Apollo - Atmospheric Entry Phase (1968)

Credit: NASA/JSC
Explains the geometry of the return trajectory and Earth reentry of the Apollo spacecraft, the problems involved, and the methods and action for overcoming these problems.
JSC-345 - (1968) - 26 Minutes
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[@robadams2140]

I love how this highly technical information is shown on an old-timey map.

[@stephenscott7067]

Actually so cool seeing old timey colonial history and peak space age technology combined like that. The map at 18:43 is "Nova Totius Terrarum Orbis Geographica Ac Hydrographica Tabula" from roughly 1606.

[@spenner3529]

A well produced, understated, intelligent and educational film. There is no pandering to the lowest common denominator. Regrettably, this is a production value that has been lost in present-day America. This is NASA at its finest, or, apogee, if you will.

[@Latesleeperful]

I realize why we can't return to the moon despite our incredible technological advancements: the people we're putting in charge of government programs aren't able to understand a video lecture like this one.

[@4kking966]

At its whitest...

[@SW-zu7ve]

@@4kking966 Holy fucking racist

[@YDDES]

Michael Emody Exactly What ”incredible technological advancements”, necessary for going to Moon, have been done, since Apollo?

[@robertkiestov3734]

@@SW-zu7ve It’s not wrong at all.

[@blakewalsh9489]

This Video has made it into my very exclusive "Best videos of all time" playlist.

[@sanjitdaniel4588]

I like the calm and controlled manner of the way people of the 60s explained things. As opposed to the stacatto high pitched manner of todays commentators.

[@janetcraft]

I agree. And what is so good about it that it presents you with the simple facts without the flashy, quick cuts and shaky close ups of people's faces. I remember watching some of these old 16mm films back in school and to this day, I can recall some of the information that I use, (to explain to my friends) of how the Apollo missions was put together.

[@kurtfrancis4621]

I concur heartily. Today's commentators, for the majority I've heard, seem to emphasize higher-pitched, fast-paced delivery as opposed to logical, less passionate delivery of needed information to the general viewership. I think it reflects poorly upon where society is as a whole. Give me the suit-and-tie, well-disciplined men and women of that era vs. today's "relaxed" atomosphere where "enthusiam" apparently trumps logical thought. Argh.

[@tonyb8660]

"The crew is now preparing for a 85 degree reentry at Mach 37

[@johnmanges738]

The Apollo 8 mission has always been my personal favorite and after seeing this I have even more respect for those astronauts who, among other firsts, were the first to reenter in the manner described in this film.

[@tvre0]

Also the most dangerous Apollo mission

[@PhilR.]

As a very young child I remember my family rushing out into the back yard to watch one of the Apollo re-entries over Auckland, New Zealand. It was nothing more than a bright point of light going in roughly a North Easterly direction, so this video is a nice find. I’d love to know if they all had the same path, and if not, which mission I saw.

[@HantsLeo]

Absolutely amazing. This part of the mission has always fascinated me the most. The calculations are mind-boggling.

[@sundsrik2154]

Kudos to the first set of designers and engineers who calculated the perfect reentry angles and speed . Very useful documentary

[@TimPerfetto]

The moon does not revolve around the earth OMG WTF IT REVOLVES AROND ITSELF AND THERE IS A HAIRBALL INBETWEEN AND THE EARTH IS DOUGHNUT SHAPED AND HAS A CAT IN THE MIDDLE AND HIS HAIR FEEDS US ALL

[@hmbpnz]

Thank you for posting these...this is national treasure...

[@mjproebstle]

this has to be one of the most intelligent videos on KZbin. Cheers!!

[@yassassin6425]

Which is precisely why the comments section is devoid of dumb conspiracy theorists.

[@techtinkerin]

Today I learned even more about spaceflight! Thanks a million 😁

[@ronaldgarrison8478]

Surprisingly deep analysis of the aerodynamics. Clearly, a lot of thought and planning went into this part of the flight, as it had to. TBH I did not know there was a controlled skip phase, where they actually rose to a higher altitude briefly, but it makes sense.

[@clayel1]

it also reduces g forces by a lot, from like 8-9 to 5-6 i believe

[@irish89055]

" Now clear your desks, time for a quiz"...

