SpaceX Falcon 9 v1.1 - Jason 3 - SLC-4E Vandenberg - Jan 17, 2016 - DISCUSSION

[QuantumG]

I'd be back in bed if we had confirmation of landing (or kaboom). It's almost like they're trying to make us hang around for 45 minutes to watch the circularization burn

[Zach Swena]

Did they forget to put the Sat uplink in a radome?  I don't see a satellite up link surviving without one.  All the wind wash from the thrust could easily tear off a dish...  Lets hope that was the problem, this is the first time they have showed a live feed as opposed to posting footage after the fact, ie no uplink.

[inventodoc]

stage crashing a good explanation for sudden loss of comms.

[vanoord]

I'm pretty sure the light from the rocket had just become visible before the feed froze, maybe some vibrations apparent too?

Certainly seemed to show a glow.

The barge was pitching up and down a lot - try and land when the barge was canted over and one of the legs may well have broken on impact with the deck, which would lead to loss even if the targeting was bang-on.

The up-side may be another demonstration that they can put the stage where they want to, even if it isn't recovered.

[Robotbeat]

stage crashing a good explanation for sudden loss of comms.

Or they lost communications due to rough seas. The feed was crappy before landing, too. Of course, rough seas doesn't bode well for landing success.

[Lar]

broken leg, again, due to hard landing. There will be those calling the droneship strategy into question, of course.

[AJA]

Poor JRTI keeps getting beat up by falling rockets.

You're sympathetic to the barge? I think half the forum would be ready to lynch you

If only it would "JUST READ THE INTENTIONS" and stay STILL!

IIRC, the barge is below the horizon from Vandy, so they would have no comms with the recovery zone except for relay from the barge. They have to wait until the support ships arrive on site and can tell them what's going on.

But they had confirmation right up until Merlin restart for the landing burn. (And...they safed FTS a bit earlier than that)... so they must have communications with the stage, until it's fairly close to the barge. Isn't the telemetry coming via satellite?

And as I type, they've gotten data indicating that one of the legs broke on landing. So no upright Falcon. :-(

[Ohsin]

 

We hope SpaceX breaks a leg—but not literally.

oooh boy..

[Hog]

NSF.com back up, some serious traffic!

[vanoord]

broken leg, again, due to hard landing. There will be those calling the droneship strategy into question, of course.

There was a lot of pitching visible on the video feed.

Try and land on a deck that's canted by - say - 15° and one leg will land first, with the whole weight on it, with entirely predictable results.

As for the strategy: sometimes it will work, sometimes it won't.

Even if it works 1 in 10 times and it costs $1m a try, that's a $50m stage they're recovering.

[Robotbeat]

Just out of curiosity, is the parking orbit stable? And how much delta-v is needed to get into final orbit? And how much delta-v does Jason-3 have on-board?

[Ben the Space Brit]

So, the one of the landing legs broke (velocity at a=0 being above the margin, obviously). One wonders which direction the stage tumbled after the event. It's just possible that what killed comms was it falling on the mast array and jamming there (wild optimism alert!).

We'll learn more in time, no doubt.

[a_godumov]

broken leg, again, due to hard landing. There will be those calling the droneship strategy into question, of course.

The Orbcom landing proved that the concept is viable but they will probably need additional attempts to iron it out. In this particular case the waves looked very serios before the feed cut off. It already is very impressive how they have consistently reached the target and it would have been extremely impressive (at least to me) if they gad successfully landed on the barge in this weather.

Try and land on a deck that's canted by - say - 15° and one leg will land first, with the whole weight on it, with entirely predictable results.

I was also wondering if the landing itself was fine but due to the pitching of the deck not all of the legs touched down at the same time and this caused excessive stress on the other leg. If this is the case perhaps this would be still a good outcome because it would indicate that the landing would have worked if it was RTLS?

[abaddon]

broken leg, again, due to hard landing. There will be those calling the droneship strategy into question, of course.

True, but there already are.  The best part being it is all hot air with no chance of stopping SpaceX from trying again.

[Zach Swena]

I am surprised they didn't mention explosion along with the broken leg.  If it was low energy enough, or had low enough fuel to not explode when the leg broke, I would be presently surprised.  Estimating the vertical landing height in 15' seas even with the stabilization they have on JRTI has to be really hard.

[Robotbeat]

So, the one of the landing legs broke (velocity at a=0 being above the margin, obviously). One wonders which direction the stage tumbled after the event. It's just possible that what killed comms was it falling on the mast array and jamming there (wild optimism alert!).

We'll learn more in time, no doubt.

The feed was already marginal before the landing. Could be that the stage interfered with the signal coming in and then fell on top of the comms. Or, since it was a digital uplink, there was a big video buffer so we lost signal before the buffer was cleared. Good argument for either an analog uplink (secondary, perhaps) or a custom small-buffer digital uplink.

[yg1968]

now NASA tv goes into a commercial followed by MLK day 

What happened to the mission?

The landing leg broke... Quick, go to commercial!

[Lar]

broken leg, again, due to hard landing. There will be those calling the droneship strategy into question, of course.

True, but there already are.  The best part being it is all hot air with no chance of stopping SpaceX from trying again.

Exactly.

If the vid shows that the barge WAS pitching badly but the stage came in much closer to upright with less slew, just still hit one leg first, harder, it means this probably IS solvable, just needs control algorithm refinement.  And as was said, even 1 in 10 is better than 0 in 10 as long as it doesn't cost too much... think of it as lottery. Except the odds will get better.

now to see how I did in bingo

[gin455res]

https://en.wikipedia.org/wiki/Semi-submersible

Is it possible to build a barge with submerged pontoons to avoid the effect of large swells?

[Lars-J]

Worth noting that a known problem with the 1.1's was slow valves in the engines. This was fixed with FT's. Combine that with rough seas, the odds were against them to start, this is just another great opportunity to gather boost back and landing data.

Also, the FT's supposedly have improved legs - although we don't know if these improved legs were retrofitted into this last v1.1.