2026 Retrocomputing Challenge: Lunar Lander On The PDP-1

A lot of the retrocomputing world is focused on the 1980s, and for good reason– the home computer revolution was in full swing in that decade, and there is a veritable Cambrian Explosion of capable hardware to play with, emulate or recreate. There’s plenty of retro to look back to before that halcyon decade, though, as [Michael Gardi]’s port of Lunar Lander to the PDP-1 reminds us.

Both Digital Equipment Corporation’s PDP series and the game Lunar Lander are probably iconic enough in their own right to need no introduction, but there’s actually a connection between them. While many people think the game started with Atari’s 1979 arcade cabinet, the first version– then only text based, and called the Lunar Landing Game–actually dates back 10 years before that, and was dreamed up at DEC on a PDP-8. If you’re of a certain vintage, odds are, you probably typed in the BASIC version of the Lunar Landing Game at some point.

This is not that game. Despite the 1959 PDP-1 being more restricted, hardware-wise, than the PDP-8, [Michael Gardi] manages to get Lunar Lander in all of its graphical glory running on the PDP-1. Of course, if you’ve seen SpaceWar you know DEC’s first minicomputer can handle the graphics. You can play the emulated version online, if you’d like, or download it yourself from the link above. There is one PDP-1 that survives in working order, and [Michael] hopes to get the chance to run it there one day on the machine that started hacker culture. We wish him luck!

In the meantime, this may be the most “retro” project in our ongoing retrocomputer contest. There’s no special prize for that superlative, but if you can do older, have at ‘er! There are three weeks left to go back in time and claim both bragging rights and fabulous prizes.

 

NASA Announces Artemis III Crew And Ambitious Goals

When the Artemis lunar program was first conceived, the third mission would have seen astronauts step foot on the Moon for the first time since Apollo 17 in 1972. But as hard as getting into space is, a sojourn to our nearest celestial neighbor is even more mindbogglingly complex, and so earlier this year it was announced that actually landing on the Moon would be pushed out to the fourth mission.

In turn Artemis III would take a page out of the Apollo 9 playbook and test out rendezvous and docking procedures with commercial landers while operating in the relative safety of low Earth orbit. Moving the target date for the landing a few years down the road gave all involved parties a little more breathing room, but it also provided a valuable opportunity to gain insight into the performance of the vehicles and systems ahead of the critical moment. In the original timeline, the first time Orion would attempt to dock with the lander would have been just before descending to the lunar surface — leaving precious little time to troubleshoot should anything go wrong.

Yesterday NASA held a press conference to update the public on their progress towards the planned 2027 launch of Artemis III, which included the long-awaited announcement of the crew that will kick the tires on the next-generation lunar landers being developed by SpaceX and Blue Origin

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Forget Waldo. Where’s Luna 9?

Luna 9 was the first spacecraft to soft-land on the moon. In 1966, the main spacecraft ejected a 99-kg lander module that used a landing bag to survive impact. The problem is, given the technology limitations of 1966, no one is exactly sure where it is now. But it looks like that’s about to change.

A model of the Luna 9 lander with petals deployed.

We know that the lander bounced a few times and came to rest somewhere in Oceanus Procellarum, in the area of the Reiner and Marius craters. The craft deployed four stabilizing petals and sent back dramatic panoramas of the lunar surface. The Soviets were not keen to share, but Western radio astronomers noticed the pictures were in the standard Radiofax format, so the world got a glimpse of the moon, and journalists speculated that the use of a standard might have been a deliberate choice of the designers to end run against the government’s unwillingness to share data.

Several scientists have been looking for the remains of the historic mission, but with limited success. But there are a few promising theories, and the Indian Chandrayaan-2 orbiter may soon confirm which theory is correct. Interestingly, Pravda published exact landing coordinates, but given the state of the art in 1966, those coordinates are unlikely to be completely correct. The Lunar Reconnaissance Orbiter couldn’t find it at that location. The leading candidates are within 5 to 25 km of the presumed site.

