Author Topic: SpaceX Dragon 2 Updates and Discussion - Thread 2  (Read 195023 times)

Offline Chris Bergin

Second thread for Dragon 2 updates.

Thread 1:
https://forum.nasaspaceflight.com/index.php?topic=35381.0

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News Articles:
https://www.nasaspaceflight.com/?s=%22Dragon+2%22
https://www.nasaspaceflight.com/tag/dragon-V2/

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Stay on topic and always be civil. These threads are very, very active so remember you're not just talking to other posters, but many thousands who are reading the posts.

Offline ScottMC

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #1 on: 10/01/2016 08:26 PM »
Just absorbing the Mars presentation PDF (http://www.spacex.com/sites/spacex/files/mars_presentation.pdf) and noticed on page 38 references to PICA 3.0 advancements for Dragon 2, accompanied by this picture.  Is this a Dragon 2 heat shield (test article)?  Could those circular holes be for five little legs?

Quote from: SpaceX Mars Presentation
PICA 3.0 advancements for Dragon 2 enhance our ability to use the heat shield many times with minimal maintenance

Offline Zardar

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #2 on: 10/01/2016 09:04 PM »
Just absorbing the Mars presentation PDF (http://www.spacex.com/sites/spacex/files/mars_presentation.pdf) and noticed on page 38 references to PICA 3.0 advancements for Dragon 2, accompanied by this picture.  Is this a Dragon 2 heat shield (test article)?  Could those circular holes be for five little legs?

Quote from: SpaceX Mars Presentation
PICA 3.0 advancements for Dragon 2 enhance our ability to use the heat shield many times with minimal maintenance

I'm more curious as to why the centre panel in the head shield is so square, given that all the other panels are more curved.

Looks almost hatch-shaped.......

Offline gongora

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #3 on: 10/01/2016 09:54 PM »
I'm more curious as to why the centre panel in the head shield is so square, given that all the other panels are more curved.

Looks almost hatch-shaped.......

That's not the center of the heat shield.

Offline eriblo

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #4 on: 10/01/2016 10:02 PM »
That's a standard Dragon V1 heat shield, compare with a used one:  http://i.imgur.com/s7yORbX.jpg

Offline MrHollifield

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #5 on: 10/02/2016 11:13 PM »
Could those circular holes be for five little legs?

IANARS, but I think those are the S2 attach points.

Offline Lars-J

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #6 on: 10/03/2016 12:51 AM »
Could those circular holes be for five little legs?

IANARS, but I think those are the S2 attach points.

Trunk attachment points. And there is six of them, it is camera perspective that makes it look like five.

Offline woods170

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #7 on: 10/03/2016 02:06 PM »
That's a standard Dragon V1 heat shield, compare with a used one:  http://i.imgur.com/s7yORbX.jpg
There is nothing that prevents SpaceX from using the Dragon 1 PICA layout for Dragon 2.

Offline eriblo

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #8 on: 10/03/2016 03:07 PM »
That's a standard Dragon V1 heat shield, compare with a used one:  http://i.imgur.com/s7yORbX.jpg
There is nothing that prevents SpaceX from using the Dragon 1 PICA layout for Dragon 2.
Well of course not, it's a nice proven layout, but there should still be leg holes*. So it's either a Dragon 1 shield or they are forgoing legs, which they IMHO would only do if the first flights uses water splashdowns and there is a good reason as they want to move to land touchdowns (power assisted or fully powered) ASAP.

*Covered by (PICA?) plugs so not actual holes.

Offline woods170

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #9 on: 10/03/2016 06:08 PM »
That's a standard Dragon V1 heat shield, compare with a used one:  http://i.imgur.com/s7yORbX.jpg
There is nothing that prevents SpaceX from using the Dragon 1 PICA layout for Dragon 2.
Well of course not, it's a nice proven layout, but there should still be leg holes*. So it's either a Dragon 1 shield or they are forgoing legs, which they IMHO would only do if the first flights uses water splashdowns and there is a good reason as they want to move to land touchdowns (power assisted or fully powered) ASAP.

*Covered by (PICA?) plugs so not actual holes.
The first several flights of Dragon 2 for CCP are scheduled to splash down under parachutes, just like Dragon 1. Therefore, for the time being: no landing leg holes needed. The big exception will be Red Dragon, but that will be an extensively modified Dragon 2.

Offline eriblo

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #10 on: 10/03/2016 06:47 PM »
That's a standard Dragon V1 heat shield, compare with a used one:  http://i.imgur.com/s7yORbX.jpg
There is nothing that prevents SpaceX from using the Dragon 1 PICA layout for Dragon 2.
Well of course not, it's a nice proven layout, but there should still be leg holes*. So it's either a Dragon 1 shield or they are forgoing legs, which they IMHO would only do if the first flights uses water splashdowns and there is a good reason as they want to move to land touchdowns (power assisted or fully powered) ASAP.

