Burness won the contract from DEC and began developing a lunar landing simulation for the terminal in early 1973. He programmed the game in PDP-11 assembly language, as the GT40 contained within it a PDP-11 CPU, essentially making it a standalone computer system. “But the graphics processor had its own instruction set,” adds Burness, “and I programmed that in assembly as well.”
To make a realistic simulation, Burness went straight to MIT, which had co-designed the real NASA lunar module. “It only took a few hours of perusing around to dig up enough information (weight, fuel burn rate, etc.) to write the program,” he says.
As for inspiration, Burness doesn’t recall seeing Storer’s exact version of the “Lunar Landing Game,” but by 1973, clones of the Storer’s text-based simulation were already commonplace. Still, Burness’ version had one very important difference from those that had come before it: it had graphics. His game, which he called “Moonlander,” took advantage of the GT40′s vector display to draw a moonscape as seen from the side.
Gameplay was simple, but challenging: The player wielded the GT40′s integrated light pen and carefully guided the lunar module’s descent by touching areas of the screen that controlled thrust. The player attempted to land via thrusting the lunar module’s rockets in real time while avoiding too fast an entry, or too steep an angle. With Burness’ innovations, the modern action-based Lunar Lander we all know today was born.
“Start of the project to completion was ten days. That’s it,” says Burness. “When you only have a small amount of computer memory, choices become simpler.”
Moonlander proved an immediate hit with DEC and other users of the GT40. From there, it spread wherever GT40s were in use, and influenced a sizable audience as one of the first graphical computer games.
Years later, a co-worker told Burness that the reason he got into programming was because he had played Moonlander as a teenager. “I think it’s kind of neat the way you do something and it can have a rippling effect,” he says.
Burness never made any money on Moonlander, but his experience with the GT40 solidified his interest in computer graphics. He spent the next 26 years of his career bouncing between various computer graphics companies, and still consults for technology startups today.
Landing at the Arcade
Before the decade was out, one of Burness’ biggest fans brought Lunar Lander out of the halls of mainframe academia and into the commercial realm, further widening its audience: Atari.
By 1979, video game pioneer Atari had been working on bringing vector technology to its arcade games for two years. They were inspired by Cinematronics’ 1977 Space Wars arcade game to develop vector hardware of their own. Rick Moncrief led the project.
“Before there was a game, we had to make a vector graphic system,” recalls Howard Delman, an Atari engineer who co-created many Atari arcade games in the 1970s. “Rick and I worked on that. When we were done, we said ‘What should we do with it?’ I said, ‘How about we make Lunar Lander?’
With the help of Rich Moore on software, the two created Atari’s first commercial arcade game with vector graphics titled, unsurprisingly, “Lunar Lander.”
As for Delman’s inspiration, he says he saw a graphical Lunar Lander game–likely Burness’ Moonlander–long before development on Lunar Lander began: “I recall going over to [NASA's] Ames research center–some Atari folks and I had a tour there–and they showed us a Lunar Lander game running on some machine.” But he doesn’t recall the specifics of the occasion.
Atari’s Lunar Lander was very similar to Burness’ version, except that players controlled the lander with a thruster lever and two rotate buttons. Of course, to make a good arcade video game, Delman had to forgo the hardcore simulation aspect of the computer version and make it fun and simple for anyone to walk up and play. “Not everyone is trained to land a spacecraft on the moon,” he says.
The game included four play modes of varying difficulty — “One is a realistic mode like a real spaceship, and nobody could land that,” says Delman, chuckling. “But the mode it defaults to is very simple. There’s friction on your ship, and the ship only rotates when you touch the controls. We did all these things to make it easier to play.”
Then there was a special button that Delman calls the “save your ass” button: “If you’re out of control, you could hit that and it would straighten out the lander, give you full thrust and try to stop you. It cost you a lot of fuel, but if all hope was lost, you could hit it.”
Atari released Lunar Lander in August, 1979–just after the tenth Anniversary of the Apollo 11 moon landing . Strangely, it appears that Atari didn’t capitalize on the anniversary while marketing their new machine. It’s forgivable, because Atari’s attention was quickly diverted when another vector game’s sales started taking off like a rocket ship.
Atari’s Asteroids, also released in 1979, used the same vector hardware as Lunar Lander. Asteroids became so successful that Atari soon stopped production of Lunar Lander to start building Asteroids machines. “The first 300 Asteroids games went out with Lunar Lander artwork on the side,” recalls Delman. Still, Atari sold about 4700 Lunar Lander machines, which Delman says was a “good run” at the time. It’s likely that Atari would have sold more Lunar Lander units if Asteroids hadn’t stolen the spotlight.
Overall, it was this version of Lunar Lander by Atari that received the widest audience, and soon hobby programmers of the early software revolution began coding their own versions of the game for home computers of the time: the TRS-80, Apple II, Commodore PET, Atari 800, and other. The trend continues on nearly every computer platform released.
To this day, neither Storer or Burness have played Atari’s arcade version of their game, and neither one received any financial compensation from Atari for borrowing their idea. Burness doesn’t seem too upset with the prospect. He seems satisfied in knowing he got there first: “A co-worker told me that my Lunar Lander was actually used as an example of prior art to stop Atari from having a patent on an entire class of computer games.”
After that, Lunar Lander was free to be cloned and re-cloned a million ways, ensuring that its legacy will live on for generations beyond those who created it.
Notable Versions of Lunar Lander Through the Years
The following list isn’t comprehensive–we would be here for weeks if I tried to account forevery version of Lunar Lander ever made. Instead, we’ll focus on some notable versions released through the years. You can even play some of them online.
So Godspeed, virtual astronauts. May the moon’s grip be gentle on your ships.
Lunar Landing Game (1969)
(PDP-8, by Jim Storer)
It’s amazing to think that while men were landing on the moon for the first time, some people were back on Earth playing computer games. This is one of them.