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.
Windows and Linux users can easily play Lunar Landing Game with Vintage BASIC by Lyle Kopnicky. Download the game here.

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July 20th, 2009 at 12:46 am
Hi there and thanks for the mention! A really interesting article, I never realised the game had a life before the arcade game.
I’ve just finished a 3D Lunar Lander Flash game just in time for the 40th anniversary : http://www.sebleedelisle.com/?p=473
cheers!
Seb
July 20th, 2009 at 6:00 am
I wrote a DSL in the Scala programming language that implements a dialect of BASIC which I then used to write a textual Lunar Lander game. :)
http://blog.fogus.me/2009/03/26/baysick-a-scala-dsl-implementing-basic/
-m
July 20th, 2009 at 8:08 am
I went to work for DEC in 1976 and got to play Lunar Lander on a machine in the Mill. I always crashed.
If you landed successfully there was a McDonalds on the Moon.
July 20th, 2009 at 8:16 am
@Dave Barnes
there was a McDonalds on the Moon.
If you landed near it, an astronaut exited the LEM and visited it.
Played it at Westfield in 1976/7 and crashed, too. The tech who “owned” the system showed me the McDonalds, and helped me acquire enough scrap parts to build a VT05 to use for grad school
July 20th, 2009 at 8:37 am
I used to play the GT40 version and there was a McDonalds somewhere on the lunar surface. If you landed close enough a little guy would walk to the arches and order two big macs and a cheeseburger to go. (Not 100% sure about the order!).
R.
July 20th, 2009 at 8:51 am
Hp-25 calculator had a simple version
49 programmable steps
circa 1975
http://www.hpmuseum.org/software/25moonld.htm
July 20th, 2009 at 9:09 am
I played Lunar Lander on 12/24/1967, on a GE timesharing system (ASR33 teletype, 110 baud acoustic coupler modem). I was a fourteen-year-old and thought I was going to be a chemical engineer. My dad called from the office and said that computer time that day (normally $50/hour) was free and I should come down and play some games. After a few games of Lunar Lander and a football simulator I asked him how it worked, and he said “just type LIST”. The rest, as they say, is history. That day is etched in my memory, and is the day I decided to write software for a living, which I’ve been doing ever since. [The system used Dartmouth BASIC and I recall the Lunar Lander program was only a few hundred lines of code, of which over half was text describing the game.]
July 20th, 2009 at 9:29 am
Here’s a nice implementation.
http://www.lushprojects.com/lunarlander/
It’s with some equally fine exhibits at Southwold pier
http://www.underthepier.com/06_new.htm
July 20th, 2009 at 10:04 am
@Jim: HP-25, eh? I wrote a version for the TI-59 a couple of years after that. Kept it on one of those little whizz back’n'forth memory cards.
Been quite a while since I thought of that.
July 20th, 2009 at 11:03 am
I was at Univ of Miami (FL) in 1970 when I played this game on Dr. Earl Winer’s Lab 8 computer (Industrial Engineering Dept). It was a hybrid PDP-8 and analog machine which used DEC Tape, random access tape, for bulk storage. It had a vector graphic CRT (not TV raster) display. You controlled the LEM using the toggle switches on the PDP-8 face. I believe it might have been written at MIT.
If you landed sucessfully (horizontal and vertical velocity within tolerance and on flat surface), Armstrong emerged, planted a flag, and said One small step for man, one giant leap for mankind.” If you found the MacDonalds (complete with golden arches), he went into the the restaurant and ordered (I think) “a Big Mac to Go”. It was the first computer game I ever played, followed by the Colossal Cave on a PDP-11 and Pong.
Very cool for the time!
Bill Marshak
July 20th, 2009 at 11:33 am
Austin Meyers has a mars lander already built into X-Plane. He also talks about the physics of flight on mars here..
http://www.x-plane.com/mars.html
July 20th, 2009 at 12:29 pm
I developed a character graphics-based version for USCD Pascal in the early 80s at the University of Rochester.
