SpaceX Manifest Discussion Thread

[kevin-rf]

Or a rideshare with 24 or so satellites...

Curious how many they could lift with a RTLS mission.

[vaporcobra]

Or a rideshare with 24 or so satellites...

Curious how many they could lift with a RTLS mission.

Starlink Gen1 Group 1 is missing about 80 satellites and is in a near-identical orbit to Group 4, so one other possibility is that SpaceX finishes Group 4 and launches ~30 Group 1 replacements on one mission.

[Chinakpradhan]

Or a rideshare with 24 or so satellites...

Curious how many they could lift with a RTLS mission.

Starlink Gen1 Group 1 is missing about 80 satellites and is in a near-identical orbit to Group 4, so one other possibility is that SpaceX finishes Group 4 and launches ~30 Group 1 replacements on one mission.

how much delta v is required for 2nd stage to like say first deploy some shell one sats in 53° orbit then burn and deploy group 4 says that is in 53.2° orbit.

[Steven Pietrobon]

how much delta v is required for 2nd stage to like say first deploy some shell one sats in 53° orbit then burn and deploy group 4 says that is in 53.2° orbit.

7585*2*sin(0.2/2) = 26.5 m/s.

[Chinakpradhan]

how much delta v is required for 2nd stage to like say first deploy some shell one sats in 53° orbit then burn and deploy group 4 says that is in 53.2° orbit.

7585*2*sin(0.2/2) = 26.5 m/s.

oh so it looks achievable to launch them in a combo just need 2 different Starlink tension rods

[AmigaClone]

Or a rideshare with 24 or so satellites...

Curious how many they could lift with a RTLS mission.

Starlink Gen1 Group 1 is missing about 80 satellites and is in a near-identical orbit to Group 4, so one other possibility is that SpaceX finishes Group 4 and launches ~30 Group 1 replacements on one mission.

Two questions:

1) What is the maximum number of Starlink v1.x satellites that would allow for an RTLS landing of the first stage booster?

2) Could SpaceX launch some 'in-orbit spares'?

[Chinakpradhan]

Or a rideshare with 24 or so satellites...

Curious how many they could lift with a RTLS mission.

Starlink Gen1 Group 1 is missing about 80 satellites and is in a near-identical orbit to Group 4, so one other possibility is that SpaceX finishes Group 4 and launches ~30 Group 1 replacements on one mission.

Two questions:

1) What is the maximum number of Starlink v1.x satellites that would allow for an RTLS landing of the first stage booster?

2) Could SpaceX launch some 'in-orbit spares'?

i think on orbit spares for gen1 group 1 are already launched as more than 1700 are launched in a 1584 sat group1 constellation

[vaporcobra]

how much delta v is required for 2nd stage to like say first deploy some shell one sats in 53° orbit then burn and deploy group 4 says that is in 53.2° orbit.

7585*2*sin(0.2/2) = 26.5 m/s.

oh so it looks achievable to launch them in a combo just need 2 different Starlink tension rods

To the contrary and as I suspected, the cost (26.5 m/s) is low enough that the satellites could almost certainly do the plane change themselves as part of orbit-raising. Might raise the total delta V cost by like 10-25%, which is likely easily doable for a LEO spacecraft designed to maintain its orbit for 5+ years.

[OceanCat]

2) Could SpaceX launch some 'in-orbit spares'?

They launched hundreds of in-orbit spares. See the orbital charts on https://starlink.sx/ Almost all yellow satellites are in-orbit spares. The chart has accuracy issues (none of the in-orbit spares are actually out of their planes) but overall the chart is ok. It shows for example there is only a dozen of gaps in shell 1.

Shell 4 has odd planes that have way more spares than other planes. The forth plane on the left has 10(!) spares. Maybe they are no longer spares but actually work in pairs together the blue underperforming satellites in the "regular" slots.