*Covered by (PICA?) plugs so not actual holes.
The first several flights of Dragon 2 for CCP are scheduled to splash down under parachutes, just like Dragon 1. Therefore, for the time being: no landing leg holes needed. The big exception will be Red Dragon, but that will be an extensively modified Dragon 2.
Yes, which is what I said. But they would need a good reason to do so as it would move heat shield redesign and, more importantly, validation of this new design until after the initial flights. Meaning that they would either have to fly it untested on a crewed mission (don't think that is going to happen), do a dedicated test flight or wait until a CRS2 Dragon 2 flight (if NASA agrees). All hints so far are that they are working on moving to land landings as early as possible.

Offline mfck

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #11 on: 10/03/2016 07:07 PM »
That's a standard Dragon V1 heat shield, compare with a used one:  http://i.imgur.com/s7yORbX.jpg
There is nothing that prevents SpaceX from using the Dragon 1 PICA layout for Dragon 2.
Well of course not, it's a nice proven layout, but there should still be leg holes*. So it's either a Dragon 1 shield or they are forgoing legs, which they IMHO would only do if the first flights uses water splashdowns and there is a good reason as they want to move to land touchdowns (power assisted or fully powered) ASAP.

*Covered by (PICA?) plugs so not actual holes.
Do you, guys, have an idea why the attachment points symmetry is offset relative to the  shield layout symmetry?
« Last Edit: 10/03/2016 07:08 PM by mfck »

Offline cscott

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #12 on: 10/04/2016 01:16 AM »
Because the capsule re-enters at a positive angle of attack, to generate lift.  The heat shield is symmetric around the "nose" of the capsule as it re-enters "nose up".

EDIT: actually, probably symmetric about the zero angle-of-attack point (ie, oncoming airflow).  Presumably we'd call the geometric center of the heat shield the "nose", and it's not symmetric about that.
« Last Edit: 10/04/2016 02:00 AM by cscott »

Offline SWGlassPit

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #13 on: 10/04/2016 02:02 AM »
I think the term you're looking for is "stagnation point"

Online Comga

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #14 on: 10/04/2016 02:56 AM »
That's a standard Dragon V1 heat shield, compare with a used one:  http://i.imgur.com/s7yORbX.jpg

There is nothing that prevents SpaceX from using the Dragon 1 PICA layout for Dragon 2.

Well of course not, it's a nice proven layout, but there should still be leg holes*. So it's either a Dragon 1 shield or they are forgoing legs, which they IMHO would only do if the first flights uses water splashdowns and there is a good reason as they want to move to land touchdowns (power assisted or fully powered) ASAP.

*Covered by (PICA?) plugs so not actual holes.

The first several flights of Dragon 2 for CCP are scheduled to splash down under parachutes, just like Dragon 1. Therefore, for the time being: no landing leg holes needed. The big exception will be Red Dragon, but that will be an extensively modified Dragon 2.

(my emphasis)
or.... three or four of these also function as footpads that extend, or the centers of extending footpads.

These attach points are also heat shields.  They are just structural heat shields of a material too dense to use over the entire large bottom surface.
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline OnWithTheShow

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #15 on: 10/04/2016 03:07 AM »
The first several flights of Dragon 2 for CCP are scheduled to splash down under parachutes, just like Dragon 1. Therefore, for the time being: no landing leg holes needed. The big exception will be Red Dragon, but that will be an extensively modified Dragon 2.

Why would a Red Dragon, or a regular Dragon 2 need legs? If the Super Dracos throttle satisfactorily why not just land on the heat shield?

Offline gongora

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #16 on: 10/04/2016 03:20 AM »
The first several flights of Dragon 2 for CCP are scheduled to splash down under parachutes, just like Dragon 1. Therefore, for the time being: no landing leg holes needed. The big exception will be Red Dragon, but that will be an extensively modified Dragon 2.

Why would a Red Dragon, or a regular Dragon 2 need legs? If the Super Dracos throttle satisfactorily why not just land on the heat shield?

It's not a load-bearing sort of material.  You'd have to replace it every time.

Offline darkenfast

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #17 on: 10/04/2016 04:46 AM »
Red Dragon isn't coming back.  It's a one-way trip.  As long as the pressure hull isn't breached, it doesn't matter what happens to the heat shield.  Edit to add: Dragon 2 will need legs.
« Last Edit: 10/04/2016 04:47 AM by darkenfast »

Offline rocx

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #18 on: 10/04/2016 07:24 AM »
The first several flights of Dragon 2 for CCP are scheduled to splash down under parachutes, just like Dragon 1. Therefore, for the time being: no landing leg holes needed. The big exception will be Red Dragon, but that will be an extensively modified Dragon 2.

Why would a Red Dragon, or a regular Dragon 2 need legs? If the Super Dracos throttle satisfactorily why not just land on the heat shield?

It's not a load-bearing sort of material.  You'd have to replace it every time.

Besides, the surface the Dragon is landing on might be uneven, so you can't be sure which part of the heat shield will touch the ground. So then all of the heat shield would have to be load-bearing and scratch-resistant, instead of just the soles of the feet.
Any day with a rocket landing is a fantastic day.

Offline whitelancer64

Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #19 on: 10/04/2016 06:03 PM »
Just a general question, does anyone here have any reason to think that the LAS on the Dragon would not have been sufficient to pull a crew away from the failing Amos-6 rocket?
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