Can you point to a discussion? I thought I have read everything about this on NSF and I have never seen a reference to drogues for propulsive landing.
Quote from: guckyfan on 10/23/2015 10:04 amCan you point to a discussion? I thought I have read everything about this on NSF and I have never seen a reference to drogues for propulsive landing.I was intentionally vague on drogues because I can't think of a specific discussion on drogues with respect to Dragon landing profiles either. What I am pointing out, though, is that it's irrelevant as part of the current debate, based on what has been publicly stated and discussed quite a bit here on NSF.
Quote from: Req on 10/23/2015 10:06 amQuote from: guckyfan on 10/23/2015 10:04 amCan you point to a discussion? I thought I have read everything about this on NSF and I have never seen a reference to drogues for propulsive landing.I was intentionally vague on drogues because I can't think of a specific discussion on drogues with respect to Dragon landing profiles either. What I am pointing out, though, is that it's irrelevant as part of the current debate, based on what has been publicly stated and discussed quite a bit here on NSF.You changed your post after my request. You had unequivocally stated that droges would be part of any descent, parachutes or full SD powered landing. That is why I requested a pointer.
Quote from: guckyfan on 10/23/2015 10:13 amQuote from: Req on 10/23/2015 10:06 amQuote from: guckyfan on 10/23/2015 10:04 amCan you point to a discussion? I thought I have read everything about this on NSF and I have never seen a reference to drogues for propulsive landing.I was intentionally vague on drogues because I can't think of a specific discussion on drogues with respect to Dragon landing profiles either. What I am pointing out, though, is that it's irrelevant as part of the current debate, based on what has been publicly stated and discussed quite a bit here on NSF.You changed your post after my request. You had unequivocally stated that droges would be part of any descent, parachutes or full SD powered landing. That is why I requested a pointer.Why wouldn't drogues be part of any descent? They are a cheap and cheerful way of reducing speed, and therefore would result in less fuel being required in the case of propulsive landing, and would be required anyway for parachute landing to stabilise the Dragon prior to main chute deploy. So they are always on board, as they are needed for abort scenarios.
Landing takes much less fuel than the abort. Since the engines need to do both, a drogue is not required. It would just reduce payload.
Friends, friends, it seems we're doing stuff. Wasn't this settled over a year ago?Try Chris B.'s 8/2014 article where NASA and SpaceX says how typical Crew Dragon landings are to be done.
Quote from: MattMason on 10/23/2015 12:07 pmFriends, friends, it seems we're doing stuff. Wasn't this settled over a year ago?Try Chris B.'s 8/2014 article where NASA and SpaceX says how typical Crew Dragon landings are to be done.Read it, must have missed the bit about whether a propulsive landing also used drogues to do initial slowdown and stabilisation, and in order to save fuel.
Quote from: JamesH on 10/23/2015 12:37 pmQuote from: MattMason on 10/23/2015 12:07 pmFriends, friends, it seems we're doing stuff. Wasn't this settled over a year ago?Try Chris B.'s 8/2014 article where NASA and SpaceX says how typical Crew Dragon landings are to be done.Read it, must have missed the bit about whether a propulsive landing also used drogues to do initial slowdown and stabilisation, and in order to save fuel.The 2014 article doesn't say that. Were you being sarcastic?
Quote from: JamesH on 10/23/2015 12:37 pmQuote from: MattMason on 10/23/2015 12:07 pmFriends, friends, it seems we're doing stuff. Wasn't this settled over a year ago?Try Chris B.'s 8/2014 article where NASA and SpaceX says how typical Crew Dragon landings are to be done.Read it, must have missed the bit about whether a propulsive landing also used drogues to do initial slowdown and stabilisation, and in order to save fuel.Also.. Having the drogue already deployed should significantly reduce reaction time to deploy mains in an emergency.
