I'd put the voyager probes as more lonely. Not to mention any number of defunct spacecraft that are still operating out there. They don't have off switches. Somewhere out there is a space probe periodically trying to phone home only to discover we are no longer listening.

https://www.npr.org/2020/04/24/843493304/long-lost-u-s-milit...

""The oldest one I've seen is Transit 5B-5. And it launched in 1965," he says, referring to a nuclear-powered U.S. Navy navigation satellite that still circles the Earth in a polar orbit, long forgotten by all but a few amateurs interested in hearing it "sing" as it passes overhead."

This reminds me of the article "What football will look like in 17776?" a short story about football from the perspective of space probes. https://www.sbnation.com/a/17776-football

Thanks for the link. I hadn't seen this before and enjoyed it very much.

Yeah, mars is getting pretty crowded at this point! I guess the voyager probes might be lonelier, if you count them as robots.

At least as lonely as WALL-E...

No, because a robot cannot feel loneliness yet.