Rocket wizard Scott Manley has used a ZX Spectrum to land a Kerbal on the Mun and I am phenomenally impressed
Here's a list of things the ZX Spectrum is better at than me. One, maths. Two, being an iconic retro computer. And three, landing on the Mun in Kerbal Space Program, apparently.
YouTuber and KSP extraordinaire Scott Manley has taken to X to show off his latest achievement, using the 43-year-old device to control a lunar lander that makes a beautifully efficient touchdown on the Mun-ar surface.
Flying a simulated spacecraft controlled by a ZX Spectrum and Sinclair BASIC my first computer and programming language.Terribly inefficient right now because the serial port is so slow and the CPU spends lots of cycles bit banging to talk to it.There's a Python program in… pic.twitter.com/LUywMLnYFGFebruary 2, 2026
Manley says that the ZX Spectrum and the Sinclair BASIC programming language it runs were the first he had experience with, and that the setup is "terrible inefficient" right now because of the slowness of the serial port connection, with lots of CPU cycles spent bit banging in an attempt to talk to it.
The original ZX Spectrum didn't have a serial port, although the ZX Interface 1 acted as an RS-232 adaptor via a DE-9 connector, supporting white-hot speeds of 19.2 kbit/s. Later models included built-in ports, so it'll be interesting to find out which particular flavour of Spectrum is handling the calculations and connections here.
Manley also describes a Python program running in-between the Spectrum and kRPC, which allows for remote control of Kerbal Space Program using scripts running outside of the game. It sounds like something of a daisy-chained setup, which makes the smoothness of its landing all the more impressive.
My KSP adventures almost always ended in disaster, as my rash approach to spaceflight ended up stranding (and indeed, murdering) many a Kerbal. Anyone who's attempted a Mun landing will know the feeling of abject terror created by skimming far too quickly across the surface, gently tapping the boosters and eyeing the fuel gauge in an attempt to reassure yourself you're not entirely doomed.
The ZX Spectrum, though? Nope, it gently plops the little lander down on the surface as if it's no big deal, even with a roped-together connection interface. Curse you, ancient piece of hardware. You claim yet another victory, but one day I shall have my revenge.