Recovering Data from 1969 Lunar Lander Mission

Lunar Landing Papertape
Mysterious papertape with hand-printed text that reads “Start 1000 tty RUN -> 90”

Pat Hilend of Pheonixville, PA stopped by the shop, and with appropriate “social distancing”, dropped off a papertape to be archived that he claims to have had been created using a Honeywell DDP-516 minicomputer containing a “data dump” from the 1969 American Apollo lunar landing taken from White Sands, New Mexico. Back then if a person wanted a portable copy of a computer file they would send their data to the papertape punch of a Teletype model ASR-33. Would this have been permitted or was this data smuggled out? Pictured below is such a system, scanned from the 1965 Honeywell product brochure. Pat brought the tape to Kennett Classic to see if we could read the tape and extract its secrets. Reading ancient data is part of our mission. Pat found the right place!

Lunar Landing (data) or Lunar Lander (the game)?

Honeywell DDP-516
Operator using Teletype and front panel to operate a Honeywell DDP-516

There are really no known-working DDP-516’s out there, or maybe just one but nothing in the USA. We are lucky to have only the a few bits and pieces from the DDP-516 that we do have, including the front panel (below) and some core memory. We also have a set of operations and product manuals for the Honeywell 300-500-700 systems.

Front Panel of the DDP-516. To run the tape above on an actual DDP-516 one would set the program counter to 1000 octal (push button 10 IN) insert the tape in the reader and press START.

Despite the fact that we have no working DDP-516, we can still attempt to extract the data and read the tape. 8-bit papertapes from the late 1960’s are more or less “universal” in that most tapes are punched in the American Standard Code for Information Interchange format, commonly known as “ASCII”. This format is still in use today, even if the Teletypes that they were originally created for are no longer in use. At Kennett Classic we can read converted Honeywell DDP system tapes using our in-house Teletype. If we can manage to capture the data stream from the Teletype into modern computer we can then save it into a format that a program called a “hardware emulator” can read. There is a pretty good Honeywell DDP-516 emulator that should do the trick. Using the emulator we can analyze the data and make sense of it. Not easy, but if we’re persistent we should be able to do recover what might be historic Apollo lunar landing data. Who knows what we’ll find!

Teletype ASR 33 With Cover Removed
Teletype ASR 33 (with cover removed). Note the bottom left papertape reader with a small piece of papertape fed into it.
Papertape reader with tape
Pictured is a closeup of the Teletype’s papertape reader with a short ASCII tape inserted. Each line of data is represented horizontally, holes = 1, no hole = 0. For example a “W” would read 1010111 as represented by holes (or no hole) punched in the tape. Teletype data is transmitted at 110 baud, which is a tiny fraction of the data speeds we have today. It takes about 30 minutes to read 8K (8196 bytes) of data…much less than the average email message with a photo.
Oops, first we needed to replace the capacitor and 3.0 Amp fuse used to drive the Teletype motor and papertape reader. Pictured is the back the Teletype while repairs were being made.
Pictured above is the device we use to convert the signals from a Teletype (current loop) into modern electronic pulses (RS232 serial). The wires to the right are attached to the Teletype on the other end. The ribbon cable on the left attaches to an older Windows computer.
1993 Compaq Presario 425. This computer will be used to bridge between the modern world and the ancient (1969) world. It’s new enough to save data in a format that can be used by a modern PC, but old enough to read data directly from the Teletype signal converter without additional hardware to buffer the 110 baud transmission rate.

Stay tuned, more to come! If you want to get into more technical details we will list them on vintagecomputer.net.