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Latest landing attempt by SpaceX. (Original Post) Cassiopeia Jan 2016 OP
it did have a mechanical Duckhunter935 Jan 2016 #1
Definitely. Cassiopeia Jan 2016 #4
it did look like a perfect Duckhunter935 Jan 2016 #5
IIRC, according to Elon Musk, one of the landing legs didn't quite latch. backscatter712 Jan 2016 #6
yep, they will find the cause and correct it Duckhunter935 Jan 2016 #9
Those legs look kinda lightweight for the size of the craft. Spitfire of ATJ Jan 2016 #8
they seem to be working fine though Duckhunter935 Jan 2016 #11
That's "fine"? Spitfire of ATJ Jan 2016 #16
Bad choice of words Duckhunter935 Jan 2016 #18
On a level hard surface I'm sure they're fine. Spitfire of ATJ Jan 2016 #20
If you looked, it landed fine Duckhunter935 Jan 2016 #25
Well,....any landing you can walk aw,...okay,...let's just blow that off. Spitfire of ATJ Jan 2016 #39
They have to be. backscatter712 Jan 2016 #13
They could use sensors then to let them know they locked. Spitfire of ATJ Jan 2016 #17
they may indeed have them and that is how they Duckhunter935 Jan 2016 #19
If they knew they weren't latched during landing they could have aborted.... Spitfire of ATJ Jan 2016 #21
aborted to where and how? Duckhunter935 Jan 2016 #24
I just keep thinking of NASA and their backups for the backups. Spitfire of ATJ Jan 2016 #30
No, there's no way to abort. backscatter712 Jan 2016 #26
So there's no parachute option. Spitfire of ATJ Jan 2016 #29
I suspect parachutes couldn't do the job. backscatter712 Jan 2016 #33
Maybe they could tell from the video. Spitfire of ATJ Jan 2016 #31
I always find it interesting how quickly people are to jump all over the incidents PersonNumber503602 Jan 2016 #32
good thing yuiyoshida Jan 2016 #2
that was just the booster return, the satellite made it up perfectly Duckhunter935 Jan 2016 #7
Whoopsie... catbyte Jan 2016 #3
On the bright site, the Jason satellite this rocket launched got into orbit without a hitch. backscatter712 Jan 2016 #10
Yes indeed, the prime purpose was accomplished Duckhunter935 Jan 2016 #23
Yes, a very important satellite at that. Cassiopeia Jan 2016 #36
Reminiscing ... Trajan Jan 2016 #12
1996 ! Plucketeer Jan 2016 #15
That's how the landing legs work. backscatter712 Jan 2016 #34
Even I can envision the technology for that. Plucketeer Jan 2016 #35
oops Duckhunter935 Jan 2016 #22
Hats off to the Delta Clipper. backscatter712 Jan 2016 #27
indeed Duckhunter935 Jan 2016 #28
It's "Rocket Science" Plucketeer Jan 2016 #14
Maybe it is point of view but.... Delver Rootnose Jan 2016 #37
I think that's a trick of the camera Cassiopeia Jan 2016 #38
 

Duckhunter935

(16,974 posts)
1. it did have a mechanical
Mon Jan 18, 2016, 01:36 PM
Jan 2016

Lock issue on one of the legs. If not for that it would have been another successful landing like the last one. Even more difficult as it was on the barge this time. Each one brings in more data. How many NASA rockets had issues when they startled. By the way, the satellite was successfully put into orbit.

Great job SpaceX

Cassiopeia

(2,603 posts)
4. Definitely.
Mon Jan 18, 2016, 01:57 PM
Jan 2016

They almost got it. I'm sure they will be able to develop this into a reliable system very soon saving us a lot of money.

It was an encouraging attempt. Landed exactly on target as well.

backscatter712

(26,355 posts)
6. IIRC, according to Elon Musk, one of the landing legs didn't quite latch.
Mon Jan 18, 2016, 01:59 PM
Jan 2016

They're thinking it's due to icing from landing in the mists like that.

Sooooooooooo close!

 

Duckhunter935

(16,974 posts)
18. Bad choice of words
Mon Jan 18, 2016, 03:06 PM
Jan 2016

the legs seem to be able to hold up and have not failed. It was a latch mechanism and not the leg being undersized for the application.

backscatter712

(26,355 posts)
13. They have to be.
Mon Jan 18, 2016, 02:18 PM
Jan 2016

Every ounce counts on rockets. It costs a fortune to put satellites into orbit.

The legs are designed to be juuuuuuust strong enough to hold up the rocket on landing, when it's only got a little bit of fuel and liquid oxygen left in the tanks.

 

Spitfire of ATJ

(32,723 posts)
21. If they knew they weren't latched during landing they could have aborted....
Mon Jan 18, 2016, 03:11 PM
Jan 2016

Don't they have an alternate chute recovery?

