On propulsion:::: https://forum.nasaspaceflight.com/index.php?topic=36552.1200 https://forum.nasaspaceflight.com/index.php?topic=36552.1200 https://m.youtube.

On propulsion:::: https://forum.nasaspaceflight.com/index.php?topic=36552.1200 https://forum.nasaspaceflight.com/index.php?topic=36552.1200 https://m.youtube.com/watch?v=5MEPWsdo-UE https://m.youtube.com/watch?v=5MEPWsdo-UE https://space.stackexchange.com/questions/36165/why-will-starlink-satellites-use-krypton-instead-of-xenon-for-electric-propulsio https://space.stackexchange.com/questions/36165/why-will-sta... I don't know if it's cheaper because it's something im not particularly familiar with. But there's people who think SpaceX isn't launching (internal costs) for less than 60 million anyway and reuse isn't saving money