SpaceX F9 : Starlink v0.9 : May 23, 2019 - DISCUSSION

[gongora]

The list of possible conjuctions for Starlink at Celestrak is kind of interesting, they can come close to all sorts of different sats and pieces of debris.  Any automation they can do to help sort out those situations will definitely be a plus, especially when they have hundreds or thousands of Starlink sats to keep track of.

[Danderman]

The highest is showing as 577x558km now, only six of them are below 500x500 (including the 3-4 misbehaving ones that might not raise their orbits).  The one lowering its orbit is down to 418x412.

The question is whether the ones that are not raising their orbit are precessing to a different orbital plane.

[gongora]

The highest is showing as 577x558km now, only six of them are below 500x500 (including the 3-4 misbehaving ones that might not raise their orbits).  The one lowering its orbit is down to 418x412.

The question is whether the ones that are not raising their orbit are precessing to a different orbital plane.

Iridium holds spares in an orbit a little below the active sats, and they don't just go zooming off to different planes.

[ThomasGadd]

The highest is showing as 577x558km now, only six of them are below 500x500 (including the 3-4 misbehaving ones that might not raise their orbits).  The one lowering its orbit is down to 418x412.

The question is whether the ones that are not raising their orbit are precessing to a different orbital plane.

Iridium holds spares in an orbit a little below the active sats, and they don't just go zooming off to different planes.

They want multiples of 11 to populate the planes there should be plenty for spares...

Edit: For future launches.

[gongora]

If you go to celestrak.com, choose to "Search the SatCat", and put in 2019-029 for the designator, you get the list of sats from the first Starlink launch.  If you hit the globe symbol in the first column, you get to this Starlink Launch 1 Orbit Visualization.  They don't seem to be spreading into different planes right now.  (One sat that is still in the same orbit as the debris objects is separating a little from the pack.)

[PM3]

https://twitter.com/TSKelso/status/1141906661499711491

[2megs]

...If 18 SPCS doesn’t know where they are for the past 5-14 days, satellite operators in this orbital regime probably don’t, either...

I imagine that if you didn't know where Starlink sats were, your ground station wouldn't be able to aim beams at them. And so I expect that finding and tracking them had to be designed as an inherent part of the system, and SpaceX knows exactly where they are.

(Also, which is it now? They're so hard to find that they're dangerously lost, or they're so glaringly obvious that astronomy is ruined forever? Naysayers can't have it both ways.)

[Vettedrmr]

Naysayers can't have it both ways.

Oh, of course they can!     Logic is usually a VERY small player in their complaints.

Have a good one,
Mike

[envy887]

...If 18 SPCS doesn’t know where they are for the past 5-14 days, satellite operators in this orbital regime probably don’t, either...

I imagine that if you didn't know where Starlink sats were, your ground station wouldn't be able to aim beams at them. And so I expect that finding and tracking them had to be designed as an inherent part of the system, and SpaceX knows exactly where they are.

(Also, which is it now? They're so hard to find that they're dangerously lost, or they're so glaringly obvious that astronomy is ruined forever? Naysayers can't have it both ways.)

Kelso's point is that unless SpaceX is sharing that orbital information with other satellite operators, the fact that SpaceX knows where they are doesn't help that much. SpaceX can use their information to make orbital maneuvers, but the other operators are relying on the published TLEs and cannot do the same.

[abaddon]

(Also, which is it now? They're so hard to find that they're dangerously lost, or they're so glaringly obvious that astronomy is ruined forever? Naysayers can't have it both ways.)

"Naysayers" aren't always the same people.  If this individual complained about them being too visible, fine.  But ascribing different concerns from different groups or individuals to a single group, so you can then complain about them being inconsistent, isn't really helpful either.

[NosFi]

I guess tracking will become easier once the satellites are in a stable operation orbit...

[Lar]

(Also, which is it now? They're so hard to find that they're dangerously lost, or they're so glaringly obvious that astronomy is ruined forever? Naysayers can't have it both ways.)

Both at once is perfectly possible... If the tracking data isn't being updated (and that could be a SpaceX issue or something along the pathway to the data display, it's not necessarily SpaceX's fault) then they are "lost" to other operators, and to astronomers, so they can't be planned around (collision avoidance and image avoidance, respectively), and I would think not being able to predict when to shut off imaging is a big impact as you have to do it in post processing...

