Something else that ncb1397's linked D2 PAT video brings up is the difference in test locations for SpaceX and Boeing. "Test as you fly" is often thrown around as a testing axiom. And there were a few explanations for why the crashed Starliner service module emitting smoke was not a concern. The explanation was that if this had been a real pad abort, the trunk would have gone into the ocean and sank before the capsule landed.That begs the question though. Why didn't they test an actual pad abort scenario from a location similar to the launch site, i.e. over water? I understand that Starliner is designed to land on solid ground, but this was a pad abort test, which presumably would only happen at launch sites that would put the capsule above water for the abort and recovery. Testing a pad abort where you expect Starliner to land in a normal recovery-from-orbit location seems like taking a shortcut; probably to simplify the recovery of the capsule for examination afterward. Starliner had a successful test of the abort portion, but not necessarily the landing portion (though they did test a landing scenario, it wasn't the same scenario as a real pad abort would experience.)
Quote from: Joseph Peterson on 11/05/2019 03:44 amQuote from: Comga on 11/05/2019 02:29 amQuote from: Joseph Peterson on 11/05/2019 02:00 amStarliner appeared to be surrounded in a cloud of propellant when the drogues deployed in my unexpert opinion. Is there any chance the valve problem is still a problem? This was discussed way back up-thread.So many topics are going in circles that it behooves us all to read the whole thread before starting another loop.The reply to that post confused me. I know NTO was expected to be released when the service module impacted from the webcast. I'm missing where we find out that we should expect the service module to be venting large quantities after engine shutdown.Rewatching Dragon's pad abort didn't help. I didn't expect it to because completely different spacecraft. At this point in time I'm looking for anything that might help me understand what I am seeing. This is my first post, so I'm sorry if I'm doing it wrong, but if you watch Boeing's video of the service module hot fire test ( https://www.youtube.com/watch?v=nCT6gKGWssc?t=36 ) you can see that during the shutdown for the LAE's, allot of NTO is visible on shutdown (the successful hot fire). The OMAC's also leave behind a cloud of NTO when they shutdown. So it makes sense that all this unused NTO is visible throughout the flight. Remember, the OMAC's are used throughout the abort process for control and spacecraft reorientation. That's why at apogee, when Starliner does it's flip, NTO becomes more visible again because those engines always leave a little puff when they shutdown, so when they are pulsing to maintain attitude control, you see these clouds. It's consistant with the SM hot fire video and the P.A.T. animation.
Quote from: Comga on 11/05/2019 02:29 amQuote from: Joseph Peterson on 11/05/2019 02:00 amStarliner appeared to be surrounded in a cloud of propellant when the drogues deployed in my unexpert opinion. Is there any chance the valve problem is still a problem? This was discussed way back up-thread.So many topics are going in circles that it behooves us all to read the whole thread before starting another loop.The reply to that post confused me. I know NTO was expected to be released when the service module impacted from the webcast. I'm missing where we find out that we should expect the service module to be venting large quantities after engine shutdown.Rewatching Dragon's pad abort didn't help. I didn't expect it to because completely different spacecraft. At this point in time I'm looking for anything that might help me understand what I am seeing.
Quote from: Joseph Peterson on 11/05/2019 02:00 amStarliner appeared to be surrounded in a cloud of propellant when the drogues deployed in my unexpert opinion. Is there any chance the valve problem is still a problem? This was discussed way back up-thread.So many topics are going in circles that it behooves us all to read the whole thread before starting another loop.
Starliner appeared to be surrounded in a cloud of propellant when the drogues deployed in my unexpert opinion. Is there any chance the valve problem is still a problem?
I think the question "was this test survivable or not?" is not the right question to ask. The right question is: "what does this mean statistically?"If you have just one test, statistics is pretty bad but even though, in that one test one of the parachutes fail. Small number statistics is a bit complicated, but lets say this is a mean result, that means the parachutes have a failure rate of 33% in an abort scenario and all three chutes are independent. Then there is a chance of about 26% that 2 out of 3 chutes or all 3 chutes fail. So if you look at this test in isolation, there is a 1 in 4 chance of non survival pad abort.Now the error in this analysis is, that the test does not stand in isolation and the chutes are probably not independent. Thus, a second failure might be vastly lower probability than one chute failing. Also, there might be other tests that inform of a vastly lower chance of chute failure to begin with. I didnt follow the progress of CST 100 closely enough to know its chute test history. Without deep insight into this system, its hard for me to assess the safety factors. Let the experts deal with this, I am sure it will be investigates, no matter what the success criteria of this test are.
