Finally, my long-promised reaction video to the 1995 classic Apollo 13. The movie does a great job of explaining this like free-return trajectories, so I focus on things the movie doesn’t explain, like what a cryo stir is and how CO2 scrubbers work. I also place some of the movie scenes side-by-side with the transcript from the mission communications to see what they kept and what they changed. This video was a joy to make and I hope you’ll like it too.
Michael Siegel
Michael Siegel is an astronomer living in Pennsylvania. He blogs at his own site, and has written a novel.
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I’ve always been left with the impression that the Goldberg-esque changes that could be made inside the Apollo 13 capsule were possible because things were… well, not unfinished so much as barely finished. Everything was accessible. I have wondered if the interior of the billion-dollar Orion capsules are equally amenable to on-the-fly changes. We already know that they’re not hauling along a spare engine and fuel supply like the LEM.Report
Well, the first few Apollo missions didn’t have an LEM either.
And one of the lessons learned from the Apollo mission was “don’t use a consumable cartridge-based design for your CO2 scrubber” (the triple-redundant ones in Orion can flush themselves.)
As for getting access to things in the capsule, yes, there are panels that could be removed to get access to the radios, flight computers, and ECLSS processing units. There isn’t a whole lot the crew would do with those other than maybe correct gross mechanical issues like punctured tubes or frayed cables. though. And even on Apollo 13 they weren’t ripping out bulkheads or opening panels, it was more “grab some bits of trash from around the capsule and apply large amounts of duct tape”.
Also…it’s not actually true that the Apollo capsules were underdesigned, or incompletely-designed, or that they were flying before they were ready. They made improvements throughout the program that enabled additional capability, but the mission goals were entirely achievable with the Apollo 8 versions of everything.Report
Hey, thank you for covering this movie!
(This is one of the movies where Guys Are Allowed To Cry At The End, the others being October Sky, Terminator 2, and The Iron Giant.)
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There are two active theories for the early hatch deployment of Liberty Bell 7.
So Grissom armed the hatch trigger fairly soon after landing, because the procedures for capsule closeout (and training in them) were still being worked out. This means that as the retrieval helicopter approached the capsule, the pyrotechnic actuators for the hatch were ready to fire.
One theory is that Grissom didn’t “panic” but did trip the trigger accidentally as he performed other tasks related to getting ready for pickup.
The other is that a static electricity discharge as the helicopter’s retrieval equipment touched the capsule caused the pyrotechnic hatch-deployer to fire. Static discharge is a known hazard for helicopters conducting ocean-surface operations (it shows up in “The Hunt For Red October”) and it actually did cause some cable-cutter pyros in the helicopter’s equipment to fire without being commanded.
(Later rewrites of the closeout procedure stated that the hatch pyros were not to be armed until the helicopter had made contact and attached its lifting hook, to prevent any inadvertent actuations for whatever reason.)
Discussion of the matter, at the time and later, suggests that nobody really liked the pyro-deployed hatch; it was added onto the design very late and wasn’t tested to the same degree as the rest of the capsule. If anything, everyone was thankful that losing a capsule during retrieval was the only anomaly during the program.
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“It wasn’t some miracle, we just decided to go” was a very surprising line to me. In fact, other than an occasional mention of prayer, there’s not really much God-calling in this movie at all; no moment where someone says “God please help us” or “it’s up to God now”. (They play “Spirit In The Sky” but that’s a soundtrack joke.) And there’s another “Science Is Running This Show” moment later, when they say “we just put Sir Isaac Newtown in the driver’s seat.”
If anything it reminds me of a Soviet sci-fi movie I watched once, “Ad Astra Per Aspera”, and there’s a bit in there where they terraform a planet and are happy about their success, and one of the lines was “this wasn’t God! This wasn’t angels! This wasn’t magic! This was humans, using human science!” So, maybe not a direct reference, but interesting to see this parallel to Soviet realism in a movie made by Americans about the American space program.
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One important thing to keep in mind about the Apollo program is that we spent a *LOT* of money on it. Analysis of Congressional budgets and indexing for inflation suggests that the actual dollar amount spent on the Apollo program–including the development and construction of the Saturn launch vehicles, construction of facilities, and the aspects of the Gemini program specifically intended to support Apollo–was $288 billion. And percentage-of-national-GDP between the 1960s and today would put it over $700 billion. (Meanwhile, the Artemis program — including moon landings — is just over $100 billion, and plenty of people will tell you even *that* is overspending.)
So, yeah, we got stuff done really fast, but we *paid* for that to happen. The movie’s right that it wasn’t some miracle and we just decided to go, but we damn sure paid full fare to get there.