Quote from: Chris Bergin on 10/21/2015 06:57 pmQuote from: Chris Bergin on 10/16/2015 04:53 pmBy the way, per L2's McGregor Photos and Update Section, Dragonfly has been photographed at McGregor, as has a big, big crane. I've asked SpaceX if they want to talk to us about the upcoming test objectives, but we'll be writing an article next week regardless.Here's the article - with L2 photos and some cool L2 renderings by Nathan http://www.nasaspaceflight.com/2015/10/spacex-dragonfly-arrives-mcgregor-testing/When they start the testing at McGregor we'll set up an update thread."These include the “Propulsive assist landing” test – which will see DragonFly dropped from helicopter (an Erickson E‐model or equivalent) aided by three parachutes. This will be followed by the “Fully propulsive landing” test – again utilizing a helicopter and parachutes, concluding with a five-second firing of the SuperDracos for a smooth landing."This doesn't sound correct.
Quote from: Chris Bergin on 10/16/2015 04:53 pmBy the way, per L2's McGregor Photos and Update Section, Dragonfly has been photographed at McGregor, as has a big, big crane. I've asked SpaceX if they want to talk to us about the upcoming test objectives, but we'll be writing an article next week regardless.Here's the article - with L2 photos and some cool L2 renderings by Nathan http://www.nasaspaceflight.com/2015/10/spacex-dragonfly-arrives-mcgregor-testing/When they start the testing at McGregor we'll set up an update thread.
By the way, per L2's McGregor Photos and Update Section, Dragonfly has been photographed at McGregor, as has a big, big crane. I've asked SpaceX if they want to talk to us about the upcoming test objectives, but we'll be writing an article next week regardless.
Quote from: TrueBlueWitt on 10/23/2015 02:21 pmQuote from: JamesH on 10/23/2015 12:37 pmQuote from: MattMason on 10/23/2015 12:07 pmFriends, friends, it seems we're doing stuff. Wasn't this settled over a year ago?Try Chris B.'s 8/2014 article where NASA and SpaceX says how typical Crew Dragon landings are to be done.Read it, must have missed the bit about whether a propulsive landing also used drogues to do initial slowdown and stabilisation, and in order to save fuel.Also.. Having the drogue already deployed should significantly reduce reaction time to deploy mains in an emergency.The new parachute system - as demonstrated in the Dragon 2 pad abort - is designed to deploy much faster (and at lower altitude) than the Dragon 1 parachutes.
Quote from: Lars-J on 10/23/2015 05:25 pmQuote from: TrueBlueWitt on 10/23/2015 02:21 pmQuote from: JamesH on 10/23/2015 12:37 pmQuote from: MattMason on 10/23/2015 12:07 pmFriends, friends, it seems we're doing stuff. Wasn't this settled over a year ago?Try Chris B.'s 8/2014 article where NASA and SpaceX says how typical Crew Dragon landings are to be done.Read it, must have missed the bit about whether a propulsive landing also used drogues to do initial slowdown and stabilisation, and in order to save fuel.Also.. Having the drogue already deployed should significantly reduce reaction time to deploy mains in an emergency.The new parachute system - as demonstrated in the Dragon 2 pad abort - is designed to deploy much faster (and at lower altitude) than the Dragon 1 parachutes.Yes they use mortars to deploy the drogues on D2. Im not sure if that was the case for D1 or not. (Hmmm, Do moratrs qualify as a pyrotechnic?)
Quote from: yg1968 on 10/23/2015 02:35 pmQuote from: JamesH on 10/23/2015 12:37 pmQuote from: MattMason on 10/23/2015 12:07 pmFriends, friends, it seems we're doing stuff. Wasn't this settled over a year ago?Try Chris B.'s 8/2014 article where NASA and SpaceX says how typical Crew Dragon landings are to be done.Read it, must have missed the bit about whether a propulsive landing also used drogues to do initial slowdown and stabilisation, and in order to save fuel.The 2014 article doesn't say that. Were you being sarcastic?Yes. Sorry, sarcasm doesn't come across very well except in my head. Point being, drogues were not mentioned at all in the article, so we don't know is they are used for all types of descent.