMDTTP (Ballistic Missile Defense Test Target Program) launches served as targets for Kwajalein ABM radars.  I haven't seen any photos of these vehicles, but I have read one report that they were in their IRBM configuration.  They were the final suborbital Thor launches.

 - Ed Kyle
« Last Edit: 10/05/2016 02:42 PM by edkyle99 »

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Re: Thor Booster Variants
« Reply #51 on: 10/05/2016 08:13 AM »
so far i know used BMDTTP standard Thor IRBM
also for Operation Fishbowl (High altitude Nuclear bomb test)
https://en.wikipedia.org/wiki/Operation_Fishbowl

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Re: Thor Booster Variants
« Reply #52 on: 10/10/2016 07:19 PM »
Goddard Center adopted solid motor thrust augmentation to Delta about 1.5 years after it was proven by the U.S. Air Force TAT-Agena D.  Adding three Castor 1 SRMs to the DSV-3C Delta C model created "Delta D" (DSV-3D), also known as "Thrust Augmented Delta" (TAD).  The engine skirt and engine section were slightly modified to support the SRM loads.  TAD jumped off its pad with a nearly 2.37 thrust to weight ratio.  This variant only flew twice, but both launches were historic. 

Delta 25 boosted Syncom 3 to GTO on August 19, 1964.  The extra boost allowed for a 16.5 deg GTO.  Syncom 3's own apogee kick motor and thrusters then had enough energy to boost itself into the first-ever geostationary orbit.  The satellite was positioned above the International Date Line, where it relayed coverage of the 1964 Tokyo Olympics.   

Delta 30 performed a similar launch, on April 6, 1965, for "Early Bird", the first commercial communications satellite.  Early Bird, or Intelsat 1, was similar to the first three Syncoms, but provided 240 telephone circuit equivalent service (or one TV channel).  This garbage-can size satellite substantially increased trans-Atlantic circuit capacity, decisively changing how long-range telecommunication service would subsequently be provided.  Early Bird functioned for four years before being retired.

 - Ed Kyle
« Last Edit: 10/26/2016 05:25 PM by edkyle99 »

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Re: Thor Booster Variants
« Reply #53 on: 10/21/2016 12:40 PM »
Thor Burner 1 (originally "Thor Altair"), was developed to orbit Defense Meterological Satellite Program missions (originally Defense Satellite or Systems Application Program) to support NRO Corona missions.  The early DSAP satellites, built by RCA, were derived from the original TIROS spinners.  Scout, intended to launch these satellites, was still struggling at the time (three of five DSAP launches failed), so plans were made to top refurbished retired Thor IRBMs with Scout "Altair" fourth stages and payload "heat shields".  The move was costly for LTV and NASA, which saw eight planned Scout launches canceled.

Two types of motors and heat shields ended up flying atop Thor Burner 1.  The first two, in 1965, used Lockheed/Grand Central Rocket Co. MG-18 motors and 25.7 inch diameter heat shields from the two already built Scouts assigned to the program.  The final four in 1965-66 used UTC FW-4S Altair 3 motors and 34 inch diameter heat shields. 

Douglas Aircraft replaced the Thor guidance section with a shorter, lighter set of adapters and swapped inertial for lighter BTL radio guidance.  The company also added a cold gas attitude control system atop Thor to provide stability during the coast to apogee and the proper attitude for second stage spin-up and separation.  I'm looking for details on this system, which might only have been used by the FW-4S vehicles that went to higher orbits.

Launches took place from VAFB 4300 B6 (former 75-2-6, later SLC 10W) to boost the tiny satellites into sun synchronous orbits.  SAC's 4300 support squadron performed the launches.  Four of the six launches were successful.  The payload heat shield failed to separate during the first launch and the second stage motor failed to start during the fifth flight.

Subsequent "Thor Burner 2" types continued the DMSP launches until 1980, as we shall see.

 - Ed Kyle
« Last Edit: 10/23/2016 02:58 PM by edkyle99 »

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Re: Thor Booster Variants
« Reply #54 on: 10/23/2016 02:33 PM »
I've updated the Thor-Altair (Burner) card and discussion in the previous message.  I wonder if anyone knows more about the cold gas attitude control system that Douglas added atop Thor to allow a coast before second stage spin-up (possibly only for the FW-4S upper stages).  Was this on an adapter section that separated from Thor, or did Thor stay attached during the coast?  Surprisingly little information on the Internet about this. 

There was an Air Force history by Captains Richard L. Geer, James F. Roberts, and Calvin H. Markwood titled “Development of the Burner Space Launch Vehicles,” that was written for the Space Systems Division Air Force Systems Command in 1966, but I can't find it online.

In the NRO weather satellite history by Hall, there is an interesting note by Captain Geer.  He said that Douglas Aircraft Company put the new launch vehicle “on the front burner”, thus the name “Burner". 

 - Ed Kyle
« Last Edit: 10/23/2016 02:45 PM by edkyle99 »

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Re: Thor Booster Variants
« Reply #55 on: 10/26/2016 04:10 AM »
After Thrust Augmented Delta, the next logical step was to take advantage of all that thrust by increasing the second stage mass.  That step, taken in 1965, created Thrust Augmented Improved Delta (TAID).  Douglas borrowed the Able Star tanks, stretched them, and added an improved AJ10-118E engine to create the second stage.  This roughly doubled the burn time compared to the previous Vanguard-based Delta stage, increasing payload to orbit.  The TAID second stages performed a single burn, then provided attitude control during a coast prior to spin-up and separation of the third stage.   

