As Elon said in the post-presser, it's more of a fireball than an explosion. Highly unlikely there would be a shockwave that could crush the CrewDragon. Plus the base heat shield, which is designed to handle heat, as also stated by Elon in the presser.And the reaction times to these types of abort scenario events are usually in the range of milliseconds, not a couple of seconds.
Quote from: joek on 01/20/2020 01:56 amQuote from: Nomadd on 01/20/2020 01:26 amDragon commanding the engine shutdown doesn't mean the abort wasn't triggered by loss of thrust. Engine shutdown and abort thrusters firing are two different things.Correct; the abort was *not* triggered by loss of F9 thrust, but by Dragon based on other criteria, as addressed during the presser Q&A (see numerous posts above).Presumably, the parameters which triggered abort firing are merely correlated with loss of booster thrust, since in real life you can't rely on failure scenario where booster shuts down explicitly and conveniently.
Quote from: Nomadd on 01/20/2020 01:26 amDragon commanding the engine shutdown doesn't mean the abort wasn't triggered by loss of thrust. Engine shutdown and abort thrusters firing are two different things.Correct; the abort was *not* triggered by loss of F9 thrust, but by Dragon based on other criteria, as addressed during the presser Q&A (see numerous posts above).
Dragon commanding the engine shutdown doesn't mean the abort wasn't triggered by loss of thrust. Engine shutdown and abort thrusters firing are two different things.
If that explosion had occurred with the D2 attached, I'm guessing that the shockwave would likely have crushed the D2 no matter what acceleration it had. Some events aren't survivable.
https://twitter.com/nextspaceflight/status/1218999461847977986
The trunk is on board GO Navigator.https://twitter.com/Kyle_M_Photo/status/1219062943125508097
Quote from: Rondaz on 01/20/2020 02:57 amThe trunk is on board GO Navigator.https://twitter.com/Kyle_M_Photo/status/1219062943125508097Can someone explain why this thing floats?
Quote from: Lee Jay on 01/20/2020 04:06 pmQuote from: Rondaz on 01/20/2020 02:57 amThe trunk is on board GO Navigator.https://twitter.com/Kyle_M_Photo/status/1219062943125508097Can someone explain why this thing floats?Honeycomb cell material? Total guess...
Quote from: Rocket Science on 01/20/2020 04:16 pmQuote from: Lee Jay on 01/20/2020 04:06 pmQuote from: Rondaz on 01/20/2020 02:57 amThe trunk is on board GO Navigator.https://twitter.com/Kyle_M_Photo/status/1219062943125508097Can someone explain why this thing floats?Honeycomb cell material? Total guess...Hopefully they might be reuse components from it. They might start putting parachutes on it & catching it with Go Ms. Tree or Ms. Chief
They might start putting parachutes on it & catching it with Go Ms. Tree or Ms. Chief
Quote from: Tomness on 01/20/2020 05:23 pmThey might start putting parachutes on it & catching it with Go Ms. Tree or Ms. ChiefComing back from orbital velocities with no heat shield, I doubt whatever makes it to the surface will be worth anything.Have a good one,Mike
Quote from: tyrred on 01/20/2020 07:49 amAs Elon said in the post-presser, it's more of a fireball than an explosion. Highly unlikely there would be a shockwave that could crush the CrewDragon. Plus the base heat shield, which is designed to handle heat, as also stated by Elon in the presser.And the reaction times to these types of abort scenario events are usually in the range of milliseconds, not a couple of seconds.There are deflagrations that generate shockwaves, and ones that don't. As an example, the initial Amos 6 explosion probably didn't, but when the core stage blew up a few seconds later, that almost certainly did--you could hear the difference on the video.Don't confuse the reaction time to initiate the separation with the time require to reach minimum safe distance. The former is indeed only a few tens of milliseconds, maybe 100 ms. That later is highly scenario-dependent, but is likely a few seconds--as it was in this case. However, in all scenarios, engine shutdown telemetry or complete loss of telemetry are both pretty good indicators that it's time to go. So the test was likely close to worst survivable case, which is what you'd want.
Is it possible to reuse the trunk, or is it one-use only?
Quote from: Comga on 01/19/2020 11:56 pmBut remember, NASA said that the analysis of the Dragon 2 parachute failure showed that the accepted modeling was inadequate despite decades of use and acceptance. Orion and Starliner used those models to do verification of their parachutes. Yet both were allowed to continue without new drop tests. Did either of those programs have to update their models and recertifications?How much do we know about this "Mark III" parachute design? Very little.[1] How much do we know about the differences between this design and previous, potentially more conventional and well-modeled systems? Very little. How much do we know whether the models of this new design accurately reflect what has been observed in testing? Very little.Yeah, there may be an overabundance of caution. But would not be surprised if this new-improved Mark III system held some surprises which caused pause in some quarters. It's a set of parachutes, right? We've done this for years, right? What possible new-and-potentially-radical improvements could SpaceX's Mark II have which might upset the cart and make our old models questionable?I have no idea what's really in play. But I think it's safe to say that SpaceX might not have been satisfied with the humdrum well-proven designs (and models) and as typical, gone their own route...and thus the need-desire on NASA's part to perform additional validation.[1] Speaking for myself. Have seen little-to-no details. Anyone?
But remember, NASA said that the analysis of the Dragon 2 parachute failure showed that the accepted modeling was inadequate despite decades of use and acceptance. Orion and Starliner used those models to do verification of their parachutes. Yet both were allowed to continue without new drop tests. Did either of those programs have to update their models and recertifications?
Pictures or it didn't happen, as they say. C'mon SpaceX, we're all boom'd out here, how about some recovery photo love?
From Spaceflight Now article:"U.S. military search and rescue teams deployed in the Atlantic Ocean practiced procedures to approach the capsule after splashdown. The teams from Patrick Air Force Base just south of Cape Canaveral would rescue astronauts from the spacecraft after a launch abort."From NASA Press Release"Teams of personnel from SpaceX and the U.S. Air Force 45th Operations Group's Detachment-3 out of Patrick Air Force Base will recover the spacecraft for return to SpaceX facilities in Florida and begin the recovery effort of the Falcon 9, which broke apart as planned."I thought with the commercial space flight the US military (Navy and Air Force) were not to be involved in the recovery - is this only in the case of an abort? Would they be stationed on stand-by in the Atlantic Ocean for each launch? Any other units involved?Thanks.article: https://spaceflightnow.com/2020/01/19/spacex-aces-final-major-test-before-first-crew-mission/
