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How bad are satellite megaconstellations for astronomy?

leonarddavid.com

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Re: How bad are satellite megaconstellations for astronomy?

#191

Post by _dain_ »

bmitc wrote: post #106
_dain_ wrote: post #28

Earlier quoted context omitted.

> That needs some citations. The James Webb Telescope's mirror is 6.5m in diameter. It took decades and billions of dollars of overruns and a prayer to launch and work correctly. There is no hope of most hardware repairs. Because it had to get launched folded up, because the launch vehicles were so space- and mass-constrained. The unfolding mechanism was enormously complicated and added to much of the cost. Now we ca…

> future space telescopes will come off an assembly line. There will be thousands in orbit, pointed at every part of the heavens simultaneously. Like I said: citations. > Now we can send up bigger, heavier objects for much less money. This hasn't even been demonstrated.

mate I can't give you a citation for something that hasn't happened yet. it's a reasonable extrapolation of current trends. don't give me this "citation needed" whining.

Re: How bad are satellite megaconstellations for astronomy?

#192

Post by schiffern »

nimish wrote: post #172
schiffern wrote: post #164

Earlier quoted context omitted.

Budgets are fixed, so again this also boils down to "just do 5% less science." Believe it or not, actually using 100% capacity on the big expensive telescope you paid for isn't some brilliant unheard-of suggestion like people seem to think. This Dunning-Kruger idea always seems to crop up whenever this particular topic is in the news. There simply isn't any "slop in the system" that lets you get that 5% (and climbing…

Doing 5% less science is an acceptable cost for full commercial space exploitation. I'd rather have internet service in 100% of the US than an extra few graduate theses. And who knows, necessity is the mother of invention so one of those grad students could invent a way around it.

  >Doing 5% less science is an acceptable cost
That's certainly one choice we can make as a society.

However my point is we shouldn't delude ourselves that there's some "easy" fix, therefore the cost should actually by counted as zero. This defense mechanism is misguided and uninformed, yet it's shockingly common to have it (or some variation) crop up when discussing this particular topic.

Personally, I blame the current tribalize-all-the-things trend. You're either on Team Starlink or Team Astronomy. Only two options. Pick a side, we're at war!!!

  > And who knows,... one of those grad students could invent a way around it.
See? Shockingly common. :D

Even when we don't even have an idea, nevertheless we feel oddly compelled to suggest that maybe there's an easy ("grad student") solution that makes the scientific cost simply go away.

If we're willing to pay the cost in lost scientific data, then let's do it and say so. We shouldn't live in (oh so tempting!) denial about the downsides. That's all I'm saying.

Re: How bad are satellite megaconstellations for astronomy?

#193

Post by schiffern »

labcomputer wrote: post #180
schiffern wrote: post #164

Earlier quoted context omitted.

Budgets are fixed, so again this also boils down to "just do 5% less science." Believe it or not, actually using 100% capacity on the big expensive telescope you paid for isn't some brilliant unheard-of suggestion like people seem to think. This Dunning-Kruger idea always seems to crop up whenever this particular topic is in the news. There simply isn't any "slop in the system" that lets you get that 5% (and climbing…

Yes, but that's a system problem, not a user problem. The comment I replied to posited that a specific user would collect 5% less data. If you add ~5% to your grant proposal, you get the same amount of data. As for the system problem, that is solved by building 5% more observing capacity. Or, more realistically, starting new telescope projects slightly earlier. This really isn't as complicated as you're trying make i…

  >As for the system problem, that is solved by building 5% more observing capacity.
If this is to somehow come from existing funding sources, I'll need a moment to pick myself up off the floor laughing. ;D Obviously those sources are already at their budget appetite.

Or maybe this an Efficient Market / Pigouvian suggestion, where megaconstellaton operators pay (and pass on to their customers) into an Astronomical Reparation Fund worth ~5% of current global astronomy funding, to be distributed to astronomical grants and construction of new observatories? Because sure, that seems fair.

If you truly believe (as do I) that we value internet access more than the loss of scientific data, then you'll agree the internet users can easily reimburse scientists for the damage and still come out ahead. "You broke it, you buy it."

  > If you add ~5% to your grant proposal
..then I'll add 10% to mine!

It's a race to the bottom. Eventually folks get sick of it, so they enact rules and enforcement mechanisms to prevent padding. In the end all we accomplish is transforming an efficient & high-trust system into an overhead-laden, low-trust system.

Re: How bad are satellite megaconstellations for astronomy?

#194

Post by oh_my_goodness »

bmitc wrote: post #108
FredPret wrote: post #51

Earlier quoted context omitted.

If you paid attention, "this time" and also the "other hundred million times" are true, not false. We're massively more connected than ever before. Homeless people in the third world have phones now. They should be able to get on the internet too.

> We're massively more connected than ever before. In a certain electronic sense, yes, but emotionally and socially, we are not more connected than ever before. So like I said, this utopian promise of the Internet connecting and liberating and educating us has not happened. In fact, it's the opposite that has happened.

Yeah, this. And people ignoring this point or actively downvoting it ... that's not just puzzling it's symptomatic.

The capitalism I'm fine with, though we need the New Deal version to come back. But universal isolation and depression, or feeling like we live in a factory farm, no.

Re: How bad are satellite megaconstellations for astronomy?

#195

Post by Asraelite »

rickydroll wrote: post #90
feoren wrote: post #49

Earlier quoted context omitted.

Why would you assemble it at L2 instead of assembling it in LEO and then sending it out on its own?

It is not impossible. But you would have to design the telescope to be a rocketship complete with motors, fuel tanks, and all that other fun stuff. That would significantly increase the telescope's complexity to withstand the force and vibration of a rocket engine. Theoretically, one could use ion drives, but the engineering challenges of creating ion drives capable of moving a few hundred tons of telescope are signi…

> the engineering challenges of creating ion drives capable of moving a few hundred tons of telescope are significant.

Why? Just take existing ion engine designs but use a lot of them.

Re: How bad are satellite megaconstellations for astronomy?

#196

Post by nullc »

malfist wrote: post #162
nullc wrote: post #102

Earlier quoted context omitted.

You're not imaging with cryogenic CCDs --- satellite trail can blow out whole rows.

No, I'm not, I'm using cooled CMOS sensors. CCD is ancient tech these days.

> CCD is ancient tech these days.

Their performance at cryogenic temperatures is quite good which is one reason why currently in design/construction scientific instruments are still using them.

And in those instruments serious overload from shiny satellites is not just a little streak that can be easily excluded. https://www.aanda.org/articles/aa/full_html/2020/04/aa37501-...

Re: How bad are satellite megaconstellations for astronomy?

#197

Post by sitkack »

fecal_henge wrote: post #156
sitkack wrote: post #137

Earlier quoted context omitted.

You ignore the entirety of the LSST which will take more image data in its first year than all of humanity. It is wide field, and these constellations cannot just be stacked out. You think you are more informed than you are.

Why is stacking not possible in this case?

The objects are so bright and so numerous that they corrupt an entire imagers data for the entire exposure. In a CCD rows and columns can become saturated and hot pixels can spill over into neighboring pixels (blooming). When the imagers for the LSST were being designed, it was not anticipated that they would have to deal with tens of thousands of hot fast moving objects.

https://www.lsst.org/content/lsst-statement-regarding-increa...

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