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I'm sorry to say I know little about you or the subject (so I apologize if either answer is obvious or addressed elsewhere) however since you're here: What wou

I'm sorry to say I know little about you or the subject (so I apologize if either answer is obvious or addressed elsewhere) however since you're here: What would you like to see NASA do differently? What do you think of Racket (the programming language)?

lisper 4y ago
Good questions. I have been away from NASA for almost 20 years now so I can't really say what I think they should do differently because I don't really know what they are currently doing. A lot can change in 20 years, and I'm sure a lot has, but I'm no longer in the loop so I can't really say anything constructive about this. I've never used Racket but from what I can tell it's a fine system. I'm partial to Common Lisp myself, never really resonated as much with Scheme, though I do admire the elegance of the language. But if it works for you, go for it.
- costigan 4y ago
  I think lisp is still used in various nooks and crannies of NASA. As a small example, I was the payload software engineer for the LCROSS mission (a robotic mission in 2009 that demonstrated there was water ice near the moon's south pole). The software that ran on the payload computer was in C, but there was a very simple, ad hoc scripting language provided by the company that provided that payload computer. Because this language was very simple, I wrote a higher-level DSL and a simulator of the computer in common lisp and then wrote all of the instrument command sequences in that DSL. Lisp's simple, flexible syntax and macros made it easy to express patterns of commanding and timing for this. What the commands did is described in the last (topmost) blog entry here: https://blogs.nasa.gov/lcrossfdblog/ https://blogs.nasa.gov/lcrossfdblog/ . These days, I'm working on the VIPER rover, and the commanding approach for it is very manual, as Ron described. VIPER will be a moon rover, so the turn-a-round time for commanding is much shorter than it would be for a MARS rover, and teleoperation from Earth is a very reasonable and lower-risk solution than autonomy. Still, some of the systems used in self-driving vehicles today to evaluate the environment around the vehicle will be used by VIPER, but to provide advice and situational awareness for the drivers. No lisp involved.

lisper 4y ago

Good questions. I have been away from NASA for almost 20 years now so I can't really say what I think they should do differently because I don't really know what they are currently doing. A lot can change in 20 years, and I'm sure a lot has, but I'm no longer in the loop so I can't really say anything constructive about this. I've never used Racket but from what I can tell it's a fine system. I'm partial to Common Lisp myself, never really resonated as much with Scheme, though I do admire the elegance of the language. But if it works for you, go for it.

costigan 4y ago
I think lisp is still used in various nooks and crannies of NASA. As a small example, I was the payload software engineer for the LCROSS mission (a robotic mission in 2009 that demonstrated there was water ice near the moon's south pole). The software that ran on the payload computer was in C, but there was a very simple, ad hoc scripting language provided by the company that provided that payload computer. Because this language was very simple, I wrote a higher-level DSL and a simulator of the computer in common lisp and then wrote all of the instrument command sequences in that DSL. Lisp's simple, flexible syntax and macros made it easy to express patterns of commanding and timing for this. What the commands did is described in the last (topmost) blog entry here: https://blogs.nasa.gov/lcrossfdblog/ https://blogs.nasa.gov/lcrossfdblog/ . These days, I'm working on the VIPER rover, and the commanding approach for it is very manual, as Ron described. VIPER will be a moon rover, so the turn-a-round time for commanding is much shorter than it would be for a MARS rover, and teleoperation from Earth is a very reasonable and lower-risk solution than autonomy. Still, some of the systems used in self-driving vehicles today to evaluate the environment around the vehicle will be used by VIPER, but to provide advice and situational awareness for the drivers. No lisp involved.