Both Castor 1 and Castor 2 motors could be used with the TAID series.  Castor 2 provided slightly less liftoff thrust but burned slightly longer.  An MB-3 Block 3 Rocketdyne engine powered Improved Delta's Thor first stage.   MB-3-3 improved reliability and a bit more thrust. 

Third stage options included the ABL-258 and FW-4D spin-stabilized solid motors.  With ABL-258, Improved Delta was called "Delta E".  With FW-4D it was "Delta E1".  The rocket was identified as "Delta G" when no third stage was used. "Delta J", with a Star 37D third stage motor, flew once.  (Unflown types included "Delta F/F1", which was Delta E/E1 without SRMs, and "Delta H", which was Delta G without SRMs.)  An Agena-style 65 inch diameter payload fairing topped the rocket, providing much more internal volume than earlier Delta shrouds.

Twenty six TAID launches took place during 1965-71.  Every single one succeeded.  Launches took place from Cape Canaveral and Vandenberg AFB, marking Delta's introduction to the West Coast.

Payloads included Intelsat 2 communication satellites, NASA Explorer and Pioneer satellites, ESSA weather satellites, HEOS 1, ISIS 1-2, and Biosat 1-2.  The Intelsats separated into GTO and raised themselves into GEO.  The Pioneers went into solar orbits.  Most of the Explorers were launched into highly elliptical Earth orbits.  Explorer 35 (IMP-E) inserted itself into lunar orbit after a precise TAID launch.  Delta boosted HEOS 1 into a 440 x 230,000 km x 28.3 deg orbit.  The satellite's apogee kick motor subsequently raised its perigee to 6,800 km.

TAID was the first Delta to sport the soon-familiar "Delta" triangle logo.

 - Ed Kyle
« Last Edit: 10/26/2016 05:16 PM by edkyle99 »

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Re: Thor Booster Variants
« Reply #56 on: 10/26/2016 03:55 PM »
Just wanted to give some thanks for compiling all of this, Ed.  You can really see how Thor became the Delta we know today.

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Re: Thor Booster Variants
« Reply #57 on: 11/01/2016 07:27 PM »
In 1961, Douglas Aircraft proposed a series of Thor upgrades for space launch.  The "Thor Advanced" (Thorad) concept called for a constant diameter airframe that would eliminate the tapered IRBM LOX tank and increase propellant capacity.  Three Sergeant solid motors would augment thrust.  Before Thorad would fly, Douglas would add the solids to a standard Thor to create "Thorad Junior" (better known as TAT Agena-D).  Replacing the MB-3-3 engine with a higher thrust Saturn H-1 engine would create "Thorad B".  These proposals were eventually realized. 

Thorad-Agena D (also Long Tank Thrust Augmented Thor-Agena D), had the constant 96 inch diameter airframe and a 14 foot stretch.  Stage weight increased 45% to nearly 70 tonnes and burn time increased to 218 seconds MECO/227 seconds VECO.  Three Castor 2 SRMs roughly doubled the liftoff thrust provided by the first stage engine.  A new adapter section topped the stage, allowing continued use of the existing transition section and Agena D adapter.  This resulted in a distinctive three-step taper between the first and second stages.

There were 43 Thorad Agena D launches, with three failures, from Vandenberg AFB between 1966 and 1972.  Launches took place from SLC 1W, 1E, 2E, and 3W, the former 75-3-4, 75-3-5, 75-1-1, and PA-1-1.  Payloads included double bucket Keyhole 4A and 4B satellites, Poppy and Strawman signals intelligence satellites, Nimbus weather satellites, OGO 8, and the remarkable SERT 2.

The Nimbus satellites were powered by SNAP-19 RTGs.  On May 18, 1968, Nimbus B was lost when Thorad's control system failed about two minutes into the flight.  Unlike earlier SNAP RTGs, SNAP-19 was designed to survive launch vehicle failure, and it did.  The RTG was eventually salvaged from the Pacific and its nuclear material reused.

Two Thorad-Agena D variants are listed.  SLV-2G (1966-71) used a DSV-2L first stage.  SLV-2H (1969-72) used a DSV-2L-1A first stage. The stages were identical in external appearance.  It is possible that the "1A" was only added to differentiate Thorad-Agena D from Thorad-Delta (which used the DSV-2L-1B stage).  At the time, newly merged McDonnell Douglas was shifting manufacturing from the original Santa Monica Thor factory to Huntington Beach, where the Thorad stages came off a common production line.

Thor 571, launched May 25, 1972, was the final Thorad-Agena D and the last U.S. Air Force Thor-based stage manufactured, although space launches of converted Thor IRBM missiles would continue for several more years. 

 - Ed Kyle
« Last Edit: 11/01/2016 07:32 PM by edkyle99 »

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Re: Thor Booster Variants
« Reply #58 on: 11/15/2016 05:30 PM »
In March 1964, the DMSP program office approved plans to develop a more powerful Thor Burner 2 launch vehicle that still used repatriated Thor IRBMs. 