SNIPI think we can safely say that all valves closed as we had residual propellant in the tanks that gets released after the service module impacts the ground but there is zero apparent venting right before service module jettisons.SNIP
This is my first post, so I'm sorry if I'm doing it wrong, but if you watch Boeing's video of the service module hot fire test ( https://www.youtube.com/watch?v=nCT6gKGWssc?t=36 ) you can see that during the shutdown for the LAE's, allot of NTO is visible on shutdown (the successful hot fire). The OMAC's also leave behind a cloud of NTO when they shutdown. So it makes sense that all this unused NTO is visible throughout the flight. Remember, the OMAC's are used throughout the abort process for control and spacecraft reorientation. That's why at apogee, when Starliner does it's flip, NTO becomes more visible again because those engines always leave a little puff when they shutdown, so when they are pulsing to maintain attitude control, you see these clouds. It's consistant with the SM hot fire video and the P.A.T. animation.
This accounts for all the undefinable errors that can take out all three such as the same team incorrectly installing all of them (it happens).
If you have just one test, statistics is pretty bad but even though, in that one test one of the parachutes fail. Small number statistics is a bit complicated, but lets say this is a mean result, that means the parachutes have a failure rate of 33% in an abort scenario and all three chutes are independent. Then there is a chance of about 26% that 2 out of 3 chutes or all 3 chutes fail. So if you look at this test in isolation, there is a 1 in 4 chance of non survival pad abort.
Quote from: Captain Crutch on 11/05/2019 02:17 pmHazmat officials are told to secure the area surrounding large spills of N2O4 for 1200ft in all directions and up to several miles down wind.Scott Manley mentioned that too. The Starliner service module apparently impacted the desert a short distance from where the capsule landed and produced a big brown ground-level plume. Wind might easily have blown the plume in the direction of the just-landed capsule, making astronaut egress problematic.
Hazmat officials are told to secure the area surrounding large spills of N2O4 for 1200ft in all directions and up to several miles down wind.
Quote from: Yazata on 11/05/2019 05:21 pmQuote from: Captain Crutch on 11/05/2019 02:17 pmHazmat officials are told to secure the area surrounding large spills of N2O4 for 1200ft in all directions and up to several miles down wind.Scott Manley mentioned that too. The Starliner service module apparently impacted the desert a short distance from where the capsule landed and produced a big brown ground-level plume. Wind might easily have blown the plume in the direction of the just-landed capsule, making astronaut egress problematic. I imagine it taking days to rescue your crew as they bob about in a ship that was meant to go to space instead of the water. Granted that's wrose case scenario. Does anyone know if theyve been able to get to the capsule yet? It seems like the are would be contained and nobody would be allowed in the area for a while but maybe I'm wrong...
Quote from: Captain Crutch on 11/05/2019 05:26 pmQuote from: Yazata on 11/05/2019 05:21 pmQuote from: Captain Crutch on 11/05/2019 02:17 pmHazmat officials are told to secure the area surrounding large spills of N2O4 for 1200ft in all directions and up to several miles down wind.Scott Manley mentioned that too. The Starliner service module apparently impacted the desert a short distance from where the capsule landed and produced a big brown ground-level plume. Wind might easily have blown the plume in the direction of the just-landed capsule, making astronaut egress problematic. I imagine it taking days to rescue your crew as they bob about in a ship that was meant to go to space instead of the water. Granted that's wrose case scenario. Does anyone know if theyve been able to get to the capsule yet? It seems like the are would be contained and nobody would be allowed in the area for a while but maybe I'm wrong...No, it wouldn't take anything like that long because of the NTO. In water, even less time. In wet/high humidity conditions the NTO becomes nitric acid then is diluted rather rapidly, and a hose will accelerate the process.In dry conditions, like the desert, there's still enough water in the air for things to break down, just a bit less rapidly.Protective wear against acids would be wanted, about like what you'd wear for servicing batteries, after the BFRC is gone. Current standards might require a full acid suit if you're going in soon afterward.
Quote from: saundby on 11/05/2019 07:08 pmQuote from: Captain Crutch on 11/05/2019 05:26 pmQuote from: Yazata on 11/05/2019 05:21 pmQuote from: Captain Crutch on 11/05/2019 02:17 pmHazmat officials are told to secure the area surrounding large spills of N2O4 for 1200ft in all directions and up to several miles down wind.Scott Manley mentioned that too. The Starliner service module apparently impacted the desert a short distance from where the capsule landed and produced a big brown ground-level plume. Wind might easily have blown the plume in the direction of the just-landed capsule, making astronaut egress problematic. I imagine it taking days to rescue your crew as they bob about in a ship that was meant to go to space instead of the water. Granted that's wrose case scenario. Does anyone know if theyve been able to get to the capsule yet? It seems like the are would be contained and nobody would be allowed in the area for a while but maybe I'm wrong...No, it wouldn't take anything like that long because of the NTO. In water, even less time. In wet/high humidity conditions the NTO becomes nitric acid then is diluted rather rapidly, and a hose will accelerate the process.In dry conditions, like the desert, there's still enough water in the air for things to break down, just a bit less rapidly.Protective wear against acids would be wanted, about like what you'd wear for servicing batteries, after the BFRC is gone. Current standards might require a full acid suit if you're going in soon afterward.Assuming a drift rate of 1 mile per hour, it would be 48 miles away from the service module impact point 2 days later. Could be in Daytona Beach by then.
