Questions needing answers

[Sus_pilot]

I really could care less whether you believe I'm an engineer or not.  My diploma says otherwise.  But I've listened to many educated idiots such as Neil Tyson and believe me I'm not impressed.  Scientists today are nothing more than modern day magicians and shamans who weave their spells with high level math that only they can understand. 

Whoa there bucko. I said it was unreasonable for people to ask to see your diploma, but if YOU want anyone to give any credit to your education, that's on YOU to prove. There's ample evidence you are not an engineer, such as characterizing science and math that's at a high school level as "high level math that only they can understand".

Indeed, were I to actually take everything you say as being honest and reflective of critical thinking on  your part, I would have to assume that you are mostly likely a somewhat clever bot that replies in an ELIZA like fashion to statements, as you seem literally completely ignorant of basic observable properties of the physical world.

What's worse is that I'm not an engineer (I'm sure I've made the pros like Jay and STS wince a few times), just a flight instructor and professional manager with a degree in psychology and I understand the math and principles involved.  It's not that hard, really. 

[Sus_pilot]

Another question that flat earthers can't seem to answer: why does a flight from Frankfurt to Singapore take 12.5 hours, when a flight from Singapore to Frankfurt, flying over the exact same trajectory takes 13.5 hours?

The real question should be why doesn't the flight against the supposed rotation of the earth ( take less than a few hours since the plane would be flying against 1,000 to 700 mph rotation (depending upon what latitude you were at)?

Why would the plane magically lose the velocity it had on the ground simply by taking off?  What force would cause that?

Good question.  What holds the atmosphere glued to the earth while it is rotating 1,000 mph?  Magic?

Friction.

I was always taught to ignore friction in problems in classes such as Dynamics and Fluid Dynamics.  I was robbed!

Riddle me this:  why do I have to teach my students that the wind generally changes direction by about 30 degrees to the right (north of the equator) as they climb above 1,000 or so feet above the surface? 

[sts60]

The first one looks CGI.

Nope.  I can tell you when it was taken, and where, and I could probably tell you who took it.   But I am not retained to supply your deficiencies; do your own work for a change, or at least don't be such a boring troll.

The second one means nothing

It means I don't need Google; I've actually worked on the satellites you said don't exist. 

The third one is blurry and means nothing.

It's a picture of one satellite taken by another.  The vehicle I personally helped assemble, integrate, test, and operate took that picture in response to commands I personally sent.

I've got a better one; This is me floating in space enjoying some sun.   No, really it is me because I'm providing a "picture" and I wouldn't lie....

Sure you would.  You keep telling us you're an engineer, when you literally (as Jay pointed out) don't know the difference between linear velocity and angular velocity.

Now, it's amusing and all to listen to you bluster and say ridiculous things, and to point out your various ineptitudes, but only for a little while.  You're not a very innovative troll; to keep us amused, you need to put a little more effort into it.  For example, pretend to acknowledge a couple of your more glaring errors, then circle around and try a fringe reset in a couple of days.  Your schtick has gone flat; your service life as a cat toy has expired.  No more attention for you unless you put some effort into your trolling.

[Apollo 957]

It's a picture of one satellite taken by another.  The vehicle I personally helped assemble, integrate, test, and operate took that picture in response to commands I personally sent.

You'll have to excuse me a moment, but  ... COOL!

All in a day's work to you, but... got any more photos to share?

[bknight]

...

The third one is blurry and means nothing.

It's a picture of one satellite taken by another.  The vehicle I personally helped assemble, integrate, test, and operate took that picture in response to commands I personally sent.

...

It is not blurry to me and I'm way older than tradosaurus.  Which Shuttle is it?

[sts60]

Endeavor.  I'll get around to some other pictures eventually.

I should point out that at least three other folks here that come immediately to mind have hands-on spacecraft/launch vehicle experience, and many others have done an immense amount of really first-rate engineering and imagery analysis.  A few pretty pictures are nice, but those folks do the heavy lifting around here.

[ApolloGnomon]

And do me a favor; google "satellites" and see if you find one actual picture and not a composite drawing or a CGI animated. 

Good luck!

Well, thanks; but no luck needed.  Nor Googling; that's for pretend engineers [population: you]. 

The first one is a satellite I helped build, integrate, test, and operate on three separate missions.
The second is me aboard one of the vehicles that gave it a ride to and from orbit, during preflight integration tests. 
The third is a picture taken by our satellite of another such vehicle, which was also a satellite at that point.

The first one looks CGI.
The second one means nothing
The third one is blurry and means nothing.

I've got a better one; This is me floating in space enjoying some sun.   No, really it is me because I'm providing a "picture" and I wouldn't lie. 

Is this really the level of post people here consider worth a response?