[kevin-rf]

i think on orbit spares for gen1 group 1 are already launched as more than 1700 are launched in a 1584 sat group1 constellation

Shell 1, 1727 launched, 1510 still in orbit, 1448 considered operational with 62 decaying or actively being disposed of.

For Shell 1, (including spares) that leaves SpaceX 136 satellites short of the planned 1584 satellites.

See: https://planet4589.org/space/con/star/stats.html

[Barley]

how much delta v is required for 2nd stage to like say first deploy some shell one sats in 53° orbit then burn and deploy group 4 says that is in 53.2° orbit.

7585*2*sin(0.2/2) = 26.5 m/s.

oh so it looks achievable to launch them in a combo just need 2 different Starlink tension rods

To the contrary and as I suspected, the cost (26.5 m/s) is low enough that the satellites could almost certainly do the plane change themselves as part of orbit-raising. Might raise the total delta V cost by like 10-25%, which is likely easily doable for a LEO spacecraft designed to maintain its orbit for 5+ years.

Right Idea, but it's even lower.
During the orbit raise you apply about 90 m/s along the trajectory and about 26 m/s orthogonally.  Do vector addition and use Pythagoras and the extra delta-V for the orbit change is less than 4 m/s.  If you split the difference and require all satellites to do a 0.1 degree inclination change its less than 1 m/s.

Not sure how many months of station keeping 4 m/s is.  There's no reason to be sloppy and spend it if you don't have to, but it's not a lot and there's no reason to be afraid of it.  If you're filling holes either from failures or because number of satellites in a plane size is not an integer multiple of satellites in a launch it's probably attractive to treat both planes as a unit.

Drifting between planes with the same inclination has its own cost, both time and fuel to counter drag in the lower orbit.  Two orbits with slightly different inclinations but the same RAAN may be closer together than two orbits with the same inclination but different RAAN.

From a launch perspective these two planes are effectively the same, you can release a whole batch at once and move them individually to either or both planes.

[Barley]

They launched hundreds of in-orbit spares. See the orbital charts on https://starlink.sx/ Almost all yellow satellites are in-orbit spares. The chart has accuracy issues (none of the in-orbit spares are actually out of their planes) but overall the chart is ok. It shows for example there is only a dozen of gaps in shell 1.

Shell 4 has odd planes that have way more spares than other planes. The forth plane on the left has 10(!) spares. Maybe they are no longer spares but actually work in pairs together the blue underperforming satellites in the "regular" slots.

I'm puzzled by this discussion of in orbit spares.

There are two ways to have spares.  One is to have non-operating spares that can be installed after a failure.  The second is to have excess capacity installed and in use at all times.

For starlink I can see no operational reason to keep satellites on orbit but not operating.  There could be some special license condition, but it would have to be a pretty silly condition to kick in before the entire constellation is complete.  It seems strange that you can distinguish "spares" from satellites not yet in operation but moving as fast as they can towards the next available spot.

[OceanCat]

They launched hundreds of in-orbit spares. See the orbital charts on https://starlink.sx/ Almost all yellow satellites are in-orbit spares. The chart has accuracy issues (none of the in-orbit spares are actually out of their planes) but overall the chart is ok. It shows for example there is only a dozen of gaps in shell 1.

Shell 4 has odd planes that have way more spares than other planes. The forth plane on the left has 10(!) spares. Maybe they are no longer spares but actually work in pairs together the blue underperforming satellites in the "regular" slots.

I'm puzzled by this discussion of in orbit spares.

There are two ways to have spares.  One is to have non-operating spares that can be installed after a failure.  The second is to have excess capacity installed and in use at all times.

For starlink I can see no operational reason to keep satellites on orbit but not operating.  There could be some special license condition, but it would have to be a pretty silly condition to kick in before the entire constellation is complete.  It seems strange that you can distinguish "spares" from satellites not yet in operation but moving as fast as they can towards the next available spot.