The Luna series had a number of firsts, including — probably — the distinction of being the first spacecraft stolen by a foreign government. Don’t worry, though. They returned it. Since the Russians didn’t talk much about plans or failures, you can wonder what they wanted to build but didn’t. There were plenty of unbuilt dreams on the American side.


Featured Art – 1:1 model of the Luna 9, Public Domain.

Electromechanical Atari Is A Steampunk Meccano Masterpiece

If William Gibson and Bruce Sterling had written an arcade scene into “The Difference Engine”, it probably would have looked a lot like [Pete Wood]’s Meccano Martian Mission, as illustrated in the video below by the [London Meccano Club]. Meccano Martian Mission is an homage to Atari’s 1978 Lunar Lander video game, but entirely electromechanical and made of– you guessed it– Meccano.

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Lunar Lander Game Asks You To Write A Simple Autopilot

Everyone likes a good lunar landing simulator, and [Dominic Doty] wrote a fun take on the idea: your goal is to write an autopilot controller to manage the landing. Try it out!

Virtual landers are far cheaper than real ones, thank goodness.

[Dominic] was inspired in part by this simple rocket landing game which is very much an exercise in reflex and intuition, not to mention being much faster-paced than the classic 1979 video game (which you can also play in your browser here.)

[Dominic]’s version has a similar classic look to the original, but embraces a more thoughtful approach. In it, one uses plain JavaScript to try to minimize the lander’s angle, velocity, and angular velocity in order to land safely on the generated terrain.

Want to see if you have the right stuff? Here’s a direct link to Lunar Pilot. Don’t get discouraged if you don’t succeed right away, though. Moon landings have had plenty of failures, and are actually very hard.

The Lunar Odyssey: Moon Landings From The 1960s To Today’s Attempts

With the recent string of lunar landing attempts, it’s interesting to consider how much things have changed – or stayed the same – since the first soft landing attempts in the 1960s with the US Ranger and USSR Luna landers. During the 1950s the possibility of landing a spacecraft on the Moon’s surface was investigated and attempted by both the US and USSR. This resulted in a number of lunar lander missions in the 1960s, with the US’s Ranger 3 and 5 missing the Moon, Ranger 4 nearly missing it but instead crashing into the far side of the Moon, and eventually the USSR’s Luna 9 making the first touchdown on the lunar surface in 1966 after a string of USSR mission failures.

What’s perhaps most interesting was how these first US and USSR spacecraft managed to touch down, with Luna 9 opting to inflate a landing airbag and bounce until it came to a halt. This approach had doomed Luna 8, as its airbag got punctured during inflating, causing a hard crash. Meanwhile the US’s Surveyor 1 was the first US spacecraft to land on the Moon, opting to use a solid-fuel retrorocket to slow the craft down and three liquid-fueled vernier thrusters to prepare it for a drop down from 3.4 meters onto the lunar surface.

Now, nearly 60 years later, the landers we sent regularly make it to the lunar surface, but more often than not end up crashing or toppling over into awkward positions. How much have lunar landings really changed?

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Intuitive Machines’ Nova-C Makes It To The Lunar Surface In US Return After Half A Century

Intuitive Machines’ first mission (IM-1) featuring the Nova-C Odysseus lunar lander was launched on top of a SpaceX Falcon 9 on February 15th, 2024, as part of NASA’s Commercial Lunar Payload Services (CLPS). Targeting a landing site near the lunar south pole, it was supposed to use its onboard laser range finders to help it navigate safely for a soft touchdown on the lunar surface. Unfortunately, it was this component that was found to have malfunctioned as the spacecraft was already in lunar orbit. Fortunately, there was a workaround. By using one of the NASA payloads on the lander, the Navigation Doppler Lidar (NDL), the mission could continue.

Perhaps unsurprisingly, the use of the NDL as a fallback option was considered before launch, and since its functionality overlaps with that of the primary laser range finders of Nova-C, it was pressed into service with a new configuration uploaded by IM operators back on Earth before Nova-C committed to a landing burn. Then, on February 22nd, the spacecraft began its descent to the surface, which also involved the Eaglecam payload that was designed to be released before snapping a self-portrait of the lander as it descended.

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