July 20th, 2009 at 12:36 pm
Man I remember playing that game. Back then it was so cool.
July 20th, 2009 at 1:58 pm
Played it on a GE TSS-8 (PDP-8 time sharing system) in 1974 at high school in Pittsfield, MA. There was a version that would report crater size if you crashed.
July 20th, 2009 at 2:58 pm
I didn’t see this fine sim mentioned, if you have a windows machine you are in for a treat.
http://eaglelander3d.com/
July 20th, 2009 at 6:08 pm
What!? No mention of Gravitar!?
http://en.wikipedia.org/wiki/Gravitar
It was kind of a Lunar Lander + Asteroids hybrid. I never could get past the first level, but I loved that game for some reason.
July 20th, 2009 at 7:25 pm
Oi! Tosspots! You’ve missed out an entire generation of these games between ‘82 and ‘90! Have you ever heard of 8-bit Thrust? Firebird released awful versions of this for C64, ZXSpec and AMX, none of which compared to the 16 bit mastery that was Oids. A fine retrospective on the early history, but there’s a whole generation missing here…
July 20th, 2009 at 8:22 pm
I wrote a Lunar Lander years ago, for the TRS-80 Model III, in BASIC. I’ve had a similar game in the back of my mind, where the player would land on other planets, and in the case of the gas and ice giants, drop a probe into the atmosphere or jettison a satellite. If you got too far into the atmosphere, you’d be crushed. I may still write it one day; maybe for the Dreamcast, as a goof.
July 21st, 2009 at 7:40 am
This prompted me to hunt for a game for IBM that I absolutely loved: “Lunar Module”. I couldn’t find it unfortunately.
You had to take off and land on a vector-based 2D moon surface, killing evil turrets that tried to shoot you down with bullets. It included a level editor, my favorite level was humongous and included some very steep drops. It had unlimited fuel and ammo so maybe it’s not a strict descendant. Must have been from around 1990.
Ah the memories…
July 21st, 2009 at 7:43 am
hey there
awesome write up
A really interesting article
keep penning more
be well
TD
http://techdivine.com/tdblog
July 21st, 2009 at 12:09 pm
I remember a fantastic Lunar Lander simulator running on Control Data 6000 series mainframes around 1970 (one of the most powerful computer systems of the time [http://en.wikipedia.org/wiki/CDC_6000_series]) at Purdue.
The operator’s console, consisting of two vector CRT displays was the interface. One display would be a view port out of the lander show a star-field and the moon; the other display was an instrument panel, all running in real time. Control was via assigned keyboard keys for fuel flow, thrusters, etc. I can’t tell you the number of hours “invested” in honing our skills of a very realistic, demanding program during non-production hours.
July 22nd, 2009 at 4:39 am
My favorite adaptation for Windows is Gravity Well: http://www.plbm.com/gravwell.htm – analog thrust, classic graphics, progressively tough gravity.
July 24th, 2009 at 2:10 pm
I wrote a Lunar Lander graphics program for the Sharp PC1500 computer.
I used the built-in BASIC and a bit of 6502C assembler to do the graphics. At first it was just a dot going left to right. As you got closer to the landing site, you turned the thin but wide display on its side to represent landing.
All in 4K bytes…cor!
Ahh we had so much fun in the 1980s.
:-)
October 14th, 2009 at 1:04 pm
I still have a TTY printout of the source code as well as an instance of playing the game from 1980.
November 9th, 2009 at 10:52 pm
The late 60s origin must be wrong. I played LL on a 1957 text-only vacuum tube and paper tape computer in 1964/65 period. Game had to have been well known (even public domain) by then, did require a dedicated or non-batch (that is interactive) environment; I played it on a machine with no operating system, just a floating point interpreter (a bit like a cross between assembler and BASIC); do not recall whether LL game ran under FP interpreter or was stand-alone. Game printed out a line at a time as you descended to the moon and adjusted your burn rate – looked pretty much like the BASIC run on the Atari listing under wikipedia. My guess LL dates from 1958 or perhaps 1960. Can anyone provide an older example ?