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Re:SpaceX tests black satellite to reduce ‘megaconstellation... by shadowgovt on Thursday January 16, 2020 @01:39PM (#22067469)
Can adaptive optics be applied to filter out objects like Starlink satellites?
Re:SpaceX tests black satellite to reduce ‘megaconstellation... by Rebelgecko on Thursday January 16, 2020 @01:48PM (#22067585)
Don't think so. Adaptive optics works by changing the physical shape of the mirror. If you measure the atmosphere continuously and bend the mirror the right way, you can remove atmospheric distortion from the image. If anything, AO just gets you sharper images of the starlink satellites (or significantly worse ones if a satellite flies in front of the guidestar that you're using as a reference point to measure atmospheric distortions).
Re:SpaceX tests black satellite to reduce ‘megaconstellation... by toomuchtodo on Thursday January 16, 2020 @01:43PM (#22067520)
You can filter them out computationally without adaptive optics with enough frames captured.
Re:SpaceX tests black satellite to reduce ‘megaconstellation... by HorstG on Thursday January 16, 2020 @03:14PM (#22068397)
Modern astronomy works at the edges of whats possible, a single frame might take hours. Needing multiple frames would mean multiple days per observation. It would mean no longer seeing faint and distant objects, limiting us to younger, closer and frankly far more boring objects. It would make observing variability impossible for certain timescales.

You need old distant objects for cosmology, observing the structure if the universe, big bang and stuff. You need variability for finding exoplanets, measuring distance and observing transitions such as supernovae.

Oh, and then a huge part is taking spectra, which means bouncing the light directly off a grating. Filtering transients is hard to impossible there. You need spectra for relative motion, magnetic fields, composition of matter and radiation and of course temperature.

Needing such filters would set astronomy back a few decades

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Re:SpaceX tests black satellite to reduce ‘megaconstellation... by mattkrause on Thursday January 16, 2020 @06:11PM (#22070088)
> pay for a resource they’ve been getting for free (unobstructed sky)

Wow.

Re:SpaceX tests black satellite to reduce ‘megaconstellation... by toomuchtodo on Thursday January 16, 2020 @06:38PM (#22070286)
If someone doesn’t manage or govern it with economic incentives, no one does (see: most of the “public good” rainforest slashed and burned in South America and Asia that we desperately needed managed better, through private ownership and conservation management, to avert climate change).

You’re shocked at my statement, as if StarLink is entitled. Consider the alternative argument: why should astronomy slow global comms progress? If astronomy is more valuable than the ~$30 billion/year global comms market, shouldn’t someone bear that cost?

Re:SpaceX tests black satellite to reduce ‘megaconstellation... by kalenx on Thursday January 16, 2020 @08:00PM (#22070808)
Because ultimately, arguments relying solely on economics are moot.

Technically, a human life has an economic value. And yes such value is used every day to decide health policies and insurance coverage. Would this mean that SpaceX killing N humans (where N=30B*number of years of operation planned for starlink/value of a human live) is ok? Absolutely not.

Re:SpaceX tests black satellite to reduce ‘megaconstellation... by shadowgovt on Thursday January 16, 2020 @10:05PM (#22071485)
That's exactly the calculus a company like Tesla does before taking a mass consumer product like a car to market.
Re:SpaceX tests black satellite to reduce ‘megaconstellation... by XorNot on Friday January 17, 2020 @12:02AM (#22072028)
No it doesn't. If you know something will kill people, economic arguments are not considered sufficient. This was famously decided when it was revealed Ford elected not to recall the Pinto on the basis of paying compensation was cheaper then the fleet maintenance they had to do.
Re:SpaceX tests black satellite to reduce ‘megaconstellation... by shadowgovt on Friday January 17, 2020 @09:59AM (#22075099)
Not considered sufficient to avoid penalties in a court of law. But even that example can be reframed as a failure to calculate total risk in the cost / benefit analysis (i.e. they should have factored in the risk of a lawsuit and federal fine).
Re:SpaceX tests black satellite to reduce ‘megaconstellation... by WWLink on Thursday January 16, 2020 @10:18PM (#22071547)
Hot take: Because Starlink is a shitty answer to ISPs being run by shitty people.
Re:SpaceX tests black satellite to reduce ‘megaconstellation... by HorstG on Thursday January 16, 2020 @03:36PM (#22068603)
Well then, we should also have Elon pay rent for use of space...
Re:SpaceX tests black satellite to reduce ‘megaconstellation... by toomuchtodo on Thursday January 16, 2020 @03:49PM (#22068739)
I think it’s hard to argue it belongs to you if you can’t get there. If you can’t defend it or control it, you can’t stake a claim to it.

https://en.wikipedia.org/wiki/Extraterrestrial_real_estate

Re:SpaceX tests black satellite to reduce ‘megaconstellation... by shadowgovt on Thursday January 16, 2020 @05:22PM (#22069648)
This is actually one of the more interesting questions in space exploration in general. It has been ever since someone tried charging NASA for parking on the section of the moon they claim ownership of.
Re:SpaceX tests black satellite to reduce ‘megaconstellation... by HorstG on Thursday January 16, 2020 @04:14PM (#22069027)
Defense would actually be quite easy. Just undesirable. There are working antisat weapons in the major powers' arsenals. However, they would produce nasty debris clouds.

