Author Topic: SpaceX Falcon 9 / Dragon 2 : SpX-DM2 - EOM/Return: August, 2020 : DISCUSSION (Read 87404 times)

ChrisGebhardt · « **Reply #80 on:** 08/02/2020 03:22 pm »

https://twitter.com/ChrisG_NSF/status/1289944632155992064

daveglo · « **Reply #81 on:** 08/02/2020 03:26 pm »

So, just spitballin' here:

Based on the map data, the landing zone is only ~20 miles due south, directly off the coast at the Alabama-Florida state line (Flora-Bama!

).

There are dozens of condos and hotels along that coast. Wondering if anyone has a friend with a webcam along that coastline?

Here's a webcam at a resort just west of the state line, pointing southeast.

MarcPol · « **Reply #82 on:** 08/02/2020 04:11 pm »

Despite heavy cloud cover, I managed to grab a few frames of ISS and Endeavor roughly an hour after undocking (appriximately 8:40pm EST). Not my best effort at ISS photography, but the best I could do with overcast and mid level clouds. Of the 8 minutes or so the ISS pass should have been visible, I only had about 30 seconds total visibility between clouds. Captured with a Celestron C8 at F/10, manual guiding

hektor · « **Reply #83 on:** 08/02/2020 04:40 pm »

Little Earth seems to be on board...

hektor · « **Reply #84 on:** 08/02/2020 04:43 pm »

What is the visibility of the plasma trail from Corpus Christi, Houston or New Orleans?

joncz · « **Reply #85 on:** 08/02/2020 04:57 pm »

Hawthorne reporting the water is like glass.

Just came up from the beach between Pensacola and Panama City and they could not be coming into better sea state conditions.

mlindner · « **Reply #86 on:** 08/02/2020 05:52 pm »

Elon Musk isn't wearing a mask in mission control. :-/

mlindner · « **Reply #87 on:** 08/02/2020 05:54 pm »

He's wearing mask now, and had some fun with Gywnne putting a mask over his face as well. :-P

Comga · « **Reply #88 on:** 08/02/2020 06:05 pm »

During launch, some of the models show the Instantaneous Impact Point (IIP) for the Dragon or other payload as the rocket accelerates. At the last moment before orbit it races across the Earth and disappears.
I was hoping to see the reverse for reentry, as the IIP should appear somewhere far downrange, race back along the ground track, and settle into the Gulf. With three minutes left in the reentry burn it should be over the US, sliding back to the southwest towards Pensacola.

Surfdaddy · « **Reply #89 on:** 08/02/2020 06:10 pm »

I wonder if when Doug and Bob were first chosen for SpaceX/Dragon, they thought their Boeing counterparts would be the ones who would end up flying first, and they got the "second choice" provider in SpaceX?

Well I'll bet that right now, they're happy they ended up with SpaceX!

leovinus · « **Reply #90 on:** 08/02/2020 06:12 pm »

Any idea why they close the Nosecone after jettison of trunk? I mean, if it does not work then you troubleshoot in orbit. Now, they are coming back one way or the other. What are we missing?

leovinus · « **Reply #91 on:** 08/02/2020 06:15 pm »

Quote from: edkyle99 on 08/02/2020 06:14 pm

Quote from: leovinus on 08/02/2020 06:12 pm
Any idea why they close the Nosecone after jettison of trunk? I mean, if it does not work then you troubleshoot in orbit. Now, they are coming back one way or the other. What are we missing?
Forward thrusters do the deorbit burn. The nosecone closes over them. I think.

- Ed Kyle

Makes sense, thanks!

mlindner · « **Reply #92 on:** 08/02/2020 06:16 pm »

Quote from: leovinus on 08/02/2020 06:12 pm

Any idea why they close the Nosecone after jettison of trunk? I mean, if it does not work then you troubleshoot in orbit. Now, they are coming back one way or the other. What are we missing?

Trunk jettisons most likely for more deltaV and better dynamics. Then the thruster burns. The thrusters are underneath the nosecone so they can't close the nosecone until the burn finishes.

Comga · « **Reply #93 on:** 08/02/2020 06:19 pm »

Quote from: mlindner on 08/02/2020 06:16 pm

Quote from: leovinus on 08/02/2020 06:12 pm
Any idea why they close the Nosecone after jettison of trunk? I mean, if it does not work then you troubleshoot in orbit. Now, they are coming back one way or the other. What are we missing?

