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SpaceX working on fix for Starlink satellites so they don’t disrupt astronomy

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Re: SpaceX working on fix for Starlink satellites so they don’t disrupt astronomy

#111

Post by jacquesm »

ceejayoz wrote: post #107
ForHackernews wrote: post #99

Earlier quoted context omitted.

Musk did not found Tesla, but would like you to believe that he did: https://www.quora.com/Did-Elon-Musk-found-Tesla-1 Maybe 'charlatan' is unfair, but he's certainly more of a sales-and-hype man than a real engineering type. I don't understand why so many technical people are snowed by his razzle dazzle.

While true, the company was founded in July 2003 and Musk joined in February 2004. The first Roadster prototypes were revealed in 2006. Acting like he hitched his flag to an already successful company is disingenuous.

And then there was paypal.

Re: SpaceX working on fix for Starlink satellites so they don’t disrupt astronomy

#112

Post by nordsieck »

SamReidHughes wrote: post #100
ceejayoz wrote: post #88

Earlier quoted context omitted.

It makes a difference there, sure, but SpaceX lowered orbits from 1,150 to 550km. Half the latency, but only by about as much as traffic between LA to SF incurs.

I was a bit wrong in my initial estimate. More satellites can't improve latency by much once they get dense enough, and it looks like Starlink has enough such that the altitude would be on the same scale as distance. Still doesn't matter for the typical home user. Like, I get 21 ms ping to servers in my local city.

> Still doesn't matter for the typical home user.

One very important market they're going after is global arbitrageurs.

Re: SpaceX working on fix for Starlink satellites so they don’t disrupt astronomy

#113

Post by cbanek »

dnautics wrote: post #93
buboard wrote: post #87

Earlier quoted context omitted.

since starlinks may change positions autonomously it's impossible to predict their positions. and they are so damn many

You don't need a position prediction to remove an anomaly.

Actually, you kind of do, because how do you know it's an anomaly and not something you want to observe? Especially if it's just occluding things in its path, and you can't see it. It's really helpful to know where everything is.

Re: SpaceX working on fix for Starlink satellites so they don’t disrupt astronomy

#114

Post by shaklee3 »

SamReidHughes wrote: post #81
new_realist wrote: post #76

Earlier quoted context omitted.

I think they lowered the orbit because Starlink latency was/is not competitive.

Lowering orbit doesn't substantially reduce latency, building more satellites does.

Building more satellites doesn't reduce latency. Are you referring to the ISL?

Re: SpaceX working on fix for Starlink satellites so they don’t disrupt astronomy

#115

Post by jayd16 »

new_realist wrote: post #76
sunstone wrote: post #60

Earlier quoted context omitted.

It's very unlikely that SpaceX, who has to be concerned about space debris every time they launch, didn't think about the collision risk while they were designing their satellite system. In fact they petitioned the FCC(?) to lower the constellation's altitude for the very reason that, in the case of a malfunction, the satellite's would orbit would degrade more quickly. A carefully tracked constellation of satellites…

I think they lowered the orbit because Starlink latency was/is not competitive.

I was under the impression that Starlink latency is actually very competitive with terrestrial fiber. Why do you say it wasn't or isn't? Everything I find suggest Starlink will have low latency.

Re: SpaceX working on fix for Starlink satellites so they don’t disrupt astronomy

#116

Post by rtkwe »

kerng wrote: post #98

Isn't it obvious that this will happen? It's like taking a picture of nature and having airplane evidence in it, or take a picture of a city or even countryside and there are cars in it. I'm sure the same was said about cars and planes. It will be weird and things will drastically change - but so have things the last 2000+ years.

You can easily get yourself between cars and whatever natural thing you're trying to observe on the rare cases that what you're trying to study is anywhere near cars. The only way to do the same for Starlink is to launch multi-million dollar+ space telescope.

Re: SpaceX working on fix for Starlink satellites so they don’t disrupt astronomy

#117

Post by shaklee3 »

jesseb wrote: post #41
sprash wrote: post #36

Earlier quoted context omitted.

> I do not think it is possible to find any other real solution The solution is not to fill up our precious LEO with space trash. If you want faster Internet lay some fiber. It's probably even less expensive to lay some fiber across the whole jungle than Musks megalomaniac fantasies. As hobby radio astronomer this whole story fills me with rage.

Not every country has the resources or desire to lay nation-wide fiber. Satellite internet could beneift millions of people who don't have access to reliable high-speed connections.

Satellite internet has existed for decades. Why is spacex the only way to provide high speed internet?

