Author Topic: SpaceX Falcon 9 / Dragon 2 : SpX-DM1 : March 2, 2019 : DISCUSSION (Read 601784 times)

mikegi · « **Reply #1160 on:** 03/08/2019 12:49 pm »

Did one chute end up covering the Dragon?

Lar · « **Reply #1161 on:** 03/08/2019 12:50 pm »

Quote from: PM3 on 03/08/2019 12:48 pm

<two splashdown pics, second one collapsed mains>

Do the mains collapse like that on their own or because of the reefcutter, or both?

kevinof · « **Reply #1162 on:** 03/08/2019 12:51 pm »

Was just about to post that. Looks like one was upwind of the dragon and blew onto it when it hit the water.

Quote from: mikegi on 03/08/2019 12:49 pm

Did one chute end up covering the Dragon?

Lampyridae · « **Reply #1163 on:** 03/08/2019 12:51 pm »

Quote from: mikegi on 03/08/2019 12:49 pm

Did one chute end up covering the Dragon?

Looks that way, but just partially.

CorvusCorax · « **Reply #1164 on:** 03/08/2019 12:54 pm »

That kinda defies the use of a reef cutter. You don't want the wind blowing into the parachute and dragging on the capsule.
Of course if the parachute covers the capsule and the capsule then sets sail, the chase ships find themselves in a sail regatta against the SS Dragon2

Edit: the pro side is, it really helps with parachute recovery, no risk of them sinking

Joffan · « **Reply #1165 on:** 03/08/2019 01:01 pm »

Quote from: theonlyspace on 03/08/2019 12:54 pm

Looks like one parachute is draped around the back side of Dragon

Yeah, I think the fast boat went up, had a look and a chat with the main boat and my guess is they're going in to check on everything carefully. Learning opportunity.

(and unveiled as I type

)

clongton · « **Reply #1166 on:** 03/08/2019 01:03 pm »

Not good that 1 chute covered Dragon. Potential to catch a wind and drag the spacecraft.

sfxtd · « **Reply #1167 on:** 03/08/2019 01:03 pm »

That ride under parachute looked rather nauseating. There was a pronounced pitch oscillation under the drogues and substantial "random" movement under the mains. It looks like a recipe to soil ones helmet.

I wonder if there is a reasonable modification to the rigging or aerodynamics that might mitigate that motion.

kevinof · « **Reply #1168 on:** 03/08/2019 01:05 pm »

One of the side effects of going for a 4 chute system - Bigger chance of one of them catching the capsule. Nothing you can do to prevent it unless you have a good breeze to ensure they are carried away. Looked very benign out there today and little wind.

Quote from: clongton on 03/08/2019 01:03 pm

Not good that 1 chute covered Dragon. Potential to catch a wind and drag the spacecraft.

kessdawg · « **Reply #1169 on:** 03/08/2019 01:05 pm »

There was worry about the asymmetric backshell causing a spin during re-entry. Do we know if that was avoided?

JBF · « **Reply #1170 on:** 03/08/2019 01:07 pm »

Quote from: clongton on 03/08/2019 01:03 pm

Not good that 1 chute covered Dragon. Potential to catch a wind and drag the spacecraft.

That depends on if it's actually tangled under the capsule. Remember the mains are cut; so there is a good chance it would just blow off.

Joffan · « **Reply #1171 on:** 03/08/2019 01:07 pm »

Quote from: kessdawg on 03/08/2019 01:05 pm

There was worry about the asymmetric backshell causing a spin during re-entry. Do we know if that was avoided?

I didn't see any spin at the time of drogue chute deploy.

hektor · « **Reply #1172 on:** 03/08/2019 01:10 pm »

Also the crew inside cannot see outside with the chute over the windows. So it deprives the crew from information.

yokem55 · « **Reply #1173 on:** 03/08/2019 01:11 pm »

Quote from: sfxtd on 03/08/2019 01:03 pm

That ride under parachute looked rather nauseating. There was a pronounced pitch oscillation under the drogues and substantial "random" movement under the mains. It looks like a recipe to soil ones helmet.

I wonder if there is a reasonable modification to the rigging or aerodynamics that might mitigate that motion.

Yeah, I can understand the hand wringing about the chutes now. It's the piece that has to work, but obviously has a lot of difficult to model behaviors and interactions. I was worried all the chutes were going to tangle and foul themselves. Then, I'm not sure how you prevent one of the chutes from coming down on top of Dragon after spash down like we saw.

Almost makes powered landing seem easier.

webdan · « **Reply #1174 on:** 03/08/2019 01:11 pm »

I got a bit of a chuckle when Benji Reed said "Bob and Doug", referring to DM-2...

punder · « **Reply #1175 on:** 03/08/2019 01:13 pm »

Having one of the chutes land on the capsule has to be a fair-probability event. They have prepared for it I imagine.

A12 · « **Reply #1176 on:** 03/08/2019 01:14 pm »

Mr. Bridenstine giving a short speech now on the splashdown stream, putting a strong emphasis on reuse.

CorvusCorax · « **Reply #1177 on:** 03/08/2019 01:16 pm »

Quote from: hektor on 03/08/2019 01:10 pm

Also the crew inside cannot see outside with the chute over the windows. So it deprives the crew from information.

Yeah, its definitely an anomaly, but not a very critical one. And I think its not something that can be avoided with any multi-parachute system. The chance of it is basically down to the wind and the number of parachute. You can't do more than cut them, which apparently happened correctly.

Also they managed to "fix" it very very quickly, so as far as procedures is concerned it looks all great to me.

It could be dangerous if it happens in bad sea state, the capsule is leaking and running full of water, the crew needs to leave in a hurry, and then they get caught in an entangled parachute and lines and pulled under.
That's kinda the worst case scenario, but I don't think this is likely to happen in stronger winds as the chute would just be blown off.

punder · « **Reply #1178 on:** 03/08/2019 01:22 pm »

Couple of bits that flew off during reentry... Probably just little particles of TPS or paint, but for obvious reasons I had a bit of a jolt. Things that cannot be unseen...

Or maybe things that were supposed to come off. Covers or hatches.

Ninja'd by DecoLV during edit!

DecoLV · « **Reply #1179 on:** 03/08/2019 01:24 pm »

Quote from: punder on 03/08/2019 01:22 pm

Couple of bits that flew off during reentry... Probably just little particles of TPS or paint, but for obvious reasons I had a bit of a jolt. Things that cannot be unseen...

Drogue doors coming off, mostly likely.