[@goirish2816]

Lol

[@tonyb8660]

😂😂😂😂😂...😢😢😢😢lol

[@hughbreidenbach]

EPIC. Thank you so much for posting!

[@ewan.cartwright]

I want everything explained like this

[@n3307v]

Fascinating video. I always wondered how this was accomplished.

[@larryh8072]

As I understand the reentry was controlled by the AGC (Apollo Guidance Computer) Programs 61 through 67 were used to guide them through this complicated set of maneuvers. It would be pretty complicated to do this manually but I would have to assume the astraunats trained for it. I bet they were happy to see the computer programs working their magic during reentry.

[@eddievhfan1984]

The Command Module did feature a system called the Entry Monitoring System. It was basically a scrolling tape plotter combined with an accelerometer and a numeric readout. It was able to sense spacecraft deceleration during reentry, and translate it into velocity and position changes that could be reflected on the plotter. By adjusting the spacecraft controls, you could follow a predescribed pattern on the plotter to safely bring you throughout the atmosphere, and maybe get within tens of miles of your target. Indeed, the AGC was way more accurate and easy to use for this kind of task.

[@youerny]

What an amazing video!!

[@eventcone]

Excellent presentation!

[@ericmiller7213]

That was Awesome ......and all of that was figured out long before re-entry.....can't imagine what the engineers and crew were going through without communication during re-entry, and very little control

[@tvre0]

They actually had really good control of their landing site and g force via roll. The heat shield produced lift because of an offset center of gravity and allowed them to control how much g force they endured along with the landing location

[@johnvrabec9747]

Euler's Method.

[@mesquitoful]

This makes the end of the Apollo 13 even more amazing.

[@ronaldgarrison8478]

It's interesting to note that the Artemis missions will have completely different profiles for re-entry-logical, as they will have less tight time constraints. To put it a bit cavalierly, they can afford to loiter a little on the way in. My understanding is that they will aerobrake into a long, looping orbit, then circle a bunch of times as they circularize the orbit, then finally re-enter, much as if from LEO. No problem. They will surely have better in-flight entertainment than we saw in The Martian (not that that is a very high bar).

[@clayel1]

where did you get this information? artemis 1, for example, took a direct reentry from the moon

[@ronaldgarrison8478]

@@clayel1 TBH I don't remember now where I saw that, or how it was worded. Checking on it, I did see a reference to a "skip re-entry." It's possible that I mis-interpreted that. OTOH maybe not. I don't really have time to check on it right now, but will make note of the issue for a later look.

[@tonyb8660]

Takes me back to 7th grade daze. It was an exaltation when any movie was in the schedule. 😂

[@High_Alpha]

I love how dead pan the presenter is when discussing things that would... as NASA would put it cause 'the loss of the vehicle'. When explained in this level of detail it's amazing we got back in at all! And with less computing power than is in your phone nowadays!

[@DJTechno94]

Great video! People should do this someday

[@leisureenjoyer1986]

RETVRN to high-intelligence technical explanations with soothing narration and string-music background

[@0MoTheG]

I did not know about the skip maneuver. It allows for radio contact. I now understand better why they did not first break the entire module by crossing the upper atmosphere without entry.

[@eddievhfan1984]

They originally planned on using a full skip to help with heating and such, but when they later worked the reentry math, they discovered that the Apollo spacecraft could safely enter without needing to skip, which would reduce the time spent in the entry sequence. The only time anything resembling the skip was used was during Apollo 11, when they used the "upcontrol" portion of the reentry program to get extra range, to fly over a typhoon in the originally planned reentry area. They didn't skip out completely for that one.

[@charlesballard5251]

Magnificent!!!!!

[@badmonkey2222]

The achievements of the Apallo program were amazing, to think they went to the moon 8 times with technology just basic enough to get us there and back in the most primitive of ways, to think that men actually flew in these tin cans that distance is mind boggling and have nothing but respect for those hero's.

[@erichaynes7502]

I believe it was 9 times but I still agree it was a phenomenal achievement.

[@paulward4268]

Indeed the achievements of Apollo were magnificent, and the men that piloted them were heroes for sure. But I would disagree with the description that the technology was basic. The engineering, electronics, production management and mathematical capability in flight planning were of the highest quality at the time, and most certainly not primitive by any means. And some of the knowledge gained from the use of those vehicles is still useful today, and hopefully will be used in the Artemis program. I often think that it s all too easy for us to pat ourselves on the back today for our modern technology,. But it must be remembered that the "old" technology of the 60/70s was superlative, and more than up to the task.

