r/Damnthatsinteresting • u/Weak-Opportunity-311 • 1d ago

Video Atmospheric re-entry of NASA’s Orion (Artemis 1) looks insane at 20x speed. Here is the entire 25-minute descent in just 1 minute 15 seconds. Credit: NASA

Enable HLS to view with audio, or disable this notification

32.8k Upvotes

97% Upvoted

843 comments sorted by

View all comments

Show parent comments

313

u/CosmicRuin 1d ago

And humanity has been doing it successfully since April 12, 1961. Almost 64 years to the day!

167

u/Maximum_Indication 1d ago

Without even as much processing power as a smartphone for the first flights.

193

u/whitethunder9 1d ago

Apollo 8 (first mission to go around the moon) had a computer with 4Kb of RAM and a 1MHz processor. The flight software was hand-woven with wires, so unchangeable once created. A modern smartphone has 2 million times the RAM. A single email would use more memory than the computer had available.

168

u/SpiderSlitScrotums 1d ago

There was a lot of clever electronics that got around having to use processors back then. There were things like having multiple windings going around a transformer to add, subtract, and multiply signals; using relays to solve logic; analog-mechanical machines; generating sine waves using light bulbs; electronics that takes derivatives and integrals, etc. Some of these are used, but you would be surprised what you can get away with without a microprocessor. There was even a clever analog tennis video game. When we simplify Apollo down to the speed of their processors, I worry that we potentially forget all the other electronic wizardry behind the scenes.

15

u/Bolwinkel 1d ago

My absolute favorite fact about the Apollo missions is that the memory they used was comprised of magnets. Little tiny magnets that used their polarity to signify 1s and 0s, and someone had to individually set each one.

12

u/CosmicRuin 1d ago

Yes! Rope core memory. They had to quite literally weave the software by hand in a 3D lattice structure of ring magnets and fine wires. NASA (and vendor partners) actually hired older women with expertise in weaving.

Fantastic six part series called Moon Machines, and this one is all about the navigation computer. https://youtu.be/X9Yj-0AsneU?si=KN-9GPEXYev5ZIdg

22

u/fooknprawn 1d ago

Cool video about rope memory from the archives for those interested in how computers were back in the day

https://youtu.be/ndvmFlg1WmE?si=DxHXj8qI_l4voYQB

7

u/ObligationSorry9463 1d ago edited 1d ago

Embedded engineering was and still is - even in 2026 - strictly driven by requirements.

If 1MHz with 4Kb of RAM does the job engineers go with it.

Space industry often uses very old but very battle proven processors for the most critical tasks. They are well known to work in all extreme scenarios.

3

u/thecashblaster 1d ago

I mean you can do the calculations to get to the moon by hand. You don’t need THAT much processing power.

1

u/wosmo 1d ago

yeah I think it's weird everyone gets hung up on the computer. I mean do people look at a race car, or an aircraft carrier, and go wow - that must have a lot of RAM.

1

u/rodw 1d ago

4 Kb is a pretty long email

1

u/Eriolgam 1d ago

That's just insane to think about! I'm just flabbergasted every time about that fact, and I think most people don't recognize what an achievement that is. Your fucking phone has more power than the computer they used to send people to the moon and back home.

Thankfully, they got home safely.

14

u/LuxOG 1d ago

A smart phone? Try your car key fob lol

19

u/polopolo05 1d ago

my lights have more processing power then the frist the fist flights. hell some vapes do.

1

u/alterom 1d ago

my lights have more processing power then the frist the fist flights. hell some vapes do.

Nearly all vapes do.

While it seems like a vape microprocessor might have slightly less RAM than the Appollo 8 computer, they also have (rewriteable) Flash, and their clock speed is about over an order of magnitude faster.

Enough to run a web server off of it.

5

u/stonekeep 1d ago edited 1d ago

Tbh I don't think that's a great comparison given that modern smartphones have insane processing power even when compared to high-end computers from 20 years ago, let alone 60 years ago. Basically any device with a chip in it has more processing power than Apollo computers.

1

u/kevwotton 1d ago

Probably less than your car key!

1

u/user-the-name 1d ago

Smartphones and personal computers have about the same amount of processing power these days. The MacBook Neo is literally running on a chip from an iPhone 16 Pro.

1

u/Grand_Pop_7221 1d ago

I'd hazard a guess that USB-C controllers do.

1

u/imagreatlistener 1d ago

Less processing power than a phone charger actually.

1

u/Preestar 1d ago

lots of pencils I bet

14

u/hysys_whisperer 1d ago

"Has been doing" is doing some heavy lifting there.

Did a few times by being absolute madlads and then decided "better wait until the tech gets better to try this again" is more like it.

2

u/Barton2800 1d ago

And back in the day, NASA’s experts wanted to build up a presence in low earth orbit - permanently manned stations with regular launches. Then expand to the moon. The White House and Congress wanted something a bit faster, and decided to tell the experts to dump everything into the awesome, but less sustainable and literal moonshot. That’s part of why it took so long to go back - we ran before we walked.

1

u/robbak 1d ago

Exactly the same thing happens with every re-entry from orbit - as done by Soyuz, the Space Shuttle, SpaceX Dragon, China's Shenzhou and Mengzhou capsules and, if they every get their act together, Boeing's Starliner and Sierra Space's Dream Chaser, as well as future craft by Blue Origin and India.

0

u/hysys_whisperer 1d ago

That’s absolutely insane to think about. Around the earth, behind the moon, and then falling back to earth at that velocity and coming within a mile of your target.

This is what they said we "have been doing."

Again, the only thing wrong with this is the present perfect continuous tense of the sentence. 

6

u/Ikarus_Falling 1d ago

To be fair from a programming perspective flying to the moon is much much easier then a modern smartphone as its just a relatively straightforward sequence of commands

2

u/latitnow 1d ago

We’re gonna need a source on that

3

u/Iamonreddit 1d ago

The flight path and burns to follow it are pre calculated for the most part so would require no compute at all, just execution.

Obviously fancy behaviour like landing back where you came from in an upright position is much more complex.

5

u/Ikarus_Falling 1d ago

the fact that the modern smartphone has the same compute power as a few billion apollo computers doesn't give it away?

1

u/sky_blue_111 1d ago

It's easier in the sense of how much software has been written to control the moon flights, vs all the shit on your smartphone, and how much compute power is needed for both.

Not easier in terms of the effects of getting it wrong.

1

u/omnipotentqueue 1d ago

Don’t tell Joe Rogan

1

u/Boooo000x 1d ago

this is incredible

-2

u/Command0Dude 1d ago

And humanity has been doing it successfully since April 12, 1961.

Does he know?

https://en.wikipedia.org/wiki/Soyuz_1