Author Topic: SpaceX Dragon 2 Updates and Discussion - Thread 2  (Read 773718 times)

Offline Robotbeat

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #940 on: 12/31/2017 06:59 pm »
Guided parafoil would solve all those problems. But would need a bunch of testing, so don't get your hopes up.
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Offline LouScheffer

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #941 on: 12/31/2017 07:34 pm »
If they can do this then they may very well attempt to catch a Dragon2 with a net.
I would say, not a chance!
I'm not so pessimistic.
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First you need precision landing (800m doesn't cut it),
Even in 1961, with only modified round parachutes, competitors were getting 4 meter accuracy. See this article.  Plus the boat can maneuver to catch it, and roughly cancel any horizontal component to velocity.
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second it is several magnitudes heavier than a fairing half (how big/strong would the net have to be?),
Dragon is about 4200 kg empty.  The fairing is not known exactly, but it's a robust structure to support horizontal integration.  It's thought to be about 4000 kg total, or about 2000 kg per half.  So only a factor of 2 different.
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third if it missed and hit the side of the ship, the crew could die.
The net appears to extend way over the side of the ship, see this picture.  If the landing targets off center, and it misses the net, it will fall in the ocean.

Offline Comga

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #942 on: 12/31/2017 07:34 pm »
Guided parafoil would solve all those problems. But would need a bunch of testing, so don't get your hopes up.

That's the opposite of my suggestion.
An unmodified Dragon 2, with SuperDracos, but no ballast sled and no legs, can do a desert landing with little additional testing. 
They could take the test capsule that hovered, install a used lidar unit, repeat the drop tests from the helicopter.
The capsule would brake to a crawl from some number of meters until contact.
Given their demonstrated landing precision, there is plenty of room at Edwards (for landing after reentry), with the debris from the trunk falling in the Pacific.
I wouldn't be that surprised if they announce this in mid 2019, after they have a few flights of Dragon 2 and have used ("flight proven") capsules.
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline ClayJar

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #943 on: 12/31/2017 07:42 pm »
Quote
third if it missed and hit the side of the ship, the crew could die.
The net appears to extend way over the side of the ship, see this picture.  If the landing targets off center, and it misses the net, it will fall in the ocean.

Hitting the net would be good. Missing completely and hitting the ocean should not be significantly worse than a boatless splashdown. Being in between and coming down onto one of the arms, however, would seem likely to produce the least favorable outcome.

Offline Comga

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #944 on: 12/31/2017 07:52 pm »
In this video

an Apollo text capsule is dropped on hard clay at 7 m/sec vertical and up to 15 m/sec horizontal velocity.  The Avcoat heat shield doesn't look too bad, even when it's quite visible because the capsule winds up on its nose.

This looks survivable, for well cushioned passengers, and a successfully slowed Dragon 2 would be going much slower with well controlled attitude.


edit: Trying to link, but YouTube embeds.
« Last Edit: 12/31/2017 07:54 pm by Comga »
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline JBF

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #945 on: 12/31/2017 09:10 pm »
In this video

an Apollo text capsule is dropped on hard clay at 7 m/sec vertical and up to 15 m/sec horizontal velocity.  The Avcoat heat shield doesn't look too bad, even when it's quite visible because the capsule winds up on its nose.

This looks survivable, for well cushioned passengers, and a successfully slowed Dragon 2 would be going much slower with well controlled attitude.


edit: Trying to link, but YouTube embeds.
PicaX is very different from Avcoat;  it is much more brittle.
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Offline woods170

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #946 on: 12/31/2017 11:45 pm »
Let me put it this way. There is no sled on Cargo Dragon. Nevertheless, Cargo Dragon routinely splashes down within 2 miles from the recovery ships.
Conclusion: you don't need a sled on Crew Dragon to make pinpoint ocean landings.
<bing>
'Please lean to the left'
Don't be silly
The sled was forward and back for controlling the angle of attack, not side to side.
If they put the seats on slides like for rowing machines the passengers could move "up and down". 
They would be given some display panel graphic to follow.
It would be a fun thing to do on reentry.

