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#380
by
FutureSpaceTourist
on 07 Aug, 2020 07:50
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#381
by
olemars
on 07 Aug, 2020 08:13
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I love that these launches are so routine now. Looking forward to this booster doing its sixth launch and landing.
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#382
by
FutureSpaceTourist
on 07 Aug, 2020 08:50
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Streak shot from SpaceX website
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#383
by
OneSpeed
on 07 Aug, 2020 11:15
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Starlink V1.0 L4 - L8 all inserted into their coast phase at around 216km altitude. L1 - L3 however inserted at around 168km. Starlink V1.0 L9 marks a return to the earlier insertion altitude, at a slightly higher velocity, but with only 57 Starlink satellites on board.
Why? The 60 L3 satellites were deployed at an altitude of 302km, close to a circular orbit. The 57 L9 satellites were deployed at about 400km, also roughly circular, because that is the required orbit for the BlackSky rideshare satellites. Achieving this orbit required a small reduction in overall payload to 57 Starlink satellites.
As per some of the earlier missions, the L9 S2 throttled back to about 94% throttle at the 450s mark. It also burnt longer than L3 to compensate, and shut down travelling some 25m/s faster.
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#384
by
FutureSpaceTourist
on 07 Aug, 2020 12:40
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twitter.com/blacksky_inc/status/1291714462064443396
It takes about 3 minutes after launch to pass the Kármán Line, the boundary to #space around 62 miles above us. That requires 1.7 million pounds of heart-pounding thrust coming from the nine Stage 1 engines that are pushing 1+ million pounds of #engineering through... (cont'd)
https://twitter.com/blacksky_inc/status/1291714463834542081...the atmosphere. It’s one thing to understand it. It’s another thing to actually do it. Congrats to all our amazing partners at @SpaceX, @SpaceflightInc, and @LeoStellaLLC + the incredible @BlackSky_Inc team whose efforts are taking #globalmonitoring to the next level.
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#385
by
LouScheffer
on 07 Aug, 2020 14:06
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Starlink V1.0 L4 - L8 all inserted into their coast phase at around 216km altitude. L1 - L3 however inserted at around 168km. Starlink V1.0 L9 marks a return to the earlier insertion altitude, at a slightly higher velocity, but with only 57 Starlink satellites on board.
Why? The 60 L3 satellites were deployed at an altitude of 302km, close to a circular orbit. The 57 L9 satellites were deployed at about 400km, also roughly circular, because that is the required orbit for the BlackSky rideshare satellites. Achieving this orbit required a small reduction in overall payload to 57 Starlink satellites.
As per some of the earlier missions, the L9 S2 throttled back to about 94% throttle at the 450s mark. It also burnt longer than L3 to compensate, and shut down travelling some 25m/s faster.
Are you sure the orbit is the reason for reduction to 57 Starlinks? The delta-V between 302 km circular and 400 km circular is about 56 m/s. Getting rid of 2 starlinks (at 260 kg each), then adding 2 BlackSky (55 kg each) should increase second stage performance by about this amount using the usual assumptions (total payload about 15.6t, ISP=348, burnout mass=5.5t, including residuals), plus another 5 m/s from the first stage. So if it's really for performance (and not say mechanical fit of the adapter, or slightly larger or heavier visor-sats compared to the L3 versions) then this is really on the performance edge of the F9 recoverable.
Perhaps the throttle back of S2 was for load limiting? It kept the peak load to 3.5 Gs, where a normal Starlink launch goes to 4 Gs.
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#386
by
FutureSpaceTourist
on 07 Aug, 2020 14:07
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#387
by
FutureSpaceTourist
on 07 Aug, 2020 14:39
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https://twitter.com/jinsprucker/status/1291729064751804417 I realized in the webcast this morning's Starlink flight means the last 2 launches from historic 39A were the Demo 2 booster (1st flight, left) and the Demo 1 booster (5th flight, right). In the 2+ months in-between, the Demo 2 booster has already flown again (ANASIS-II mission).
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#388
by
tbellman
on 07 Aug, 2020 17:07
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Are you sure the orbit is the reason for reduction to 57 Starlinks?
John Insprucker claimed that was the case in the launch webcast, at T+01:04:22 (or 1:21:14 into the Youtube webcast).
https://youtube.com/watch?v=KU6KogxG5BE&t=4874... typically when we're flying Starlink, we go into an elliptical orbit after one burn and then we separate the satellites, and their ion thrusters will lift them to the final orbit. But for the spaceflight customer with the BlackSky satellites we needed to get to a circular orbit, so they required two burns, the second which you saw just a little while ago, when we got to apogee. That circularized the orbit, but in order to do that, that took more propellant out of the vehicle, so you couldn't carry quite as much mass, so we traded off three of the Starlinks, so we're at 57 Starlinks on the stack.
(I hope I managed to transcribe that correctly.)
(EDIT: Link to webcast, and spelling; thanks, kdhilliard.)
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#389
by
FutureSpaceTourist
on 07 Aug, 2020 17:20
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More SpaceX launch photos by Ben Cooper
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#390
by
FutureSpaceTourist
on 07 Aug, 2020 18:57
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https://twitter.com/considercosmos/status/1291805737157627909Engines in flight, at night🔥🔭🚀
A closeup look at Falcon 9 with #Starlink & @BlackSky_Inc via telescope tracking slowmo... Congrats @SpaceX @elonmusk
Watch for the flames, stay for the sounds and colors, scope crew at it again @Erdayastronaut @OPT_Telescopes @astroferg
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#391
by
Bean Kenobi
on 07 Aug, 2020 20:26
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Are you sure the orbit is the reason for reduction to 57 Starlinks? The delta-V between 302 km circular and 400 km circular is about 56 m/s. Getting rid of 2 starlinks (at 260 kg each), then adding 2 BlackSky (55 kg each)
Getting rid of
3 starlinks
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#392
by
LouScheffer
on 07 Aug, 2020 22:23
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Are you sure the orbit is the reason for reduction to 57 Starlinks? The delta-V between 302 km circular and 400 km circular is about 56 m/s. Getting rid of 2 starlinks (at 260 kg each), then adding 2 BlackSky (55 kg each)
Getting rid of 3 starlinks
No, getting rid of
2 starlinks. I was finding an estimated performance for two fewer satellites, to show that according to my crude estimates, they could have fitted 58 Starlinks. So I was speculating that there was some reason other than mass. However, John Insprucker, later in the recent webcast, says that mass was indeed the reason. He should know, so my speculation is wrong.
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#393
by
FutureSpaceTourist
on 08 Aug, 2020 13:42
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#394
by
FutureSpaceTourist
on 08 Aug, 2020 14:03
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#395
by
FutureSpaceTourist
on 08 Aug, 2020 14:08
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#396
by
wannamoonbase
on 08 Aug, 2020 14:35
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I freaking love that SpaceX is able to put so much payload into LEO and only expend the upper stage!
The SpaceX Navy does a lot of work to make this happen, but it sure saves a lot compared to expending everything. SpaceX will only get more efficient from here on out.
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#397
by
FutureSpaceTourist
on 08 Aug, 2020 19:22
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#398
by
FutureSpaceTourist
on 09 Aug, 2020 12:43
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#399
by
FutureSpaceTourist
on 10 Aug, 2020 05:25
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