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The movie "Hidden Figures" - Alan Shepards' flight

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cvanc

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So in the movie (which is excellent and highly recommended) the Redstone used for Shepards' flight drops its' fin assembly on the way up.

That's news to me, did Redstones do this? I think not? I've certainly never heard of this before.

(In spite of this caveat and some other technical errors, really, go see this movie. It's terrific.)
 

Angie

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They separated after about 2 or 3 miles up. I'll have to check out that movie. Grew up with Mom and Dad working on parts of the space program at that time. In the Redstone arsenal area. Was always fun to have the boosters test fire on the tower. Would rock windows for miles around.
 

cvanc

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Wow, apparently this is how all Redstones worked.

I am totally surprised, as this rocket predates gimballed motors and was guided exactly as the V-2 was - by steerable graphite vanes in the motors' exhaust. These vanes are mounted on the fins, so dropping the fin unit means no more guidance. Weird!

I suppose they dropped this off at (or at least near) motor burnout?

Thanks all for the insight.
 

cvanc

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I am still scratching my head about this. What was the reason they dropped the fin can off? What was the benefit? :confused2:
 

Nytrunner

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No more exhaust, no more steering, no need for extra weight? That's my guess.

They had to make sure that final trajectory was spot on though.
 

Zeus-cat

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No more exhaust, no more steering, no need for extra weight? That's my guess.

They had to make sure that final trajectory was spot on though.
The extra weight (extra mass would be a better way to say it) is only relevant if they try to accelerate the rocket in some manner. A better reason to drop it is the fins could cause a deflection from the intended target due to winds during descent (we call it weathercocking). And of course if the heat buildup from the flight and descent is significant you could have a fuel explosion from any unburned fuel left in the booster.
 

kcobbva

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+1 on good movie. And my daughter really loved it to boot. Made her more excited to go to NARCON this weekend!
 

GregGleason

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I don't think that is correct. I have never seen anything documented that said that the plane of separation was at the fin can. The separation on Redstone was above to fuel tank to deliver either the weapons package or, in the case of Mercury, the capsule.

If someone can show documentation to the otherwise, then I will stand corrected.

Greg
 

cvanc

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I don't think that is correct. I have never seen anything documented that said that the plane of separation was at the fin can.
I hear ya; I too had never heard of this. In the movie, Shepard's rocket drops the fin can only. The motor stayed attached to the rocket, and the capsule stayed attached too (until later, of course).

The plane of separation was right at the top of the fins. The only thing that dropped away was 4 fins and the hollow cylindrical section of airframe that enclosed the motor and served as the mount point for the fins.
 

GregGleason

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I hear ya; I too had never heard of this. In the movie, Shepard's rocket drops the fin can only. The motor stayed attached to the rocket, and the capsule stayed attached too (until later, of course).

The plane of separation was right at the top of the fins. The only thing that dropped away was 4 fins and the hollow cylindrical section of airframe that enclosed the motor and served as the mount point for the fins.
Yes, I saw the movie. They just got this part of it wrong (trying to imitate Atlas staging is my guess), and there were several other technical errors as well. That said, it's a pretty good flick.

Greg
 

XolveJohn

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Did they talk about the fact that computers WERE available at the time to do the calculations? The ENIAC of 1946 could calculate artillery firing tables,

about the same as rocket ballistic paths. In 1960 they were becoming solid state, and FORTRAN was probably available.

The truth is that JOHN GLENN did not trust computers, and wanted the numbers verified by humanoids.

Considering how many Atlas boosters blew up in testing (I count 71 in this list: https://en.wikipedia.org/wiki/List_of_Atlas_launches_(1960–69),

he should have been more worried about getting atomized.
 

RocketT.Coyote

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Funny how they missed the Redstone fin-can-drop in the HBO series From The Earth To The Moon. Ditto on the Mercury Atlas in Astronaut Farmer.
 

Incongruent

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Did they talk about the fact that computers WERE available at the time to do the calculations? The ENIAC of 1946 could calculate artillery firing tables,

about the same as rocket ballistic paths. In 1960 they were becoming solid state, and FORTRAN was probably available.

The truth is that JOHN GLENN did not trust computers, and wanted the numbers verified by humanoids.

Considering how many Atlas boosters blew up in testing (I count 71 in this list: https://en.wikipedia.org/wiki/List_of_Atlas_launches_(1960–69),

he should have been more worried about getting atomized.
If I remember correctly, NASA made a bunch of modifications to make the Atlas booster safer.

