No return for Harry and Meghan... The BBC's royal correspondent, Jonny Dymond, explains what's going on with the Duke and Duchess of Sussex. We also try to figure out how poorer countries are going to get their vaccines, with Dr Robin Nandy, chief of immunisation at UNICEF. And astrophysicist, Dr Maggie Lieu, tells us exactly why landing on Mars is such a big deal.

Studio manager: Ashley Taylor