LunarOrbit: I've been mostly inactive for a couple years, here, but I think this is the point at which you can pull the plug. Please inactivate my account. I see no advantage for me, and the response I've just backspaced over to type this would earn me your ire.

If anyone wants to contact me I'm still at International Skeptics, now known as Jrrarglblarg.

[Zakalwe]

The first one looks CGI.
The second one means nothing
The third one is blurry and means nothing.

Amazing isn't it? The one that storms in insulting people left right and centre and accusing people of blindly following religious beliefs not only happily talks of being a Catholic, but then also denies any and all evidence put in front of his myopic eyes. Truly, the definition of religion is the denial of observation and evidence in order that belief be maintained.
Ever heard of irony, tradosaurus? Or, indeed of psychological projection?

I think that I am pretty much done with this thread too. There's no point in further engagement with this individual as far as I can see. Personally, I take this as further evidence that the whole Apollo conspiracy theory thing is pretty much a spent force. There used to be at least a few that at least made an effort to study the record and try to assemble a somewhat cogent argument. All we see now are the blatantly idiotic that display the temper tantrums of a child, or those the crank magnets that use the Apollo hoax as a vehicle to air their other obsessions. Baker used the subliminator bit as a proxy to engage in spittle-flecked rant about anti-Semitism and 9/11- this loon uses it as a vehicle for FE ranting, with a side order of 9/11 and Sandy Hook.

The Moon hoax thing is a spent force IMHO.

[Peter B]

Maybe you can have Mythbusters to replicate the cramped space of the command module, sit 3 guys fully dressed in space suits and then asked them to undress.  LOL.
I don't care what NASA says since they are liars and thieves.  I'm asking you and others to do some critical thinking so maybe you can stop being brainwashed. 

Have a look at this video:

In particular, watch the sections from 27:00 to 28:30 and 33:30 to 34:20. Note that the astronauts are weightless and not wearing spacesuits. Please explain how this could be faked.

The command module is just one of many discrepancies of the moon landing hoax.   Simple thought experiments that question the ability of 1960's technology to make the trip and back, no blast craters or dust under the lunar module, the ability of the astronauts to do any fine motor skills with the pressurized gloves, etc.   Is it any wonder the U.S is a joke outside of this country?   

Fine motor skills? Yes, it was hard working against the gloves, but not impossible. The astronauts' activities were designed around what they could do. So most of the time they were holding poles or handles with a diameter of a couple of centimetres, or flicking switches and pressing buttons which didn't require any fine motor skills. It's not as though, for example, anyone claims they were writing letters in copperplate or screwing together Meccano sets while wearing pressurised suits.

[bknight]

Fine motor skills? Yes, it was hard working against the gloves, but not impossible. The astronauts' activities were designed around what they could do. So most of the time they were holding poles or handles with a diameter of a couple of centimetres, or flicking switches and pressing buttons which didn't require any fine motor skills. It's not as though, for example, anyone claims they were writing letters in copperplate or screwing together Meccano sets while wearing pressurised suits.

Indeed and the A17 crew complained of skin abrasions of their hands working those tools and rocks etc.

[Ishkabibble]

The ISS is visible to the naked eye, better with a bit of magnification.

I have an app on my smartphone that tells me exactly where the ISS is, and it warns me of upcoming visible passes. I got an alarm at 6:21 pm local time tonight, informing me that there was a nearly overhead pass in two minutes, but I went outside and couldn't see it. I guess that means it doesn't exist. My wife was very angry that I tracked mud all through the kitchen as I came back inside, soaking wet from the heavy rain that was in the area, but I don't understand why she was so mad. I was trying to make some scientific observations.

[Ishkabibble]

Yes, Jay... I knew that already.

Yes, I figured you did.  Sorry for the non-answer; I was winding down for the night.

I thought as much. Believe me, I am well aware that it does take a shift in thought processes when going from a hoax believer to someone at least reasonably well-versed in science. 

What I don't know is, how were these things designed/assembled/packed/created so that they operated the way that they did.

As you may recall, one of their parachutes collapsed because the RCS safing procedure cut one of the reefing lines.

The very thing that caused me to ask about this. I remember reading something where Dave Scott had mentioned their speed at impact with the ocean was much higher than the other missions, and it was a pretty obvious jolt inside the CM.  That's what got me thinking about this, and when the vid clip of the packing came up, well... you guys know by now how my mind works.

Packing the chute is an art.  Which is to say, there's a science to it, but also great skill in executing it.

You're telling me. I played with model rockets as a kid. They usually lasted almost one flight. I could never get those stinking little plastic parachutes to fold up enough to fit inside that tube, or come out in a way that wasn't a plastic ball because everything was tangled. I can't imagine the skill it would take to fold up an 80+ foot parachute and have it open correctly.

