Can it run doom
To be fair, there was only one moon lander, not 27 different ones that all worked slightly differently.
Just like with most open source code - I have absolutely no idea what to do with it, but I still love that it’s freely available.
The article is technically correct in that the code has been open-sourced and published, except it happened in 2016, so I’m guessing the author just decided to ride the Artemis hype.
i’ve had a copy for years… Why is this news now?
Space articles get clicks when something big happens like Artemis 2
Adding that the Apollo 11 soft isn’t much more complex as the one of an current pocket calculator, I doubt that it can even run DOOM. NASA anyway has a huge OpenSource catalogue, all their soft used is OpenSource, despite some with restricted licenses only for official uses. Same for other Space agencies, eg. from the ESA. Good sources for astronomic fans.
the crucial 30 lines of assembly for calculating Apollo 11’s navigation trajectories.
I was never skeptical we went to the moon until now.
How the hell can you do all that in 30 lines?!?
Very efficiently.
Or for a less cheeky answer, I believe the method they used at a high level was pointing a camera at a few guide stars, so the 30 lines of assembly might have been a loop that checked those cameras for any drift of those stars and did a correction pulse of the rotation boosters to keep them centered. Oh, one of the references might have been the signal strength from home, too (signal gets weaker if the antenna isn’t aligned).
Unless it was an emergency, it might only need to look at 5 pixels to determine alignment and correction.
Also, just because it’s assembly doesn’t mean it can’t call subroutines and functions, so that 30 lines might be misleading in the way those several lines in the other reply have way more going on. That said, if it’s just doing a pixel brightness comparison, that’s one line to read the central pixel, then for each direction one line to read that pixel, one more to compare, one line to jump to next comparison if center is brighter, one instruction to initiate correction burn, one instruction to stop it immediately after, then one instruction to return to the start of the loop… Which comes to 22 lines total, leaving 8 for logging or maybe timing the burn. And that’s assuming their instruction set didn’t have anything fancy like read and compare, compare and jump, or a single instruction burn pulse.
Import MoonPy MoonPy.LandOnMoon() while MoonPy.OnMoon: print("john madden")Just applied to NASA with this code and they accepted me. Should have posted it under AGPL.
See ya losers I’m going to moon \s
/s everywhere making the jokes less funny, its funny to see people not getting the jokes anyway.
Ah, but it’s also funny to see people whine about /s anytime it’s used. It’s quite the conundrum.
my bad then I didnt know everyone was whining about it lol
Wait, our own space program? Is that a thing we’re supposed to have?
Mark my words, someone’s going to make a video game with 100% historical accuracy with this.
Lunar Lander wasn’t good enough for you?
Reentry is pretty darn close to 100% realistic
https://store.steampowered.com/app/882140/Reentry__A_Space_Flight_Simulator/
Ooh, this looks great!
It will be vibecoded with six-fingered physics
This code was first published 10 years ago, but I haven’t seen any such game yet.
They’ll get round to it. They’re doing the graphics first. They’re currently making individual 3D models of “all the stars”.
“If you want to make a historically accurate moon landing sim, you must first model the universe.” -Carl Sagan
Don’t we have the Universe Simulator already?
Yeah, that’s how they filmed the first moon landing.
I’m not a computer graphics guy, but I wanna math. Theoretically, if I wanted to make the smallest possible 3d model, I would define it as four interconnected points. Each point has x, y, and z coordinates, so each model takes a theoretical minimum of 12 bytes of storage. Someone who knows computers can correct me if I’m off by a bunch.
The lower estimate is around 100,000,000,000 stars in the Milky Way. That’s only 1.2 terabytes worth of my theoretical minimum 3d model. Doable! But you said all stars. The lower estimate is around 10^22 stars in the universe. That would be 120 zettabytes. That’s only a few orders of magnitude off from the total available worldwide datadata storage!
Edit: I might have thought of a way to define a 3D model in just 2 bytes. You need four points that each have values for x, y, and z. They don’t need 256 possible values for those, they can get by with two each. One bit can store two possible positions, so we can use as little as two bytes to define every point’s position with 4 bits to spare. Behold, a tetrahedron:
0000 0100 1010 1110Each set of four digits defines the x, y, and z coordinates for each point, as well as one extra dimension. You could use those extra four bits however you want. An extra spatial dimension, defining a color, etc. The theoretically smallest possible 3D model. Take the numbers I said up there and divide them by 6. A model for every star in the universe, and it would only take 20 zettabytes.
As an amateur computer graphics person, the best way to draw accurate stars is to just pre render it onto a cubemap. But if you really need that subpixel worth of parallax to be completely accurate for every star, there are a couple ways I can think of off of the top of my head. With any you’d want to make sure you only store position, size, and color, since stars are all spheres anyways. With effort, you can be very flexible with how these are stored. (4 bits color temperature, 4 bits size, 3*32 bits coordinates maybe)
- splat each star into the screen texture with atomics
- some sort of tiled software rasterization thing, like in Gaussian Splatting
Worse ideas:
- instanced hardware rasterization
- ray tracing
This is not that well suited to most usual rendering techniques, because most stars are probably going to be much smaller than a pixel. Ray tracing would mean you need to just hit every star by chance (or artificially increase star size and then deal with having tons of transparency), hardware rasterization is basically the same and additionally is inefficient with small triangles. I guess you could just live with only hitting stars by chance and throw TAA at it, there’s enough stars that it doesn’t matter if you miss some. That would react badly to parallax though and defeats the purpose of rendering every star in the first place.