Quote from: ncb1397 on 11/05/2019 07:53 pmQuote from: saundby on 11/05/2019 07:08 pmQuote from: Captain Crutch on 11/05/2019 05:26 pmQuote from: Yazata on 11/05/2019 05:21 pmQuote from: Captain Crutch on 11/05/2019 02:17 pmHazmat officials are told to secure the area surrounding large spills of N2O4 for 1200ft in all directions and up to several miles down wind.Scott Manley mentioned that too. The Starliner service module apparently impacted the desert a short distance from where the capsule landed and produced a big brown ground-level plume. Wind might easily have blown the plume in the direction of the just-landed capsule, making astronaut egress problematic. I imagine it taking days to rescue your crew as they bob about in a ship that was meant to go to space instead of the water. Granted that's wrose case scenario. Does anyone know if theyve been able to get to the capsule yet? It seems like the are would be contained and nobody would be allowed in the area for a while but maybe I'm wrong...No, it wouldn't take anything like that long because of the NTO. In water, even less time. In wet/high humidity conditions the NTO becomes nitric acid then is diluted rather rapidly, and a hose will accelerate the process.In dry conditions, like the desert, there's still enough water in the air for things to break down, just a bit less rapidly.Protective wear against acids would be wanted, about like what you'd wear for servicing batteries, after the BFRC is gone. Current standards might require a full acid suit if you're going in soon afterward.Assuming a drift rate of 1 mile per hour, it would be 48 miles away from the service module impact point 2 days later. Could be in Daytona Beach by then.Well that would be for a normal launch, in the case of an abort the service module and capsule would be pretty close together and as we saw during the video the capsule seemed to blow the fuel right towards the capsule, so it would be very dangerous to evacuate the crew from the capsule once that happens... the whole situation is a hazmat nightmare to say the least...
Quote from: Captain Crutch on 11/05/2019 09:15 pmQuote from: ncb1397 on 11/05/2019 07:53 pmQuote from: saundby on 11/05/2019 07:08 pmQuote from: Captain Crutch on 11/05/2019 05:26 pmQuote from: Yazata on 11/05/2019 05:21 pmQuote from: Captain Crutch on 11/05/2019 02:17 pmHazmat officials are told to secure the area surrounding large spills of N2O4 for 1200ft in all directions and up to several miles down wind.Scott Manley mentioned that too. The Starliner service module apparently impacted the desert a short distance from where the capsule landed and produced a big brown ground-level plume. Wind might easily have blown the plume in the direction of the just-landed capsule, making astronaut egress problematic. I imagine it taking days to rescue your crew as they bob about in a ship that was meant to go to space instead of the water. Granted that's wrose case scenario. Does anyone know if theyve been able to get to the capsule yet? It seems like the are would be contained and nobody would be allowed in the area for a while but maybe I'm wrong...No, it wouldn't take anything like that long because of the NTO. In water, even less time. In wet/high humidity conditions the NTO becomes nitric acid then is diluted rather rapidly, and a hose will accelerate the process.In dry conditions, like the desert, there's still enough water in the air for things to break down, just a bit less rapidly.Protective wear against acids would be wanted, about like what you'd wear for servicing batteries, after the BFRC is gone. Current standards might require a full acid suit if you're going in soon afterward.Assuming a drift rate of 1 mile per hour, it would be 48 miles away from the service module impact point 2 days later. Could be in Daytona Beach by then.Well that would be for a normal launch, in the case of an abort the service module and capsule would be pretty close together and as we saw during the video the capsule seemed to blow the fuel right towards the capsule, so it would be very dangerous to evacuate the crew from the capsule once that happens... the whole situation is a hazmat nightmare to say the least...No, in the case of an abort, the capsule is going into the ocean off the coast of florida. Your situation only happens if they miss the Atlantic.
Not really, the [service module] will explode when it hits the water, that will push some of the propellant into the air, which could result in the capsule with people on it being coated in this toxic chemical... just like what we saw in the PAT, just in a smaller quantity due to it reacting with the water.
Not really, the capsule will explode when it hits the water, that will push some of the propellant into the air, which could result in the capsule with people on it being coated in this toxic chemical... just like what we saw in the PAT, just in a smaller quantity due to it reacting with the water.
Quote from: Captain Crutch on 11/05/2019 09:40 pmNot really, the capsule will explode when it hits the water, that will push some of the propellant into the air, which could result in the capsule with people on it being coated in this toxic chemical... just like what we saw in the PAT, just in a smaller quantity due to it reacting with the water.How? The SM and Capsule are going to splash down quite apart in both distance and time. Capsule is descending on parachute, SM ballistically.