In 1974 I played the Lunar Lander game on a pocket calculator for hours on end

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The best thing about the HP-65 was the sound that reading the card made. That was sound of the (retro) future.


I had to check, it’s hard to believe the 65 came out two years after the HP-35.

I knew someone who got a 35, some group deal at RCA where he worked. I can’t remember if he got it in 72 or the next year. But it would have been the first pocket calculator I saw in person.

I paid ten dollars for my first calculator, four function and sold as surplus. It was either the fall of 1974, or 75. I’m pretty sure I got my TI-30 in 1976, after trying to figure out how to make fifty dollars for a orevious model. Then suddenly the 30 was “cheap enough”.


in 1978 i got a ti-59 which was programmable and had cards as well. you could buy extra chips to put into it, one of which allowed you to program in a version of the pascal programming language. the instruction manual had the code set for two games, one was a game called “codebreaker” and the other one was “lunar lander”. within a few years that line of calculators disappeared.


Reverse Polish Notation (RPN) for things that broke my brain in highschool for $1000 Alex.


I never had the chance to play with HP’s programmable calculators, but I do fondly remember the Lunar Lander game.

It was included as Lunar LEM Rocket in BASIC Computer Games, my favorite book from when I taught myself to program. I’m not sure I ever had a successful landing, but it was one of the few programs that would run in the 1K of RAM available on my Timex/Sinclair ZX81. (I had to leave out the PRINT statements that explained how to play to get it to fit, as I recall.) However I had played Atari’s vector graphics Lunar Lander game by then, so I was a little underwhelmed.

I was more interested in playing the Super Star Trek game included in the same book. But that had to wait until I bought the 16K RAM upgrade (which cost more than the ZX81), and learned enough to translate the slightly more sophisticated program into the ZX81’s limited version of BASIC.

If anyone’s interested, here’s the BASIC version, plus a couple more sophisticated versions that allow setting the attitude angle, etc.


I recall playing a ‘graphic’ version of Lunar Lander that used ascii characters to draw the lunar surface and the lander, and you controlled it with the arrow keys. That was on, if I remember correctly a Polymorphics 8080 with 3k ram.


When I was a kid dad was a telegraph technician for the Post Office. He worked at a place I only ever knew as ‘The Depot’. Sometimes he would take me there on the weekends, and I was utterly spellbound by the punched paper tapes, the machines, the cables, the racks of esoteric tools, and benches rammed with machines in various states of disassembly which spoke of various repairs underway. This would have been in the later '70s, I guess, or maybe the early '80s.

I especially remember one wonderous weekend when he showed me Lunar Lander running on a computer of some sort. I never got even close to sticking a landing, and managed to kill more NASA astronauts than Michael Bay.

I miss that wide-eyed wonder about the future.


I had a Bomar scientific calculator in 1973; it was the bee’s knee’s. Then, a fellow physics student who’s Dad was a physicist got a hand me down HP-35 . The capability was about the same, but the HP was way cooler. A little later I got a programmable TI, think it had 100 steps memory; so much fun.

The HP-35 was something to be lusted after.

But.much later, it’s anazing how fewfunctions it had. My TI-30 was a bit better, they just kept adding functions after that.

There was a period in the nineties when I found calculators at garage sales for no more than five dollars each. So a TI-57 or 58, (the one without the card reader), complete with the printer. A selection of TI I think from before the TI-30, and an early HP complete in hard cover case.

I keep them with my TI LED watch that I bought new.


Ya, LED watches were great. I remember seeing the HP calculator watch…very nice, but cost more than any car I had owned.


There is a more visually-captivating vector-graphic version of this called Mars Lander (Episode 1) at, free except for creating an account with your junk email address.
Instead of direct user input, you write an AI program (in your favorite programming language) to output an appropriate thrust value for each iteration of the landing loop.
In Episode 2 you don’t start directly above your landing-spot, so you must output angle of thrust as well – visually simulating Neil Armstrong’s predicament.
You don’t want to know about Episode 3… :rocket:


I used to play this on a Teletype. Here’s a printout of the source code for the BASIC version from 1980. (The actual code is less than one page long.)

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My dad worked for National Semiconductor when he passed away in '84. I recall a few interesting calculators in his briefcase I kept (I should dig it out, actually).

My first try on this game was hard to beat.

Took me 18 tries before I finally landed on the moon at 52,42mph. “Crash Landing: You’ve 5hrs Oxygen
Edit: Finally got 39.38MPH: “Craft Damage, Good Luck
Edit: 34.34 MPH, “Craft Damage, Good Luck
Edit: 16:3 MPH “Congratulations on a poor landing
Edit: 10:41 MPH “Congratulations on a poor landing
Edit: 9.75 MPH GOOD LANDING-(Could be better)*
EDIT Good grief.: 2.02 MPH GOOD LANDING-(Could be better)*

1.56 MPH, 69.48lbs fuel, GOOD LANDING-(Could be better)*

According to that BASIC source code, anything less than 10 was a beautiful landing? (line 510 & 570)… Or maybe that’s off by a decimal, as the javascript source says you need <1MPH for the one “Perfect Landing” I’m missing…

I’m heading to bed. :stuck_out_tongue:


I definitely typed in Moon Lander (I’m pretty sure in BASIC, but Jim Butterfield had one in 6502 for the KIM-1). But I suddenly have a vague memory of changing some variable so it would crash faster, or maybe took longer to land.

My mom was a secretary at the University of Illinois back in the early 70s. My sister and I would go to work with her occasionally during our summer vacation. I wandered into the compsci area and saw these large machines with small green/black screens. One of the guys let me play Lunar Lander on the thing. That was my first video game and I’ve been hooked since.


A rubbish version of this was among the first complete programs I ever wrote.

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That looks like it’s descended from inspired by LEM*** on Dartmouth Time-Sharing System, dating back to at least 1972, which ran on GE machines.

Huh. A GE frontend connecting to an HP3000. A bit of a Frankenstein’s monster. If that is HP-BASIC, they should have used a timed ENTER statement rather than an INPUT.

With a rough genetic algorithm, i made it :-p

       0            120      0        3600.00     16000.0      K=:16
      10            109   5250        3604.01     15840.0      K=:17
      20             99   5178        3605.86     15670.0      K=:118
      30             90   1312        3399.71     14490.0      K=:21
      40             80   4309        3391.65     14280.0      K=:62
      50             71   2784        3295.78     13660.0      K=:100
      60             62   3295        3113.28     12660.0      K=:47
      70             54    380        3044.00     12190.0      K=:84
      80             45   4395        2887.44     11350.0      K=:37
      90             37   4656        2836.78     10980.0      K=:127
     100             30   1977        2566.15      9710.0      K=:117
     110             23   3190        2306.23      8540.0      K=:95
     120             17   2607        2091.61      7590.0      K=:132
     130             12    719        1762.44      6270.0      K=:113
     140              7   3404        1468.60      5140.0      K=:70
     150              3   4274        1291.52      4440.0      K=:195
     160              1    197         694.12      2490.0      K=:199
     170              0    196          12.78       500.0      K=:11
     180              0     53           6.71       390.0      K=:11
     190              0      0           0.38       280.0      K=:10
FUEL LEFT:   268.41 LBS

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