Re: SpaceX working on fix for Starlink satellites so they don’t disrupt astronomy

#118

Post by OnlineGladiator »

jacquesm wrote: post #111
ceejayoz wrote: post #107

Earlier quoted context omitted.

While true, the company was founded in July 2003 and Musk joined in February 2004. The first Roadster prototypes were revealed in 2006. Acting like he hitched his flag to an already successful company is disingenuous.

And then there was paypal.

It's not clear to me how active Elon was with PayPal, I really think it was much more Peter Thiel that made it successful (although I am not claiming expertise). Elon founded x.com which merged with what become PayPal, but as PayPal started to become successful it was Peter Thiel at the helm. That doesn't mean Elon wasn't instrumental to its success, only that I cannot find much evidence that he was instrumental to its success.

https://en.wikipedia.org/wiki/PayPal#Early_history

> In October of that year, Musk made the decision that X.com would terminate its other Internet banking operations and focus on the PayPal money service.[25] In the same month, Elon Musk was replaced by Peter Thiel as CEO of X.com. The X.com company was then renamed PayPal in 2001,[26] and expanded rapidly throughout the year until company executives decided to take PayPal public in 2002.

Re: SpaceX working on fix for Starlink satellites so they don’t disrupt astronomy

#119

Post by doubleunplussed »

heavenlyblue wrote: post #94
krastanov wrote: post #70

Earlier quoted context omitted.

Software can make a picture look pretty, but it has very limited use when you are fighting against the limits of information theory. You want an actual new measurement, not a guess of what a reasonable measurement would look like based on past measurements.

But that measurement is literally a dot that you know would not be there at time T-1, then should be there at time T and then shouldn't be there at time T+1. Astronomers are lazy.

It's not a dot, in a long exposure photograph, it's a line. You don't delete it spatially, you'll want to subtract off the extra photon counts along that line so you can retain whatever was in that part of the image. Now, I think that's possible - find lines one diffraction-spot wide, fit to its brightness and subtract it off. They should be damned near straight lines of constant brightness given how fast satellites move, and the transverse profile should be exactly given by your telescope's point-spread-function, so you should be able to locate them and model them for subtraction very well. I think it can be done.

Photon shot noise is sqrt(N) though, so even after the subtraction you're left with more noise along that line than elsewhere. So that's not ideal. But increased noise is less of a concern that "totally ruined data".

Another caveat is that the lines have to not be so bright as to saturate your CCD, otherwise you truly have lost data that subtraction won't help with.

Edit: it turns out astronomers take many shorter exposures [1] and simply reject the pixels that are too far away from the mean in any given exposure when combining them. This seems mostly better than what I was proposing, though it does mean increased readout noise since you read out multiple times and so for very sensitive measurements I would still expect astronomers might want to do true single long exposures.

[1] https://www.skyandtelescope.com/astronomy-blogs/imaging-foun...

Re: SpaceX working on fix for Starlink satellites so they don’t disrupt astronomy

#120

Post by escape_goat »

ForHackernews wrote: post #99
allovernow wrote: post #84

Earlier quoted context omitted.

>charlatan like Musk I'm not a fanboy by any means but the guy built two companies and launched a car from his factory into space from a rocket his other business built. He's personally spearheading the early stages of commercial space exploration. I don't know that I'd describe him as a charlatan.

Musk did not found Tesla, but would like you to believe that he did: https://www.quora.com/Did-Elon-Musk-found-Tesla-1 Maybe 'charlatan' is unfair, but he's certainly more of a sales-and-hype man than a real engineering type. I don't understand why so many technical people are snowed by his razzle dazzle.

What I have observed over the years is that Musk routinely burrows into engineering considerations, for better or for worse, most especially at SpaceX but also with regards to manufacturing, specifically, at Tesla. He is an engineering enthusiast with a well documented skillset.

Regardless of how we characterize Musk, however, reducing the issue at hand to a pro/anti Musk ad hominem argument is a distraction and a waste of time. It is suddenly relatively cheap to put a huge number of small satellites in low earth orbit. This creates a conflict with astronomical interests. What remains is a policy debate worth having.

SpaceX's statement may be ignorant, erroneous, or even deceitful. I have no doubt that the astronomy community identified the problem immediately and has been trying to bring it to public attention. However, as with light pollution at both optical and radio frequencies, they are relatively powerless compared to the interests with which they are in conflict. If the FCC is the arbiter of how many satellites a company can launch into LEO, they have already lost. This was a regulatory and legislative battle that they needed to be fighting, and probably were fighting, and basically had very little chance of winning unless they were somehow able to mobilize public support for earth-based astronomy against the telecommunications industry.

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