Author Topic: SpaceX F9 : Starlink group 3-4 : Vandenberg : 31 August 2022 (05:40 UTC) (Read 29146 times)

FutureSpaceTourist · « **Reply #80 on:** 08/31/2022 06:25 pm »

Photos from SpaceX

Rondaz · « **Reply #81 on:** 08/31/2022 08:56 pm »

CelesTrak has ephemeris-based SupGP data for all 46 satellites from the launch (2022-105) of #Starlink Group 3-4 from Vandenberg SFB on Aug 31 at 0540 UTC. STARLINK-4570 is currently leading the pack, for pass visibility scheduling:

https://twitter.com/TSKelso/status/1565038565674795009

gsa · « **Reply #82 on:** 08/31/2022 09:27 pm »

Quote from: Alexphysics on 08/31/2022 05:30 pm

Quote from: OneSpeed on 08/31/2022 11:56 am
[snip]
this mission demonstrates unprecedented first stage performance. Despite throttling back early for a wider throttle bucket, the 3-4 booster thereafter showed increased thrust up until terminal guidance, and MECO was at 2292m/s, some 30 m/s faster than for 3-3.

If someone is tracking when things happen in the countdown, LOX load was finished later than usual on both stages for this mission. This is one of the things they're doing now to pack more propellant on the tanks

If I'm not mistaken the "usual" times are T-3 minutes for the first stage and T-2 minutes for the second stage. For this mission the first stage report was at T-3 minutes ("usual"), but the second stage report was at ~T-1:30 ("later").
Is it possible that the first stage LOX was topping off for some time after T-3 minutes?

Comga · « **Reply #83 on:** 08/31/2022 09:47 pm »

Quote from: OneSpeed on 08/31/2022 11:56 am

Here is a comparison of the webcast telemetry from the Starlink 3-3 and 3-4 missions.

The most recent Starlink 4-27 mission demonstrated increased second stage performance, but this mission demonstrates unprecedented first stage performance. Despite throttling back early for a wider throttle bucket, the 3-4 booster thereafter showed increased thrust up until terminal guidance, and MECO was at 2292m/s, some 30 m/s faster than for 3-3.

It will be interesting to see what Falcon 9 can do when both stages are pushed to their new maxima.

Marvelous data.
So informative

Since when have they throttled the first stage for constant acceleration rather than turning off two of the nine engines? I don’t remember the switch.

The first stage finishes ~2 seconds earlier on 3-4 but the entire flight of the first stage takes ~6 seconds less. Yet the entry burn starts earlier which should lower the average velocity.
What gives?

Thanks again!

edkyle99 · « **Reply #84 on:** 08/31/2022 10:45 pm »

I think they only shut down the Merlin 1C engines in stages, on the v1.0 series Falcon 9. Merlin 1D could throttle enough to eliminate that set up, if I'm remembering correctly.

My question now is this. Is SpaceX getting this extra thrust by replacing all of the engines on the used boosters, or is it just pushing existing engines harder?

- Ed Kyle

OneSpeed · « **Reply #85 on:** 09/01/2022 05:46 am »

Quote from: Comga on 08/31/2022 09:47 pm

Since when have they throttled the first stage for constant acceleration rather than turning off two of the nine engines? I don’t remember the switch.

I'm pretty sure the only on purpose shutdowns of M1D prior to MECO were for Falcon Heavy side boosters. It will be interesting to see what they do for the next Heavy launch.

Quote from: Comga on 08/31/2022 09:47 pm

The first stage finishes ~2 seconds earlier on 3-4 but the entire flight of the first stage takes ~6 seconds less. Yet the entry burn starts earlier which should lower the average velocity.
What gives?

It might not be clear from the plot, but the apogee of 3-4s ballistic trajectory was 118km, 4km lower than for 3-3, and travelling some 52m/s faster. So, 3-4 with her flatter, faster trajectory took less time to get to her entry burn at an altitude of 60km, while 3-3 started 11 seconds later at 57km. The downrange distances I calculate are 649 and 651km respectively, so much the same distances travelled despite the different elapsed times.

Quote from: edkyle99 on 08/31/2022 10:45 pm

Is SpaceX getting this extra thrust by replacing all of the engines on the used boosters, or is it just pushing existing engines harder?

I'm not sure how many engines are being replaced, but from the plots, they are running all of them a few percent harder. Just not S1 and S2 at the same time, yet.

Quote from: Herb Schaltegger on 08/31/2022 12:00 pm

Thanks for the overnight (US) coverage Steven, and the data analysis OneSpeed. You guys are what makes NSF the best.

Thanks Herb, for the kind words. I just need to qualify that the mission coverage is very much the result of a team effort, by a lot of people who don't necessarily expect any recognition for their hard work, but all thoroughly deserve it.

crandles57 · « **Reply #86 on:** 09/01/2022 01:00 pm »

Quote from: OneSpeed on 09/01/2022 05:46 am

Quote from: edkyle99 on 08/31/2022 10:45 pm
Is SpaceX getting this extra thrust by replacing all of the engines on the used boosters, or is it just pushing existing engines harder?

I'm not sure how many engines are being replaced, but from the plots, they are running all of them a few percent harder. Just not S1 and S2 at the same time, yet.

Does later LOX load resulting in denser oxygen cause some or all of the power increase?

FutureSpaceTourist · « **Reply #87 on:** 09/01/2022 08:45 pm »

https://twitter.com/_tomcross_/status/1565433156907388928

Quote

Streak close up of SpaceX’s 39th launch of 2022 showing stage sep and booster reentry burn.
@SuperclusterHQ

#spacex
#falcon9
#starlink

SPKirsch · « **Reply #88 on:** 09/02/2022 12:33 am »

https://twitter.com/SpaceOffshore/status/1565484649098481673

Quote

Starlink 3-4: OCISLY is well underway towards Long Beach with B1063.

Vessel is self-reporting an ETA of 7am PT on Saturday.

NRC Quest is further ahead, arriving ~1am PT tonight , hopefully with two faring halves.

Rondaz · « **Reply #89 on:** 09/03/2022 01:21 pm »

OCISLY droneship is on track to arrive at the Port of Long Beach at approx. 6am PT this morning.

Delivering B1063 from Starlink 3-4.

https://twitter.com/SpaceOffshore/status/1566019867240701955

Rondaz · « **Reply #90 on:** 09/03/2022 02:19 pm »

West Coast sunrise arrival booster 1063-8 after launching Starlink 3-4 from Vandenberg, CA.

https://twitter.com/_TomCross_/status/1566065568070832128