SpaceX F9 : Starlink v1.0 L21 : KSC LC-39A : 14 March 2021 (10:01 UTC)

[FutureSpaceTourist]

https://twitter.com/nasaspaceflight/status/1371055428600270849

[Jansen]

https://twitter.com/SpaceX/status/1371055836802387971

[FutureSpaceTourist]

https://twitter.com/johnkrausphotos/status/1371056198376689666

SpaceX's Falcon 9 rocket left behind a beautiful, artificial noctilucent cloud over the Space Coast this morning after its launch of 60 Starlink satellites from Cape Canaveral, Florida

[FutureSpaceTourist]

https://twitter.com/spacecoast_stve/status/1371046187890053121

Liftoff! And that’s a new record for Falcon 9 reuse! 🚀♻️

After separating from the second stage, which carried the #Starlink satellites, B1051 went on to land for a record 9th time on Of Course I Still Love You. See ya in port!

Mission overview: nasaspaceflight.com/2021/03/spacex…

[FutureSpaceTourist]

Photos from SpaceX website (by Ben Cooper)

[Edit to add: thanks to ChrisC for noting I’d attached the wrong image   Now corrected]

[OneSpeed]

Here is a comparison between the telemetry for Starlink L20 and L21. My only observation would be that from about T+115s to MECO1 L21 was throttled back by a few % compared to L20. To compensate, the terminal guidance phase ran about 3 seconds later, and at a slightly higher throttle. Overall, L21 might have had a slightly less taxing boost phase than for B1051's previous eight missions.

[cscott]

Nice view of the second stage gas nebula from the ground infrared tracking camera again.  This time they kept showing the camera view of a "star" which I'm pretty sure was the first stage.  It could be seen to vent once, but then they cut away just before the re-entry burn startup.

[guyw]

I was able to see the expanded plume from the second stage from my bedroom window here in New Hampshire. Could see it from at least a minute or so before second stage engine cutoff. It expands a lot.
 

[FutureSpaceTourist]

https://twitter.com/r2x0t/status/1371054115875348480

Freshly received #SpaceX #Falcon9 video, enjoy these incredible shots!

Thanks goes to @uhf_satcom for receiving this signal. We will be listening on 2nd orbit as well.

[ZachF]

By my calculations, Booster 1051 has now lifted more payload mass to orbit than any other booster:

116,722kg F9-1051
102,870kg SA-513 (Skylab)
91,440kg F9-1049

 

[LouScheffer]

Here is a comparison between the telemetry for Starlink L20 and L21. My only observation would be that from about T+115s to MECO1 L21 was throttled back by a few % compared to L20. To compensate, the terminal guidance phase ran about 3 seconds later, and at a slightly higher throttle. Overall, L21 might have had a slightly less taxing boost phase than for B1051's previous eight missions.

It would be interesting to see the difference between two flights of the same booster, perhaps L16 and L21 (both booster 1051).

Another explanation for the throttle down (and this is pure, pure speculation) might be a precautionary backoff.  Suppose each engine has, in addition to red lines, yellow lines for its parameters.   If one of these warning limits  is reached, they throttle back the engine to (say) 70%, smack in the middle of its operating region.  This is then compensated in the terminal guidance phase.  Such a throttle-down would have much less effect on the trajectory than a complete shutdown, but still be safer then continuing to run at full power and risking a failure than might hurt other engines.  This behavior would correspond to how we treat machines in our daily life, and SpaceX might have enough data on these engines to make this formal.

We know from acceleration on GTO flights that they run the second stage engine at about 70% for the GTO insertion.  I always assumed that this was because the engine was a single point of failure, and they wanted to run it at its most reliable setting. (And there are no gravity losses, and little Obereth losses since the burn is very short anyway.)

[Herb Schaltegger]

We know from acceleration on GTO flights that they run the second stage engine at about 70% for the GTO insertion.  I always assumed that this was because the engine was a single point of failure, and they wanted to run it at its most reliable setting. (And there are no gravity losses, and little Obereth losses since the burn is very short anyway.)

Payloads also have G limits and frankly, Mvac is almost over-powered for a relatively small second stage.

