What was this?

On Sat, 18 Jan 2014 01:43:57 -0500, David Spain wrote:

On 1/17/2014 2:07 AM, wrote:
I was watching an episode of Space Voyages on the SMithsonian Channel last night
and early in the show, they showed the launch of a modern era rocket. Could have
been an Atlas or Delta, couldn't really tell. But as soon as it started to take
off, there was very visible rocket exhaust coming from the top, at the payload
area. I never saw anything like that before. It wasn't an emergency escape
system, as it didn't pull the top off the rocket. Any idea what this could have
been?


If what you saw matches the first second of this video trailer for the
series:

http://www.smithsonianchannel.com/sc.../space-voyages

Then I think you are watching a computer simulation of an SLS launch. It
looks to me to be gasses venting off the top. But in reality I would
suspect there would be little venting. Usually venting is stopped just
prior to lift-off to maintain flight level pressures within the the
LOX/LH2 tankage.

Dave


Yup, that's the shot I saw and the one I'm refering to.