Re: [Starlink] "Interesting set of developments with Starlink. Musk says they will support "international aid orgs" in Gaza, Israel now says they will use "all available means" to stop SpaceX from doing so.

[Alexandre Petrescu <alexandre.petrescu@gmail.com>]

Le 13/11/2023 à 17:03, David Lang a écrit :
> On Mon, 13 Nov 2023, Alexandre Petrescu via Starlink wrote:
>
>> It has a Donate button, which seems to make it a site built by an 
>> independent end user.  It is a great tool already!   With respect to 
>> the starlink sats positions: celestrak might simply reflect an 
>> original data which is made by space-track.org which is a US 
>> authority.  Or maybe not, they dont say it.  I dont know.
>>
>> My question is how is the original data on space-track.org (or other 
>> original source of sat position data) created: do they range the sats 
>> (i.e. point lasers at them and wait for replies, radar, or similar) 
>> or do the sats transmit their positions on a voluntary and 
>> cooperative basis?
>
> It is in the interests of every country to avoid having satellties hit 
> each other, which requires that everyone have accurate information on 
> where existing satellites are. The US space command (or whatever their 
> name is under the USSF now) tracks everything in orbit that they can 
> (I thinkit's everything above ~10cm)

Fair enough, I agree with both statements.  But certainly they're not 
the only ones to track for the benefit of all, it is not the only 
publicly available original tracking data.  Ideally, one would have a 
single trackign authority and the tracking method - not only the 
tracking data - would be documented publicly.


>
> companies coordinate with each other when they need to move satellites 
> so that you don't have two satellites trying to avoid a collision both 
> move in a way that make the collision more likely to happen.
>
> There's even an International agreement (going back to the cold war 
> between the US and USSR) that requires satellite launcher telemetry to 
> be unencrypted so that everyone can monitor it.
Thanks, I'll have to  look that up.  I think I've seen publicly 
available tracking data of launchers of all sorts, but I'll have to dig 
it up again from the Internet.
>
> so the orbits of everything (including spy satellites) is well known 
> and not some deep secret.
Sure.  But plans are one thing and the implementation might be different.
>
>> Another question is about which starlink sats are 'in-service' and 
>> deliver service, and which not?  It is not only a matter of 
>> altitude.  The current websites telling 'in-service' or similar 
>> attributes, do not seem to be related to starlink, and do not seem to 
>> take that data from DISHYs.  They seem to be simply telling that if 
>> it is at a 550km altitude then they're in service.
>
> What would be the value in having a satellite in the proper orbit, 
> using a orbital slot, but not in use? unless the satellite electronics 
> have failed, they would use it (electronics do not wear out from use)

I agree with the question.  It makes sense.

But what is a 'proper' orbit, what altitude? Is one  sure that a 
starlink sat at 350km altitude for several weeks, if not months, is 
_not_ in service?  Maybe I'll have to go look at the ITU and FCC orbit 
altitude reservations for starlink, because probably that is the only 
data available.

Alex

>
> David Lang