And in general, the AERs are a very good source of technical information on all aspects of Apollo design and operation.

Thanks for the detailed response. I always knew a great deal of documentation from Apollo existed, but of late, I'm getting a much better appreciation of just how much documentation there really is. If the hoaxers only knew.

[Peter B]

What I don't know is, how were these things designed/assembled/packed/created so that they operated the way that they did.

I can't give you specifics about how I learned about parachute design.  It's one of those things that's too far back to remember specific sources, although I like to think I retained all the knowledge.  That said, the Preliminary Mission Report for Apollo 15 might prove helpful.  As you may recall, one of their parachutes collapsed because the RCS safing procedure cut one of the reefing lines.  Because the RCS fuel is toxic, as much of it as possible is burned off during the descent once it's no longer useful for control.  This requires burning all the jets until the fuel is exhausted, leaving only a residue.  One of the jets impinged on a reefing line and cut it.

As an aside, this is a great example of failure in integration engineering and testing.  The RCS and Earth Landing System were considered "orthogonal" systems in that one had nothing to do with the other -- supposedly.  The team that designed the  ELS is thinking about aerodynamics and structural mechanics.  Aerodynamics because the center of drag is computed by knowing the attach points for the suspension lines.  The parachute exerts its drag at those points, and that in turn determines how the spacecraft will orient itself under the drag load.  Conversely the drag has to be communicated safely to the structure via those attach points.  They aren't thinking about RCS, because that's not the part of the mission they deal with.  They just sit patiently until the last ten minutes.

Similarly, the RCS team is thinking about optimal jet placement.  But most importantly, when the CM drogue deploys, their job is done.  They aren't nominally responsible for anything that happens beyond that point.  The integration engineers and testing team are supposed to think at a higher level and investigate the interactions between systems that are well designed individually to work.  That's one of several examples from space engineering that I use when I teach workshops on design engineering and project management.

Out of interest, Jay, does this mean that what happened on Apollo 15 could have happened on any earlier mission?

And does it mean that the problem could have occurred with two or three parachutes instead of just the one?

[JayUtah]

Out of interest, Jay, does this mean that what happened on Apollo 15 could have happened on any earlier mission?

Yes.

And does it mean that the problem could have occurred with two or three parachutes instead of just the one?

Probably not.  Not all the main parachute risers were near RCS jets.

[bknight]

Yes, Jay... I knew that already.

Yes, I figured you did.  Sorry for the non-answer; I was winding down for the night.

What I don't know is, how were these things designed/assembled/packed/created so that they operated the way that they did.

I can't give you specifics about how I learned about parachute design.  It's one of those things that's too far back to remember specific sources, although I like to think I retained all the knowledge.  That said, the Preliminary Mission Report for Apollo 15 might prove helpful.  As you may recall, one of their parachutes collapsed because the RCS safing procedure cut one of the reefing lines.  Because the RCS fuel is toxic, as much of it as possible is burned off during the descent once it's no longer useful for control.  This requires burning all the jets until the fuel is exhausted, leaving only a residue.  One of the jets impinged on a reefing line and cut it.

As an aside, this is a great example of failure in integration engineering and testing.  The RCS and Earth Landing System were considered "orthogonal" systems in that one had nothing to do with the other -- supposedly.  The team that designed the  ELS is thinking about aerodynamics and structural mechanics.  Aerodynamics because the center of drag is computed by knowing the attach points for the suspension lines.  The parachute exerts its drag at those points, and that in turn determines how the spacecraft will orient itself under the drag load.  Conversely the drag has to be communicated safely to the structure via those attach points.  They aren't thinking about RCS, because that's not the part of the mission they deal with.  They just sit patiently until the last ten minutes.

Similarly, the RCS team is thinking about optimal jet placement.  But most importantly, when the CM drogue deploys, their job is done.  They aren't nominally responsible for anything that happens beyond that point.  The integration engineers and testing team are supposed to think at a higher level and investigate the interactions between systems that are well designed individually to work.  That's one of several examples from space engineering that I use when I teach workshops on design engineering and project management.

But I digress.  The report has a brief description of the Apollo mechanism.

The science of parachutes is pretty straightforward.  You need materials with considerable and predictable tensile strength and low mass, and methods of reliably distributing tension to the rim.  Those distribution networks incidentally offer the advantage of stopping rips.  Another way of mitigating the tension is the ribboning method, which cuts holes or slits in the canopy to let some of the air through.  Materials science governs most of what we consider innovative in parachute design.

The idea of variations in the canopy aperture producing different degrees of drag is as old as parachuting itself.  In the early 1900s practitioners were able to measure its effect also on canopy tension.  That was when the bright idea emerged that variable-drag parachutes might be a useful thing.  I can only remember two types of reefing mechanisms off the top of my head:  the ring method and the skirt method.

