Author Topic: SpaceX F9 : Starlink v0.9 : May 23, 2019 - DISCUSSION  (Read 233690 times)

Online meekGee

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I wrote an article about the recent Starlink-1 news and I'm also speculating that SpaceX might soon stop doing static fires before Starlink launches.

https://www.elonx.net/falcon-9-will-launch-dozens-of-starlink-satellites-and-there-could-be-up-to-7-such-launches-this-year/
That would be interesting.

My view on this from a few years back was that static fires could be eliminated for reused boosters once SpaceX feels comfortable that data collected through ascent and descent is understood well enough to be used in lieu of static fire data for the following flight.

Maybe we have arrived...
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Offline Rondaz

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SpaceX’s Starlink launch debut to orbit dozens of satellites later this month..

By Eric Ralph Posted on May 8, 2019

https://www.teslarati.com/spacex-schedules-starlink-launch-debut/


Offline whitelancer64

I wrote an article about the recent Starlink-1 news and I'm also speculating that SpaceX might soon stop doing static fires before Starlink launches.

https://www.elonx.net/falcon-9-will-launch-dozens-of-starlink-satellites-and-there-could-be-up-to-7-such-launches-this-year/
That would be interesting.

My view on this from a few years back was that static fires could be eliminated for reused boosters once SpaceX feels comfortable that data collected through ascent and descent is understood well enough to be used in lieu of static fire data for the following flight.

Maybe we have arrived...

Several years ago ULA stopped doing WDRs for the Atlas V (unless for military, NASA, or customer request) because they got to the point where they almost never uncovered an issue before launch.
"One bit of advice: it is important to view knowledge as sort of a semantic tree -- make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to." - Elon Musk
"There are lies, damned lies, and launch schedules." - Larry J

Offline gongora

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Shouldn't discussion of the need for static fires go somewhere in the reusability section?

Offline whitelancer64

Shouldn't discussion of the need for static fires go somewhere in the reusability section?

It's relevant IIF Starlink launches aren't doing a static fire.
"One bit of advice: it is important to view knowledge as sort of a semantic tree -- make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to." - Elon Musk
"There are lies, damned lies, and launch schedules." - Larry J

Offline envy887

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Shouldn't discussion of the need for static fires go somewhere in the reusability section?

It's relevant IIF Starlink launches aren't doing a static fire.

The static fire should be sometime around the 12th, based on previous flows. Has it hit the range yet?
« Last Edit: 05/09/2019 04:12 pm by envy887 »

Offline gongora

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Shouldn't discussion of the need for static fires go somewhere in the reusability section?

It's relevant IIF Starlink launches aren't doing a static fire.

We have no indication that Starlink launches won't do static fires.  More specifically, this thread is about a single mission and we have no indication that this mission won't do a static fire.

Offline FutureSpaceTourist

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https://twitter.com/emrekelly/status/1126564331838156803

Quote
#SpaceX's next mission, the in-house launch of Starlink satellites, is now firmly on the Eastern Range's calendar for Wednesday, May 15. Launch hazard area will be in effect from 2030 ET to 0100 ET +1 (0030 to 0500 UTC). Drone ship landing.

Offline PM3

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"Never, never be afraid of the truth." -- Jim Bridenstine

Offline Rondaz

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Details emerge about upcoming Starlink launch

TMF Associates blog
Satellites, spectrum and other stuff  05.09.19

http://tmfassociates.com/blog/2019/05/09/backing-winners/

Offline Rondaz

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SpaceX granted authorization to communicate with up to 75 Starlink satellites during launch and early orbit phase operations [before they reach destination orbit]..

Attachment Space Exploration Ho
Space Exploration Ho
DECISION submitted by IB,FCC

2019-05-09

https://fcc.report/IBFS/SAT-STA-20190405-00023/1679286


Offline docmordrid

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I'd say "up to 75" hits the upper boundary of the "dozens" guessing game 😨
DM

Offline daedalus1

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Based on max of about 12000kg to that orbit (reusable). 48 @ 250kg each would be a reasonable estimate. Provideing the volume is within the volume of th shroud.

