A hardware hacker named Ken Shirriff has restored NASA’s Apollo Guidance Computer (AGC) to mine Bitcoin (BTC). Fifty years ago, the AGC was responsible for controlling the guidance and navigation systems aboard the Apollo spacecraft.

In a blog post, he describes the details of his personal project in technical detail and the observations he gathered from conducting the experiment.

Apart from Shirriff, the AGC restoration team is comprised of Mike Stewart, Carl Claunch, and Marc Verdiell. Stewart had previously created a Field Programmable Gate Array (FPGA) simulation of the AGC and Claunch hand-built a replica of the Apollo Display Keyboard (DSKY). The project’s mastermind Shirriff had even previously tried his hand in mining Bitcoin by restoring a 1960’s IBM 1401 mainframe.

Apollo Guidance Computer: A Primitive Genius

The AGC was one of the first computers to use integrated circuits. In spite of the large computing power it possessed for its day and age, it weighed a ‘mere’ 70 pounds and could fit into a box just a couple of feet in size.

Unlike modern computers that utilize a processor to compute mathematical data, the AGC used around 5,600 electronic NOR gates. This allowed it to perform around 40,000 mathematical additions every second. Each integrated circuit held two NOR gates.

The AGC had just 2,000 words of Random Access Memory (RAM), along with 36,000 words of Read-Only Memory (ROM), exhibiting how primitive the technology was compared to today’s standards.

Mining a Single Bitcoin Block

Shirriff displayed the results of his experiment in a YouTube video using a Display/Keyboard (DSKY) replica built by one of the team members, Carl Claunch. The DSKY has a simple numeric keypad with large buttons to enable astronauts to use it with gloves on. The output was displayed numerically and astronauts had to know if the output was in feet, seconds, degrees, or in some other units.

To run the AGC, the user has to select the action by pressing the ‘verb’ key on the DSKY, and pressing ‘Enter.’ Shirriff and his team allocated BTC mining as verb 65 in the DSKY in a program known as Borealis.

A basic BTC mining machine on a USB stick which costs around $70 can calculate 130 billion hashes each second. In comparison, the AGC took around ten seconds to generate a single hash.

According to Shirriff’s calculations,

“Currently, the Bitcoin network is performing about 65 EH/s (65 quintillion hashes per second). Since the universe is only 4.3×10^17 seconds old, it would take the AGC about a billion times the age of the universe to successfully mine a block.”

With technological efficiency improving every year, what do you think the new generation of supercomputers could offer with regard to cryptocurrency mining? Let us know your thoughts in the comments below.