And then there is also the vulnerability of the lauch site and control center...

Re:SpaceX tests black satellite to reduce ‘megaconstellation... by gpderetta on Thursday January 16, 2020 @04:53PM (#22069399)
And it is probably significantly cheaper to take down a sat than putting it up. So it would be a losing battle.
Re:SpaceX tests black satellite to reduce ‘megaconstellation... by shadowgovt on Thursday January 16, 2020 @05:20PM (#22069640)
Not in general. A kinetic striker would require as much energy to reach the satellite as the satellite used to get there. Something fancier, like a targeted laser, to my knowledge doesn't exist with anything like the wattage needed to punch through atmo and still have effective kill on anything that far out (assuming you could solve the targeting problem to resolve the beam that tightly in the first place).
Re:SpaceX tests black satellite to reduce ‘megaconstellation... by gpderetta on Thursday January 16, 2020 @05:29PM (#22069715)
The satellite is in orbit. It requires significantly more energy to put something in orbit than merely reachin that altitude. Satellite killers are relatively small rockets that can use a small supersonic fighter jet as first stage, while it requires a much bigger rocket to put a satellite in space (it would depend on the orbit of course).

It is true that spacex can put a significant amount of satllites in orbit witha single launch though, so it probably evens it out.

Re:SpaceX tests black satellite to reduce ‘megaconstellation... by shadowgovt on Thursday January 16, 2020 @05:24PM (#22069672)
That makes the relationship sound adversarial, when really there's mutual benefit to SpaceX and the international astronomy community. Astronomy can use cheap lifting capabilities.
Re:SpaceX tests black satellite to reduce ‘megaconstellation... by SiempreViernes on Thursday January 16, 2020 @03:36PM (#22068610)
And why does SpaceX get the privilege to rule the sky and the radio waves simply because they could stream Seinfeld somewhat cheaply?
Re:SpaceX tests black satellite to reduce ‘megaconstellation... by shadowgovt on Thursday January 16, 2020 @05:22PM (#22069651)
It's a complicated question, but there are echoes of it in "Why does the US get the privilege of having their flag on the moon, just because they could get it there and nobody can take it back down?" or "Why do people have any right to the land they occupy, merely because they got there before other people did?"

First-mover advantage is real.

Re:SpaceX tests black satellite to reduce ‘megaconstellation... by toomuchtodo on Thursday January 16, 2020 @05:24PM (#22069678)
It’s not complicated. The answers to your questions are, “Because they can.” Possession, control, and force carry much more weight than some would like. It just makes those without power, authority, or any other stakeholder equity uncomfortable.

The US is not a super power because it asked politely and a committee granted it permission. Similarly, SpaceX will move forward because anyone with the authority to challenge them allows them to proceed.

Re:SpaceX tests black satellite to reduce ‘megaconstellation... by shaklee3 on Friday January 17, 2020 @12:45AM (#22072210)
What is the SpaceX constellation enabling that others aren't? Hint: theirs is not for consumers.
Re:SpaceX tests black satellite to reduce ‘megaconstellation... by toomuchtodo on Friday January 17, 2020 @01:38PM (#22077677)
You're not wrong! The US DoD is already paying StarLink for proof of concept work for low latency, high bandwidth connectivity services.
Re:SpaceX tests black satellite to reduce ‘megaconstellation... by jsweojtj on Friday January 17, 2020 @12:26AM (#22072136)
Hey you're back! I asked you previously "That might work for imaging, but what's your fix for spectroscopy?" here: https://news.ycombinator.com/item?id=21577081

You replied "Optical, RF, or Xray?"

Then I said, "Let's start with optical." but then you disappeared!

So, what's your solution for long-slit optical spectroscopy?

Re:SpaceX tests black satellite to reduce ‘megaconstellation... by toomuchtodo on Friday January 17, 2020 @12:09PM (#22076589)
Hey! I'm still waiting to hear back from the astronomer I paid to do the research. I still intend to report back with their DOI from the resulting paper. I recognize when I've exceeded my domain knowledge and need an expert.

To be clear, I think we're well in the realm of academic discussion; no one is stopping any global constellation due to astronomy concerns. As I've said many times in this thread and elsewhere, I think it's a growth opportunity for the astronomy community to move towards space based observation platforms, and with the plummeting cost of lift (ie SpaceX Falcon and Starship) I don't think that's an unreasonable position to hold.

Re:SpaceX tests black satellite to reduce ‘megaconstellation... by SiempreViernes on Thursday January 16, 2020 @03:35PM (#22068586)
No, they are too bright and will saturate the detector with even very short exposures. Best you can do is just discard the affected area, at worst you have to discard several exposures because the saturation effected the readout electronics.