Lisp in space (podcast, 38 minutes)

An interview on the Corecursive podcast with Ron Garret.

In 1988 (when, for context, I was in the second year of my BSc) Garret started working on autonomous navigation software for Sojourner, NASA’s first Mars rover, which flew in 1997. He used Lisp to do planning, essentially developing an entire domain-specific language for autonomous vehicles. The project was never flown, as NASA opted for a far less ambitious approach to driving to rovers – a decision that Garret now considers to have been the correct one.

But that isn’t the end of the story, because Garret then went on to develop an autonomous Remote Agent controller for the Deep Space 1 technology demonstration mission that performed asteroid and comet fly-bys. Without spoiling to story, the spacecraft flies with a full Lisp system onboard, and Garret gets to interact with its REPL at a distance of 30 light-minutes via the Deep Space Network – surely the longest latency of any REPL session ever!

It’s an fascinating insight into both the potentials of Lisp and the political difficulties that using a non-standard development language can engender.

UPDATE 2024-05-16: Ron also wrote a short essay about his experiences.