SpaceX F9 : Starlink v1.0 Flight 3 : January 29, 2020 - Master Thread

[eeergo]

One of the Starlinks caught up with something and rolled faster around its longitudinal axis than the rest of the stack, showing somewhat clear views of its appearance all around, including the nadir panel.

Do the sats have lights on them? maybe it's just reflections but it looks like there's light sources on them.
Maybe the Argon drives but i wouldn't think they'd start up without the panels deployed.

May look like it from a few stills, but from the moving video it's clear the sats have many reflective surfaces that glint off the second stage's camera light, not light sources on their own.

PS: The ion engines are fueled by krypton, not argon.

[LandingZone-1]

https://spacenews.com/spacex-launches-fourth-batch-of-starlink-satellites-tweaks-satellite-design/

The launch — SpaceX’s fourth for Starlink not counting two demonstration satellites launched in 2018 — carried an upgraded set of satellites designed for better spectral efficiency and throughput.

[FutureSpaceTourist]

twitter.com/spacecoast_stve/status/1222541000268230658

Falcon 9 takes flight! Add another 60 satellites to the #Starlink constellation - just a little bit closer to being operational. Shot from just under 3 miles away. More shots below 👇

https://twitter.com/spacecoast_stve/status/1222541023525601280

Here you'll see the vapor cone as Falcon 9 goes transonic, the smoke ring left behind, and the aftermath at the pad shortly after departure.

https://twitter.com/gregscott_photo/status/1222535047170940928

Launch of today's #SpaceX #Starlink mission was picture perfect. Booster B1051.3 lifted off the pad right on schedule this morning at 9:06am EST. Beautiful launch. #NASA #Space #SpaceForce

[FutureSpaceTourist]

twitter.com/johnkrausphotos/status/1222524638787526659

Liftoff of Falcon 9 from Cape Canaveral!

60 Starlink satellites head to orbit at 9:06am this morning as a part of SpaceX’s mission to provide internet access to locations where coverage has been limited, unreliable, or unavailable.

https://twitter.com/johnkrausphotos/status/1222525951751401473

Falcon 9 climbs toward orbit and goes transonic with 60 Starlink satellites.

[racevedo88]

Core landing used up the crush material..

Speculation on what caused this landing to cause that ??

Hard to tell at this point but any engine bell damage when crush core maxed ??

Can Octograbber still grab at max leg pad crush or back to chains to hold core down ??

Maybe the engine shut down a half second before touchdown.

Or it might just be a wave up-swell causing the barge to move up at the moment of landing. The landing always amaze me because on land you only have to worry about three static axis (long,Lat, and altitude to correctly land, At sea you have three dynamic axis and in term of the suicide burn you have a constantly varying altitude that in calm/moderate seas can be +- 5ft, so in an up swell you might be landing without achieving your optimal velocity at landing, and in a down-swell shutting down the engine early

[ZachS09]

Core landing used up the crush material..

Speculation on what caused this landing to cause that ??

Hard to tell at this point but any engine bell damage when crush core maxed ??

Can Octograbber still grab at max leg pad crush or back to chains to hold core down ??

Maybe the engine shut down a half second before touchdown.

Or it might just be a wave up-swell causing the barge to move up at the moment of landing. The landing always amaze me because on land you only have to worry about three static axis (long,Lat, and altitude to correctly land, At sea you have three dynamic axis and in term of the suicide burn you have a constantly varying altitude that in calm/moderate seas can be +- 5ft, so in an up swell you might be landing without achieving your optimal velocity at landing, and in a down-swell shutting down the engine early

I mentioned the possible early shutdown because the Iridium-2 landing had a similar fate. The booster hovered a few feet above JRTI and it plopped on the deck after shutdown. It was obvious that all the crush core was used up on that specific landing.

[lawlessl]

Core landing used up the crush material..

Speculation on what caused this landing to cause that ??

The barge comes out of a trough in the waves just afterwards. It definite thought it landed above the deck. Maybe the delay in the commanding can not cope with certain sea states and length of swell.

[PreferToLurk]

Core landing used up the crush material..

What is your source for this?  There is a big difference between using some of the margin you built in, and using ALL of the margin you built in.  My mark 1 eyeball tells me that the legs spread a bit farther than usual, but if the crush material was "used up", that would imply a seriously off-nominal landing.

Landing a rocket, on a barge, in the middle of the ocean, is hard.  That's why they have the crush core in the first place.

[Doesitfloat]

The rocket is standing strait up dead center of the barge. What is your source that something went wrong ?
The rocket has margin to land harder when the wind is strong and the barge is pitching.  The rocket used it's margin and hit the bullseye. Way to go Spacex!