And the first Dragon landed within a half mile of the target (800 meters), not two miles.
Plenty accurate for ocean landings, it would appear.

On a serious note, do you have any data, woods170, to back up the "routinely splashes down within 2 miles" comment or is that just an observation from the videos?
SpaceX gave that 0.8 km value, and one or two more, IIRC, but then stopped.

No public source to back up my statment, other than the public statements you refer to. However, I've discussed this with my own sources at SpaceX and they are the ones who gave me the "routinely within 2 miles from the recovery ships". And they should know given that one of them is routinely involved with Cargo Dragon recovery.
Also, it is worth noting that 800 meters falls well within the "within 2 miles" part. Given how my SpaceX sources phrased their description of recovery I have reason to believe that no Cargo Dragon ever splashed down beyond 2 miles from the recovery ships.

Offline Comga

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #947 on: 01/01/2018 02:33 am »
(snip)
On a serious note, do you have any data, woods170, to back up the "routinely splashes down within 2 miles" comment or is that just an observation from the videos?
SpaceX gave that 0.8 km value, and one or two more, IIRC, but then stopped.

No public source to back up my statment, other than the public statements you refer to.
However, I've discussed this with my own sources at SpaceX and they are the ones who gave me the "routinely within 2 miles from the recovery ships". And they should know given that one of them is routinely involved with Cargo Dragon recovery.
Also, it is worth noting that 800 meters falls well within the "within 2 miles" part. Given how my SpaceX sources phrased their description of recovery I have reason to believe that no Cargo Dragon ever splashed down beyond 2 miles from the recovery ships.

That makes sense.
And a 2 mile radius circle fits nicely in the desert east of Edwards. ;D
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline Comga

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #948 on: 01/01/2018 02:37 am »
In this video an Apollo text capsule is dropped on hard clay at 7 m/sec vertical and up to 15 m/sec horizontal velocity.  The Avcoat heat shield doesn't look too bad, even when it's quite visible because the capsule winds up on its nose.

This looks survivable, for well cushioned passengers, and a successfully slowed Dragon 2 would be going much slower with well controlled attitude.

PicaX is very different from Avcoat;  it is much more brittle.

Yah, but the videos are still cool.
The point is that the landing should be much gentler than these, even without SuperDracos firing, and the heat shield would be expended anyways.  The critical point would be no damage to the capsule's structure and a survivable impact. Crushing PicaX might even help with that if needed.
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline Roy_H

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #949 on: 01/01/2018 02:39 am »
No public source to back up my statment, other than the public statements you refer to. However, I've discussed this with my own sources at SpaceX and they are the ones who gave me the "routinely within 2 miles from the recovery ships". And they should know given that one of them is routinely involved with Cargo Dragon recovery.
Also, it is worth noting that 800 meters falls well within the "within 2 miles" part. Given how my SpaceX sources phrased their description of recovery I have reason to believe that no Cargo Dragon ever splashed down beyond 2 miles from the recovery ships.
Note that 2 miles from the ship and 2 miles from target are two different things. The target would be a safe distance from the ship so this lends credence to the 800m accuracy.
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Offline darkenfast

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #950 on: 01/02/2018 12:16 am »
Don't remember seeing this before, apologies if it's a duplicate.  According to this article, SpaceX is leasing property at Area 59 from CCAFS as a home for Dragon.

http://www.floridatoday.com/story/tech/science/space/2018/01/01/spacex-leases-cape-canaveral-home-crew-dragon/982606001/
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Offline Flying Beaver

Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #951 on: 01/02/2018 12:32 am »
Don't remember seeing this before, apologies if it's a duplicate.  According to this article, SpaceX is leasing property at Area 59 from CCAFS as a home for Dragon.

http://www.floridatoday.com/story/tech/science/space/2018/01/01/spacex-leases-cape-canaveral-home-crew-dragon/982606001/

(One of) These buildings.

https://www.google.ca/maps/@28.4696037,-80.5786328,1019m/data=!3m1!1e3

Watched B1019 land in person 21/12/2015.

