Season 4 of Neil deGrasse Tyson’s “StarTalk” NatGeo series premieres Sunday night with the astrophysicist interviewing Lance Armstrong on the science behind cycling and steroid use in the sport.

The fourth season of the celebrity scientist’s National Geographic Channel program returns tonight at 11 p.m. EDT (10 p.m. CT) as he sits down with controversial former professional cyclist Lance Armstrong, who won the Tour de France a record seven consecutive times from 1999 to 2005 before becoming the center of a doping scandal that effectively ended his career.

The two discuss a wide range of issues including high and low octane energy conversions behind the mechanics of cycling, Big Pharma, drafting as a tactic and performance enhancing drugs (PEDs) usage in the sport. Tyson told the New York Post he wanted to focus the conversation on the wider science behind cycling, but he obviously was not going to avoid the steroid scandal.

Had the pleasure to join @neiltyson for a @StarTalk on @NatGeo Season 4 premiere airs this Sunday October 1 https://t.co/n3OA6BV6LA pic.twitter.com/SBeqeM0UIP — Lance Armstrong (@lancearmstrong) September 29, 2017





“I wanted Lance to tell me about the history of bicycle technology -- what’s accepted and what’s not -- and can you invent something that’s really innovative and still have it used in a tournament? Tyson told the Post. “How does energy get converted to the mechanics of a bicycle? We had a whole physics conversation about energy and bicycle performance.”

However, he did say he wasn’t going to make Armstrong apologize to his fans or push guilt on him as many said of his post-scandal interview with Oprah Winfrey in 2013.

“I’m not going to dust the whole [doping] scandal under the rug, so we talked about doping and had a whole conversation about the chemistry of doping — what it does to the body, how it works,” said Tyson. “I’m not Oprah saying, ‘Are you going to apologize to your fans? Are you contrite?’ I don’t care.”

Bioethicist Arthur Caplan discussed the pervasiveness of PEDs in cycling, although Armstrong said the sport is much “cleaner” now than it was when he was still in the professional cycling circuit.

Featured in later episodes this season, Tyson interviews science celebrities including Stephen Hawking and Jane Goodall as well as entertainment figures including Katy Perry and Stephen Colbert. Comedians and academics are also on-hand to discuss the topics on panels.