Shortly after if launched, there was was looked like a bubble of smoke around the front section of the rocket. Anyone know what that was?
Very short version. Under the right meteorlogical and aerodymanic conditions that often happens when a vehicle is close to the speed of sound. I’ve seen it on the wings of passenger jets under the right conditions.
It is the water vapor in the air condensing out temporarily as the pressure and temp in a region are rapidly changing, which can happen to the air when you force a solid object through it at a high rate of speed.
That was my impression, too. Is the explanation as simple as the upper stage was not supposed to ignite today? Perhaps on a suborbital flight they just wanted to see how that first stage worked.
from NASA
The upper stage was a dummy. No thrusters or anything. This didn’t have the real engine or much else on it. It was more of a full scale wind-tunnel test than anything. Which is important: it didn’t pogo, which many nay-sayers said it would.