
Astronomy group calls for urgent action on SpaceX Starlink satellites - hef19898
https://www.newscientist.com/article/2205172-astronomy-group-calls-for-urgent-action-on-spacex-starlink-satellites/
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gpm
The satellites are hard to spot already, the satellites still haven't been
fully risen to their orbits, the solar arrays presumably aren't yet tracking
the sun because they need to be oriented to point the engine in the right
direction. Any complaints about this constellation seem either late
(completely hypothetical and should been raised years ago when approval was
sought from the FCC) or early (based on real world data that doesn't yet
exist).

The article is substantially more sensational than the IAU letter is is based
on:

[https://www.iau.org/news/announcements/detail/ann19035/](https://www.iau.org/news/announcements/detail/ann19035/)

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privong
> The satellites are hard to spot already,

To the naked eye, perhaps. But large telescopes and their instruments are
incredibly sensitive. So even if the satellite constellations are minimally
visible to the naked eye they can still have a substantial impact on science.

Additionally, these satellites are likely to be very bright in the radio
portion of the spectrum (due to their uplink/downlink), which could negatively
affect radio telescopes.

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Robotbeat
Satellite track removal is already a well-understood capability that serious
telescope projects already do.

Satellite radio emissions are well-regulated already, and appropriate measures
are in place well before the launch is even approved.

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tntn
Why didn't the IAU petition the FCC during the comment period for SpaceX's
application? Seems sorta weird to wait for the first launch to express
concerns when the application was submitted to the FCC many months ago (and I
think I recall an earlier version years ago).

(Or if they did, could someone provide the link? I'm not able to find it.)

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trickstra
That's like a trade off between 0.000001% chance that the satellite would
block some interesting important unique event, against 100% chance of stopping
the worldwide satellite internet network and potentially the SpaceX Mars
funding

I'm calling for urgent action on astronomy groups.

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Obi_Juan_Kenobi
So, realistically, it's going to mean that ground-based telescopes become less
productive. Some won't be affected much at all (narrow FoV), while others may
have to fundamentally shift how they operate (wide FoV). More exposures will
need to be made to overwrite any satellites that pass through the field. This
is already done due to existing satellites, so it's simply a question of
rates.

The radio astronomy issue is potentially more significant, but then I don't
understand why these issues weren't raised when the spectrum was being
allocated.

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trickstra
> why these issues weren't raised when the spectrum was being allocated

Because they are bogus. This is riding on a wave of populism, at a time when
journalists woke up to an "Elon's train" and twitter was buzzing with many
people who saw a satellite with their naked eye for their first time.

Actual professional astronomers would either realize this is not such a big
problem, or would raise the issues during the spectrum allocation, or would
raise issues during the whole time SpaceX was showing animations of the
finished constellation to all their fans etc etc... there was a lot of time,
no way somebody whose project depended on free skies wouldn't be prepared.

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notus
What is more useful, satellites or astronomers being able to view the stars
clearly from the planets surface. Genuine question, but it seems to me that in
the long run satellites would win out.

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kitd
Well, in the _really_ long run, a clear view of potential celestial
destinations may be paramount :)

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lazyjones
Orbital telescopes are much better suited for this.

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rtkwe
They're also much much more expensive and less flexible. With earth based
satellites new experiments with new instrumentation is easy, in space
currently we have no way to fix any issues.

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thecount122195
We can and have fixed space telescopes before, probably the most famous
example is Hubble and its poor sight.
[https://en.wikipedia.org/wiki/Hubble_Space_Telescope#Flawed_...](https://en.wikipedia.org/wiki/Hubble_Space_Telescope#Flawed_mirror)

~~~
kuschku
So which space shuttle should we use to fix James Webb if anything would go
wrong after the launch?

Currently no country has a well-working solution for that, nor does any
company (not even SpaceX themselves)

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mdorazio
Your comment assumes we still _need_ fleshy meatbags wearing clunky suits in
orbit to fix things. This was true 15 years ago, but I'm not convinced it's
still true today. A couple of repair drones housed at the ISS combined with
repair parts brought up along with normal resupply missions could probably be
made to work if it was deemed cost effective.

~~~
rtkwe
The ISS isn't in a particularly good orbit because it's highly inclined (so
Russia could easily launch to it) which is an expensive issue to fix dV wise
unless all the target satellites are in a similarly inclined orbit. In terms
of making them easy to swap out that's certainly possible but it will add
weight compared to a monolithic satellite and so far we have very very little
experience building and repairing things in space without using people.

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w8vY7ER
While I share the community's concern for preserving the dark skies wherever
possible, is it not premature considering _none_ of the 60 satellites launched
have yet to reach their destination altitude?

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gnode
Why would this be significant? The separation altitude in the launch was
around 450km, according to the numbers in the livestream. The orbital shell
being targeted is 550km. This doesn't constitute a large difference in
visibility.