Burner 2 used a Thiokol Star 37B motor (TE-M-364-2, a modified Surveyor retro-rocket motor) to power the "Burner 2" second stage.  Boeing's Burner 2 stage was built around the Star 37B.  It had a strap-down inertial guidance system and a 3-axis reaction control system, allowing it to coast without spin stabilization. Four 10 kgf hot-gas hydrogen peroxide thrusters performed stage separation, provided pitch and yaw reaction control thrust during the Star 37B motor firing, and completed a vernier maneuver immediately after the Star 37B burn.   Eight 1 kgf gaseous nitrogen cold-gas thrusters on the stage provided pitch-yaw-roll attitude control during coast and performed spacecraft spinup and post-spacecraft separation maneuvers.  Thor Burner 2 was topped by a new Goodyear conical phenolic shroud that enclosed the upper stage and payload.  The unpainted fairing was distinctively vermilion (orange-red) in color. 

Thor Burner 2 flew 12 times from September 16, 1966 to June 8, 1971, carrying 10 DMSP Block 4 and 5A satellites and performing a pair of U.S. Air Force Space Test Program (STP) missions.  All 12 launches were successful.  One of the STP missions, flown on June 29, 1967, used a Star 13A apogee kick motor to insert Aurora 1 and SECOR 9 into a 3,792 x 3,947 km x 90.1 deg polar orbit.

Thor Burner 2A added a third stage and a modified fairing to the Thor Burner 2 design.   A Star 26B motor served as the third stage motor.  The 3-axis Burner 2A control bus was built around the Star 26B.  A Star 37B motor served as the second stage, with the 3rd stage bus providing guidance and control during its burn.  The shroud was extended by the addition of a cylindrical section.  Thor-Burner 2A performed eight launches with DMSP Block 5B and 5C satellites between October 14, 1971 and February 19, 1976. 

The final launch failed because the Thor was not loaded with enough kerosene fuel, causing Thor to burn out a few seconds early.  The upper stages performed their burns, but the end result was insufficient velocity to maintain a stable orbit.  A old mixture ratio typographical error on the LR79 main engine certification testing data sheet was deemed responsible for the improper fuel load.
See:  http://www.thespacereview.com/article/1287/1

 - Ed Kyle
« Last Edit: 11/15/2016 05:40 PM by edkyle99 »

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Re: Thor Booster Variants
« Reply #59 on: 12/02/2016 09:55 PM »
Long Tank Thor Delta

In 1968, NASA gained access to the stretched Long Tank Thor stage already proven as an Agena booster.  Long Tank Thor served as the first stage for Delta Models L, M, N, M6, and N6, which all used the TAID second stage.  L, M, and N used a trio of Castor 2 strap-on solid motors to augment liftoff thrust.  M6 and N6 used six SRMs with three ground-lit and three air-lit.  All motors jettisonned in sets of three beginning after T+90 seconds.

Delta L used the FW-4D third stage motor.  Delta M, the most often-flown Long Tank Thor Delta model,  used the more powerful Star 37D third stage motor.  Delta N did not have a third stage. Deltas M6 and N6 were the six SRM versions (also called "Super Six") of Deltas M and N.

Delta 58, an "N" carrying the Tiros 17 weather satellite from Vandenberg on August 16, 1968, was the first Long Tank Thor Delta (also called "Thorad Delta" or "Long Tank Thrust Augmented Thor Delta").  Altogether, there were twenty-four L, M, N, M6, and N6 flights, with four failures, during 1968-72. They launched eight Intelsat 3, two Skynet 1, two NATO 2, two ESSA, two OSO, and three ITOS/NOAA satellites.  Single launches included HEOS 2, IMP I (Explorer 43), Biosat 3, and TD-1A.

Delta 59, the first "M" with Intelsat 3-1, failed on September 18, 1968 from Cape Kennedy.  The rocket suffered a pitch rate gyro failure that became noticeable about 20 seconds after liftoff.  It began to break up at T+102 seconds.  The range safety officer sent a destruct command 6 seconds later.

Delta 71, another M, left Intelsat 3-5 in a useless orbit on July 25, 1969 when its Star 37D third stage motor either suffered a motor case rupture or a nozzle failure during its burn.

Delta 73, the first Delta L, failed on August 27, 1969 when it attempted to launch Pioneer E from the Cape.  This time the culprit was an unstable high pressure relief valve in the MB-3-3 first stage power pack.  Pressure fluctuations caused a line to rupture and leak hydraulic oil.  First stage main engine gimbal control was lost 213 seconds after liftoff, during the latter portion of the first stage burn.  The second stage separated and ignited, but was too far off course to make up the lost velocity.  Range safety sent a destruct command at T+ 8 minutes 3 seconds.

Delta 86, an N6, failed on October 21, 1971 when its second stage suffered an oxidizer leak.  The stage tumbled out of control after its attitude control system fought the side thrust from the leak.  The control system finally used up its supply of control gas.   

Delta 85, an N, nearly failed after launched from the Cape on September 29, 1971 with OSO 7.  During the AJ10-118E second stage engine's second burn, the stage suffered a control system failure, caused by a nitrogen pressure leak that cascaded into a main engine gimbal thrust vector control (TVC) hydraulic pressure decay.  (The hydraulic pump was run by pressurized nitrogen gas during the coast phase prior to the burn.)  The stage tumbled, but it and OSO-7 still managed to achieve a usable low earth orbit.  Ground crews stablized OSO 7 after it separated, a "save" that allowed it to perform its mission.

Delta 88, launched on March 12, 1972 with Europe's TD-1A science satellite, was the last "N" and the final launch from Vandenberg AFB SLC 2E.  Delta 88 used a transitional Long Tank stage equipped with the first "Universal Boat Tail" - a beefed up aft thrust structure equipped with mounting points for nine solid motors.  The change was part of the transition from Long Tank to Extended Long Tank Delta that began in 1972.