I read a review of the movie and it said that the African-American mathematicians seemed oblivious to the racism present in the "outside world", though having never seen the movie (I don't usually watch movies) I can't say for myself.
 

markkoelsch

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At what altitude does the fin can drop off? Beyond a certain altitude fins do little or nothing but add weight.
 

Incongruent

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(from the Wikipedia page: https://en.m.wikipedia.org/wiki/Mercury-Redstone_Launch_Vehicle)

Image with labeled sections: https://upload.wikimedia.org/wikipedia/commons/2/2d/Mercury-Redstone_Booster_Units.gif

The most visible difference between the Jupiter-C first stage and the Mercury-Redstone was in the section just below the Mercury capsule and above the propellant tanks. This section was known as the aft section, a term which was inherited from the military Redstone. (The actual rear end of the rocket was called the tail section.) The aft section held most of the Mercury-Redstone's electronics and instrumentation, including the guidance system, as well as the adapter for the Mercury capsule.[21] In the military Redstone and the Jupiter-C first stage, when the rocket had burned out, its lower portion, containing the rocket engine and propellant tanks, would separate from the aft section and be discarded, and the aft section, with its guidance system, would direct the top half of the rocket during its unpowered ballistic flight. However, in the Mercury-Redstone, the aft section was permanently attached to the lower portion of the rocket.[22] When the rocket had shut down, the Mercury capsule would separate from the aft section and would rely on its own guidance.


And this is what the other page (linked in an earlier post) says:
The missile body was separated from the thrust unit 20–30 seconds after the termination of powered flight, as determined by the preset range to target. The body continued on a controlled ballistic trajectory to the target impact point. The thrust unit continued on its own uncontrolled ballistic trajectory, impacting short of the designated target.

I'm probably misunderstanding the text, so I won't try to explain.
 
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cvanc

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Interesting discussion! But I gotta say some of these citations are very ambiguously worded. I'm still not at all clear if Redstones did, in fact, drop their fins at some point in the flight...

Is there a resident Redstone expert in our ranks that we can reach out to?
 

GregGleason

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From NASA document TMX 53107, "THE MERCURY - REDSTONE PROJECT"


Redstone.Booster.Recovery.jpg
Greg
 

GregGleason

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The boosters used for the Mercury-Redstone project were a hybrid of the Redstone booster family (ibid.).

At the time of its selection in January 1959 for the MERCURY Program, two versions
of the REDSTONE design existed. The first, an advanced model (Block II) of the tactical
missile, utilized an improved engine, the A-7, and alcohol and LOX as propellants.
The second, the JUPITER-C, was a multistage vehicle utilizing increased capacity
tanks compared to the REDSTONE, the Model A-5 engine, and the more toxic Hydine
(60 percent UDMH, 40 percent diethylene triamine) and LOX as propellants. This
extended performance booster stage was coupled with upper stages of scaled Sergeant
solid propellant motors. A four stage version of the JUPITER-C placed EXPLORER I,
the free world's first satellite, into orbit.

Since the Block II REDSTONE,the most advanced and reliable version could not meet
the MERCURY performance requirements, the configuration selected coupled the
Model A-7 engine and propellants of the Block II model with the enlarged capacity tanks
of the JUPITER-C. It is interesting to note that by the time of the first manned launch
(MR-3), the total reliability of all 69 previous REDSTONE flights was 81percent; however,
the Block II model had achieved 11consecutive successes and the JUPITER-C
had achieved seven consecutive successes.
Redstone.Booster.Family.jpg

Greg
 
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Zeus-cat

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I haven't seen anyone use ibid in, well, decades?
 

ColumbiaNX01

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I saw the movie. It was okay. Could of done with all the extra "drama" They add crap to a movie to make it more you know. Most movies based on a true story are not really that accurate. One movie that comes to mind as super accurate was Apollo 13.
 

boatgeek

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I read a review of the movie and it said that the African-American mathematicians seemed oblivious to the racism present in the "outside world", though having never seen the movie (I don't usually watch movies) I can't say for myself.
I don't see how anyone who watched the movie could come to that conclusion. From the very first scene with the policeman through all of the issues with bathrooms to "I'd already be one", it was obvious that the main characters knew all about racism in the outside world.

My father-in-law's main complaint after seeing the trailer was that many cars were of the wrong era (1964 police car set in 1961, for example). He's such a car nut I don't think he ever watched the movie.
 

