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
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