Trunk jettisons most likely for more deltaV and better dynamics. Then the thruster burns. The thrusters are underneath the nosecone so they can't close the nosecone until the burn finishes.

Not really
Well discussed earlier
Short answer: Deorbit burn starts reentry. Any problem with trunk disposal after that could be fatal with little time to correct.

Comga · « **Reply #94 on:** 08/02/2020 06:21 pm »

Quote from: edkyle99 on 08/02/2020 06:18 pm

Quote from: leovinus on 08/02/2020 06:15 pm
Quote from: edkyle99 on 08/02/2020 06:14 pm
Quote from: leovinus on 08/02/2020 06:12 pm
Any idea why they close the Nosecone after jettison of trunk? I mean, if it does not work then you troubleshoot in orbit. Now, they are coming back one way or the other. What are we missing?
Forward thrusters do the deorbit burn. The nosecone closes over them. I think.

- Ed Kyle
Makes sense, thanks!
I suspect that the nosecone can be jettisoned somehow if it fails to close.

- Ed Kyle

Everyday Astronaut discussed it and recalled seeing a "nosecone jettison" button or switch in the Dragon simulator.

mlindner · « **Reply #95 on:** 08/02/2020 06:21 pm »

Quote from: Comga on 08/02/2020 06:19 pm

Quote from: mlindner on 08/02/2020 06:16 pm
Quote from: leovinus on 08/02/2020 06:12 pm
Any idea why they close the Nosecone after jettison of trunk? I mean, if it does not work then you troubleshoot in orbit. Now, they are coming back one way or the other. What are we missing?

Trunk jettisons most likely for more deltaV and better dynamics. Then the thruster burns. The thrusters are underneath the nosecone so they can't close the nosecone until the burn finishes.

Not really
Well discussed earlier
Short answer: Deorbit burn starts reentry. Any problem with trunk disposal after that could be fatal with little time to correct.

Ah, that's a good point, but I haven't heard any official source confirm that as the reason, but perhaps I missed it.

photonic · « **Reply #96 on:** 08/02/2020 06:24 pm »

Quote from: edkyle99 on 08/02/2020 06:18 pm

Quote from: leovinus on 08/02/2020 06:15 pm
Quote from: edkyle99 on 08/02/2020 06:14 pm
Quote from: leovinus on 08/02/2020 06:12 pm
Any idea why they close the Nosecone after jettison of trunk? I mean, if it does not work then you troubleshoot in orbit. Now, they are coming back one way or the other. What are we missing?
Forward thrusters do the deorbit burn. The nosecone closes over them. I think.

- Ed Kyle

Makes sense, thanks!
I suspect that the nosecone can be jettisoned somehow if it fails to close.

- Ed Kyle

Someone reconstructed all of Dragon's user interface screens and buttons from existing videos (by Everyday Astronaut et al.), see here: https://uxdesign.cc/how-i-recreated-crew-dragons-ui-15877eddf3ed
One of the physical buttons is clearly labeled "jettison nose cone".

leovinus · « **Reply #97 on:** 08/02/2020 06:26 pm »

Quote from: photonic on 08/02/2020 06:24 pm

Quote from: edkyle99 on 08/02/2020 06:18 pm
Quote from: leovinus on 08/02/2020 06:15 pm
Quote from: edkyle99 on 08/02/2020 06:14 pm
Quote from: leovinus on 08/02/2020 06:12 pm
Any idea why they close the Nosecone after jettison of trunk? I mean, if it does not work then you troubleshoot in orbit. Now, they are coming back one way or the other. What are we missing?
Forward thrusters do the deorbit burn. The nosecone closes over them. I think.

- Ed Kyle

Makes sense, thanks!
I suspect that the nosecone can be jettisoned somehow if it fails to close.

- Ed Kyle

Someone reconstructed all of Dragon's user interface screens and buttons from existing videos (by Everyday Astronaut et al.), see here: https://uxdesign.cc/how-i-recreated-crew-dragons-ui-15877eddf3ed
One of the physical buttons is clearly labeled "jettison nose cone".

Impressive, thanks.

daveglo · « **Reply #98 on:** 08/02/2020 06:41 pm »

Anyone else disappointed with the lack of graphical illustrations with data during the reentry process? Kind of unlike SpaceX.

Comga · « **Reply #99 on:** 08/02/2020 06:42 pm »

These guys are amazing
Such a matter-of-fact report of experiencing 3.5 g's as they come out of the plasma blackout!