Dr Chris Smith and the Naked Scientist team present the latest science news, analysis and breakthroughs. This week: The regulator says the Alzheimer's drug Lecanemab is safe, but NICE say we can't afford it. The UK Ministry Of Defence launches its first Earth imaging satellite. And the BBC's Frank Gardner on why the UK's butterflies need our help. Plus is there a link between some cosmetics and cosmetic trends and cancer? We examine this in more detail in the second part of the programme.