Here is the official description for Castle season 7 episode 16, "The Wrong Stuff" - airing February 23rd.
Season 7 Episode 16 "The Wrong Stuff"
When an astronaut training for a trip to Mars is mysteriously killed inside a Mars simulation, Castle and Beckett don spacesuits to investigate. But when they discover no one inside the sealed simulation could have committed the murder and no one from the outside could get in, the case takes a shocking turn
Nathan Fillion as Richard Castle
Stana Katic as NYPD Detective Kate Beckett Susan Sullivan as Martha Rodgers
Molly Quinn as Alexis Castle
Penny Johnson Jerald as NYPD Captain Victoria Gates
Tamala Jones as Medical Examiner Lanie Parish Jon Huertas as NYPD Detective Javier Esposito
Seamus Dever as NYPD Detective Kevin Ryan
guest & recurring cast:
Yves Bright as Tom Richwood
Gwendoline Yeo as Elise Kim
David Rogers as Viggo Jansen
Sterling K. Brown as Ed Redley
Maxwell Caulfield as Sir Ian Rasher