Kelso's point is that unless SpaceX is sharing that orbital information with other satellite operators, the fact that SpaceX knows where they are doesn't help that much. SpaceX can use their information to make orbital maneuvers, but the other operators are relying on the published TLEs and cannot do the same.

Without knowing WHY the updates aren't getting to the website, this is concern trolling, really. The blame may or may not be with SpaceX

[mn]

Perhaps someone can shed more light on how SPCS tracks things.

Is it solely from their own equipment (radar, whatever?)

Or do they request and/or receive info from satellite operators?

Does this mean their radar is somehow not picking up the starlink satellites? or are they not getting info from SpaceX that they normally would from other operators?

Is it fully automatic or could it be simply that a human has to view the raw data and apply it and they need more 'bandwidth' to handle more objects?

Anyone have any ideas on how this works?

[meekGee]

(Also, which is it now? They're so hard to find that they're dangerously lost, or they're so glaringly obvious that astronomy is ruined forever? Naysayers can't have it both ways.)

Both at once is perfectly possible... If the tracking data isn't being updated (and that could be a SpaceX issue or something along the pathway to the data display, it's not necessarily SpaceX's fault) then they are "lost" to other operators, and to astronomers, so they can't be planned around (collision avoidance and image avoidance, respectively), and I would think not being able to predict when to shut off imaging is a big impact as you have to do it in post processing...

Kelso's point is that unless SpaceX is sharing that orbital information with other satellite operators, the fact that SpaceX knows where they are doesn't help that much. SpaceX can use their information to make orbital maneuvers, but the other operators are relying on the published TLEs and cannot do the same.

Without knowing WHY the updates aren't getting to the website, this is concern trolling, really. The blame may or may not be with SpaceX

When deployed, satellites are about 60 degrees apart in most of the sky (except very near the horizon where you can see more).  And usually they are as dark as you are.  This can't be a serious issue for imaging - and satellites (in higher orbits, where they are lit longer) have been around before Starlink.

As for collisions, yes - as far as operators who have satellites in the same altitudes, yes - information should be shared.

[rsdavis9]

Is there any difference in RAAN?
Are all in the same plane or are they trying to put some in a slightly different plane to test that condition?

[Okie_Steve]

I hope the three that stopped communicating phoned home with useful telemetry about what was failing before going silent. I wonder if it was some common failure mode on something like a reaction wheel or three different random issues.

[lonestriker]

I hope the three that stopped communicating phoned home with useful telemetry about what was failing before going silent. I wonder if it was some common failure mode on something like a reaction wheel or three different random issues.

I had forgotten that SpaceX made slight variations in the satellites to test different configurations.  Hopefully, even if they didn't get telemetry pointing to the failures, just knowing which satellites failed and differences between the three dead ones vs. the rest informs their future builds.

[ThatOldJanxSpirit]

Is there any difference in RAAN?
Are all in the same plane or are they trying to put some in a slightly different plane to test that condition?

They are all at 53 degrees plus or minus a very small amount.

[GWR64]

Is there any difference in RAAN?
Are all in the same plane or are they trying to put some in a slightly different plane to test that condition?

Celestrak has an extra page for Starlink.

https://www.celestrak.com/NORAD/elements/starlink.txt

There are RAAN differences.
How big is the difference by the "Nodal precession" between the 350 km and the 550 km orbit?

Edit:
hmm,
The different age of the TLE makes it difficult.
I can only compare satellites with current data.
But there are RAAN differences as well.

[rsdavis9]

Is there any difference in RAAN?
Are all in the same plane or are they trying to put some in a slightly different plane to test that condition?

Celestrak has an extra page for Starlink.

https://www.celestrak.com/NORAD/elements/starlink.txt

There are RAAN differences.
How big is the difference by the "Nodal precession" between the 350 km and the 550 km orbit?

Edit:
hmm,
The different age of the TLE makes it difficult.
I can only compare satellites with current data.
But there are RAAN differences as well.

so about 10-14 degs for the RAAN.
one 18 and another 31.

So is the spread intentional?
Would allow some cross plane testing.
I assume I am reading it correctly. 2nd line 3rd field from the left.