Two transitional Long Tank Thor Delta models flew in 1972-73.  Delta 300 used three Castor 2 strap on boosters and a modified second stage powered by a more-powerful AJ10-118F engine derived from the Titan 3 Aerojet Improved Transtage Engine Program (ITIP).  It burned nitrogen tetroxide and Aerozine 50 (a 50-50 mix of UDMH and hydrazine) rather than the previous nitric acid/UDMH.  Delta 900 used nine Castor 2 boosters (six ground-lit) and the same second stage.  Both models used the Universal Boat Tail.  Neither flew with a third stage. Both used the Delta Inertial Guidance System (DIGS).  Prior Deltas had used radio-inertial guidance. 

Three Delta 300 and two Delta 900 launches took place from Vandenberg AFB.  One (Delta 96) failed to orbit ITOS E from Vandenberg on July 16, 1973 when a hydraulic pump failed 270 seconds after the second stage ignited.  The pump failure led to loss of thrust vector control.  Successes included NOAA 2 and 3, ERTS 1, and Nimbus 5.

Long Tank Thor ended service as an Air Force Agena launcher on May 25, 1972.  The final Long Tank Thor Delta launch occurred several months later on November 6, 1973 when Delta 98, a Delta 300 model, orbited NOAA 3 from Vandenberg's still-active SLC 2W.

Long Tank Thor Summary

During seven years of service, 72 Long Tank Thor launches occurred, boosting 29 Delta and 43 Agena missions.  Long Tank served as the basis for the follow-on Extended Long Tank Delta stage.

 - Ed Kyle
« Last Edit: 12/02/2016 09:58 PM by edkyle99 »

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Re: Thor Booster Variants
« Reply #60 on: 12/21/2016 08:16 PM »
Extended Long Tank (ELT) Delta flew 93 times from 1972 until 1990, succeeding 89 times and orbiting all manner of important payloads. 

Extended Long Tank included a roughly 120 inch first stage tank stretch compared to the Long Tank stage.  It flew with both MB-3-3 and RS-27 engines.  Rocketdyne's RS-27 was essentially a repackaged H-1 engine salvaged from the large inventory of unflown Saturn IB engines. A total of 83 RS-27 engines flew.

Three different second stages flew atop ELT Deltas. 

The first was the AJ10-118F powered stage that was a holdover from Long Tank Delta. It was topped by the  65 inch diameter Agena shroud. 

The second was powered by the TR-201 TRW Lunar Module descent engine derivative.  This stage was the first to be suspended within an extended interstage cylinder, through the use of a "Miniskirt".  The design allowed use of a 96 inch diameter payload fairing.  It was informally named "Straight Eight" because, for the first time, the entire launch vehicle had a constant eight foot diameter.

The third was the AJ10-118K powered "ITIP" (Improved Transtage Injector Program) stage that began flying in 1982.  This stage used fatter tanks originally developed for Japan's N-2 launch vehicle.  Today's Delta 2 second stage is similar.

Spin-stablized Star 37D, 37E, and 48B third stage motors flew atop ELT Deltas aimed beyond LEO.  During the Shuttle era when Delta served as an STS backup, NASA carded Delta 3910/PAM-D and Delta 3920/PAM-D variants.  The PAM stage, a Star 48B spin-stable solid motor, was considered part of the "payload" just as it was on Shuttle. 

Delta 147, launched on December 17, 1978, used the first Delta Redundant Inertial Measurement System (DRIMS).  DRIMS improved the inertial measurement unit introduced with DIGS, but kept the DIGS guidance computer.  DRIMS added redundancy on all axes of motion.

ELT Delta's used the four-number model identification system.

                        Delta Model Numbers

        First Digit:  First Stage and Strap on Motor Types

        0:  Long Tank, MB-3-3 engine, Castor 2 motors (1968)
        1:  Extended Long Tank, MB-3-3 engine, Castor 2 motors (1972)
        2:  Extended Long Tank, RS-27 engine, Castor 2 motors (1974)
        3:  Extended Long Tank, RS-27 engine, Castor 4 motors (1975)
        4:  Extended Long Tank, MB-3-3 engine, Castor 4A motors (1989)
        5:  Extended Long Tank, RS-27 engine, Castor 4A motors (1989)

        Second Digit:  Number of Strap on Motors

        Third Digit:  Second Stage Type

        0:  AJ10-118F (Aerojet Transtage derivative, 1972)
        1:  TR-201 (TRW LM Descent Engine derivative, 1972)
        2:  AJ10-118K (Aerojet ITIP engine, 1982)

        Fourth Digit:  Third Stage Type

        0:  No third stage
        3:  Star 37D (TE-364-3, 1968)
        4:  Star 37E (TE-364-4, 1972)
        5:  Star 48B (TE-M-799, 1989)

 - Ed Kyle
« Last Edit: 02/04/2017 03:18 AM by edkyle99 »

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Re: Thor Booster Variants
« Reply #61 on: 01/11/2017 08:27 PM »
Thor Burner 2A could not lift DMSP 5D1, a much upgraded, heavier military weather satellite.  Two Star 37 upper stage motors were needed to reach orbit.  Thus, the final five Thor LV-2F flights, launched between September 11, 1976 and July 14, 1980, flew as Thor Star 37/Star 37/ISS launch vehicles.  "ISS" stood for "Integrated Stage System", a hydrazine-based propulsion system on the satellite that provided 3-axis control during the solid motor burns and a final trim burn.  A Star 37XE motor served as the second stage while a Star 37S-ISS acted as the third stage.  A longer payload fairing with a blunter nose housed both stages and the payload.  The upgraded launch vehicle could lift roughly 500 kg to the DMSP sun synchronous orbit.   