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You mention the filmmaking several times, and one of the things I thought was interesting was the difference between the first and second “simulator” sequences. In the first one it’s wide shots, little camera movement, no reaction shots, flat full lighting, no music. In the second one it’s all whoo-scary closeups and pans and focus-pulls, dark backgrounds, dramatic music, shots of actors grimacing or looking pensive. In both situations the actual crew was equally engaged and feeling the same degree of intensity, but the *viewer* is far more emotionally involved in the second; an example of how emotion is created by filmmaking technique, and in the first scene a communication of how these guys have got this *entirely* under control.
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I remember the “making-of” documentary on the DVD where they said that the “staged freefall”, with the actors on seesaws being lifted up and down by the crew, ended up looking more convincing than the ones where they were actually in the airplane floating around.Report
Reference for Apollo program costs:
https://www.thespacereview.com/article/3737/1Report
Reference for static electricity causing Liberty Bell 7’s hatch anomaly:
https://www.astronomy.com/space-exploration/did-static-electricity-not-gus-grissom-blow-the-hatch-of-the-liberty-bell-7-spacecraft/Report
Two things:
You’re right that the movie often does work to get non-technical audiences to understand what’s happening and what the stakes are, but there are other times where it’s very clearly “for the space nerds”.
There’s a moment where we see three balls rotating, and the balls have big red dots, and Tom Hanks yells “we’re flirting with gimbal lock!” What’s going on there is that the attitude-determination system (reading out the capsule’s Roll, Pitch, and Yaw) has three parts called “gimbals”. Spinning is a form of velocity, and that means when something spins it maintains its axis and doesn’t tip over (which is why spinning tops stay upright, and why it’s easier to balance on a moving bicycle than a stationary one.) So these gimbals have spinning tops inside them, and they’re in a cage that lets them tumble around, and as the spacecraft rolls and pitches and yaws the gimbals stay in the same orientation. So if your spacecraft pitches up twenty degrees, the “pitch” gimbal stays pointed toward zero degrees, and the line against the gimbal surface reads “PLUS 20 degrees”.
The “gimbal lock” happens when the gimbals’ spinning axes get lined up with each other. Like, let’s say you pitch up 90 degrees, then roll left 90 degrees, then yaw left 90 degrees, then roll right 90 degrees. You’re back where you started, but your gimbals will still say that you’re at plus-90 degrees pitch and plus-90 degrees yaw. That’s “gimbal lock”, and if you’re in space with no real reference of “up and down” then it can really cause trouble for you. If you have time you can reset your gimbals using a known attitude reference (usually star sighting) but when your spaceship is exploding it’s best to just avoid the issue…unless you have gas spewing out the side and making your spacecraft roll, pitch, and yaw in unpredictable ways.
(The way we get around this now is by using “quaternions”, a fourth-dimensional expression of relative attitude that doesn’t have a gimbal-lock issue. You need math to turn that back into roll-pitch-yaw; modern computers are fast enough to do the math and let us use quaternions for everything.)
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There’s another bit where they aren’t quite at the right angle, and someone says “our mass is too low” and it turns out the issue is they didn’t pick up the lunar samples they were supposed to have. So they throw more trash into the CM as ballast. And you might be thinking “wait, aren’t they in space? Where they’re weightless?” And yes (well, technically “freefall”) but “weight” and “mass” aren’t the same thing. If you’re sitting on an office chair and I push you with a certain amount of force, you’ll roll a distance and then stop. If you’re carrying a stack of books and I push you with the same amount of force, you’ll roll less distance because “same force with more weight” doesn’t get you going as fast. And for spacecraft, very little flying (and nothing involving orbital navigation) is done by eye; it’s all done by computers doing math, saying “we need 15 meters-per-second more velocity, burn Thruster Nine for twelve seconds”, and that calculation (of which thruster and how long to burn it) is based on the estimated mass of the vehicle–which is the same even in space.Report
Loved the film, loved your review. I’m surprised you’re that much younger than me to not remember this when it happened. Tom Hanks, when it came out, talked about running home from school every day to find out what the latest news on A13 was.
I wasn’t quite there, but yeah, that thing got my attention.
It just occurred to me that this is a story like the Odyssey. The point is not slaying the dragon, and winning the day. It’s getting back home to your wife and family. Jim Lovell is Odysseus, and Marilyn is Penelope, only instead of a horde of suitors to deal with, she has a horde of reporters.Report
You mention the Apollo program and th3 COVID vaccines as examples of what we can do if we put our will, and resources, to it.
I want to add the Panamá Canal to it. Even after one hundred years some of the engineering feats, like the sluice gates, are unrivaled. To have built that in only ten years, and in the meantime to rid a country of endemic yellow fever by breaking out the transmission vector, is nothing short of mind blowing.
I strongly recommend David McCullough’s book The Path Between the Seas as the best and most complete narrative of that processReport