It’s much more efficient to do a manual splatting thing, where for each star you look at what pixel(s) it will be in. You can also group stars together to cull out of view stars more efficiently. Subpixel occlusion will be wrong, but it probably doesn’t matter.
This is all just for the viewport, though. Presumably there are other objects in the game besides stars, which need to have reflections on them of the stars. Then that becomes an entirely different problem.
The real answer though is that you wouldn’t try to render all of the stars, even if you want parallax. Maybe some of the closer and larger ones as actual geometry, simplify a ton of stuff in the background, render things as volumes or 2d billboards, have a cubemap for the far distance, etc
Edit: also ofc this presumes you know the position, scale, temperature of every star
I also like the idea of baking all of the stars into a volume in spherical coordinates, centered around the origin
David Braben did it 1984, in a cave, with a box of scraps
https://ctrl500.com/tech/how-frontier-managed-to-re-create-our-entire-galaxy-in-elite-dangerous/
‘Elite Dangerous’ is from 2014.
Elite is from 1984. Per the wiki I cited
“…The Elite universe contains eight galaxies, each with 256 planets to explore. Due to the limited capabilities of 8-bit computers, these worlds are procedurally generated. A single seed number is run through a fixed algorithm the appropriate number of times and creates a sequence of numbers determining each planet’s complete composition (position in the galaxy, prices of commodities, and name and local details; text strings are chosen numerically from a lookup table and assembled to produce unique descriptions, such as a planet with “carnivorous arts graduates”). This means that no extra memory is needed to store the characteristics of each planet, yet each is unique and has fixed properties. Each galaxy is also procedurally generated from the first. Braben and Bell at first intended to have 248 galaxies, but Acornsoft insisted on a smaller universe to hide the galaxies’ mathematical origins.[36]”
Elite Dangerous expands on this mechanic, per cited article.
"Of course, David Braben and his team didn’t dot their virtual galaxy manually with all those star systems, they used procedural generation. But there’s absolutely more to it, Braben explained when we recently sat down with him in San Francisco.
“I think it is a distraction when you start describing it as ‘we generated our galaxy procedurally’. It belittles the fact that we actually put a lot of artistic work in it and gathered real data.
We have a one-to-one scale model of the milky way in our game, with all the 400 billion star systems. What we’ve done is we got real data from 160,000 star systems. That’s every single star in the night sky. About 7,000 are visible to the human eye and a lot more with a telescope. These are all in the game. And all the nebulae and things like that.
Now, beyond 30 or 40 light-years from Earth, even Hubble can’t resolve the smallest stars. So, the most common star we know about is a Class M Red-star, and beyond those 30 to 40 light-years, Hubble can’t see them. But you CAN see them as a sort of smoke, you just can’t see individual stars.
And I’m sure in our lifetime, we’ll see further and further with better telescopes. But the point is, we can populate that smoke with stars –with the right sort of mix of stars as well as the density. Because we know how much radiation is coming out of that smoke. And that’s the sort of approach we have taken.
Using procedural generation to create that smoke, in much the same way an artist uses an air brush or computer. The artists doesn’t mind where the individual dots come, what he’s doing, is getting the pattern of the smoke right, or whatever it is he’s drawing with the air brush."
Remarkable that you can copypaste all that and still can’t comprehend what was done in 1984 and what was done in 2014.
If you find a way to represent our existing Milky Way galaxy with a procedural algorithm and a seed that can be run in a reasonable time on any current computer or even a cluster (say, running for a few dozen years), you’re welcome to claim the Nobel prize.
That’s some damn fine maths, thank you :)
You can automate control of your craft in KSP with a mod. All you need is to have it send the data to the Apollo computer and then send the output to the craft. It should probably work with the real solar system mod.
Now that I saw this though, I swear I saw this exact video already. Scott Manley or someone may have already done this.
If that works with the real solar system mod that is honestly the finest testament KSP can get for its mathematical accuracy.
KSP is not mathematically accurate and it can’t be or it would have trouble running on computers. They split up and use simplified 2 body dynamics in the game.
We use super computers to model the n-body problem bcz of how complex it is.
Of course, NASA ain’t modelling actual missions in KSP.
I imagine KSP is simple Newtonian physics which is accurate at macro-scales, whereas obviously NASA is going to use Einstein’s equivalent. Far more computationally intense but really important once you scale up the small errors in Newton’s equations.
Actually, we don’t use relativity so much. For some stuff like light time delays, yes, but for orbit determination we use newtonian mechanics still. It’s just that once you start adding more than two bodies, you have to shift to doing numerical integration to find solutions, which doesn’t work for real-time stuff like video games.
For most applications, F = -GM1M2/r^2 is still a valid approximation.
Edit: And by most applications, i mean sending a satellite to a planet in our solar system. If you were trying to go to Alpha Centauri, you damn sure better use Relativity to model your trajectory.
I haven’t tried it, but yeah, at small scales KSP (which is just using floating point numbers) is pretty accurate. It’s at large scales where it fucks up, which it does have to deal with too, being a game about traveling between planets.
I assume it probably would work though. The Apollo computers, as I’m sure you know, weren’t super complex. They basically just assisted the pilot. I’m not exactly sure what math they did, but it probably just had to do with descent rate/time to impact and stuff like that. Again, this is all just guessing. I don’t remember it.
That makes sense, floating-point precision falls apart with large numbers but is pretty good with small numbers.
Perhaps there’s a mod that can swap out the position system to use doubles instead of floats? But I’m pretty sure that’s a Unity thing with its Transform positioning system so that’d be quite a challenge to change.
Finally! An expansion pack for Lunar Lander(1979).
