Four Mars missions are launching next year
It's worthwhile watching the launch of the Chinese Long March vehicle: https://www.nasaspaceflight.com/2019/06/china-first-sea-laun...They appear to shoot the entire vehicle out of a cannon-like container, then air-ignite the booster. I can't think of another launch vehicle that does this. The US did this sort of launch for the Sprint anti-ballistic missile: https://www.youtube.com/watch?v=msXtgTVMcuA