The first four launches were good, but the July 14, 1980 finale was a disheartening failure.   Refurbished IRBM Thor 304 flew true, and the first Star 37 burn looked good, but at Stage 3 startup all telemetry was lost.  It was subsequently determined that connectors between the second and third stages had not disconnected due to a misalignment.  When the Star 37S motor ignited, the wiring harness was jerked out of the third stage and satellite, killing the flight control system.  The stage pitched down and failed to generate sufficient orbital velocity.  It turned out that an incident during launch vehicle erection - a broken pin that caused the rocket to suddenly drop a few centimeters - had most likely caused the connector misalignment.

Thor 304 was the final Thor IRBM to fly, and the final launch from Space Launch Complex 10 West. 

 - Ed Kyle
« Last Edit: 01/12/2017 01:19 PM by edkyle99 »

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Re: Thor Booster Variants
« Reply #62 on: 02/05/2017 02:53 AM »
From 1975 through 1992, it was possible to see "Delta" lookalike rockets liftoff from Tanegashima, Japan.  A total of 24 Thor-based rockets, assembled in Japan under license from the U.S., flew for the National Space Development Agency of Japan (NASDA). There were three variants, all unique to Japan.

N-1 ("N" stood for "Nippon"), launched from 1975 through 1982, was an MB-3-3 powered Long Tank Thor Delta with three Castor 2 boosters.  An MHI built LE-3 pressure-fed hypergolic engine powered the second stage.  A Star 37N solid motor served as the third stage.  An Agena shroud topped the rocket.  N-1 could lift 1.2 tonnes to LEO or 0.36 tonnes to GTO.  It flew 7 times with one failure.  Notable successes included Japan's first geostationary orbit launch, of Kiku 2 (ETS-2) on February 23, 1977.   The lone failure occurred on February 6, 1979 when the fifth N-1's Star 37N third stage collided with its Experimental Communications Satellite (ECS-A) satellite payload shortly after spacecraft separation.

N-2, which flew 8 times during 1981-87, used an MB-3-3 powered Extended Long Tank Thor stage augmented by nine Castor 2 strap on motors.  The second stage was powered by a restartable Aerojet AJ10-118FJ pressure-fed engine (after NASDA's planned LE-4 engine stumbled during development).  The stage used new fatter tanks that would later be adopted by NASA's 3920 series and later Deltas, including today's Delta 2.  Star 37E served as a third stage motor.  N-2 used DIGS inertial guidance.  It could lift 2 tonnes to LEO or 0.73 tonnes to GTO.

H-1, which flew 9 times during 1986-92, introduced a new NASDA-developed common bulkhead liquid hydrogen fueled second stage that was powered by a brand new NASDA-developed LE-5 engine built by MHI and IHI.  The rocket was controlled, for the first time, by an inertial guidance system developed in Japan. H-1 could lift 2.25 tonnes to LEO or 1.1 tonnes to GTO. 

For a time during the post-Challenger accident period, McDonnell Douglas considered adopting Japan's upper stage, or at least the LE-5 upper stage engine, for use on U.S. Delta launch vehicles.

 - Ed Kyle
« Last Edit: 02/05/2017 01:59 PM by edkyle99 »

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Re: Thor Booster Variants
« Reply #63 on: 02/05/2017 05:29 PM »
hi Ed Kyle

There were also another nations interested in license Delta rocket

Delta Made in Germany
Germany look into option to build license or buy Delta rocket during 1960s early 1970s
But I have not solid information about model, who gonna build it, how they want to launch from were.
It's very likely they had to launch from Cape Kennedy.

Source
Several German space books mention the German license Delta rocket
but just a sentence, not further information.

Europa Deltas
ESRO look after the Europa  fiasco for a alternative for launching there Satellite
in 1974 they contacted McDonnell/Douglas  for order on Delta 2314, 2914 and 3914
and construction of Delta launch pad on Kourou space port to be ready in 1977
The French Government and CNES were not amused of this Idea of ESRO...

Source in French language
http://www.capcomespace.net/dossiers/espace_europeen/ariane/ariane1/naissance_1970_1975.htm

Offline edkyle99

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Re: Thor Booster Variants
« Reply #64 on: 02/14/2017 02:20 PM »
Happy Delta 2 Day everyone!

The first Delta 2, a 6925 model with nine Castor 4A SRMs, the first Extra Extended Long Tank first stage, an AJ10-118K powered second stage, a Star 48B third stage motor, and a 9.5 foot diameter metal fairing, orbited GPS-2 1 from Cape Canaveral LC 17A on Valentine's Day (February 14) in 1989.  This was Delta 184, the first of 49 Delta 2 GPS launches, 48 of which would succeed.

I'm working on a Delta 2 (EELT) card, which I'll post here soon.

 - Ed Kyle
« Last Edit: 02/14/2017 02:39 PM by edkyle99 »

Offline edkyle99

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Re: Thor Booster Variants
« Reply #65 on: 02/15/2017 02:24 PM »
During the mid-1980s, McDonnell Douglas shut down the long-running Delta production line as NASA moved payloads to Space Shuttle.  The 1986 Challenger disaster changed everything.  Soon, the U.S. Air Force was asking for an expendable launcher that could orbit the GPS satellites originally slated for STS.  McDonnell Douglas won the resulting Medium Launch Vehicle competition over General Dynamics (Atlas K), Martin Marietta (Titan 3 Commercial), and Hughes (Jarvis).