The ring method uses a frangible or detachable ring around the suspenders near the aperture.  This forms an apex far above the risers or hoist point and keeps the aperture closed.  Via various release mechanisms, the ring is detached at the right time and the parachute opens fully.

The skirt method is far more common.  Rather than attach the suspenders at a single point on the canopy rim, you run it through an eyelet and then along several adjacent eyelets and then back down to the hoist point.  Interleaving this arrangement around the rim allows you vary the circumference of the aperture by taking in or paying out suspenders.  The modern variation on that method separates reefing lines from suspenders so that you don't have the drag tension on the reefing lines.  To mimic the one-time reef-open behavior of the ring method, the reefing lines are initially regulated to a short fixed length by a frangible or pyrotechnic restraint.  At the appropriate time this restraint is fired and the line pays out to longer fixed length.

In practice, any automatic method of reeling will serve as the actuator for a controllable reef.  The rest becomes straightforward control-system design.  Any number of inputs (ram air pressure, barometric altitude, radar altitude, timers, manual control) can be translated into commands to an addressable winch.  These days such things are quite sophisticated and very reliable.  For safety nets in fall applications we actually use a constant-tension digitally addressable winch.  It will pay out line under load in order to maintain a constant tension.  Control systems can be as simple as relay-based combinatorial logic (i.e., the reef cutter signal is just a combination of sensor outputs), or as sophisticated as a full PID controller (equivalent to full-fledged airplane flight control).

Packing the chute is an art.  Which is to say, there's a science to it, but also great skill in executing it.  The big problem, as you've probably guessed, is avoiding everything getting all tangled up during deployment.  The basic element of the art is the accordion pleat.  Rather than coiled, the lines are laid out side-by-side on the ground, then carefully serpentined so as to produce a bulk of cord that can be pulled from one end without a loop forming around the standing mass of line.  Similarly for the canopy fabric.  At the very end is the pilot chute, which pulls at the top of the canopy and unfolds it from the package.  This method appeals to common sense, but was worked out through trial and (sometimes fatal) error.

The secondary problem is going instantly from fully confined to fully free.  You don't want everything to have to come through an opening in the packaging such that some of it might get hung up.  Engineering has a whole bunch of methods for instantly and simultaneously "failing" all the seams in a container.

As you can guess, the skill required to pack parachutes and the need (in the military) to provide braking chutes for each flight of some aircraft led to the notion of componentized parachute packages.  As part of preparing the aircraft for flight, the ground crew installs a pre-packaged parachute assembly.  After use, the assemblies are removed and sent to a specialized shop for repacking.

Wind tunnel testing has been the mainstay of investigating behavior in parachutes.  As with much engineering, you learn a lot just by trying it and seeing how it behaves.

What I'm obliquely referencing is some documentary I may or may not correctly recall seeing when I was a pre-teen...

I sympathize.  I saw a film when I was young called Pack Your Own Chute.  (It's searchable on YouTube.)  While it got me interested in parachutes and how they work, the film itself tells very little of the story.

Something that specifically dealt with recovery systems, and how the future shuttle would not need them. I'd like to have my memory refreshed, but 35 years is a long time.

If it's specifically about the shuttle, I can help you look around.  Because of the STS's high landing speed, runway braking isn't generally sufficient.  Large airframes stretch our skill at brake design.  We use multiple friction layers and so forth, but the problem is often literally where the rubber meets the road.  Early in the shuttle program they experimented with different tire designs and different runway surfacing methods to provide enough grip without risking shredding the tires.  While especially acute for STS, it was a problem all through the early jet age for high-performance military jets.  They just couldn't get enough grip on the runway to slow down.  Modern airliners, as you've seen, not only use reversible thrust but they deploy their spoilers automatically to allow the full weight of the airframe to ride on the wheels and also provide additional down force.

I think the most exciting thing (at least for space) is the combination parachute and retro rocket method.  This requires less reefing from the parachute because it allows a faster descent rate until just before landing, when rockets at the riser ring fire at the very last second to apply a smooth terminal deceleration.

Here is the Apollo 15 mission report.  http://history.NASA.gov/alsj/a15/ap15mr.pdf  The relevant section begins on PDF page 187.

This is the Apollo Experience Report on the Earth Landing System, including the parachutes.  http://ntrs.NASA.gov/archive/NASA/casi.ntrs.NASA.gov/19740003586.pdf  It goes into substantial detail about Apollo's parachutes.  And in general, the AERs are a very good source of technical information on all aspects of Apollo design and operation.

IIRC during a 40th anniversary of the mission Al Worden seeing the fuel/oxidizer create holes in that chute, of course that description was of a 40 year old event.