RocketT.Coyote

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The Saturn V markings in Apollo 13 were that of the Revell kit which was from the full-scale mockup and not of any mission-ready Saturn V, according to PopSci.
 

Mushtang

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The Saturn V markings in Apollo 13 were that of the Revell kit which was from the full-scale mockup and not of any mission-ready Saturn V, according to PopSci.
That's one of the things about this movie that bug me. They went to a LOT of trouble to do research about so much of the content, and then they launch the rocket with the wrong markings.

Another is that they went to so much effort to film scenes in the Vomit Comet in order to show weightlessness - but then other scenes they simulate weightless astronauts by letting them bounce up and down. I guess they were sitting on one end of a see-saw like level and were moved up and down. The result is that they move slowly up, stop for no reason, and then move back down. It looks unnatural and silly.

Overall the movie is great, but a few things like that just bug me when I'm watching it.
 

georgegassaway

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The only U.S. built rocket or missile that I can think of that dropped a tall section off was the Atlas. Launching with three engines, then when it was light enough to only need the thrust of the center engine, dropping the outer two inside of one assembly. Referred to Stage-and-a-half. Part of the reason for that were the problems of igniting liquid upper stages.

Certainly the Redstone did not drop its tail unit.

What the wiki actually says:
. The missile body was separated from the thrust unit 20–30 seconds after the termination of powered flight, as determined by the preset range to target. The body continued on a controlled ballistic trajectory to the target impact point. The thrust unit continued on its own uncontrolled ballistic trajectory, impacting short of the designated target.
The wiki is referring to what we think of as the WARHEAD SECTION separating, from the Redstone Rocket booster. "Missile body" is somewhat misleading to us now but in the drawing below the part containing the "Warhead section" is listed as "Body" (on the drawing at right) versus the rocket portion which is what we would consider to be the Redstone ROCKET, is referred to as the "Thrust Unit" on the leftmost drawing.



The separation point was between the Thrust Unit (entire rocket booster) and "Aft Unit" which had the air vanes to help steer the warhead section during the downward leg of the trajectory (of course missile accuracy in those days was very poor, this short range missile could easily miss by a mile or more. And in many ways this was more like an updated and uprated V-2).

This is the problem of reading details about one version of a rocket when there are significantly different versions (Jupiter-C and Mercury Redstone) but the author does not clarify what applies and what does not. Of course that wiki page was about the missile version. And while the author seems to have been historically correct in referring to the Redstone rocket portion the "Thrust Unit", it is too misleading, as seen in posts above. I mean, "THRUST unit" being the whole rocket body, while "TAIL unit" is the portion that actually had the THRUST producing device (engine) inside of it. :facepalm:

So I can't fault the author too much for use of "historical" terms, but the author should have realized the potential for confusion. But when he referred to the separated front section (Body, warhead, whatever) as the "missile body", that really messed things up. I cannot think of any military missile where the whole rocket was not called a missile, and only a separated front end with no rocket engines was referred to the missile instead of the whole rocket that launched it.

So, on the MERCURY Redstone, the only things that separated were the Escape tower from the capsule, and the Capsule from the Redstone rocket. Well, and the retro-pack after retrofire.

FWIW - drawing of the three Redstone based rockets. Jupiter-C (aka Juno-I later) also separated from the top end of the Redstone body and had steering thrusters to aim the upper section to the correct position to fire the spinning 2nd/3rd/4th stages to put Explorer satellites into obit. While the Mercury Redstone, the "instrument unit" stayed attached to the Redstone.

 
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Incongruent

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What the wiki ACTUALLY says:

The wiki is referring to the WARHEAD SECTION separating. "Missile body" is somewhat misleading to us now but in the drawing below the "Warhead section" is listed as "Body" (on the drawing at right) versus the rocket portion, and what we would consider to be the Redstone ROCKET, is refereed to as the "Thrust Unit" on the leftmost drawing.



The separation point was between the Thrust Unit (entire rocket booster) and "Aft Unit" which had the air air vanes to help steer the warhead section during the downward leg of the trajectory (of course missile accuracy in those days was very poor, this short range missile could easily miss by a mile or more. And in many ways this was more like an updated and uprated V-2.

So, on the MERCURY Redstone, the only things that separated were the Esaape tower from the capsule, and the Capsule from the Redstone rocket. Well, and the retro-pack after retrofire.
This is my interpretation as well.
 
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