>>215245424 (OP)
Recycling old notes:
Crew of the Leonov, l-r, 1-8:
1) Victor Steinbach as Nikolai Ternovsky. A minor crew hand. In the novel, this character gets a bit more play in that he helps Chandra get HAL running again.
2) Czech actor Jan Triska as Alexsandr Kovalev. This character has an English line or two after a probe crashes, but it's easy to miss. The novel's character by same name is similarly inconsequential.
3) Natasha Shneider as Irina Yakunina, a largely ineffectual chickie who still has an English line. In the book, a character by this name is initially slated to be part of the Leonov's crew. However, this book-character meets with a hang gliding accident before the mission commences, and is therefore replaced for the mission by an understudy, one Zenia Marchenko - who is in fact fucking Max during the trip. The film simply dispenses with this backstory in favor of using the early listed name for "second minor female character".
4) Oleg Rudnik as Vasily Orlov, really the chief science man on the ship. He plays with the space probes and actually leads sciency stuff. In the novel, this character and captain Tanya (Orlova) are spouses.
5) Vladimir Skomarovsky as Yuri Svetlanov. He helps Tanya run the bridge and has some Russian exchanges, but never speaks English. This character is a pure invention of the film's, and has no equivalent in the book.
6) Elya RENT! Baskin as Maxim "Max" Brailovsky, who has a good spacewalk scene with Lithgow's character. In both book and film, the two characters develop a bro-ship, with the novel making a faint suggestion (IMO) that something a bit more might be going on. Baskin often plays a stock Russian/eastern-euro guy for western movies.
7) Helen Mirren as Tanya Kirbuk, captain.
8) Saveliy Kramarov as Dr. Vladimir Rudenko. A little dialogue, simple doctor-character. This actor replaces the book's character which instead describes (Katerina) Rudenko as a fat, matronly babushka-woman.