Offline smoliarm

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Based on max of about 12000kg to that orbit (reusable). 48 @ 250kg each would be a reasonable estimate. Provideing the volume is within the volume of th shroud.

NASA's LSP calculator gives performance of
14460 kg
for "Falcon 9 Full Thrust" with ASDS
at 400 km circular orbit with 51.6° inclination.

Of this performance I'd reserve about ~1400 kg for dispenser, which leaves us with slightly better total payload mass:
~13000 kg.

Offline oldAtlas_Eguy

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Based on max of about 12000kg to that orbit (reusable). 48 @ 250kg each would be a reasonable estimate. Provideing the volume is within the volume of th shroud.

NASA's LSP calculator gives performance of
14460 kg
for "Falcon 9 Full Thrust" with ASDS
at 400 km circular orbit with 51.6° inclination.

Of this performance I'd reserve about ~1400 kg for dispenser, which leaves us with slightly better total payload mass:
~13000 kg.
At ~380kg that is at most 36.

Reason for using the 380 value which is the planned mass is that this dispenser design would be common with launching the full weight sats even assuming these first ones are lighter.
« Last Edit: 05/10/2019 07:18 am by oldAtlas_Eguy »

Online vaporcobra

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Based on max of about 12000kg to that orbit (reusable). 48 @ 250kg each would be a reasonable estimate. Provideing the volume is within the volume of th shroud.

NASA's LSP calculator gives performance of
14460 kg
for "Falcon 9 Full Thrust" with ASDS
at 400 km circular orbit with 51.6° inclination.

Of this performance I'd reserve about ~1400 kg for dispenser, which leaves us with slightly better total payload mass:
~13000 kg.
At ~380kg that is at most 36.

Reason for using the 380 value which is the planned mass is that this dispenser design would be common with launching the full weight sats even assuming these first ones are lighter.

Even these second stage prototypes are far lighter than Tintin A/B ("~400 kg"). All I can say is that if your math ends with ~30 satellites, your mass estimate is far too conservative.

Offline smoliarm

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...

At ~380kg that is at most 36.

Reason for using the 380 value which is the planned mass is that this dispenser design would be common with launching the full weight sats even assuming these first ones are lighter.

- exactly.

I assume one of the objectives of this launch is validation of the new dispenser (which will be standard for Starlink launched with Falcons), as well as deployment pattern and software.
It seems Gwynne's quote
Quote
This next batch of satellites will really be a demonstration set for us to see the deployment scheme and start putting our network together,
goes along with this assumption.

So, IF they indeed have this objective THAN they have to use THE SAME (the standard) dispenser AND the SAME (or close) mass of individual satellite - as for the "fully operational" batches.

Offline thxbmp3

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Details emerge about upcoming Starlink launch

TMF Associates blog
Satellites, spectrum and other stuff  05.09.19

http://tmfassociates.com/blog/2019/05/09/backing-winners/

It's worth noting that Tim's article - infamous FUD-ing aside - has the following nugget of insider info:

Quote from: TMF Associates
... SpaceX plans to launch “dozens of satellites” (perhaps as many as 40-50 from what I’ve heard in Washington DC this week)...

That'd be a little more than half the 75-unit test constellation, so I wonder if we might even see a mix of test and operational sats on the second launch - assuming they need to fully load the dispenser every time.

Offline Semmel

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I wouldnt be surprised to see all 75 sats being launched at the first try. They probably have the payload adapter design changed because its internal and they can integrate the adapter with the dispenser. So there are some mass savings there. Totally different load structure, no mass for the mechanisms, etc. 75 is conveniently 25*3 or 15*5. Nice options for a number of dispenser designs. Lets wait and see though.

Offline russianhalo117

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I wouldnt be surprised to see all 75 sats being launched at the first try. They probably have the payload adapter design changed because its internal and they can integrate the adapter with the dispenser. So there are some mass savings there. Totally different load structure, no mass for the mechanisms, etc. 75 is conveniently 25*3 or 15*5. Nice options for a number of dispenser designs. Lets wait and see though.
PLF length comes into play. 25×3 matches the 3 scheduled flights stated on the manifest probably one launch per IOC plane. 3 2019 launches is possible because they will launch in schedule gaps between external paying customers.

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