 

Duckhunter935

(16,974 posts)
24. aborted to where and how?
Mon Jan 18, 2016, 03:17 PM
Jan 2016

I do not think they had chutes as they are conserving weight to get the payloads bigger.

not to mention, I did not say they knew for sure or had sensors. I said it is entirely possible.

backscatter712

(26,355 posts)
26. No, there's no way to abort.
Mon Jan 18, 2016, 03:31 PM
Jan 2016

The Falcon 9 first stage lands using a "hoverslam" - its engine's minimum power is so powerful it would cause the rocket to shoot back up into the air, on its lowest throttle setting (understand that the rocket stage is pretty light at this point, as its tanks are almost empty). So it has a landing scheme where it fires up the engine juuuuust at the last possible second, so as it's falling, the rocket slows its fall, until exactly at zero altitude, the rocket is slowed to zero descent rate.

There is no abort. You can't boost back into the air and throttle back down - the throttle's as low as it'll go. Apparently, there are a lot of technical reasons why it's hard to make a rocket engine that will "deep-throttle" - they usually will run great at full thrust, and if engineered right, will still run OK at 65% thrust, but they start sputtering and vibrating and shimmying and banging when you try to cut the throttle further than that. Something about instabilities in fuel and LOX flow when they're not flowing at a high enough flow rate - they don't mix well in the combustion chamber as they burn.

Besides, even if the Falcon 9 first stage did have the capability to deep-throttle, and thus abort, go back up, hover, and retry the landing, it wouldn't be able to hover for very long - as it's landing, the rocket's almost out of gas and LOX.

backscatter712

(26,355 posts)
33. I suspect parachutes couldn't do the job.
Mon Jan 18, 2016, 04:51 PM
Jan 2016

The rocket has to land pretty gently, and on its legs, to be able to survive. The video shows what happens if it tips over - the tanks are not strong enough to handle those kinds of side-forces, they split open, and kablooie.

The landing has to be pretty precise, and parachutes don't do precise.

PersonNumber503602

(1,134 posts)
32. I always find it interesting how quickly people are to jump all over the incidents
Mon Jan 18, 2016, 04:34 PM
Jan 2016

and use it to attack Space X. Often times they have no idea what exactly Space X is ultimately perfecting with these. It's just Space X either, but with pretty much with anything related to space flight.

backscatter712

(26,355 posts)
10. On the bright site, the Jason satellite this rocket launched got into orbit without a hitch.
Mon Jan 18, 2016, 02:02 PM
Jan 2016

The landing was the only part that didn't go right, and that part's experimental.

Cassiopeia

(2,603 posts)
36. Yes, a very important satellite at that.
Mon Jan 18, 2016, 05:20 PM
Jan 2016

I think SpaceX is going to work out the bugs on landing the first stage pretty soon. It will drastically cut down on the cost to launch things into space.

 

Plucketeer

(12,882 posts)
15. 1996 !
Mon Jan 18, 2016, 02:45 PM
Jan 2016

This thing should already be old hat. For this and the Space-X ship - why not have 4 or 6 long pneumatically extendable stabilizers that would clamp the rocket upright at the moment just before the engine(s) is shut off? I can't believe such a thing isn't already in use!

backscatter712

(26,355 posts)
34. That's how the landing legs work.
Mon Jan 18, 2016, 04:58 PM
Jan 2016

They're extended pneumatically.

The hard part is that the landing legs have to be able to keep a long, skinny object stable, which is why they extend outwards, and they have to be LIGHT, LIGHT, LIGHT. Every ounce counts in launch vehicles, so the suggestions "add another gadget to the vehicle to let it do this!" run into that roadblock.

And the rocket isn't going to land precisely down to the inch - it may be off the center of the landing pad by a few feet in any direction, so that makes developing a gadget on the landing barge to hold the rocket down difficult. That, and the gadget has to be able to withstand the hot exhaust blast from the rocket engine.

 

Plucketeer

(12,882 posts)
35. Even I can envision the technology for that.
Mon Jan 18, 2016, 05:04 PM
Jan 2016

Heck, I can go to Lowes right now and buy a laser measuring device. How hard would it be to tie such an input into the control of pneumatic cylinders to where the individual cylinders that surround the landing spot would only move as far as is necessary to follow the rocket to it's touchdown point and extend accordingly?

backscatter712

(26,355 posts)
27. Hats off to the Delta Clipper.
Mon Jan 18, 2016, 03:38 PM
Jan 2016

It did its job as an experimental craft, and did have a few successful landings before that accident.

The Delta Clipper did pave the way for the Falcon 9.

Delver Rootnose

(250 posts)
37. Maybe it is point of view but....
Mon Jan 18, 2016, 05:25 PM
Jan 2016

...it looks to me as if the main cylinder is bent at landing and causes the fall.

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