Offline biosehnsucht

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #952 on: 01/02/2018 05:18 am »
In this video an Apollo text capsule is dropped on hard clay at 7 m/sec vertical and up to 15 m/sec horizontal velocity.  The Avcoat heat shield doesn't look too bad, even when it's quite visible because the capsule winds up on its nose.

This looks survivable, for well cushioned passengers, and a successfully slowed Dragon 2 would be going much slower with well controlled attitude.

From video description :
Quote
"The model used in the investigation was a 1/4-scale dynamic model of the command module of the Apollo spacecraft. Detailed information of the model construction is given in reference 6 and model dimensions are given in figure 1.

"The model was constructed of an aluminum frame to which an outer skin of approximately 1/8 in. (0.635 cm) (model scale) thick fiber glass and plastic was attached. The bottom of the crew compartment was filled with balsa wood to reduce structural vibrations. Mahogany blocks were inserted in the balsa wood to serve as accelerometer mounts...

Sounds like there's no avcoat to be impressed by here, you're looking at a 1/4 scale model made from aluminum, fiber glass, plastic, and balsa wood. This was to study potential impact absorption systems (various methods of extending the heat shield away from the capsule and then using shocks and things to use it as an impact absorber)
« Last Edit: 01/02/2018 05:18 am by biosehnsucht »

Offline FutureSpaceTourist

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #953 on: 01/03/2018 11:38 am »
(One of) These buildings.

https://www.google.ca/maps/@28.4696037,-80.5786328,1019m/data=!3m1!1e3

Different view for context:

Quote
This is where I think is the location. On a KSC map, it's called SATELLITE PROCESSING & STORAGE AREA. The entry road is called SATELLITE ROAD. It's on Flight Control Road east of Phillips Parkway, the major north-south artery through CCAFS.

https://twitter.com/WordsmithFL/status/948532424794755072

Offline spacenut

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #954 on: 01/03/2018 01:08 pm »
Could Dragon 2 actually be launched now, or is it ready for human flight?  I ask this question because of NASA delays, not just SpaceX delays.  If so, why doesn't SpaceX go ahead and launch it unmanned for testing?  Why the delays?

Offline philw1776

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #955 on: 01/03/2018 01:12 pm »
Could Dragon 2 actually be launched now, or is it ready for human flight?  I ask this question because of NASA delays, not just SpaceX delays.  If so, why doesn't SpaceX go ahead and launch it unmanned for testing?  Why the delays?

The most likely answer is no, it is not ready or complete per NASA requirements, so launching it now would not qualify the NASA design.  Counterproductive.
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Offline envy887

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #956 on: 01/03/2018 01:16 pm »
Could Dragon 2 actually be launched now, or is it ready for human flight?  I ask this question because of NASA delays, not just SpaceX delays.  If so, why doesn't SpaceX go ahead and launch it unmanned for testing?  Why the delays?

SpaceX has several in production, but I don't think any of them are complete yet.

Offline Nik Tmi

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #957 on: 01/03/2018 02:45 pm »
Is spacex currently online for the launch of the manned dragon in August?

Offline gongora

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #958 on: 01/03/2018 02:47 pm »
Is spacex currently online for the launch of the manned dragon in August?

NASA has not publicly changed the dates, but some recent unofficial postings would suggest the answer is probably no.

https://forum.nasaspaceflight.com/index.php?topic=37802.msg1766115#msg1766115
https://forum.nasaspaceflight.com/index.php?topic=8184.msg1766457#msg1766457
« Last Edit: 01/03/2018 02:48 pm by gongora »

Offline Semmel

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #959 on: 01/03/2018 06:20 pm »
Is spacex currently online for the launch of the manned dragon in August?

NASA has not publicly changed the dates, but some recent unofficial postings would suggest the answer is probably no.

https://forum.nasaspaceflight.com/index.php?topic=37802.msg1766115#msg1766115
https://forum.nasaspaceflight.com/index.php?topic=8184.msg1766457#msg1766457

How do you read a delay out of these posts?  CRS launch should have a gap for the crew launch and it has. The other link seems unrelated. Can you explain your deduction please?

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