[@badmonkey2222]

@@paulward4268 I meant the computer tech and the lander itself more than the rocket tech which was far ahead of it's time.

[@paulward4268]

@@badmonkey2222 Hi Clarkke. Ok, I can see your point regarding the computer. But for instance, I would raise the following: all the time I keep reading comments about the LM computer having "less memory than a mobile phone today". But we can't compare the two -- a modern phone has capacity for multiple tasks - from full internet connection to operating hundreds of apps / hi res camera/video - all on One handset. (The original use as a phone is almost incidental). The LM DISKY had to perform just 2 functions - land - take off. So although the memory capacity was Vastly less than today's PCs, what was available was sufficient to handle the required tasks. The same applied to the CM computer/sextant unit having to handle TLI /TEI navigational plotting, and Earth re entry computations. Next time it will be much different, but I don't believe there is a valid comparison with those old units and Modern - the functionality is just Too different. And as for the LM itself - IMO that machine was a masterpiece of lightweight, strength, and manouverability that is not given the credit it deserved. The original stay times of Apollo were only ever meant to be measured in hours - from A14 were the stays getting longer however,and the LM had enough design capacity to begin tweaking the fuel/ supplies for longer duration visits. The designs being floated around at the moment for the next generation ( Lunar Starship/ Blue Origin & others) look shaky at best. Research the Grumman LM design history, and we can see what they threw out over the years as the design changed - and it looks like the new players haven't learned very much. Still, old vs new - that debate will always be there.

[@johnaugsburger6192]

Thanks

[@Turambar3791]

It could be funny see a modern documental from history channel about this 3 hours of repeating Will they die? all especial efects and 0 useful information.

[@jackeppington6488]

For anyone like me who remembered this and came here going "Huh?" after Artemis Orion was proclaimed as First Skip, I figured it out. First of all, the Russian Zond spacecraft may have done a skip, but apparently nobody cares because it is Russia. Whatever. Then people say of this film that the Apollo skip was PLANNED but never executed. The problem is that the Apollo skip (which occurred on at least some missions) was much shorter than the Artemis one, and therefore "does not qualify" as a proper skip. To me, the edge of the atmosphere is 400K, and neither Apollo nor Orion (I think) left the atmosphere and entered a second time. To me, skip simply meant changing the lift vector and briefly climbing out to reduce heating and G-load, which both Apollo and Orion did. I don't care if it is short or long. I would have said the Orion entry was a more refined and specialized version of Apollo's entry. I guess that was not sufficient for NASA Communications, which made a big deal out of "Orion is the first skip entry EVERRRRAHHHHH!!!!! Jeez.

[@iveharzing]

I should try this in KSP! The center of mass being off-center with the center of geometry for passive control is pretty smart.

[@fridaycaliforniaa236]

Still used today, with the Orion capsule =)

[@SpiritOfDalton]

But it was never used during the Apollo era. They lacked the data power to implement it. Apollo used direct entry.

[@PaulPassarelli]

And to think that this was all accomplished with 1960s technology! Paper, pencil, snail-mail, fax, they didn't even have FedEx for the important stuff.

[@eventcone]

The procedures, discipline and knowledge are far more important than the IT.

[@hoytoy100]

Slide rule

[@careystrother9785]

Lol...Right ... don't think FAX machine came out till late 70's.... Googled it..... says invented like 1840... Lmao...phone wasn't invented till late 1870s... GOOGLE INFO is as unreliable as Wikipedia. .... It's pathetic. ....

[@PaulPassarelli]

@@careystrother9785 sorry dude. Fascimilie images were sent by telegraph.

[@PaulPassarelli]

@@careystrother9785 a facsimile image could be transmitted via *TELEGRAPH*.

[@tedpeterson1156]

Great voice on that guy

[@billhumburger5583]

I give them a world of respect. Very limited movement for a long period, id go nuts

[@johnvrabec9747]

All the Apollo splash downs occurred within a few minutes of planned. Except Apollo 13, of course. I always ask young people, "do you know how we got to the moon and back? Math!".

