Found: Exploring a distant star system, small group men & women, assisted by "Christmas tree" artificial intelligence or robot

FOUND. Answer is Rocheworld and Return to Rocheworld by Robert Forward. I am looking for a novel, perhaps written 20 to 30 years ago, about a small group of 6 to 8 men and women sent on a one way trip to another star system to spend the rest of their lives traveling around its planets and studying them. They shared an assistant called the Christmas tree that was a robot made of many small pieces (perhaps nanobots??) that helped with physical work, calculations, monitored their medical conditions. At the end the one elderly survivor is met by a newer faster ship from Earth which has come to find out what happened to them. I think it was a long established science fiction writer near the end of their career. I have no idea of title or author name. Any suggestions would be appreciated.

Maybe one of Robert L. Forward's Rocheworld books? The bush robot was in at least the first one IIRC (of four, and I didn't read the later ones).

Thank you. Yes, it is Rocheworld and Return to Rocheworld. FOUND!
Thank you so much for your help. I will find my copies and enjoy rereading them, or buy copies if needed.

Happy to assist!