[meekGee]

The rocket is standing strait up dead center of the barge. What is your source that something went wrong ?
The rocket has margin to land harder when the wind is strong and the barge is pitching.  The rocket used it's margin and hit the bullseye. Way to go Spacex!

Usually the engines shut-off as the legs touch, and weight is transferred from engines to legs smoothly.

Here the rocket reaches zero velocity too high, the engines shut down (as they have no choice but to do), and the stage accelerates downwards before touching down.

Whether it used up all of the crush core or not is not clear.  It looks pretty rough.

[eriblo]

I'm still waiting for when SpaceX manages to actually live stream the moment of deployment. We've missed it every time (4/4) so far.

Unlikely to be a coincidence. I think they are keeping the rod release/ejection details under wraps.

Agreed. Must have some simple but ingenious engineering involved. Not to be leaked to the competitors!

Drop out in four out of four launches does not say much when all of them occur with the second stage in the same orientation at the same location following similar trajectories...

[burgi]

T+2 minutes.

I've never seen the plume look so asymmetrical before.

Maybe some pitch correction? In the first minute it looked a little bit off.

[Vettedrmr]

What is your source for this?  There is a big difference between using some of the margin you built in, and using ALL of the margin you built in.

Crush material is used/not used.  Use it at all, you have to replace it.  Doesn't matter how much you use or not.  This one looked to be one of the hardest successful landings I've seen.  I'm curious if the engine bells hit the deck or not.  They don't appear to be touching after everything stabilized, but there's always some rebound on touchdown.

To your point, it IS a successful landing.  Crush zones, engine bells, etc. are all replaceable parts.  So, a good day, but a day to learn as well.

Have a good one,
Mike

[StuffOfInterest]

I wonder if the amount of crush core used will affect folding vs. removal of legs when they get back to port.  We've seen flights where four legs were removed, two legs were removed, and no legs were removed.  If all four are taken off this time I'd use that as an indication of used crush core requiring leg removal.

[Vettedrmr]

I wonder if the amount of crush core used will affect folding vs. removal of legs when they get back to port.  We've seen flights where four legs were removed, two legs were removed, and no legs were removed.  If all four are taken off this time I'd use that as an indication of used crush core requiring leg removal.

Bold mine.  I think you're contradicting yourself there.

[Stan-1967]

Usually the engines shut-off as the legs touch, and weight is transferred from engines to legs smoothly.

Here the rocket reaches zero velocity too high, the engines shut down (as they have no choice but to do), and the stage accelerates downwards before touching down.

Whether it used up all of the crush core or not is not clear.  It looks pretty rough.

Is is a known fact that leg contact with the deck is the only cue/signal for engine shutdown? It seems like it would also make sense to cue engine shutdown if the position information says th vehicle is your "zero" elevation, probably the nominal deck height above sea level, & the vehicle is also at zero vertical velocity.

When you look at the deck height vs. horizon, especially to the right side of the drone ship, you can see that the timing of the landing is during a downward trough.  It still looks to my eye that the landing was pretty good, if not nominal.   

[racevedo88]

Usually the engines shut-off as the legs touch, and weight is transferred from engines to legs smoothly.

Here the rocket reaches zero velocity too high, the engines shut down (as they have no choice but to do), and the stage accelerates downwards before touching down.

Whether it used up all of the crush core or not is not clear.  It looks pretty rough.

Is is a known fact that leg contact with the deck is the only cue/signal for engine shutdown? It seems like it would also make sense to cue engine shutdown if the position information says th vehicle is your "zero" elevation, probably the nominal deck height above sea level, & the vehicle is also at zero vertical velocity.

When you look at the deck height vs. horizon, especially to the right side of the drone ship, you can see that the timing of the landing is during a downward trough.  It still looks to my eye that the landing was pretty good, if not nominal.

it was an awesome landing

[tleski]

What is your source for this?  There is a big difference between using some of the margin you built in, and using ALL of the margin you built in.

Crush material is used/not used.  Use it at all, you have to replace it.  Doesn't matter how much you use or not.  This one looked to be one of the hardest successful landings I've seen.  I'm curious if the engine bells hit the deck or not.  They don't appear to be touching after everything stabilized, but there's always some rebound on touchdown.

To your point, it IS a successful landing.  Crush zones, engine bells, etc. are all replaceable parts.  So, a good day, but a day to learn as well.

Have a good one,
Mike

I don't think the engine bells are replaceable. From what I remember this was debunked several times on this forum.

[Vettedrmr]

I don't think the engine bells are replaceable. From what I remember this was debunked several times on this forum.

I've not read that but I can see it being more expensive to repair/replace than it is just to replace the Merlin engine in its entirety.

[RotoSequence]

The booster seemed to undershoot the target trajectory noticeably in the Mission Control Audio stream.