After pondering use of Japan's H-1 liquid hydrogen upper stage, McDonnell Douglas pulled an early 1980s proposal off the shelf to create "Delta 2".  The rocket was built around a stretched "Extra Extended Long Tank" first stage that was 148 inches longer than the "Extended Long Tank" version.  It carried 96 tonnes of propellant, a 16 tonne increase.

The first, interim Delta 6000 series vehicles used RS-27 engines and upgraded steel-case Thiokol Castor 4A strap on motors.  The ultimate Delta 7000 series rockets used new RS-27A engines that were more efficient in vacuum and new GEM-40 Graphite Epoxy Motors developed by Hercules.  All versions used the existing Aerojet AJ10-118K ITIP-powered second stage.  Star 48B served as the third stage for GPS missions.  A new 9.5 foot diameter standard fairing housed most payloads.  The old 8-foot fairing flew a few times.  McDonnell-Douglas also developed a 10 foot diameter metal shroud based on the company's Titan 3C fairing.

Delta 2 initially used the existing DRIMS guidance and control system, but on December 30, 1995 Delta 230 became the first to use the Redundant Inertial Flight Control Assembly (RIFCA).  RIFCA, built around six ring laser gyroscopes and six accelerometers, provided triple redundant guidance, flight control and mission sequencing functions.

The first Delta 2, a 6925 identified as Delta 184, orbited GPS-2 1 from Cape Canveral LC 17A on February 14, 1989.  Seventeen  6000-series Deltas flew.  Delta 212, the last in 1992, was the final flight of a Saturn H-1 derived RS-27 engine.  Delta 201, the first 7925, orbited the first of the heavier GPS-2A satellites on November 26, 1990.  All told, Delta 2 performed 49 GPS launches with one failure.

In December 1994, NASA requested bids for a Medium Light Expendable Launch Vehicle (Med-Lite).  McDonnell-Douglas's offered Delta 732X and 742X, which used three and four GEM-40 boosters respectfully.  In 1997 a new 10 foot diameter composite payload fairing (10C) began flying for Iridium.  A stretched 10L version was developed for NASA beginning in 2002, ending use of the Titan-derived fairing. 

From 1989 through 2011, Delta 2 was the most often-flown, versatile, productive, and reliable U.S. launch vehicle.  It became the longest-lived essentially unchanged U.S. launcher, even though its ownership and production sites moved twice.  It flew from three launch pads at two launch sites.  It was common to see multiple Deltas stacked simultaneously.  151 Delta 2 rockets flew by the end of 2011 with two failures, making Delta 2 one of the most successful orbital launchers in history.  In addition to its bread-and-butter GPS work, Delta 2 orbited commercial, non-U.S. government, and NASA satellites. 

For NASA, Delta 2 did something no previous Thor/Delta had done - it reached into deep space, to Mars, and to asteriods.  The list of payloads includes Mars Pathfinder, Odyssey, Spirit, Deep Impact, and many others.  Commercial payloads included Iridium and Globalstar "little LEO" satellites.

In 2003, Delta 7920H and 7925H began flying.  They used powerful GEM-46 solid rocket motors reassigned from the terminated Delta 3 program (about which more soon).  They launched the Opportunity Mars rover, the SIRTF/Spitzer space telescope, the planet Mercury orbiter MESSENGER, asteroid Vesta and Ceres orbiter Dawn, gamma ray telescope GLAST, and lunar orbiters GRAIL A and B.

Although Delta 2's Cape launch site was closed after 2011, the Delta 2 story is not over.  Two more launches from Vandeberg AFB SLC 2W remain on tap.  If both succeed - never a given - the rocket's consecutive success string would reach 100.

 - Ed Kyle
« Last Edit: 03/16/2017 02:55 AM by edkyle99 »

Offline Jim

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Re: Thor Booster Variants
« Reply #66 on: 02/15/2017 02:52 PM »
Ed, the 10 foot composite fairing was developed for Iridium.  The long composite was developed for NASA.

Offline edkyle99

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Re: Thor Booster Variants
« Reply #67 on: 03/16/2017 02:52 AM »
During the post-Challenger era, McDonnell Douglas studied liquid hydrogen fueled upper stages for its Delta launch vehicle.  In 1986, it briefly considered  Japan's H-1 LH2/LOX upper stage for the U.S. Air Force Medium Launch Vehicle (MLV) program before deciding on the "Delta 2" approach.  Two years later, it proposed a new LH2/LOX upper stage to be built by Martin Marietta for the MLV-2 program (won by GD Atlas 2).  The company continued to study the idea until, on May 10, 1995, it announced that it would develop "Delta 3" using more than $200 million of its own funds, with a planned first launch in 1998.

Soon, Delta 3 held contracts for 18 launches through 2002, including NASA/NOAA GOES N, O, and P and five ICO Global Communications launches.

Delta 3 used a 4 meter diameter "Delta Cryogenic Upper Stage" (DCUS) and more-powerful Alliant 46 inch diameter Graphite Epoxy Motors (GEM-46) to lift the heavier stage and payload.   The first stage had a shorter but fatter kerosene fuel tank (4 meters rather than 2.4 meters diameter) so that Delta 3 would fit within the Delta 2 service tower.   A Pratt & Whitney RL10B-2 engine with a large Snecma-built extendible nozzle powered DCUS.  At liftoff, the boosters and RS-27A main engine would together produce more than 1 million pounds of thrust.  The rocket could lift 3.8 tonnes to GTO.
 