[@Freq412]

Great stuff, it blows my mind that we figured all this stuff out and were so successful (I love STEM). But now I wonder: How did each of the re-entries go (Apollo, Gemini, etc)? What were some of the errors and why did they occur?

[@eddievhfan1984]

In general, the reentries went pretty well. Apollo and Gemini both had the ability to adjust their reentry trajectory, thanks to the center-of-gravity offset both vehicles had. Mercury, by contrast, was a purely ballistic entry, usually meaning higher G's during descent, and targeting only performed by timing the retrofire. The Russian Soyuz vehicles utilize lift-controlled reentries as well. There are many sources of possible error in reentry, as among other things in spaceflight, so it's hard to nail down any specific source of error. What did you have in mind?

[@effervescentrelief]

I believe it was Gus Grissom who after coming in a bit too early on one of the Gemini missions, was able to hold a slightly more aggressive angle on the craft to travel further down range to get closer to the originally intended target zone as they were going to wind up woefully short. Of course they were coming in only from a low earth orbit, therefore they flight dynamics of such a reentry were a bit more forgiving.

[@VercilJuan]

Anyone know the full name of this documentary series?

[@foxmccloud7055]

This is going to apply to the Artemis program starting with Artemis I.

[@weebgrinder]

How was the command module's CG changed to adjust attitude on re-entry?

[@eddievhfan1984]

The CM's center-of-gravity was essentially fixed by design, but the crew could also use the craft's storage bays to help adjust it further. Once the spacecraft is in the atmosphere, aerodynamic forces would hold the ship stable in pitch and yaw, while roll would be controlled by the RCS thrusters.

[@Skoran]

Hullo to my fellow Scott fans!

[@chrisstairs2237]

Apollo 8 was the best flight out to the Moon in my opinion.

[@hoytoy100]

Wonder why they chose direct entry instead of entering a parking orbit to allow for greater re entry options. Probably consumables.

[@PachoForeroD]

Not enough fuel.

[@eddievhfan1984]

The CSM did not have enough fuel to slow the spacecraft into a parking orbit, then do a reentry burn. Much cheaper to use to the atmosphere to do all of your braking.

[@rhagfyr987]

On 26 May 1969 Apollo 10 set a speed record for the highest speed attained by a crewed vehicle at 39,897 km/h or 24,791 mph; Google says that it converts to Mach number 32.5. The film said that nominal reentry speed was 24,500 mph. Was their computer given bad input information that they overshot their reentry speed? Were they carrying too many moon rocks? Why hasn't this speed been surpassed by subsequent Apollo missions?

[@user-mr1um1cg5v]

A fine educational film. I’m wondering, though, why NASA’s “first woman and first black human to land on the Moon” Artemis people claim that Artemis 1 skip reentry was the first ever in human history? It’s in their recent video on NASA’s KZbin channel about Artemis 1. Are they disregarding Apollo achievements because they claim they were “racist” and “sexist”? I don’t recall Apollo people ever talk about male, female, black or white.. But these folks do. Phrases like “First Man on the Moon”, “Manned flight” and “Mankind” linguistically mean all human beings, not just males, but modern folks claim these words are “sexist”. and forbid their employees to use them. They also are terrifyingly ignorant.

[@Dolores5000]

Engineering marvel

[@moboutmen]

Could you imagine if they found Moon Diamonds, or some other crazy valuable materials up there? We would STILL be firing off upgraded Saturn V heavy lifters!

[@erichaynes7502]

Sorry American's, this was as good as it was ever going to get.

[@bernardhossmoto]

Now that's rocket science. I think I know how it works but I would never be able to do a calculation.

[@omniyambot9876]

this is it, they're like Gods looool can't imagine fuckin complexity

[@samanbandara3213]

Is that moon landing is true

[@Latesleeperful]

Don't anyone tell the Russians that we posted this!

[@erichaynes7502]

Believe it or not the commander of the crew did not guide his crew through the Atmospheric Entry Phase, it was the lonely guy(CMP) that had to stay in the command module while the other two walked on the moon. Heck, this lonely guy actually guided all three of the crew TO the moon as well!

[@arminulrich2319]

Min 12:00 We talk about DRAG-Queens .....

[@gaittr]

Oh oh oh oh oh, did you hear him say "let's look at a flat map of the Earth?" See, even NASA admitted back then that the Earth was flat. I'm making fun of Flat Earth hoax NUTS!

