Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Shaheen Mongam on 15/06/2016 09:45:18

Title: why does the Delta IV rocket engine have a smokeless exhaust?
Post by: Shaheen Mongam on 15/06/2016 09:45:18

United Launch Alliance (ULA) has launched the world's heaviest rocket of all the time last week. I observed that its having an almost smokeless exhaust compared to other rockets. Why is it so

Title: Re: why does the Delta IV rocket engine have a smokeless exhaust?
Post by: chiralSPO on 15/06/2016 11:59:41

I believe (and wikipedia confirms: https://en.wikipedia.org/wiki/Delta_IV#Delta_IV_first_stage) that the first stage of a Delta IV rocket uses liquid hydrogen and liquid oxygen as propellants. This combination will only result in gaseous water (no smoke), which is also very hot, so it may have time to dissipate before condensing into vapors, which might be visible.