Comment by schiffern | Hacker News Reader

Comment by schiffern | Hacker News Reader

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Those links don't say what you claim they say. Big red flag alert!

Your first link is ancient (September 2020) so it doesn't reflect any of the latest-and-greatest brightness mitigations. The study just looked at VisorSat, and SpaceX never claimed VisorSat "fixed" the issue completely.

Your second link has nothing to do with visible light reflections, and is actually about the same RF emissions as the current article (emissions which SpaceX is already in the process of mitigating[0] btw).

You're not even lying with statistics here. You're just lying with.... lying. :-\

  >SpaceX knew their satellites would cause issues

Citation needed. I'm also 100% sure you can't provide one.

All the reports from SpaceX and from the astronomical community alike both say the impact was surprising and unexpected. Do you have a (reliable, documented, and critically non-misrepresented) source that says otherwise? No?

[0] https://news.ycombinator.com/item?id=38863424

I'm totally fine believing SpaceX/Starlink did not expect it, the astronomical community on the other hand as far as I'm aware expected this and has been raising issues with SpaceX/Starlink the whole time (source: am an astronomer). As for things getting significantly better, that'd be news for me as well (https://arxiv.org/pdf/2309.14152.pdf seems to be the latest review I found on the issue, with Post-VisorSat being worse than VisorSat, and worries about Gen 2 sats).

The astronomical community, in fact, did not expect it. (Go ahead and do an internet search before the first large Starlink batch was deployed... there was no outcry; in fact, there's a public comment period for such things, and if there HAD been concerns, they would've been raised there, but they were not. After the first launch, it was a shock to the astronomy community... And SpaceX was also surprised.) The astronomical community was just as surprised as SpaceX. SpaceX acted remarkably quickly in inventing several different brightness mitigations and deploying them within months.

As far as your claim that the latest sats, are worse, that contradicts what your link says in the abstract: "The first of these [new V2 satellites], called Minis, are dimmer than Gen 1 Starlinks despite their greater size. Photometric observations verify that brightness mitigation efforts employed by SpaceX reduce spacecraft luminosity substantially"

> the astronomical community on the other hand as far as I'm aware expected this

Huh I didn't realize that. Do you have a source handy?

I couldn't find it in my brief literature search.[0] I found a couple references to Starlink brightness from 2019, but they're all after the first operational launch.

> https://arxiv.org/pdf/2309.14152.pdf seems to be the latest review I found on the issue, with Post-VisorSat being worse than VisorSat

Yes SpaceX needed to delete the visors to add laser hardware, so they developed a novel space-rated dielectric mirror as the new mitigation method. That was their first generation mirror, with the current second-gen mirror having better optical performance. As far as I know they haven't been characterized yet.

Iterative development takes time, it's true. It also takes money, which is why Starlink competitors are investing essentially zero resources in dark sky stewardship and R&D. Why bother? They know skywatchers will call anything and everything Starlink, so Bad Billionaire will soak up the blame regardless of who really caused it.

The competitors are astronomy's real 'enemy at the gate,' but most folks are too distracted by the shiny Elon Musk bouble to notice.

[0] for example https://scholar.google.com/scholar?q=megaconstellations+brig... and https://scholar.google.com/scholar?q=starlink+brightness&as_...

https://ui.adsabs.harvard.edu/ works much better for astronomy than google scholar, my search query was "starlink" and limited to astronomy papers.

My research is theory (not directly affected), so most of my background on this has come from grumblings over beers and the occasional talk (so I'm not really in the loop). Satellites (and other forms of interference such as RFI) have always been a problem for some groups (basically, anyone with long exposures, wide exposures or working with faint sources, it all comes down to the probability of a satellite appearing in the field of view mixed with how bad that is), but it's the massive increase in numbers plus the move over the last ~10 years to looking for transients (LSST is the poster child here, but there are lots of others) that have made it a more community-wide issue.

Other groups have been mentioned (I recall Amazon being mentioned), but the "focusing on Starlink" thing might be a reflection of what pop-science reports, and what's actually able to be measured being published.

Par for the course, unfortunately.

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