Author Topic: SpaceX F9 : Starlink group 2-4 : VSFB SLC-4E : 19 January 2023 (15:43 UTC) (Read 62570 times)

FutureSpaceTourist · « **Reply #160 on:** 01/19/2023 09:14 pm »

A couple of SpaceX launch photos

edkyle99 · « **Reply #161 on:** 01/19/2023 09:25 pm »

I wonder if today's launch used the second stage that had the problem during the November 17, 2022 static fire held before the planned Starlink 2-4 launch using B1061.11.

- Ed Kyle

Alexphysics · « **Reply #162 on:** 01/20/2023 02:29 am »

Quote from: edkyle99 on 01/19/2023 09:25 pm

I wonder if today's launch used the second stage that had the problem during the November 17, 2022 static fire held before the planned Starlink 2-4 launch using B1061.11.

- Ed Kyle

Who said the issue was on the second stage?

OneSpeed · « **Reply #163 on:** 01/20/2023 05:22 am »

Here is a comparison of the webcast telemetry from the Starlink 4-31 and 2-4 missions.

4-31 flew 53 satellites to an orbital inclination of 53.2°, whilst 2-4 flew 51 satellites to 70°.

Some first stage differences are:
1. The 2-4 throttle bucket was about 5 seconds earlier, from 240 to 320m/s, barely supersonic at that altitude. The 4-31 bucket was from the usual 300 to 355m/s.
2. The 2-4 MECO was 2s earlier, re-entry burn was 4s earlier, and the landing burn was 10s earlier. This all points to a slightly less energetic booster trajectory, as you might expect with fewer satellites to a higher inclination.

For the second stage, the differences are:
1. Because of the SpaceX telemetry inertial frame of reference, orbital velocity of 2-4 at 70° inclination is faster at 7661m/s than for 4-31 at 53.2° and 7,521m/s. In an orbital frame of reference, the numbers would be the same for both, at about 7,820m/s.
2. The acceleration for 2-4 is a few percent greater towards SECO due to the lighter payload.

Steven Pietrobon · « **Reply #164 on:** 01/20/2023 05:27 am »

Here's a pdf of the archived press kit.

https://web.archive.org/web/20230119141646/https://www.spacex.com/launches/mission/?missionId=starlink-2-4-pre-launch

Skyrocket · « **Reply #165 on:** 01/20/2023 05:52 am »

Quote from: edkyle99 on 01/19/2023 09:25 pm

I wonder if today's launch used the second stage that had the problem during the November 17, 2022 static fire held before the planned Starlink 2-4 launch using B1061.11.

- Ed Kyle

This launch did not use B1061.11. This one used a new stage, B1075, as mentioned earlier in this thread.
SpaceX confirms the new stage: https://www.spacex.com/launches/mission/?missionId=sl2-4-pl

ZachS09 · « **Reply #166 on:** 01/20/2023 11:23 am »

Quote from: Skyrocket on 01/20/2023 05:52 am

Quote from: edkyle99 on 01/19/2023 09:25 pm
I wonder if today's launch used the second stage that had the problem during the November 17, 2022 static fire held before the planned Starlink 2-4 launch using B1061.11.

- Ed Kyle

This launch did not use B1061.11. This one used a new stage, B1075, as mentioned earlier in this thread.
SpaceX confirms the new stage: https://www.spacex.com/launches/mission/?missionId=sl2-4-pl

Ed meant the second stage only.

kdhilliard · « **Reply #167 on:** 01/21/2023 01:57 am »

Did anyone else notice that at stage separation part of the film (aluminized Kapton?) covering the MVac came loose? From the second camera view you can even see the three strips of tape which had held it down!

Video link to stage separation: https://youtube.com/watch?v=bNAebzSvWt4&t=11m26s

Not an event of any consequence; just one I've never noticed before.