Quote from: deruch on 03/11/2019 12:23 amQuote from: Vettedrmr on 03/10/2019 06:38 pmHave we heard anything from NASA/SpaceX about the performance and interaction of the 4 chutes? No. Probably will have to wait for the next ASAP meeting to see if it gets discussed. I don't think we're likely to get many specific statements from SpaceX or NASA on technical matters or systems performance beyond just, "Everything went well." Or generalizations about "few minor issues being worked through," etc.The more chutes you add the more weird interactions between them you are liable to get. Even ASAP should realize that eventually.
Quote from: Vettedrmr on 03/10/2019 06:38 pmHave we heard anything from NASA/SpaceX about the performance and interaction of the 4 chutes? No. Probably will have to wait for the next ASAP meeting to see if it gets discussed. I don't think we're likely to get many specific statements from SpaceX or NASA on technical matters or systems performance beyond just, "Everything went well." Or generalizations about "few minor issues being worked through," etc.
Have we heard anything from NASA/SpaceX about the performance and interaction of the 4 chutes?
The more chutes you add the more weird interactions between them you are liable to get. Even ASAP should realize that eventually.
Here is my completed DM-1 article which I talked about back in Jan or Feb! This one took more research but I am overall very proud of it. Enjoy!https://pfhstheroar.com/7144/news/other-news/the-dawn-of-a-new-era-in-human-spaceflight/#
Quote from: Lars-J on 03/11/2019 01:11 amThe more chutes you add the more weird interactions between them you are liable to get. Even ASAP should realize that eventually.Agreed. Normally when you add redundancy you're adding complexity that can be fairly well characterized (weight, power, space, software,etc.), but with the chutes you have the aerodynamics as well.IIRC, D2's chute system requires 2 for safe landing, Spx went to 3 for redundancy, and ASAP required a 4th for some reason. But, I can't remember what that reason was.Thanks for the response, and have a good one,Mike
D2's chute system requires 2 for survivable landing. Safe landing requires 3 chutes.
Quote from: Vettedrmr on 03/11/2019 10:52 amQuote from: Lars-J on 03/11/2019 01:11 amThe more chutes you add the more weird interactions between them you are liable to get. Even ASAP should realize that eventually.Agreed. Normally when you add redundancy you're adding complexity that can be fairly well characterized (weight, power, space, software,etc.), but with the chutes you have the aerodynamics as well.IIRC, D2's chute system requires 2 for safe landing, Spx went to 3 for redundancy, and ASAP required a 4th for some reason. But, I can't remember what that reason was.Thanks for the response, and have a good one,MikeD2's chute system requires 2 for survivable landing. Safe landing requires 3 chutes.Fourth chute was not required by ASAP. ASAP is not in a position to require/demand anything.The fourth chute is there because NASA talked SpaceX out of propulsive landing. That had the undesired effect of Crew Dragon splashing down with a fairly substantial load of propellant still on-board (unused abort propellant). The vehicle is thus a lot heavier than previously anticipated. To add extra redundancy to counter for this weight increase a fourth chute was added to the system, by SpaceX.
Quote from: woods170 on 03/11/2019 11:57 amQuote from: Vettedrmr on 03/11/2019 10:52 amQuote from: Lars-J on 03/11/2019 01:11 amThe more chutes you add the more weird interactions between them you are liable to get. Even ASAP should realize that eventually.Agreed. Normally when you add redundancy you're adding complexity that can be fairly well characterized (weight, power, space, software,etc.), but with the chutes you have the aerodynamics as well.IIRC, D2's chute system requires 2 for safe landing, Spx went to 3 for redundancy, and ASAP required a 4th for some reason. But, I can't remember what that reason was.Thanks for the response, and have a good one,MikeD2's chute system requires 2 for survivable landing. Safe landing requires 3 chutes.Fourth chute was not required by ASAP. ASAP is not in a position to require/demand anything.The fourth chute is there because NASA talked SpaceX out of propulsive landing. That had the undesired effect of Crew Dragon splashing down with a fairly substantial load of propellant still on-board (unused abort propellant). The vehicle is thus a lot heavier than previously anticipated. To add extra redundancy to counter for this weight increase a fourth chute was added to the system, by SpaceX.Just curious, why don't they just dump the prop on entry?
Quote from: Rocket Science on 03/11/2019 05:07 pmQuote from: woods170 on 03/11/2019 11:57 amQuote from: Vettedrmr on 03/11/2019 10:52 amQuote from: Lars-J on 03/11/2019 01:11 amThe more chutes you add the more weird interactions between them you are liable to get. Even ASAP should realize that eventually.Agreed. Normally when you add redundancy you're adding complexity that can be fairly well characterized (weight, power, space, software,etc.), but with the chutes you have the aerodynamics as well.IIRC, D2's chute system requires 2 for safe landing, Spx went to 3 for redundancy, and ASAP required a 4th for some reason. But, I can't remember what that reason was.Thanks for the response, and have a good one,MikeD2's chute system requires 2 for survivable landing. Safe landing requires 3 chutes.Fourth chute was not required by ASAP. ASAP is not in a position to require/demand anything.The fourth chute is there because NASA talked SpaceX out of propulsive landing. That had the undesired effect of Crew Dragon splashing down with a fairly substantial load of propellant still on-board (unused abort propellant). The vehicle is thus a lot heavier than previously anticipated. To add extra redundancy to counter for this weight increase a fourth chute was added to the system, by SpaceX.Just curious, why don't they just dump the prop on entry?See ASTP and, for the nth time, if the conversation is focused on propulsive landing, there's a thread for that...
Ok thanks for the correction, I will edit that one error if I can. If you read it was the article overall well rounded?
Quote from: FutureSpaceTourist on 03/10/2019 06:41 pmIs there any further information on why there was an aluminum grid fin on this booster? Was the opposite grid fin also aluminum? I must admit, I didn't notice this on any earlier coverage.
Isn't there supposed to be a post-mission briefing at some point?