True, they are likely operational all the time. But you can clearly see each plane has 18 main evenly distributed slots. Extra satellites are placed inconsistently between them. Especially in shell 1 (the bottom image). While the extras can be used to boost capacity temporary over the areas they pass they do not provide consistent 24/7 capacity boost. Starlink cannot use them to sign up more customers. The excess capacity is not sellable.

[Barley]

They launched hundreds of in-orbit spares. See the orbital charts on https://starlink.sx/ Almost all yellow satellites are in-orbit spares. The chart has accuracy issues (none of the in-orbit spares are actually out of their planes) but overall the chart is ok. It shows for example there is only a dozen of gaps in shell 1.

Shell 4 has odd planes that have way more spares than other planes. The forth plane on the left has 10(!) spares. Maybe they are no longer spares but actually work in pairs together the blue underperforming satellites in the "regular" slots.

I'm puzzled by this discussion of in orbit spares.

There are two ways to have spares.  One is to have non-operating spares that can be installed after a failure.  The second is to have excess capacity installed and in use at all times.

For starlink I can see no operational reason to keep satellites on orbit but not operating.  There could be some special license condition, but it would have to be a pretty silly condition to kick in before the entire constellation is complete.  It seems strange that you can distinguish "spares" from satellites not yet in operation but moving as fast as they can towards the next available spot.

True, they are likely operational all the time. But you can clearly see each plane has 18 main evenly distributed slots. Extra satellites are placed inconsistently between them. Especially in shell 1 (the bottom image). While the extras can be used to boost capacity temporary over the areas they pass they do not provide consistent 24/7 capacity boost. Starlink cannot use them to sign up more customers. The excess capacity is not sellable.

Domestic customers are usually massively oversubscribed.  Supply meeting demand is statistical.  You absolutely can sell capacity that turns up occasionally.  Alternatively, you can let it show up as slightly improved reliability or throughput, which also adds value.

[wannamoonbase]

The Shell 5 flights are going to come and go pretty quickly.

With 43 birds in 4 shells and a total of 172 less than 4 full flights are required.

2023 is going to be fill out the phase 1 shells.

[cpushack]

What are the odds of a VSFB launch somewhere between February 16th and March 1st?

My wife to be wants to see a rocket launch and we shall be on Honeymoon at Lompoc then

[Alexphysics]

Given that they're aiming for 30 launches from Vandenberg this year I'd say the chances are rather high

[wannamoonbase]

Given that they're aiming for 30 launches from Vandenberg this year I'd say the chances are rather high

I would love to see 30 VSFB launches a year, but I'll believe it when I see it.  They have long promised a higher west coast flight rate and we have yet to see it.

[Alexphysics]

Given that they're aiming for 30 launches from Vandenberg this year I'd say the chances are rather high

I would love to see 30 VSFB launches a year, but I'll believe it when I see it.  They have long promised a higher west coast flight rate and we have yet to see it.

Part of the problem for that has always been that Vandy didn't have enough demand but through Starlink they're creating their own demand. They can launch almost every Starlink launch from Vandenberg as well as Florida so being able to shift the load to Vandenberg allows them to launch more and they've upgraded the pad, teams and fleets (booster and droneship) to do just that. Already this year they saw a record of 12 launches with another coming up next week for a total of 13. Previous record of launches from Vandenberg by SpaceX was 6 launches in 2018 and they've shown they can turnaround the pad in as little as 11 days. I don't think they'll do 30 but I'd be surprised if they don't at least go over 20 launches from Vandenberg this year given all of that.

[virtuallynathan]

The Shell 5 flights are going to come and go pretty quickly.

With 43 birds in 4 shells and a total of 172 less than 4 full flights are required.

2023 is going to be fill out the phase 1 shells.

The ASDS positions don't support a 97.6 degree inclined orbit... The position is almost the same as Starlink 4-7: https://twitter.com/Raul74Cz/status/1486374280380174338