[@yosoydeyarumal]

The only chance NASA would have to reach the moon and come back in the 60s it would be a flat earth and a flat moon ;-) o

[@lebojay]

Who’s the intended audience for this video?

[@tedpeterson1156]

Junior High

[@betaorionis2164]

Anyone interested on science, technology or space.

[@KSparks80]

Those born prior to 1980. After that, there's nothing but Gumby's who can't spell, figure out that 2+2=4, or even tell if they're a boy or a girl. Their sweet collection of participation trophies really didn't help them out after all.

[@LordDeBahs]

idiots

[@jonstephenson609]

Far out..

[@spenner3529]

Ian Sinclair: Please, keep your comments to yourself. And, could you work on your grammar?

[@jscottupton]

Bottom line...without their radio they can't get re entry data. Without re entry data they are cooked.

[@gunternetzer9621]

Reentry data worked our before reentry.

[@fixizin]

Wow, good luck reaching a switch, or even having vision, at 10+ Gs... IIRC, Mercury 'nauts were wearing the 1950s style "shiny" test pilot suits... did they have the anti-G air-bladders feature? Also the Mercury guys were weightless for only very brief periods, whereas Apollo crews would be starting to atrophy into mush from weeks in micro-grav (esp. the Skylab crews), greatly reducing their G-tolerance. Finally, why doesn't Disneyworld have a ride called "The Full Apollo Experience"???

[@kellyweingart3692]

“The Full Apollo Experience featuring Walt Disney’s frozen corpse” 😂😂😂😂

[@YDDES]

Ian Sinclair ”Anti-G bladders” wouldn’t do much good when they laid down. They mostly prevent the blood from rushing to the pilots feet, when they sit up.

[@yosoydeyarumal]

This can happen just in a disney enviroment: no blood, nor batteries for comunication that never need to recharge and never got empty, and of course no toiletts for 3 guys ( in a closed enviroment.... 8 days????!!!!) Everything was good till.... the Surveyors (at least they showed us the moon was solid) after that just orbiting and fake BS und till today: 10.000 simulations and "enhancements" of wacky pics their satellites make.

[@YDDES]

yosoydeyarumal Why would they need ”toilettes”, when they had sealable plastic bags, with odor killing chemicals? They were on a scientific expedition and not on a leisure Journey. Also, even if had been able to be just a Disney movie, it didn’t have to and wasn’t.

[@YDDES]

Ian Sinclair How would You simulate zero-g or 1/6g in a ”full Apollo experience”?

[@gaittr]

It's so obvious that those pictures of the Earth and Moon are computer-generated images. I'm just making fun of all the lunatic moon landing hoax NUTS.

[@KeshaUlyetov]

Lool

[@YDDES]

You silly cow. They didn’t even pretendent it was photos. And No, it wasn’t CGI. Anyone can see it was manuelly drawn.

[@pasteface2000]

First!

[@yosoydeyarumal]

Nice but no way to bring a capsule from the moon in just 3 or 4 days with those unclear theoretical speeds and that amount of fuel. Just 200 km/h difference and the capsule would land in the himalayas russia or wherever. No way to control the speed or position.

[@paulward4268]

Nevertheless, the Apollo Guidance Computer was able to compute the required calculations accurately. The information presented here clearly shows that the theory and dynamic principles were well understood. The computations for Mid course corrections and lifting entry trajectory were able to be planned well in advance. A monumental achievement.

[@eventcone]

Of course there was a way to control "speed and position" - the SM's big engine and it's RCS thrusters.

[@careystrother9785]

From what the SAME PEOPLE say that there isn't any oxygen or any thing in space. ... how could any engine ignite much less how would they be able to create propulsion ..... (DON'T anyone bother "Explaining" it... it's slightly difficult to feed me Horse Shit... it's not on my diet menu) : )

[@eventcone]

@@careystrother9785 It's simple. You take your oxidiser with you. Basic rocketry.

[@careystrother9785]

@(S)-Riley Dunn Lol.... Negative...... I'm assuming it ignites by the way you phrased the question. It doesn't matter , to me , what it does....I don't give a flying fuck ....hence....why I made notation. ...I'm not going to debate the matter. My Apologies if I didn't make that clear enough. Thank You.....

[@LordDeBahs]

what iam even watching . very bad cartoon