Delta 3 was assembled in Pueblo, Colorado.  Japan's Mitsubishi Heavy Industries made the 4 meter diameter second stage liquid hydrogen tank and first stage kerosene tank using tank tooling from its H-2 stage. 

On December 15, 1996, McDonnell Douglas and Boeing announced their intention to merge under the Boeing name.  The merger was consummated on July 1, 1997.  The merger would have decisive consequences for the Delta 3 program, though that was not initially apparent.

A relatively smooth development program was followed by a troubled flight program.  Delta 259, the first Delta 3, launched from Cape Canaveral SLC 17B (the only pad rebuilt for the type) on August 27, 1998 with the Galaxy 10 communications satellite.  At about T+50 seconds, the rocket began to suffer 4 Hertz roll oscillations, using up the GEM-46 TVC hydraulic fluid.  The rocket pitched over and broke apart at T+72 seconds.  Flawed roll control equations were found to be the cause.
 
The second Delta 3, Delta 269, launched with the Orion 3 communications satellite on May 5, 1999.  This time the flight proceeded flawlessly through the first RL10B-2 burn, pushing the stage and payload into a parking orbit. After a coast period, the RL10B-2 engine restarted for a planned 162 second burn, but it shut down after only 3.4 seconds, stranding Orion 3 in LEO.  An investigation found that the RL10B-2 engine's combustion chamber had burst during the restart due to defective brazing of a welded reinforcing strip.  Pratt & Whitney subsequently modified its brazing process and its inspection methods.

Delta 3 finally succeeded on August 23, 2000 when Delta 280 launched the 4,348 kg DM-F3 mass simulator to subsynchronous transfer orbit.  By then, however,  Boeing was committed to its Sea Launch commercial launch partnership and had begun to develop Delta 4 for the EELV program.  In 2000, Boeing bought Hughes Space & Communications, the satellite builder that held the bulk of the Delta 3 backlog.  Then the commercial satellite market collapsed, leaving Boeing deeply overextended.  Something had to give, and the first of those somethings was Delta 3, which was quietly shut down after Delta 280.

In the end, Delta 3's primary accomplishment was to prove RL10B-2 in flight for Delta 4, and to prove DCUS, which was the first all-new high energy upper stage developed in the U.S. since the 1960s.  The Delta 4 Medium "Delta Cryogenic Second Stage" was largely derived from DCUS.

This should end the "as-flown" portion of this thread.  It only took eight months to get here!

 - Ed Kyle
« Last Edit: 03/16/2017 08:45 PM by edkyle99 »

Online ZachS09

Re: Thor Booster Variants
« Reply #68 on: 03/31/2017 09:43 PM »
Wasn't there a Delta II 7930 design conceptualized? It was supposed to be like a Delta II 7920, except that the hypergolic-fueled second stage was replaced by the larger LH2-fueled second stage. This is NOT the Delta III I'm referring to, because according to http://www.spacelaunchreport.com/thorh13.html:

"Designers initially contemplated a "Delta 7930" design similar to the MLV II bid.  It was a Delta 2 with a 3.2 meter diameter liquid hydrogen second stage powered by a single RL10 engine.  This rocket would have been able to lift 2.6 tonnes to GTO.  It also would have adhered to Delta's long-term incremental growth tradition."

If this 7930 design DID fly, then the interstage of the first stage would have to be modified to fit the larger diameter of the second stage.
« Last Edit: 04/01/2017 02:35 AM by ZachS09 »
"Liftoff of Falcon 9: the world's first reflight of an orbital-class rocket."

Online brickmack

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Re: Thor Booster Variants
« Reply #69 on: 04/02/2017 04:44 AM »
I found this on my computer. Can't find anything else, but it does show there was some work put into it. Also wondering about that double-barrel version. Also found mention of a Delta III variant using 3 large SRMs in place of the GEMs, and a Delta Lite using a Delta K with 2 of those large SRMs serving as first and second stage (looked about the size of Castor 120, MD's version of Athena?)

Offline edkyle99

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Re: Thor Booster Variants
« Reply #70 on: 04/02/2017 06:25 PM »
I found this on my computer. Can't find anything else, but it does show there was some work put into it. Also wondering about that double-barrel version. Also found mention of a Delta III variant using 3 large SRMs in place of the GEMs, and a Delta Lite using a Delta K with 2 of those large SRMs serving as first and second stage (looked about the size of Castor 120, MD's version of Athena?)
This image came from a February 1990 article in Flight International by Tim Furniss, which can be found here:
https://www.flightglobal.com/FlightPDFArchive/1990/1990%20-%200300.PDF

This article ran about a year-and-a-half after McDonnell Douglas had offered an RL-10 upper stage based bid for MLV II, a contract won by General Dynamics Atlas II.  These early studies eventually led to the 1995 decision to develop Delta III.  Interestingly, Delta III ended up with about the performance shown for the right-most "double-barrel" design in the article.  McDonnell Douglas got there by using more powerful GEMs rather than two RS-27A stages strapped together!

