They need thrusters to orient the fairings to come in at the correct orientation.
I guess what I'm asking is why do the fairings need to maintain a particular orienation at all? They aren't seperating much higher/faster than stage 1 MECO, and the fairings are both big and light, so I can't imagine they're all that thermally stressed on reentry. Why not let them tumble until parachute altitude?
what I'm asking is why do the fairings need to maintain a particular orienation at all?...Why not let them tumble until parachute altitude?
Quote from: WBY1984 on 03/07/2016 07:22 amCan't quite understand what you're getting at: If you zoom in *where*, we see a black round *what*?https://imgur.com/lUPlvL9
Can't quite understand what you're getting at: If you zoom in *where*, we see a black round *what*?
seeing as how there aren't any known gas bottles on the fairings
Quote from: CJ on 03/07/2016 04:36 amseeing as how there aren't any known gas bottles on the fairingsThere are and this could be the system breaching from aero affects
Quote from: thor1872 on 03/07/2016 08:26 amQuote from: WBY1984 on 03/07/2016 07:22 amCan't quite understand what you're getting at: If you zoom in *where*, we see a black round *what*?https://imgur.com/lUPlvL9 not sure if its related but it looks like there is the top of a COPV with a pipe coming out right above the right shoulder of the guy on the right in blue jumpsuit.
Quote from: Jim on 03/07/2016 01:29 pmQuote from: CJ on 03/07/2016 04:36 amseeing as how there aren't any known gas bottles on the fairingsThere are and this could be the system breaching from aero affectsA mere 50 or so seconds after fairing sep? Unlikely. The thing was likely to still be way up above the atmosphere at that time. Edit: trajectory analysis by Reddit user ianniss shows fairing sep at a velocity of around 2.5 km/s, velocity angle around 13 deg above horizontal. The vertical displacement from faring sep altitude is then:sin(13 deg)*2500m/s*50s - 10m/s /2*50s*50s = 28 km upward - 12.5 km downward. So the fairing halves were, in fact, still coasting up at that point.The gas might have been autonomously vented, but aeroloads it wasn't.
Quote from: ugordan on 03/07/2016 01:42 pmQuote from: Jim on 03/07/2016 01:29 pmQuote from: CJ on 03/07/2016 04:36 amseeing as how there aren't any known gas bottles on the fairingsThere are and this could be the system breaching from aero affectsA mere 50 or so seconds after fairing sep? Unlikely. The thing was likely to still be way up above the atmosphere at that time. Edit: trajectory analysis by Reddit user ianniss shows fairing sep at a velocity of around 2.5 km/s, velocity angle around 13 deg above horizontal. The vertical displacement from faring sep altitude is then:sin(13 deg)*2500m/s*50s - 10m/s /2*50s*50s = 28 km upward - 12.5 km downward. So the fairing halves were, in fact, still coasting up at that point.The gas might have been autonomously vented, but aeroloads it wasn't.Or the actual separation event....
I'm wondering if it was those helium bottles leaking instead of thrusters. Is there any difference in the visibility of helium outgassing vs. something like nitrogen?
I might be mistaken, but in a vacuum Nitrogen freezes and produces ice crystals (hence the name "Cold Gas Thrusters" on the first stage). Where as helium simply disperses invisibly.
Maybe this is a stupid question, but wouldn't the fairing half passing through the second stage plume also create an effect like this?
Quote from: Flying Beaver on 03/07/2016 03:05 pmI might be mistaken, but in a vacuum Nitrogen freezes and produces ice crystals (hence the name "Cold Gas Thrusters" on the first stage). Where as helium simply disperses invisibly.No, nitrogen does not freeze nor does it contain any water. Any gas venting in a vacuum would be visible
Quote from: Saabstory88 on 03/07/2016 03:45 pmMaybe this is a stupid question, but wouldn't the fairing half passing through the second stage plume also create an effect like this? There would be around 10 km distance between the fairing and engine around 50 seconds after fairing sep. Highly unlikely.