Last weekend a joint European-US satellite blasted into space to begin its mission - monitoring the oceans back here on earth. Sentinel 6 Michael Freilich is one of a long line of satellites and has a striking design – appearing like a bright gold farmyard barn with a big pitched roof. Anand Jagatia speaks to Dr Ralph Cordey at Airbus Space and Defence about the latest design iteration and the technology on-board. Oceanographer Professor Penny Holiday from the National Oceanography Centre explains how Sentinel 6’s readings will enhance understanding of sea-level rises and give more detail about the currents in our oceans. We journey back to the cosmic ‘Dark Ages’, a period of time that we know hardly anything about. Dr Emma Chapman is an astrophysicist at Imperial College London who has written a book ‘First Light: Switching on Stars at the Dawn of Time’ to throw light on this illusive chapter in the history of our universe. How close are scientists to finding the first stars? With ambitious new government targets to end the sale of petrol and diesel cars by 2030 how ready are electric cars to fill the gap? One key area many companies are trying to improve are the batteries powering electric vehicles. Peter Bruce, professor of materials science from Oxford University and chief scientist at the Faraday Institution has been working on rechargeable lithium ion energy storage since the 1990s. He speaks with Anand about the current limitations and the most recent developments in battery research and development. Presented by Anand Jagatia Produced by Melanie Brown