 - Ed Kyle
« Last Edit: 04/03/2017 04:01 PM by edkyle99 »

Offline edkyle99

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Re: Thor Booster Variants
« Reply #71 on: 05/24/2017 02:31 AM »
I've compiled the flown Thor variant "baseball cards" here.
http://www.spacelaunchreport.com/thorflew.html
also accessible here
http://www.spacelaunchreport.com/thorh.html
and here
http://www.spacelaunchreport.com/library.html

 - Ed Kyle

Offline WallE

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Re: Thor Booster Variants
« Reply #72 on: 05/24/2017 12:15 PM »
Ed might want to fix his page on Atlas orbital failures because the link has been broken for months.

Offline edkyle99

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Re: Thor Booster Variants
« Reply #73 on: 05/24/2017 01:40 PM »
Ed might want to fix his page on Atlas orbital failures because the link has been broken for months.
Thanks.  Should be there now.  Feel free to contact me offline, by email, for things like this.

 - Ed Kyle

Offline RIB

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Re: Thor Booster Variants
« Reply #74 on: 05/26/2017 09:45 PM »
I've compiled the flown Thor variant "baseball cards" here.
http://www.spacelaunchreport.com/thorflew.html
also accessible here
http://www.spacelaunchreport.com/thorh.html
and here
http://www.spacelaunchreport.com/library.html

 - Ed Kyle

Can I stick this launch vehicle baseball cards in the spokes of my  bike wheels? ;D

Offline WallE

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Re: Thor Booster Variants
« Reply #75 on: 07/24/2017 06:01 PM »
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.

No missile parts were recovered from "Bluegill" and the debris dispersal of the warhead was not tracked. Although it was far out to sea and radioactive material did not reach land, there were nonetheless several Navy ships in the area.

The 6/20/62 attempt was known as "Starfish" and it must be one for the record books. The dummy RVs mounted to the Thor caused the turbine exhaust to be deflected back up into the thrust section, heating and softening the engine mounts until they failed, at which point the engine broke loose and rammed into the LOX tank above. The Thor broke up 59 seconds into launch, and the RSO destruct command was sent six seconds later, destroying the warhead and raining down plutonium. Navy divers recovered 251 missile parts from the shallow waters around Johnson and Sand Island, some of which were contaminated with radioactive material.

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.

On "Bluegill Prime", what happened was that the Thor's main LOX valve only opened part-way, which prevented the engine from achieving stable mainstage combustion. It apparently lifted about a quarter to half an inch before settling back down on the pad. At this point, RP-1 spilling into the hot combustion chamber started a fire. The Range Safety Officer was also an inexperienced newbie, and he should have actually just sent the manual cutoff command which would close the RP-1 valve and stop the flow of fuel that was feeding the fire. Instead, he issued the destruct command and blew the entire missile up. The video of Bluegill Prime is on Youtube, it's pretty crazy. The RSO destruct ruptures the Thor's fuel tank and explodes the warhead, but the LOX tank and thrust section are still intact. After a few more seconds, the LOX tank goes up in a ball of white flame.

After that, "Bluegill Double Prime" was to take place on September 23, but concern over Wally Schirra being exposed to high altitude radiation on his Mercury flight delayed the test until October 16. The Thor suffered a flight control system failure at 85 seconds and did a cartwheel before being finally destroyed by RSO action at 156 seconds. At this point, the Air Force were ready to tell Douglas that their rocket was a piece of junk and they needed to find some other option. Unfortunately, there weren't many other choices. Redstone lacked the range needed for the tests and Polaris was too new and not many of them were available, also it needed extensive modifications for the mission.

Thor was given one last chance and "Kingfish" succeeded on November 1. In the end, the failures don't seem to have been the fault of the Thor itself, which was highly reliable by 1962, but radar tracking problems and the pods attached to the base of the missiles which were adversely affecting their aerodynamic profile.

Offline fs10inator

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Re: Thor Booster Variants
« Reply #76 on: 08/01/2017 09:54 PM »
I wanted to add a little, but probably worthwhile note on the LE-3:

The engine was tested in space by mounting the LE-3-powered second stage to a M-3C rocket. This combination was called the Engineering Test Vehicle, and flew the LE-3 twice to test its performance, once in 1974, and once again in 1975.

Note the N-1 MST in the background.

Offline koroljow

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Re: Thor Booster Variants
« Reply #77 on: 10/11/2017 04:42 PM »
Delta A introduced MB-3 Block 2 engines that produced 170 klbf liftoff thrust.  Delta A, which flew twice in 1962, also featured a shorter interstage between Thor and Able to shave weight.  The improved Delta actually stood 4 to 5 feet shorter than the original Thor-Delta. 
 - Ed Kyle
Coming back to this topic one year late. But I think it's better to ask here than in the Q&A section. I'm trying to go in to the details of the Delta-A development. Couldn't find much info at NTRS, DTIC and the open archives. So here some of the points which are giving me a serious headache:
I have see different statements regarding the Delta-A guidance. Some say it still used a BTL-300, others BTL-600.
I have been reading again and again that Delta-A's second stage had restart capability. True or not? If yes it seems that there was no need to use it for the HEO of Explorer IX and XV. (How about Delta-B?)
Missiles and Rockets (Sept 24th, 1962) stated that Delta-A (and maybe Delta-B) used RJ-1 fuel instead of RP-1. True? If so, when this was reverted to RP-1?
Same source (see here https://archive.org/details/missilesrockets1119unse - search for 'reliable delta') states 1st stage thrust as 165k lbf. Usually one can read of 170k lbf. Maybe interim for DSV-2A only?
Geschichte und Geschichten aus sechs Jahrzehnten Raumfahrt:
http://www.raumfahrtkalender.de

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