[zubenelgenubi]

Freshly received #SpaceX #Falcon9 video, enjoy these incredible shots!

Wow! That is an almost empty 2nd stage LOX tank!
Also, liquid oxygen is lovely. 

[overby]

Nice view of the launch this morning from the Boston, MA area. Sunrise was about an hour after launch, and the sun illuminated the exhaust cloud and the stage.  I was able to see the stage even after burn-out. The only previous Falcon launch I've seen (GPS III last year) was in much darker skies and the 2nd stage disappeared when it shut down.

Glen

[punder]

A new (IR?) camera used in the last two launches, unless I’m behind the times. Great shots of both stages and both fairing halves, awesome 2nd stage plume, but on both flights commentators seem curiously uninterested.

[abaddon]

A new (IR?) camera used in the last two launches, unless I’m behind the times. Great shots of both stages and both fairing halves, awesome 2nd stage plume, but on both flights commentators seem curiously uninterested.

Maybe they've had these views available internally for longer than the last two flights.  I agree, they're very interesting to see.

[Comga]

Freshly received #SpaceX #Falcon9 video, enjoy these incredible shots!

Wow! That is an almost empty 2nd stage LOX tank!
Also, liquid oxygen is lovely. 

Images from the LOX tanks are among my favorites
Is this from after the orbital insertion (2nd) burn?
What keeps the LOX so intact and stuck to the act end in 0g?

[Tommyboy]

Freshly received #SpaceX #Falcon9 video, enjoy these incredible shots!

Wow! That is an almost empty 2nd stage LOX tank!
Also, liquid oxygen is lovely. 

Images from the LOX tanks are among my favorites
Is this from after the orbital insertion (2nd) burn?
What keeps the LOX so intact and stuck to the act end in 0g?

Considering the assymetrical pooling, this is propable during the yeet-maneuver in which the stage is spinning head over heels, and thus not in 0g.

[kdhilliard]

...
Considering the assymetrical pooling, this is propable during the yeet-maneuver in which the stage is spinning head over heels, and thus not in 0g.

That would make sense, except you can see from the exterior shots (either those in which the Earth is visible, or those where you can see non-moving shadows on the Merlin) that it is not yet in its flat spin.

So I guess it must be surface tension, but I'm surprised there aren't some LOX globules floating about.

[ChrisC]

Photos from SpaceX website (by Ben Cooper)

Really?  The first one says Stephen Marr on it.  Wrong photo attached?  Or is Stephen helping out Ben?

A new (IR?) camera used in the last two launches, unless I’m behind the times. Great shots of both stages and both fairing halves, awesome 2nd stage plume, but on both flights commentators seem curiously uninterested.

Absolutely, this view that we have been seeing in the last two launches is fantastic.  I agree that they should be commenting on it more (e.g. explain why four dots) and then keep tracking (and showing us) the first stage as it enters.  Maybe put up three screens (S1+S1+S2) instead of just two (S1+S2).

[From r00t tweet]
Freshly received #SpaceX #Falcon9 video, enjoy these incredible shots!

Wait WHAT?!  They are able to downlink and decode the SpaceX telemetry?  That's new, and I sure hope it's OK, and continues!  I could see how this might violate ITAR and SpaceX has to now start encrypting their feed.  Or has to improve their encryption

There's a lot more explanation here: https://www.reddit.com/r/RTLSDR/comments/m4xbvc/so_today_at_1021utc_i_got_my_own_recording_of/
... starting with this summary:

So today at 10:21UTC i got my own recording of Falcon9 video feed downlink on S band 2272.5MHz and with u/Aang253's software SatDump i could easily decode it from the recording straight down to mxf, avi or mp4 video file! Even with very simple recieving setup!

And here's their writeup on what they've learned about the SW2 telemetry downlink:
https://www.r00t.cz/Sats/Falcon9

Considering the assymetrical pooling, this is propable during the yeet-maneuver in which the stage is spinning head over heels, and thus not in 0g.

Thanks for that, I was also wondering why we weren't seeing free-floating liquid.  Extremely cool.