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gpm
Since it likely also affects satellite orientation and possibly configuration.
Also since brightness obeys a square law so they should ignoring effects other
than distance be 1.5 times their final level still.

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gnode
A factor of 1.5 doesn't strike me as being enough to suggest the problem will
go away (the satellites become too small a part of images to matter).
Additionally, the satellites are not two-dimensional, so there is no
orientation in which they would not occlude the view.

It appears that the objections are not to the size of the satellites (they are
relatively small compared to other satellites in LEO), but that they are to be
highly numerous. The planned size of the constellation is 11927 satellites.

The frequency with which these satellites photobomb astronomical images is the
concern, rather than how much area they affect. In fact, their being smaller
makes them more of a menace, as they will be more challenging to spot, or
easier to confuse with an astronomical entity.

This said, I don't think this is a strong argument against putting such
satellites in orbit, and progress will and should continue. Astronomers will
have to be careful to avoid contamination.

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w8vY7ER
For my part, I wouldn't put it past the minds that land orbital class, first
stage rockets on the regular to come up with something that surprises us. Not
suggesting that's a meaningful strategy for ensuring dark skies, just pointing
out they've surprised us more than once!

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m0llusk
Tragic, and yet the future of astronomy is clearly with extraterrestrial
observation platforms.

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nsilvestri
We only really need to send telescopes to space for observing the wavelengths
that are otherwise absorbed by the atmosphere. Adaptive optics are almost
unbelievably effective at cutting out the interference that the Hubble
telescope is practically obsolete (and indeed obsolete, since it will be de-
orbited soon).

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garmaine
Hubble is never going to be deorbited...

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monocasa
What makes you say that? It's already decaying.

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garmaine
N/m Hubble’s orbit is less than I thought it was.

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ldoughty
Would it be a difficult challenge to develop a imaging process that ignores
such fast movements of a object?

Musk said they would try to avoid impact, making such an software product and
releasing it for free would be a great step in that direction. I imagine,
also, that good night shots are long exposures or multiple long exposures.

~~~
Robotbeat
Satellite tracks are already super common and are already algorithmically
removed from long exposures (not hard when you're compositing from a stack of
images).

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isostatic
Last night (1900GMT), I’m sure we saw a Dragon capsule a few degrees ahead of
the ISS as it went overhead. That’s with the naked eye.

Anyone know what the apparent magnitude of ISS, Dragon, and Star Link would
be?

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Robotbeat
ISS is approximately the same magnitude as the entire SpaceX megaconstellation
combined. At its peak, ISS is brighter than Venus and brighter than 20,000
Starlink-sized satellites.

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SkyBelow
It is my guess that the majority of those who raise concerns already have
communication access, specifically high speed internet access, provided by
other means. I would further guess that they are considering the cost to
themselves and not the gains to others. Would they be willing to pay the price
to provide internet access by other means to those who would be served by
these satellites, or are they hoping that those who don't have it will
continue to be able to do without?

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kire456
Let me pose this unfair question back at you. Are you willing to pay the price
for providing an alternate means of sky observation at a scale suitable for
astronomy, and for cleaning up the debris that might result from expiration
of, or collisions between, tens of thousands of commercial satellites?

You are implying that launching many commercial (American) satellites is the
best, or even a good, solution to the problem of many people not having what
you consider adequate internet. Moreover, apparently this problem is so urgent
and the solution so perfect that you feel the need to chastise these
scientists for even expressing concern. I don't think you are approaching this
discussion in a fair manner.

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Ajedi32
> and for cleaning up the debris that might result from expiration of, or
> collisions between, tens of thousands of commercial satellites

FWIW, at the altitudes Starlink operates at, that completely hypothetical
scenario would only take a few years to remedy, and would cost $0 as the
debris naturally de-orbits due to atmospheric drag.

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carapace
The almost-poetic irony of blinding ourselves to the outer world to better
navel-gaze our digital nirvana.

(To the astronomy-haters on the thread: Y'all realize we can have connectivity
_and_ clear skies, right? There's no intrinsic trade-off here.)

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whatshisface
Why not paint the satellites black on the bottom?

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kijin
I'm not sure which is worse, a shiny satellite that screams where it is (so
you can avoid it) or a dark satellite that silently blocks a patch of the sky.

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Robotbeat
By far the shiny satellite is worse. Besides, the satellites are tracked
carefully by multiple parties, so any serious astronomical observation that
could even theoretically be sensitive to a sub-millisecond obscuration of a
~microradian portion of the sky (such as certain exoplanet searches) would be
well aware of this ahead of time (and atmospheric aberration would be a _far_
greater effect). A dark satellite is effectively irrelevant to optical ground
astronomy.

